Abstracts
31st Annual AASP Meeting, October 27-31, 1998 Ensenada, Baja, California, Mexico
ON THE POLLEN MORPHOLOGY OF SICYDIUM DAVILIAE LIRA (CUCURBITACEAE)
José Luis Alvarado1, Mónica L. Ayala
Nieto2 and Rafael Lira3
1
2 Instituto Mexicano del Petróleo. Eje Central Lázaro Cárdenas # 152, Col. San Bartolo Atepehuacan. Apartado Postal 14-805, México, D.F. 07899.
3 Laboratorio de Recursos Naturales, Unidad de Biotecnología y Prototipos, ENEP-IZTACALA, UNAM. Av. de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Edo. de México. 54090.
The 7 species of
Sicydium are distributed in the Neotropics. They have been traditionally
distinguished mainly on the basis of stamen structure and the presence or absence and distribution of vestiture. In
this genus, pollen grains are of small size (20-35 x 17-27 micrometers), 3-colporate, and present prolate
to subprolate shape and striate exine.
Sicydium daviliae Lira is an herbaceous vine collected in Chiapas, Mexico, growing in disturbed
tropical rainforest. As a result of of a light and scanning electron microscope palynological study of the
mexican cucurbitaceae, S. daviliae was the only species within the genus that showed unusual pollen
morphology: 2- and 4-colporate as well as sincolpate pollen grains. These pollen characteristics are interesting and
open new investigation lines, related to pollination ecology and molecular analysis, aimed to explain
these morphological abnormalities.
POLLEN MORPHOLOGY OF MEXICAN CUCURBITACEAE AND THEIR IMPORTANCE IN TAXONOMIC AND ARCHAEOBOTANICAL STUDIES
José Luis Alvarado1, Rafael
Lira2 and Mónica L.
Ayala-Nieto3
1
2 Laboratorio de Recursos Naturales, Unidad de Biotecnología y Prototipos, ENEP-IZTACALA, UNAM. Av. de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Edo. de México. 54090.
3 Instituto Mexicano del Petróleo. Eje Central Lázaro Cárdenas # 152, Col. San Bartolo Atepehuacan. Apartado postal 14-805, México, D.F. 07899.
Within the Cucurbitaceae family, palynology has showed to be a useful tool in delimitation of many
of their components. This work summarizes what is known about pollen morphology of the
Cucurbitaceae occurring in Mexico. The genera included are:
Apodanthera, Cayaponia,
Citrullus, Cucumis,
Cucurbita, Doyerea,
Ibervillea, Lagenaria, Luffa,
Melothria, Microsechium,
Momordica, Parasicyos,
Rytidostilis, Sicana, Sicydium
and Sechium.
Our interpretations are based on light and scanning electron microscope analyses. Pollen
characteristics are variable in some of the genera analyzed, and taxonomic implications are discussed. Some
morphological differences were observed between pollen of wild and cultivated plants within the genera
Apodanthera, Sechium and
Cucurbita. This information should be very useful in the interpretation of ancient
cultural activities, based on the results of palynological analyses of coprolites and sediments from
archaeological sites.
LATE APTIAN-EARLY ALBIAN PALYNOMORPHS OF THE CEARA BASIN - NE BRAZIL
Luzia Antonioli1, Maria Antonieta Rodriues
C.1 and Rodolfo Dino2
1
2 Petrobras, Cenpes-Divex-Sebipe, Cid. Univ. Ilha do Fundão, 21949-900 - Rio de Janeiro - Brazil. UERJ - Univ. do Estado do Rio de Janeiro - 20550-013 - Rio de Janeiro - Brazil.
This study is a palynological analysis carried out from Late Aptian to early Albian strata of the
Ceará Basin constituted by the Mundaú, Paracuru and basal Ubarana Formations. They consist chiefly
of sandstones, shales and carbonates deposited during the rift and transitional (evaporitic) phases of
the tectonic-sedimentary evolution of the Brazilian continental margin.
The palynoflora consists of one hundred and fifty four species, of which one is member of the
algal group; four are dinoflagellate cysts; four are fungal spores; forty five are spores of bryophytes
and pteridophytes; seventy are gymnosperm pollen grains; twenty eight are angiosperm pollen grains;
and two are palynomorphs of uncertain botanical affinities. One new combination has been proposed.
Three formal palynostratigraphic zones of the Cretaceous Brazilian palynological framework
were recognized. The age of each zone was determined on the basis of vertical stratigraphic ranges of
guide species, which was further corroborated by occurrence of dinoflagellate cysts and angiosperm
pollen grains: Sergipea variverrucata Zone, which encompasses the Mundaú and Paracuru formations of
Late Aptian age.; Caytonipollenites? sp. 1 Zone, encompassing the uppermost deposits of the Paracuru Formation of earliest Albian age;
Elateropollenites jardinei Zone, including the lowest
deposits of the Ubarana Formation of early to middle Albian age. These palynostratigraphic units
are present also in the biozonation scheme propose for several Cretaceous Brazilian and South
American basins.
Evidence from the palynological assemblage and lithology suggests a fluvial deltaic
lacustrine paleoenvironment at the base of the section, gradually changing into a brackish marine condition at
the middle portion and showing a continually increasing in the marine influence upwards.
The climate is inferred to have been warm, arid to semi-arid supported by the dominance of
xerophytic elements in the assemblage. The general increase in dinoflagellates cysts in the upper part of the
section suggests a relatively continuous lightening in wetter conditions by the marine influence.
Comparisons with palynological assemblages from others continents support the concept of
W.A.S.A. palynofloristic belt.
NEW RECORD OF AGLAOREIDIA (ERDTMAN, 1960) Fowler, 1971 IN MEXICO
Mónica L. Ayala-Nieto
Instituto Mexicano del Petróleo. Eje Central Lázaro Cárdenas No. 152. Col. San Bartolo Atepehuacan. C.P. 07899. Apdo. Postal 14-805, México
Aglaoreidia is a fossil monocotyledon genus of unknown affinity and originally described from the
Upper Eocene of Southern England. Later it was reported from other Eocene-Oligocene deposits of
Northwestern Europe. This genus probably represents an extinct member of the Restioniaceae family, with
Laurassic distribution throughout the Tertiary. The morphological characteristics which define this genus are:
monoporate pollen grains with bilateral symmetry, and some faces usually flattened. It's exine is reticulate with areas
clearly demarcated in a distinctive pattern on the surface of the grain.
In Mexico, this genus was first reported from the state of Puebla in central Mexico by
Martínez-Hernández (1994), who found the species
A. cyclops in Eocene strata. Up to now this has been the
only known report of the genus in Mexico.
Recently, we found the species
A. pristina in upper Eocene strata from the Burgos Basin, in
northeastern Mexico. According to Fowler (1971), this species probably represents an aquatic plant which
inhabited brackish areas where there was little competition from other plants. This species has only been
reported from upper Eocene strata, thus resulting in its use as an excellent age indicator.
Nicholas Bader Salt Core DV93-1, from Badwater Basin in California's Death Valley, contains a 185.5 meter section
of mud and evaporite deposits which records deposition over the past 100 ka. An analysis of
fossil palynomorph assemblages from the lower section of the core indicates a gradual vegetation
change between depths of 134 and 118 meters. Increase in
Juniperus pollen and decrease of
Pinus pollen in this section indicates gradual warming between ca. 133 and 123 ka. A more dramatic vegetation change
is apparent between depths of 117.2 and 117.4 meters. A simultaneous drop in
Juniperus and increase in Pinus in this zone, as well as the sudden appearance of iron sulfides and increases in Poaceae and
Sarcobatus pollen in the sample, probably correspond to the beginning of MIS (Marine Oxygen Isotope Stage) 5.
The estimated age of this section is ca. 123 ka. This age for Termination II agrees with the interpretation
of Owens Lake core OL-92 by Litwin et al. (1997).
REFERENCE
LITWIN, R.J., ADAM, D.P., FREDERIKSEN, N.O., and WOOLFENDEN, W.B.,
1997. An 800,000-year pollen record from Owens Lake, California: Preliminary analyses.
In: Smith, G.I., and Bischoff, J.L., (eds.), An 800,000-Year Paleoclimatic Record from Core OL-92, Owens Lake,
Southeast California. Geological Society of America Special Paper 317: 127-142.
UPPER JURASSIC AND LOWER CRETACEOUS DINOFLAGELLATES, SPORES AND POLLEN FROM THE TEXAS, ARKANSAS AND LOUISIANA GULF COAST, UNITED STATES
D.G. Benson, Jr.1, M.A.
Miller2, R.A. Saloman2, R. Guillory
3 and G.D. Wood2 2 Amoco Exploration and Production Technology Group, P.O. Box 3092, Houston, Texas
77253, U.S.A.
3 7287 Kingston Cove, Willis,Texas 77378, U.S.A.
The Jurassic-Cretaceous boundary interval (Kimmeridgian through Valanginian) from the
subsurface of Arkansas, Louisiana and Texas contains diverse and well-preserved palynomorph assemblages.
The stratigraphic interval examined includes the Cotton Valley Group through Sligo Formation and
their equivalents. The biostratigraphic interpretations are based on tops, or Last Appearance Datums
(LAD), in cuttings and core samples. Dinoflagellates are represented by
Achomosphaera, Amphorula,
Atopodinium, Batioladinium,
Canningia, Cantulodinium,
Cleistosphaeridium, Cribroperidinium,
Ctenidodinium, Cyclonephelium,
Dichadogonyaulax, Dingodinium,
Dissiliodinium, Druggidium,
Ellipsoidictyum, Endoscrinium,
Fromea, Gardodinium,
Gonyaulacysta, Hystrichodinium,
Kleithriasphaeridium, Microdinium,
Muderongia, Occisucysta,
Pareodinia, Phoberocysta,
Prolixosphaeridium, Pseudoceratium,
Scriniodinium, Subtilisphaera and
Systematophora. Spores and pollen include
Callialasporites, Ceratosporites,
Cicatricosisporites, Classopollis,
Concavissimisporites,
Deltoidospora, Ephedripites,
Gleicheniidites, Klukisporites,
Kraeuselisporites, Taurocusporites,
Trilobosporites and Verrucosisporites.
PALYNOMORPHS AS PALAEOCLIMATIC/ PALAEOHYDROLOGICAL PROXIES: PRELIMINARY RESULTS FROM THE CONGO FAN DURING UPPER MIOCENE
E. Braccini1, M.J.
Pérez-Vila2 and G. Bulher1
1 Preliminary selected results of Palynological studies performed on cores and side wall cores from
an exploration well of Congo are presented. Discussion about the results and the methodology is open.
Cores and side wall cores have been dated upper Miocene (NN11) by Nannofosils. Hydrology
along Congo shelves is predominantly characterized by strong fluvial dynamic (palaeo Congo river). Pollen
and Spores are easily transported, incorporated in the sediment and relatively abundant in the
samples. Dinoflagellate cysts are scarcely represented except in a few levels while they are dominant. The
study focuses on the climato/eustatic interpretation of the palynological assemblages / palynofacies and
the link with palaeo-oceanographical events for the upper Miocene.
PALAEOCEANOGRAPHY OF LOWER TOARCIAN (JURRASIC) MARINE ANOXIC EVENTS IN THE BOREAL AND TETHYAN REALMS
Raffaella Bucefalo Palliani1, Emanuela
Mattioli1, and James B Riding2
1 2 British Geological Survey, Keyworth, Nottingham NG125GG, United Kingdom
The early Toarcian was characterised by several major oceanic anoxic events which led to
organic-rich sedimentation over wide areas of the Northern Hemisphere. These dysaerobic/anoxic phases affected
a wide range of oceanic palaeoenvironments in the epicontinental seas of northern Europe and in the
pelagic Tethyan Realm. An integrated biostratigraphic and geochemical investigation of the Brown
Moor Borehole, North Yorkshire, England (i.e. Boreal Realm) was undertaken in order to elucidate the
origins and the spatial/temporal relationships of these carbonaceous sediments. The resulting data have
been compared with published information from central Italy in the Tethyan Realm. Based on the
resulting high-resolution, integrated calcareous nannofossil and dinoflagellate cyst biostratigraphy, a
temporal overlap between the English Harpoceras
falciferum ammonite zone and the Tethyan Dactylioceras
tenuicostatum ammonite zone of Italy has been elucidated. The Lower Toarcian Total Organic Carbon (TOC)
maximum and the coeval positive d13C isotopic excursion are synchronous in the two regions. The
phytoplanktonic and geochemical data suggest similar palaeoenvironmental evolution, although significant
differences were recorded due to phytoplankton provincialism and the disparate geological settings and palaeolatitudes.
PLIENSBACHIAN AND TOARCIAN (LOWER JURASSIC) DINOFLAGELLATE CYST BIOEVENTS IN THE BOREAL AND TETHYAN REALMS
Raffaella Bucefalo Palliani1 and James B
Riding2
1 2 British Geological Survey, Keyworth, Nottingham NG125GG, United Kingdom
A comparison of the most significant Boreal and Tethyan dinoflagellate cyst range tops and range
bases during the Pliensbachian and Toarcian interval reveals significant provincialism between the
two paleogeographic realms. Three dinoflagellate cyst bioevents are precisely coeval throughout
the Pliensbachian and Toarcian of the Boreal and Tethyan realms according to the standard
macrofossil zonations. Apparent discrepancies in the stratigraphic ranges of several Pliensbachian-Toarcian
dinoflagellate cyst taxa are interpreted as the effects of migrational events controlled by
palaeoceanographic events (e.g. eustatic changes, anoxic phases). Biostratigraphically significant endemic species are
present in the both realms. This scenario precludes the erection of a biostratigraphic scheme for the
Pliensbachian-Toarcian of both northern and southern Europe. The highest biostratigraphic resolution in the
more northerly Boreal Realm has been recorded in the late Pliensbachian
(Amaltheus margaritatus and Pleuroceras
spinatum ammonite zones). By contrast, in the more southerly Tethyan Realm, dinoflagellate cysts
provide high biostratigraphic resolution during the early Toarcian
(Dactylioceras tenuicostatum ammonite
zone). The evolutionary pattern of Pliensbachian-Toarcian dinoflagellate cysts appears to have been
largely controlled by eustatic fluctuations. Speciation events are related to major marine transgressions
and extinctions appear to be related to regressive phases. The difference in the spatial/temporal
distribution of Pliensbachian-Toarcian dinoflagellate cyst bioevents throughout the Boreal and Tethyan realms
is related to a combination of eustatic events with other global palaeoceanographic events.
PALYNOSTRATIGRAPHY OF THE ALBIAN SANTA
LUCÍA BASIN, FROM URUGUAY*, **
Carla Cristina Campos1, Maria Judite
Garcia1, Rodolfo Dino2, 3, G.
Veroslavsky4, A.R. Saad 1, 5,
V.J. Fulfaro1, 5
1 2CENPES, PETROBRAS
3Universidade Estadual do Rio de Janeiro, UERJ, Brazil
4Facultad de Ciencias, Universidad de la Republica, Uruguay
5IGCE-UNESP- Rio Claro, Brazil
The Castellanos and Migues Formations of fluvio-lacustrine origin represent the Cretaceous section
of the Santa Lucía Basin. Presently a structural high named Santa Rosa divides this Basin in two sectors,
the North and South sub-basins.
**Contribution of the Project IGCP-381 "South Atlantic Mesozoic Correlations" - UNESCO.
INVESTIGATION OF THE LYCOPSID STROBILUS
FROM THE LATE DEVONIAN CLEVELAND SHALE OF OHIO,U.S.A.
Shya Chitaley
The Cleveland Museum of Natural History, 1 Wade Oval, University Circle, Cleveland, Ohio,
44106-1767.
The grayish black silty shale of Late Devonian age got freshly exposed when the Interstate Rout I-71
was being constructed through Cleveland, Ohio, during the years 1965-1968. Many lycopsid axes and
strobilii were salvaged for the Museum by the digging crew. Most of them are compressions.
A HOLOCENE FOSSIL POLLEN RECORD FROM
LOS PEÑASQUITOS LAGOON, SAN DIEGO, CALIFORNIA
Kenneth L. Cole1 and Eugene
Wahl2
1 2 Quaternary Studies Program, University of Minnesota, St. Paul, MN 55108, U.S.A.
Holocene estuarine sediments from Los Peñasquitos Lagoon were studied to reproduce the
past environments of the Torrey Pines State Reserve, California. Fossil pollen, spores, charcoal,
chemical stratigraphy, particle size analysis, and magnetic susceptibility of the sediments were analyzed in a
3600 year old core and a sewer trench dating back to 4000 yr B.P.
THE JURASSIC TERRESTRIAL PALYNOFLORA OF MICHIGAN
Aureal T. Cross
Department of Geological Sciences, Michigan State University, East Lansing MI 48824, U.S.A.
Palynomorphs of mid-Mesozoic age in the Michigan "Red Beds" were reported by Cross and
Shaffer in 1964. More recent studies in Canada and western Europe make more precise age determination
and correlation possible. The presence of
Classopollis in profusion, and a diverse mix of podocarps,
tsugoid, laricoid, araucarian and other gymnosperms, cycadeoids, ginkgoaleans and absence of angiosperms
and paucity of Anemia-type ferns indicate pre-Cretaceous age. No Pennsylvanian pollen or spores are
found except occasional recycled specimens.
STATISTICAL MODELLING OF ECOLOGICAL
SIGNALS FROM DINOFLAGELLATE CYSTS: A NEW METHOD FOR DEVELOPING MORE ROBUST APPLICATIONS OF PALYNOLOGY TO SEQUENCE STRATIGRAPHY
Barrie Dale1 and Amy Dale2
1 2GeoResearch Consulting, Bakli, 2100 Skarnes, Norway
For more than 30 years, we have studied the ecology of living dinoflagellate cysts in order to
develop models for interpreting changing cyst distributions downcore. A global database of over 500 samples
and roughly 250 cyst types was built up and analyzed for global, basinal and regional trends in recent
cyst distributions relating to ecology. A multivariate statistics package was developed to assess the
relative contributions of different environmental parameters to the biogeographic pattern of cysts in
bottom sediments today. Statistical modelling allowed us to identify ecological signals from the cysts relating
to the following environmental parmeters: changing latitude ( = temperature), water depth, salinity,
and varying nutrient enrichment due to both coastal and oceanic upwelling, and river input. The
most influential environmental parameter in the global database was identified as latitude and the second
as water depth. The water depth variable, which can be considered a proxy for distance from shore or
oceanic versus coastal water influences, is particularly relevant for applications of palynology to
sequence stratigraphy.
BIOSTRATIGRAPHY OF LOWER CRETACEOUS DINOFLAGELLATE ASSEMBLAGES FROM THE KUWAIT SUBSURFACE, WITH COMMENTS ON A NEW SPECIES OF MUDERONGIA
Thomas D. Davies and Nicos S. Ioannides
Exxon Exploration Company, P.O. Box 4778, Houston, Texas, U.S.A. 77210-4778, U.S.A.
The Lower Cretaceous Ratawi Shale Formation from the Kuwait subsurface contains diverse and
well-preserved dinoflagellate cyst assemblages, which allow subdivision into three stratigraphically
distinct biozones. The biostratigraphic interpretations are based on first downhole appearances and bases
from cuttings and core samples. The dinoflagellate assemblages are dominated by
Subtilisphaera, Muderongia,
Phoberocysta, Tehamadinium,
Perisseiasphaeridium, Circulodinium, Dissiliodinium
and Batioladinium. These assemblages contain certain elements frequently reported from the Australian region, as well as
others better known from the Northern Hemisphere. The abundance and diversity of the
Phoberocysta group seen here have never been reported from the Northern Hemisphere.
THE PROBLEMS WITH "CHENO-AM" CHENOPODIINEAE, OR "CHENOPODIUM-TYPE" POLLEN
Owen K. Davis
Department of Geosciences, University of Arizona, Tucson, AZ, 85721, U.S.A.
The Astraceae (= Compositae), Poaceae (= Gramineae), and Chenopodiaceae present challenges
to Quaternary palynologists. During the Neogene, these families underwent an explosive radiation
that resulted in their dominance of the vegetation of the world's temperate regions. Perhaps due to this
rapid evolution, the pollen morphology of these families shows little variation (stenopalyny). The ubiquity
and abundance of their pollen, the lack of morphological differentiation, and confusing systematics of
these taxa have produced bewildering pollen - terminologies. The three families have one "general"
morphological type that represents most genera, as well as a few unique taxa that can be readily distinguished.
For the Chenopodiaceae the "general" type is psilate, spheroidal, and periporate, and the exception is
the Genus Sarcobatus (monospecific) which can be distinguished by gross morphology. It is annulate and
few-pored. However, unlike Asteraceae and Poaceae, the "general" morphological type of the
Chenopodiaceae is indistinguishable (by gross morphology) from the pollen of the genus
Amaranthus in a different plant family (Amaranthaceae.) This cross-family similarity, combined with systematic revision of the
order Centrospermae have produced a confusing pollen terminology. In 1963, three separate terms for
this morpho-type were proposed,
"Chenopodium-type (Cushing, 1963)," "Chenopodiineae (McAndrews
in Wright et al., 1963," and "Cheno-ams (Martin, 1963)." All three terms have remained in general use in
the Quaternary literature, essentially as synonyms, but typically with neither morphological or
systematic characterization nor literature citation. Another challenge presented by the "Cheno-am" pollen
morpho-type is identification of various plant species of differing autecologies. The most ambitious attempt
to differentiate "Cheno-ams" is that of McAndrews and Swanson (1967). Subsequent publications
have modified the formula used, but they are all based on calculating the number of (evenly-spaced) pores
on the grain using the chord / diameter ratio. Although the technique is an aid to identification, the
number (> 1300) of plant species in this morpho-type precludes a definitive characterization of the pore
number of "Cheno-ams."
THE INTERPRETATION OF
CHENOPODIACEAE-AMARANTHUS POLLEN IN DIAGRAMS FROM WESTERN NORTH AMERICA
Owen K. Davis1 and John H.
McAndrews2 1 2 Dept. of Botany Royal Ontario Museum 100 Queen's Park Cres. Toronto, Ontario M5S 2C6 Canada
The invariant morphology of the Chenopodiaceae -
Amaranthus pollen type presents an
interpretive problem in costal California. There, modern pollen samples have abundant (> 60%) "Cheno-am"
pollen in halophytic estuarine environments, but generally low values (< 10%) in non-estuarine
vegetation. Unfortunately this contemporary pattern may not have existed in the past. A pollen diagram from
Tulare Lake in the southern San Joaquin Valley records > 40% "Cheno-am" pollen throughout much of the
late Holocene. At this site increased values of Chenopodiaceae -
Amaranthus correlate with greater aridity. Furthermore, in coastal settings, the disturbance flora contains several "non-halophytic" members of
the Chenopodiaceae. Pollen diagrams from San Joaquin Marsh, Orange County, California, show
dramatic fluctuations in "Cheno-am" pollen percentages. The "Cheno-am" increases may be interpreted either
as increased salt marsh or as increased salinity. Both interpretation suggest decreased rainfall, but they
have different implications for the local plant communities. San Joqauin Marsh and nearby Newport Bay
were the locus of prolonged occupation by prehistoric peoples. Identification of the Chenopodiaceae
and Amaranthus pollen could provide useful information regarding the plant resources and vegetation
types used by the Holocene inhabitants of the area. Plant macrofossil remains of both upland and
halophytic species have been recovered from archaeological sites near San Joaquin Marsh. Because the list of
potential Chenopodiaceae and Amaranthus species in coastal California is relatively small, it might be possible
to identify species, or identify ecologically-meaningful groups, such as estuarine vs upland, based on
pollen morphology. We applied McAndrews and Swanson's (1967) pore-number procedure to fossil and
modern reference pollen samples from western U.S.A. For each of seven species, common in the coastal
vegetation of southern California, we measured the chord (between the centers of the pores) distance and
diameter for 50 grains. The diameters and pore numbers of the two salt marsh taxa pickleweed
(Salicorina utahensis UA 5812) and seep-weed
(Sueda depressa ROM 35) overlap with the values for upland
Chenopodiaceae such as pigweed (Amaranthus
palmeri UA 5871) and saltbush (Atriplex
polycarpa UA 1216). Similarly, plots of "Cheno-am" pore number versus depth for three Southwestern sites show stratigraphic trends, but
with much overlap. We conclude that this techinque, though promising, does not offer an simple solution to
the "Cheno-am" problem of coastal southern California.
EOCENE PALYNOMORPHS FROM A DEEP BATHYAL ENVIRONMENT IN THE EQUATORIAL ATLANTIC (ODP HOLE 959D): PRELIMINARY BIOSTRATIGRAPHIC AND PALEOENVIRONMENTAL OBSERVATIONS
Department of Geology and Geophysics, University of Missouri-Rolla, Rolla, Missouri 65401, U.S.A.
Ocean Drilling Program Hole 959D on the Cote d'Ivoire-Ghana transform margin provides a
nearly complete Albian to Pleistocene sedimentary sequence. The Early to Middle Eocene experienced
maximum expansion of vegetation in several parts of the world, including tropical areas, due to very
equitable climate. Thirteen samples from the biosiliceous lower to upper Eocene interval were studied mainly
for their sporomorph content, although sporomorph:dinocyst ratios were observed. This pelagic
biosiliceous interval, which is characterized by high amorphous organic matter content, periods of upwelling,
and varying sedimentation rates, occurred in a deep bathyal, sub-CCD environment. The amorphous
organic matter in all the samples has been previously interpreted as indicating both marine and terrestrial
sources. Out of the 124 species of pollen and spores identified so far, none was abundantly represented in
any sample in this deep environment. This distribution pattern is most likely due to the distance from
the adjacent West African land mass from which the taxa have been transported by current systems.
The diversity of the sporomorph assemblage is a reflection of the continental vegetation, and is dominated
by angiosperms, which are represented by many tricolporates and monosulcate palm pollen.
Inaperturate pollen are quite abundant, whereas spores are very few. Important taxa include
Spinizonocolpites echinatus, Perfotricolpites
digitatus, Retibrevitricolpites
triangulatus, Proxapertites cursus, Araucariacites
australis, Spirosyncolpites bruni, Cicatricosisporites
dorogensis, and Verrucatosporites
usmensis. There are no bissacate pollen. The sporomorph assemblage is similar to those from tropical areas, such as the Caribbean,
northern South America, India, Vietnam, and Indonesia. Fossil fungal remains are abundant in many
samples, while acritarchs, scolecodonts, algal remains, and plant debris occur occasionally. Effects of reworking
at some horizons can be seen on badly preserved specimens of
Aquilapollenites sp.
APTIAN TO LOWER ALBIAN POLLEN AND SPORE ASSEMBLAGES FROM THE POTIGUAR BASIN, NE BRASIL
Petrobras/Cenpes/Divex/Sebipe, Ilha do Fundão, 21949-900 Rio de Janeiro, RJUERJ - Univ. Est. do
Rio de Janeiro - Fac. Geol. - Depto. Estrat./Paleont., Rua S. Francisco Xavier 524, 20559-900 Rio
de Janeiro, Brazil.
The palynostratigraphy of the late Early Cretaceous (Alagoas Stage) Alagamar Formation of
the Potiguar Basin has been revaluated on the basis of two hundred ninety one samples from eighteen
onshore and offshore wells. The unit is essentially non-marine and bounded by erosional surfaces. Two
hundred and twenty eight species of spores, pollen, fungi and microplankton have been identified. Two new
genera and five new species are recognized. Three species are newly combined. A hierarchical zonation
consisting of four palynostratigraphical units is proposed, and correlations with zonal schemes from other basins
are made.
DINOCYST BIOSTRATIGRAPHY AND HYDROLOGIC IMPLICATIONS IN THE SOUTH CAROLINA COASTAL PLAIN
U.S. Geological Survey, 926A National Center, Reston, VA 20192, U.S.A.
The Southeastern Coastal Plain Project at the U.S. Geological Survey conducts geologic mapping
and regional geologic studies in selected areas of the South Carolina and Georgia Coastal Plains.
Benchmark drillholes have been drilled across South Carolina, and continue to be drilled, to elucidate the
subsurface stratigraphy. Here, I report on lower Tertiary dinocysts from six of these cores, and show how these
studies will influence understanding of the hydrology of the Coastal Plain.
HOLOCENE PALEOECOLOGY OF THE UPPER RUSH CREEK DRAINAGE BASIN, EASTERN SIERRA NAVADA, CALIFORNIA, U.S.A
Eric Edlund1 and Robert Dull2
1 2 University of California at Berkeley Department of Geography.
Stratigraphic studies of Holocene sediments were carried out at two localities in the upper Rush
Creek drainage basin, California. Both sites, Lower Rush Meadow Pond (LRM) and Waugh Lake (WL),
record dynamic environmental changes throughout the Holocene. Sediment cores were analyzed for
pollen, magnetic susceptibility, x-radiography and organic content. The LRM core provides an 11,000-year
record of terrestrial vegetation change and volcanism in the eastern Sierra. The proxy data from WL reveal
a record of middle and late Holocene volcanism, paleohydrology and vegetation change.
FESHWATER DINOFLAGELLATE CYSTS FROM PEAT BAY, A CAROLINA BAY, ON THE SAVANNAH RIVER SITE, SOUTH CAROLINA, U.S.A.
Donald W. Engelhardt1 and Robert S. Van
Pelt2
1 2Bethel Savannah River Inc. Savannah River Site, Aiken, SC, U.S.A.
Freshwater dinoflagellate cysts comparable with
Peridinium limbatum (Stokes) Lemmermann have
been recovered from cores from Peat, a Carolina bay, on the Savannah River Site in Barnwell County,
South Carolina. P. limbatum and other peridiniod cysts were observed in several samples taken from two
peat cores analyzed during the study of the paleoecology of this Carolina bay. The onset of peat
accumulation has been dated as approximately 4000 years B.P. Carolina bays are surficial elliptical depressions
that occur in large numbers throughout the Atlantic Coastal Plain that are not of marine origin. Their
origin is not completely understood but the most accepted theory is that are aeolian features formed and
oriented by paleo-wind currents during the late-Pleistocene (Kaczorowski, 1977: Bliley and Burney,
1988). Palynologically the dinoflagellate cysts occur mainly during hydroperiods that are dominated by
floating aquatics, Myriophyllum, Nymphoides
and Nymphaea. Botryococcus is present along with zygospores
or aplanospores of Spirogyra, Zygnema and Mougeotia.
PALYNOMORPH TRANSLUCENCY: APPRAISED BY ELECTRONIC COLOR ANALYSIS AND VITRINITE REFLECTANCE
John F. Grayson1, Merrell A.
Miller2, Karl W. Schwab3, and Gordon D.
Wood2
1 2 Amoco Exploration and Production Technology Group, P.O. Box 3092, Houston, TX 77253 In an attempt to quantify palynomorph color alteration using translucency, John Grayson, then
of Amoco Production Research, identified a group of standards using Tertiary well samples from the US
Gulf Coast, Gulf of Suez, Canada and Peru. These standards reflected decreasing translucency with
increased maturation. Grayson attempted to utilize a single genus,
Caryapollenites, for measuring the
translucency of palynomorph exines. The translucency technique did not gain wide application. In
reexamining Grayson's standards using Integrated Color Analysis/Spectral Power Distribution, it became evident
that measurements from a variety of in situ maceral types yielded estimated reflectance values
(%eRo) similar to those made on individual specimens of
Caryapollenites. With the exception of a tighter range in
minimum and maximum values for individual specimens of
Caryapollenites, the average between the overall
kerogen suite and the individual genus remain very close. Values (minimum/average/maximum) listed in
the Table below are given in %eRo.
S-2 0.30/0.41/0.56 0.35/0.44/0.55 0.03 cuttings
S-3 0.42/0.53/0.64 0.35/0.46/0.59 0.07 cuttings
S-4 0.59/0.71/0.81 0.63/0.71/0.78 0.00 cuttings
S-5 0.72/0.80/0.88 0.80/0.85/0.90 0.05 0.60/0.72/0.83 core
JURASSIC DINOFLAGELLATE CYSTS OF SIBERIA
Vera I. Ilyina, Anna V. Sushakova, and Anna N. Trubicyna
Institute of Petroleum Geology, Siberian Branch of RAS, Ac. Koptuga pr. 3, Novosibirsk 90,
630090, Russia
Dinoflagellate cysts from Jurassic marine sections of different regions in the northern and
western Siberia have been studied. It permitted to establish that dinocysts occur unregularly in the
Jurassic sediments of Siberia. They were not found in the Hettangian, Sinemurian and most of Pliensbachian.
The first dinocysts represented by sub-boreal genus
Nannoceratopsis were recorded in the
uppermost Pliensbachian. This genus is dominant in the Lower Toarcian beds in the northern part of East Siberia.
The uppermost Pliensbachian to Upper Toarcian succession of northern Siberia includes three
dinoflagellate cyst zones. These are Nannoceratopsis
deflandrei with two subzones,
Nannocetratopsis gracilis and
Phallocysta eumekes-Susadinium
scrofoides with two subzones. The latter one is erected for the
Upper Toarcian. This first Boreal dinoflagellate cyst association with
Phallocysta eumekes, Susadinium
scrofoides, Valvaeodinium
aquilonium, Parvocysta spp. is traced through different regions of northwest Europe
and Arctic Canada. On the Toarcian/Aalenian boundary stage dinocysts disappear in the marine sections
of northern Siberia. They are extremely rare also in the Bajocian and Bathonian sediments of this region.
The latest Bathonian and earliest Callovian were a time of marked provincialism of dinoflagellate
floras in Siberia. Boreal association with Crussolia dalei
, Paragonyaulacysta retifragmata, Chytroeisphaeridia
hyalina was dominated in the earliest Callovian (ammonite zones Cadoceras falsum, C. anabarense) on the
North of Eastern Siberia. In contrast, the association of West Siberia characterized by abundance of
Fromea tornatilis, which was widespread in the Early Callovian on the Russian Platform.
PALEOGENE FUNGAL SPORES AND
FRUCTIFICATIONS FROM THE AMPHITHEATRE FORMATION, YUKON TERRITORIES, CANADA
Ramakant M. Kalgutkar
Geological Survey of Canada, Calgary, Alberta, Canada
The upper Eocene to lower Oligocene Amphitheatre Formation yields a noteworthy population
of fungal spores and microthyriaceous ascocarps. Previous palynological data indicated that the
Eocene global temperature decline at the end of the Eocene resulted in a shift from warm temperate,
angiosperm-dominated to cooler temperate, gymnosperm-dominated (mainly coniferous) forest types. This
interpretation is supported by the presence of characteristic fungal assemblages comprising abundant
and diversified fungi in the Eocene sections and declining population in samples from the Oligocene strata.
PALYNOLOGICAL ANALYSIS OF CORE DV93-1 FROM DEATH VALLEY, CALIFORNIA THROUGH MARINE OXYGEN ISOTOPE STAGE 5: PRELIMINARY RESULTS
Miriam Mack
Department of Geosciences, University of Arizona, Tucson, Arizona, U.S.A.
Core DV93-1, taken from Badwater Basin in Death Valley, California
is 184 meters in length, and contains a nearly complete sedimentological
record over the last 193 ka. Preliminary results from
the palynological analysis of the upper 37 meters show marked climatic changes. From 45 to
30 ka (37 to 16 m) herbaceous and arboreal pollen percentages fluctuate
widely. At 30 ka (16 m) iron sulfides appear and Sarcobatus has its last
occurrence in this portion of the core. The stronger signal of Quercus
and Abies pollen may suggest a transition to a cooler glacial climate in
Badwater Basin, possibly the transition between Marine Oxygen Isotope
Stages 3 and 2. A general decline of herbaceous pollen and increases
in Artemisia and arboreal types is typical from 30 to 10 ka (16 - 8 m).
Between 12 and 9 ka there is a decrease in arboreal pollen, and the last
appearance of Cupressaceae in the core, perhaps marking the end of
Marine Oxygen Isotope Stage 2. This interpretation agrees with the preliminary
results from Litwin et al. (1997), a palynological analysis pf core OL-92
from Owens Lake, California. From 10 to 2 ka (8 - 1.6 m) there is
an overall increase in herbaceous pollen percentages, especially at 4152
B.P. where Ambrosia, Chenopodiaceae-Amaranthus and other Asteraceae
pollen types dominate the spectrum. These high percentages
may represent a period of increased moisture during the mid-Holocene in Death Valley,
causing herbaceous and salt-loving species to migrate towards the basin.
High percentages of Chenopodiaceae -Amaranthus during the late Holocene
probably indicate halophytic vegetation on the basin margins. Reference
Litwin, R.J., Adam, D.P., Frederiksen, N.O., and Woolfenden, W.B., 1997. An 800,00-year pollen record from Owens Lake, California: Preliminary
analyses In An 800,000-year Paleoclimatic Record from Core OL-92, Owens
Lake, Southeast California, Smith, G.I., and Bischoff,
J.L., eds.. Geol. Soc. Am. Special Paper 317: 127-142.
QUANTITATIVE PALYNOLOGICAL DATA
INTERPRETATION, NEW CONCEPTS
Salah El-Din Ragab Mahmoud
The University of Texas at Dallas, Geosciences Dept., MS: FO21,P.O. Box 830688, Richardson,
TX 75083-0688, U.S.A.
After detailed quantitative palynological analyses of subsurface core samples, very marked
and correlatable vertical relationships were observed between the changes in abundance and diversity
of marine organic walled microplankton and terrestrial miospores. There are previously established
relationships between the above mentioned four parameters "bold-faced" but less detailed. The new
concepts will enable the palynologist to do more refining of quantitative analyses in order to give more precise
and correct interpretations as whether these changes are resulting from changes in the
palaeodepositional setting, palaeoecological or palaeoclimatological changes. The application of these concepts will help
in avoiding misinterpretations such as the wrong prediction of a marine regression while the main
reason of quantitative change is due to a palaeoclimatic change. Moreover, the observed changes were
highly correlatable between nearby boreholes. So, these concepts will help allow high resolution correlation
even in intervals which are not correlatable by other methods. Accordingly, these concepts can be used
in multidisciplinary sequence stratigraphic studies in order to predict hydrocarbon plays more accurately.
THE TERTIARY DINOFLAGELLATES AND EVOLUTION OF PALEOCEANIC ENVIRONMENTS OF THE PEARL RIVER-MOUTH, SOUTH CHINA
Shaozhi Mao and Yulin Xu
China University of Geosciences (Beijing)
The oil-bearing Pearl-River-Mouth basin developed in the northern continental shelf of South
China Sea since Eocene. Topographically, the basin is divided into three depressions and three rises.
An integrated study on the Tertiary microbiota including dinoflagellates was carried out for the purpose
of sequence stratigraphic analysis.
POLLEN ANALYSIS AND THE PACIFIC RIM
HYPOTHESIS FOR THE PEOPLING OF THE AMERICAS
Rolf W. Mathewes
Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby,
B.C., V5A 1S6, Canada
The first arrival of humans in the Americas has long been controversial. Archeological discoveries
at Monte Verde in Chile have pushed human presence back to at least 12,500 yr BP, about 1,000 years
before the Clovis hunters left their mark. The "Ice-free Corridor" route was long assumed to have been the
route of entry from Beringia, but is no longer tenable since the corridor was closed before 12,000 years
ago. Geological and palynological research along the continental shelf of Alaska and British Columbia
now supports a coastal corridor as a more likely route of entry into the New World.
FUNGAL SPORES FROM DIRA-1 WELL, S.E. COASTAL TANZANIA THEIR STRATIGRAPHICAL, PALAEOECOLOGICAL PALAEOENVIRONMENTAL AND PALAEOCLIMATIC SIGNIFICANCE
Jean-Frank Mayagilo
Tanzania Petroleum Development Corporation, Directorate of Exploration, Production and
Technical Services, P. O. Box 523, Dar es Salaam, Tanzania
A qualitative study of fungal palynomorphs encountered in the DIRA-1 well samples from South
East coastal Tanzania was undertaken. Fourteen fungal genera and species were identified and
their stratigraphical, paleoecological, palaeoclimatic and palaeoenvironmental importance were studied.
PALYNOMORPHS FROM KAROO COAL FIELDS IN
THE RUKWA BASIN, SOUTHWEST TANZANIA
Jean-Frank Mayagilo
Tanzania Petroleum Development Corporation, Directorate of Exploration, Production and
Technical Services, P. O. Box 523, Dar es Salaam, Tanzania
Permian coal-bearing strata occur in a number of intracratonic rift basins in Tanzania. This
study examines coals, shales and mudstones palynologically to determine thermal maturity palaeoecology
and palaeoenvironment. Palynomorph assemblages were characterized by the predominance of taeniate
and non-taeniate pollen and trilete spores in the Namwele-Mkomole, and Muze coal fields, whereas in
the Galula coalfield the palynomorph assemblages were poor (rare in trilete, alete and monolete
spores). Based on the age correlation's with Karoo basins in South Africa and the Collie Basin of western
Australia, an Artinskian to Kungurian (?) age is suggested for the coal measures in the Rukwa Basin.
OFFSHORE BELGIUM EOCENE
PALYNOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT
Daniel Michoux1 and Patric
Jacobs2
2 Renard Centre of Marine Geology, Geological Institute, University of Gent, Gent, Belgium.
Four shallow coreholes drilled a few km off the coast of Belgium provided a composite section
covering the Eocene succession. Five sedimentation stages were recognized during this time interval, based
on sedimentary facies analysis, grain size trends and sediment genetic interpretation. Rich and
diverse palynological assemblages were recovered from suitable lithologies. They are usually dominated
by dinocysts. The latter are calibrated against the regional dinocyst zonation of Costa & Manum
1988, modified by Heilmann-Clausen & Costa1989. They also provide reliable ties with onshore
reference outcrop sections and boreholes. Depositional Stage 1 starts with the offhsore mudstones of the Kortrijk
Fm. They contain dinocyst species indicative of the following zones: D7b (First Occurrence FO- of
Wetzeliella varielongituda), D8 (FO of Rhombodinium
politum and Wetzeliella samlandica, abundant
Membranilarnacia compressa) and lower D9 (FO of Areosphaeridium diktyoplokus and Samlandia chlamydophora).
The occurrence of Ochetodinium romanum in the upper Kortrijk Fm was also reported onshore, from
coeval sediments of the Kallo borehole. Significant percentages of reworked (mostly Jurassic)
palynomorphs were recorded in these levels. Following this deep depositional stage, a drop in relative sea level
triggered deposition of the deltaic sediments of the Tielt and Gent formations (Stage 2). The base of the Tielt Fm
is marked by a flood of Pediastrum. These sediments are assigned to Zone D9. They are characterised
by abundant Homtryblium tenuispinosum group, abundant
Charlesdowniea cf columna. W.
samlandica is still present. Phthanoperidinium
comatum group has its lowest occurrence in the Gent Fm. This species has
a middle D9 stratigraphic base. Stage 3 corresponds to barrier and lagoonal sediments of the Aalter Fm.
They yielded Wetzeliella pachyderma and W. articulata
brevicornuta, and are given and uppermost D9/basal
D10 zonal assignment. The latter 2 taxa occur onshore in the Aalter Fm of the Woendrecht borehole.
The intermediate member of the Aalter Fm (Oedelem Mb) is marked by an influx of pollen referable to
the extant back-mangrove palm genus Nypa. Stage 4 sees the return of a deltaic environment and
the deposition of the prodelta muds of the Maldegem Fm. The FO of
Wetzeliella ovalis at the base of the Maldegem Fm is taken to indicate definite D10 sediments. This is supported by the FO of
(abundant) Areosphaeridium arcuatum slightly higher. Zone 11 was recognized at the top of the formation, based on
the FO of Rhombodinium porosum. The tidal sands and lagoonal mudstones of the Zelzate Fm were
deposited during stage 5 and are still considered to belong to Zone D11.
ACRITARCHS FROM THE LLANDOVERY CABOT HEAD SHALE, ONTARIO, CANADA
Merrell A. Miller
Amoco Exploration and Production Technology Group, P.O. Box 3092, Houston, TX 77253, U.S.A.
The Cabot Head Shale (Medina Group) of southern Ontario consists of gray shales with
minor interbedded siltstones. Megafossils are rare in this marine unit but acritarchs are abundant and
thermally unaltered. The Cabot Head Shale and Power Glen / Grimsby formations are part of the same Early
Silurian depositional sequence but represent different facies. Acritarchs from the Cabot Head include:
Clypeolus tortugaides, Diexallophasis
remota, Disparifusa sp.,
Elektoriskos pogonius,
Estiastra sp., cf. Glyptosphaera
sp., Leiofusa spp., Leprotolypa
evexa, Lophodiacrodium pepino, Moyeria
cabotii, Multiplicisphaeridium spp.,
Nanocyclopia sp., cf.
Pteroverricatus sp., Retisphaeridium
?fragile, Tunisphaeridium sp.,
Veryhachium europaeum and
Veryhachium trapezionarion among others. Cryptospores and chitinozoans present include:
Dyadospora sp., Tetrahedraletes
medinensis, Plectochitina sp. and Spinachitina
maennili.
PALYNOLOGY OF THE NEAGHA SHALE AND ITS IMPLICATIONS ON LLANDOVERY SEQUENCE STRATIGRAPHY OF WESTERN NEW YORK AND SOUTHERN ONTARIO
Merrell A. Miller
Amoco Exploration and Production Technology Group, P.O. Box 3092, Houston TX 77253
The Neagha Shale (basal Clinton Group) is areally restricted to western New York and
southern Ontario. It is correlative with the Maplewood Shale in the vicinity of Rochester. The Neagha is
Llandovery (Aeronian) in age and bounded unconformably below by the Thorold Sandstone and overlain by
the Reynales Formation. Lithologically the Neagha consists of gray-green platy shales with a
phosphatic pebble zone at the base of the unit. Conodonts from the Reynales immediately above the Neagha
include Distomodus kentuckyensis, Icriodella
deflecta and I. descrita which support an Aeronian age. The
Neagha contains an extremely diverse acritarch assemblage that includes:
Baiomeniscus camurus, Carminella
maplewoodensis, Cymatiosphaera
densisepta, Clypeolus
tortugaides, Dactylofusa.
rhomba, Diexallophasis caperoradiola,
D. denticulata, Disparifusa
psakadoria, Elektoriskos aurora,
E. pogonius, E.
sequestratus, Geron guerillerus,
Helosphaeridium spp., Holothuriadeigma
heterakainum, Leiofusa irroratipellis,
L. rhikne, L.
tanaocyta, Leprotolypa evexa, Lophodiacrodium
pepino, Moyeria cabottii, Multiplicisphaeridium
fisheri, M. mergaeferum,
M. paraguaferum, Neoveryhachium
neocarminae, Sol planus, Tunisphaeridium
caudatum, T. parvum,
T. tentaculaferum, Tylotopalla
caelamenicutis, T. digitifera, and
Visbysphaera sp. among others.
PALEOENVIRONMENTAL CHANGE IN THE
COLORADO RIVER DELTA. A PALYNOLOGICAL
RECONSTRUCTION FOR THE HOLOCENE AT EL DOCTOR AND THE LAST
100 YEARS AT SANTA CLARA WETLANDS
Martín Eduardo Ortiz1 and María Cristina
Peñalba2
1 2UNAM Instituto de Ecología Estación Regional Noroeste, Hermosillo, Sonora., México
The present ecosystems reflect the changes in the landscape that succeeded during hundreds
to thousands of years. Therefore, a thorough study of the past is needed to understand the present
patterns. We present here a multidisciplinary study of Holocene environmental change in the Colorado River
Delta, in Sonora, Mexico.
LATE-PLEISTOCENE AND HOLOCENE
VEGETATION CHANGES IN THE SONORAN AND CHIHUAHUAN DESERTS, FROM POLLEN ANALYSIS*
Pollen analysis of deep sea cores in the Gulf of California (Davis, 1982; Byrne et al., 1990) show
different responses of the vegetation to the glacial / interglacial Late-Pleistocene climate oscillations. While
the central Gulf record (Byrne et al., 1990) presents periodical changes associated to successive climatic
pulses, the northern Gulf record (Davis, 1982) shows no evidence of major vegetation changes at the
Pleistocene-Holocene transition. The significance of this apparent incoherence is discussed on the basis of new
and published continental pollen records.
PALYNOFACIES DISTRIBUTION IN A
PALUSTRINE-LACUSTRINE BASIN (LA CERDANYA,
VALLESIAN, PYRENEES): IMPLICATIONS IN SOURCE ROCK
CHARACTERISATION*, **
M.J. Pérez-Vila1, C.
Martin-Closas1, J.M. Moron2, A.
Permanyer3 and G. La-crampe-Couloume2
1 2 ELF Exploration Production, CSTJF, 64018 - Pau Cedex, France
3 Dept. Geoquimica, Petrologia i Prospeccio Geologica, Univ. de Barcelona, Spain
Modelling of deposition systems according to the relative abundance in organic components is a
useful tool in source rock exploration. The palaeo-lake of La Cerdanya (Vallesian, Easter Pyrenees) belongs to a
well-studied fluvio-lacustrine basin. Its small size and well-known structure, sedimentology and plant
taphonomy constitutes an ideal basis to analyse the palynofacies distribution and its relationships to the oil potential.
1. MIC: microfossils such as pollen, spores, algal cysts and mycelia,
2. SOM: structured organic matter composed of plant cuticles,
3. SC: structured charcoal such is a black phytoclasts,
4. SWR: structured woody remains such as tracheids,
5. NSC: non-structured charcoal,
6. AOM: amorphous organic matter and
7. PPW: poorly preserved woody remains
Palustrine facies (lignite, organic clays with rootlet marks and macroremains of aquatic plants)
yield diverse associations of organic components. The abundance of SOM, which is especially high in
this samples, is consistent with a short transport. Highly diverse assemblages of microfossils (small and
dense spores of Osmundaceae,
zygmatalean cysts, diverse associations of pollen from aquatic and terrestrial
plants) also indicate proximity to the lakeshore. The organic content is low, about 1% TOC (Total Organic
Carbon) except for lignite layers, which have higher contents ( 43 to 50 % TOC). The Hydrogen Index (HI)
ranges from 70 to 189 for all samples from palustrine facies, including clays and lignites. Lacustrine
facies (diatomite and finely laminated mud with well-preserved leaves and insect remains) typically show
less diversity in organic components than palustrine facies. In contrast, these samples are very rich in
AOM , and particularly in sapropelic matter. Also, lacustrine samples contain abundant algal remains
(Botryococcus) and a high percentage of wind-drift bisaccate pollen. All these data indicate a distal position of
samples within the lake. Geochemical data show a higher organic content (about 3.5 % TOC) and a very
significant increase of the hydrogen index (up to 700) in comparison to palustrine facies. This is consistent with
the lacustrine palynofacies found. The oil potential (S2) of these facies is higher than 30 mg HC/ g rock.
The agreement found between palynofacies, macrofloral taphofacies distribution, geochemistry and
sedimentology is an integrated example of source rock evaluation in fluvio-lacustrine basin.
PALYNOSTRATIGRAPHY AND LITHOSTRATIGRAPHY OF PALEOGENE OUTCROP SECTIONS IN THE MERIDA ANDES, WESTERN VENEZUELA
David T. Pocknall and Robert N. Erlich
Amoco Corporation, Box 3092, Houston, TX 77253, U.S.A.
Detailed palynologic and lithostratigraphic studies of outcrop sections on the northern flank of
the Merida Andes in Western Venezuela were undertaken to establish a framework for interpreting
subsurface data obtained during the 1995 Venezuela Exploration License Round. The Paleogene section in
the Maracaibo basin consists of laterally continuous reservoir, source, and seal rocks contained within the
Los Cuervos, Mirador, and Carbonera formations. The reservoir units that produce in the subsurface of
the basin are exposed in the outcrop belt and provide an excellent laboratory for study. The main focus of
the palynological work done was the establishment of a chronostratigraphic framework for the basin and
the recognition of environments of deposition in the mainly continental to marginal marine
Paleogene sequence.
PALYNOSTRATIGRAPHIC ANALYSIS OF THE
CENOZOIC OF THE BAY OF CAMPECHE, GULF OF MEXICO
Judith Rosales-Lomelí1 and Richard V.
Tyson2
1 2 University of Newcastle, Fossil Fuels and Environmental Geochemistry, Drummond
Building, University of Newcastle, Newcastle upon Tyne NE1 7RU, UK
A quantitative palynological study of thermally immature Cenozoic sediments has been carried out
on one Well, from the Bay of Campeche, Gulf of Mexico. The primary objectives were to determine
the biostratigraphy of the well, to assess the changes in the depositional environment. These objectives
were realised by performing both total kerogen (palynofacies) and palynomorph counts on 127 cutting
samples (approximately one sample every 20 m), and then calculating and plotting a range of different
palynofacies parameters. A small number of geochemical analyses (8) were also performed.
STRATIGRAPHIC APPLICATION OF THE
OPTICAL ANALYSIS OF ORGANIC AND INORGANIC RESIDUES AFTER ACID ATTACK OF SEDIMENTARY ROCKS AND SEDIMENTS. A CASE HISTORY
Jaime Rueda-Gaxiola
Instituto Mexicano del Petrole, Eje Central Lázaro Cárdenas No. 152, 07730, México 14, D.F.
DEPFI-UNAM, Ciudad Universitaria, Circuito Exterior, 04510, México, D.F. Ciencias de la
E.S.I.A.-TICOMAN, Calzada Ticomán 600, México, D.F.
Residues of sedimentary rocks and sediments, composed by organic and inorganic materials
resistant to hydrochloric and hydrofluoric acids, are mounted on slides and employed for qualitative
and quantitative detailed optical studies. These residues contain residual inorganic and organic matter
and pollenospores, chitinozoa, scolecodonts, dynoflagellate cysts, acritarchs, scytinaceas, phytoclasts and
also other palynomorphs such as some coccolithophores and discoasters, as well as non-chitinaceaous
internal organic membranes from microforaminifera chambers. Additionally, algal, herbaceous, woody and
coally materials hold their original color, size and shape. The mineral matter (pyrite, other crystalline
minerals fragments and non-crystalline minerals) from the original rocks and sediments is well preserved,
together with the newly formed minerals resulting from the acid attack. The microscopical analysis of all
these components in the residue allows us to interpret the physical characteristics of the organic and
mineral materials in the original rock or sediment.
1. characterize lithological units (Lithostratigraphy),
2. know the organic matter components of lithological units (Biostratigraphy),
3. establish the age of lithological units (Chronostratigraphy),
4. reconstruct the paleoenvironmental conditions (Paleoecology),
5. deduce sedimentary conditions and geographic distribution of lithological units
(Paleogeography), and
6. interpret the burial history and diagenesis of lithological units in order to know
generation, migration and accumulaton of hydrocarbons in the basin.
This palynostratigraphical method of macro- and microscopic integrated and sequential study has
been applied in Mexicain oil basins since 1975. It has permitted to establish the lithostratigraphy
and chronostratigraphy of several lithostratigraphic groups in Mexico's Gulf Coast region, such as the
redbeds of the Los San Pedros Allogroup, which crop out in the Huizachal-Peregrina Anticlinorium. They
have been used aso to reconstruct the paleogeography of the Huayacocotla-El Alamar Basin, and the origin
of the Tampico-Misantla oil basin, as well as of other Mexicain oil basins related to the Gulf of Mexico origin.
PALAEOFLORISTIC CHANGES AND CYCLICITY
ACROSS THE PALEOCENE/EOCENE BOUNDARY IN VENEZUELA, NORTHERN SOUTH AMERICA
Valentí Rull
PDVSA Exploration & Production, Box 829, Caracas 1010-A, Venezuela
A floral change occurred in northern South America at the Paleocene/Eocene boundary is
analysed using palynological data. The sequence studied is an outcrop from the Venezuelan Maracaibo
basin, deposited in shallow marine to coastal environments without apparent stratigraphic breaks.
Significant pollen and spore counts from 237 samples were studied stratigraphically and statistically in order
to compare Paleoecene and Eocene palaeofloras and palaeoecological trends.
POLLEN MORPHOLOGY OF MEXICAN SPECIES
OF SICYOS L. (CUCURBITACEAE)
Fernando Sánchez-Guevara1, Isela
Rodríguez-Arévalo2, José Luis
Alvarado1
1 2 Herbario Nacional de México, Instituto de Biología, UNAM. Apartado Postal 70-367, México,
D.F. 04510.
Sicyos L. (Cucurbitaceae) is a genus which includes approximately 20 species. The
infrageneric classification is poorly understood, and a palynological study of Mexican species was undertaken to
help resolve relationships within this genus. The species studied were:
S. barbatus (H. S. Gentry) C. Jeffrey,
S. collinus B.L. Rob. & Fernald, S.
deppei G. Don., S. echinocystoides Cogn.,
S. galleottii Cogn., S.
guatemalensis Cogn., S. laciniatus L.,
S. longisepalus Cogn., S.
motozintlensis Lott & Frixell, S.
parviflorus Willd., S. peninsularis Brandegee and
S. sertuliferus Cogn.
SPATIAL MODELING OF THE MODERN POLLEN RAIN IN THE BIG BEND NATIONAL PARK REGION OF WEST TEXAS
Peter P. Siska1, Vaughn M. Bryant,
Jr. 2, and Robert C. Maggio1
1 2 Palynology Laboratory, Texas A&M University, College Station, Texas 77843-4352, U.S.A.
For the last decade Geographic Information Systems (GIS) has advanced rapidly into natural
resource management research, providing tools for spatial data handling, mapping and spatial modeling.
Even though research in palynology is also spatially oriented, direct applications of GIS data in palynology
are absent. Therefore, we began a study to investigate, analyze, and suggest methods of using GIS
techniques and geostatistical modeling in palynology. GIS technology supported by geostatistical methods
provides a powerful tool for spatial analysis, modeling and database management. We believe that these
aspects can assist the field of palynology in many ways including the study of the modern pollen rain and
the reconstruction of paleovegetational patterns and changes.
PALYNOLOGY AND SEQUENCE STRATIGRAPHY FROM THE CRETACEOUS OF EASTERN VENEZUELA
D. Somoza1 and J. Helenes2
1 2 CICESE, Departamento de Geología, Carretera Tijuana-Ensenada, Ensenada, Baja California
22860, México.
From Jurassic to Tertiary times, northeastern Venezuela represented the continental shelf of a
tectonically passive margin. An almost completely marine Cretaceous sedimentary section, with a
maximum thickness of 3658 m, is found in the subsurface in this area. Palynomorph recovery from these
strata, together with planktonic foraminifera and nannofossils, indicate an age range from at least Aptian
to Maastrichtian.
SELECTED TAXA AND PALYNOSTRATIGRAPHICAL CONSIDERATIONS FROM THE CARBONIFEROUS OF THE BRAZILIAN PARANÁ BASIN*
Paulo Alves de Souza1, 2, Setembrino
Petri2, Mary Elizabeth C. Bernardes de
Oliveira2 and Rosemarie Rohn3
1 2 Instituto de Geociências-USP Caixa Postal 20.899 - CEP 01498-970 São Paulo, SP, Brazil
3 IGCE-Unesp Rio Claro Caixa Postal 178 - CEP 13506-900 Rio Claro, São Paulo, SP, Brazil
Palynology seems to be the most efficient tool in providing biostratigraphical data in
the Permocarboniferous strata in the Brazilian Paraná Basin, represented by the Itararé Subgroup
(Tubarão Group), unit related to the Gondwana late Paleozoic glaciation.
*This work was partially supported by research grants awarded by FAPESP.
DINOCYST SEQUENCE STRATIGRAPHY OF
TEXAN CENOMANIAN-CONIACIAN SEDIMENTS IN WESTERN TETHYS REALM AND ITS WORLDWIDE
CORRELATION POTENTIAL
Satish K. Srivastava
Geology Consultant, 3054 Blandford Drive, Rowland Heights, California 91748-4825, U.S.A.
A Cenomanian-Coniacian transgressive-regressive marine sequence is exposed in a north-south
trend in 7 counties from about Dallas to Del Rio in Texas. Extensive studies of marine fauna of the sequence,
such as ammonites and foraminifers, have provided age boundaries and their precise correlation
with European Stages. Dinocyst taxa dominated palynomorph assemblages of 63 outcrop samples from
9 stratigraphic sections. The stratigraphic distribution of dinocyst taxa indicates that the range of
occurrence of Ovoidinium verrucosum terminates at the end of the Cenomanian, and that of
Litosphaeridium siphoniphorum at the end of the Turonian.
Dinogymnium acuminatum appears in the Coniacian.
MULTI-TAXA ANGIOSPERM POLLEN PHYLOGENIES APPLICABLE TO ZONING THE PALEOGENE OF WESTERN AND NORTHERN CANADA
Arthur R. Sweet Zonations, based primarily on the Juglanaceous pollen, have proved an effective framework for a
six-fold subdivision of the Paleocene in central North America. Northward the more erratic distribution
of Juglanaceous pollen acts to limit their biostratigraphic effectiveness. In western and northern Canada,
five other disparate angiosperm pollen complexes can be used to supplement and refine the existing
zonations. 1) Eight species of Wodehouseia have biostratigraphic utility. Of those with ovoid endexinal bodies,
W. spinata, best known from the upper Maastrichtian, survives into the basal Paleocene, and a closely
similar form, W. stanleyii, occurs in the K-T boundary coal zone. The succession of
W. sp. A, W. fimbriata (s.s.)
and W. excelsa, with primarily dumbbell-shaped endexinal bodies, serve as earliest Paleocene index
species. One of three additional species extends the range and biostratigraphic utility of
Wodehouseia into the Eocene in arctic Canada. 2) Although an affected group at the K-T boundary, the biostratigraphic
utility of triprojectate pollen continues into the Paleogene.
Aquilapollenites reticulatus occurs in the
earliest Paleocene and two variants of Parviprojectus
striatus in the middle and upper Paleocene. Within
A. spinulosus (s.l.) there is a progressive shift from a more or less isometric shape in the late early
Paleocene to an subisopolar morphotype with relatively reduced equatorial projections in the late Paleocene. In
the Eocene, A. tuminagensis represents the culmination of this trend. 3) The subspherical tricolporate
pollen Brevicolporites,
Phaesoliidites and
Pistillipollenites represent a pollen complex in which change
occurs primarily in the character of the sculpture. The psilate to subtly verrucate
Brevicolporites colpella originates in the late Maastrichtian and is pervasive in the early and middle Paleocene. During the middle
Paleocene an increase in the definition and height of the verrucae results in
Phaesoliidites stanleyi. A farther increase in the height of the sculpture and the formation of a basal constriction leads to the gemmae
of Pistillipollenites mcgregorii, a well known index species for the late Paleocene and Eocene. 4)
Tiliaceaous pollen is first represented by relatively small forms with an indistinct, very fine reticulate
sculpture. Intratriporopollenites minimus, which first occurs in the late early Paleocene, is representative of the
more primitive state, Tilia danei an intermediate, and
T. vescipites the more robust state characteristic of the
late Paleocene. 5) Within ulmaceous pollen a rugulate sculpture first occurs in the middle
Paleocene. Previously the only representatives of ulmaceous pollen are those with low relief verrucae.
LOWER CRETACEOUS DINOFLAGELLATE CYST STRATIGRAPHY OF THE CISMON APTICORE (SOUTHERN ALPS, NE ITALY)
Stefano Torricelli
ENI SpA, Agip Division, STIG via Maritano 26, 20097 S. Donato Milanese, Italy.
E-mail: Stefano.Torricelli@Agip.it
Within the framework of the APTICORE Program (Larson et al., 1993), aimed to document
Earth's responses to a period of major global climate change occurred in the mid-Cretaceous, the
continuous coring and logging of an upper Aptian to upper Hauterivian succession were carried out in the
Cismon Valley (Belluno Basin, Southern Alps, northeastern Italy). This essentially complete pelagic
succession represents a "reference section" for the Hauterivian-Aptian interval at low latitudes.
PALYNOLOGICAL EVALUATION AND MATURITY OF COALS IN THE TERTIARY SECTION OF VENEZUELA'S EASTERN BASIN
Javier J. Vasquez Fuentes and Angel F. Callejón Giménez
PDVSA Exploración y Producción. Gerencia de Operaciones y Servicios Especializados.
Laboratorio Geológico
As part of the characterization of the oil-generating potential of coals in Venezuela's eastern basin,
116 samples from 18 surface sections and 64 core samples from exploratory wells were analyzed
for palynology and their Thermal Alteration Index (TAI) was determined. Additionally, the composition
of the organic residues was determined to establish environmental biomarkers, their maturity and ages,
as well as to correlate with 7 oil samples from the basin. The surface sections sampled are located in
the Cordillera de la Costa and Serranía Oriental of Venezuela, and the wells are located southward, in
the Eastern Venezuela Basin
BIOLOG: A BIOSTRATIGRAPHIC DATABASE AND ITS LOGICAL MODEL
J-L. Volat, J-C. Portalis and J-M. Moron BIOLOG is a biostratigraphic database designed for industrial needs. A comprehensive analysis
of biostratigraphic data and of their relationships led to the development of a data model which could
be mapped against the POSC EPICENTRE data model. Such a structure allows a reduction to
standardized items ensuring easy data identification, management, and exchange.
LATE HOLOCENE POLLEN STRATIGRAPHY ALONG THE HAYWARD FAULT, EL CERRITO, CALIFORNIA
James A. Wanket
Department of Geography, University of California, Berkeley, CA, U.S.A.
Pollen analysis was used in conjunction with trenching studies to help constrain the timing
and recurrence of major earthquakes along the northern Hayward Fault in the San Francisco Bay Area. A
local extensional segment of the strike-slip fault provided an ideal depositional site that yielded a
4,000-year record of terrestrial and aquatic pollen. The occurrence of the non-native pollen types
Eucalyptus and Erodium, their timing of arrival in northern California being well constrained, provided a useful
upper bounds for dating the most recent event on the fault. The pollen record of local vegetation response to
fault movement was muted, probably due to the low sedimentation rate at the site (<0.4 mm/yr.) and
the relatively minor vertical displacement (2-6 cm per event). However, the variability of aquatic
types throughout the record and the well-preserved nature of the pollen argue that palynological
approaches may be useful at other sites in the Hayward Fault Zone.
IDENTIFICATION AND PREDICTION OF SOURCE ROCK FACIES USING INTEGRATED GEOSCIENCE TECHNOLOGIES: AN EXAMPLE FROM THE KIMMERIDGE CLAY FORMATION, FISHER BANK BASIN, NORTH SEA, UNITED KINGDOM
Katherine J. Whidden1, Carl
H.Sondergeld2, Merrell A.
Miller1, Gordon D.Wood1, Susan
Palmer-Koleman1, Dick E.
Larese2 and Paul A. Cornick3
1 2 Amoco Exploration and Production Research Technology, P.O. Box 591, Tulsa, OK, 74102, U.S.A.
3 Amoco House, West Gate, London, W5 1XL, United Kingdom
A Kimmeridge Clay Formation core was analyzed for geochemistry, palynology (including
graphic correlation), quantitative palynofacies and seismic rock properties. The object of the study was to
better understand the controls on the deposition of organic rich intervals to construct a
comprehensive framework for determining source rock intervals using seismic attributes.
PALYNOLOGY, PALYNOFACIES, GEOCHEMISTRY AND INVERTEBRATE PALEONTOLOGY OF THE UPPER CRETACEOUS NAPO FORMATION, ORIENTE BASIN, ECUADOR
Gordon D. Wood1 and Antenor
Aleman2
1 2 Amoco Worldwide Exploration Business Group, P.O. Box 3092, Houston, Texas, 77253, U.S.A.
The Napo Formation, and stratigraphic equivalents in the Marañon, Oriente and Putumayo
basins, consists of sandstones, shales and carbonates. The shales are usually dark-gray to black and
sandstones are yellow-white, predominately fine-grained, and often glauconitic. Carbonates reflect low
energy conditions and often have a marine fauna that indicates deep-water deposition (e.g., ammonites).
This formation is a well-known hydrocarbon target because of the presence of source, reservoir and seal
rocks. Source rock consists of thinly laminated shales and limestones having high Total Organic Carbon
values (TOC) and Hydrogen Indices (HI). This paper documents the preliminary palynological and
geochemical analyses for three localities from the Orienté Basin.
PALEOENVIRONMENTAL SIGNIFICANCE AND SPECIES DIVERSITY OF EARLY MIOCENE AND QUATERNARY MARINE PALYNOMORPHS FROM CAPE ROBERT NO. 1 CORE, ROSS SEA, ANTARCTICA
John H. Wrenn1, Michael J.
Hannah2, and Ian J. Raine3
1 2 School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
3 Institute of Geological & Nuclear Sciences, P. O. Box 30 368, Lower Hutt, New Zealand
The Cape Roberts Project (CRP) is an internationally drilling program sponsored by the Unites
States, New Zealand, Germany, Great Britain, Italy and Australia. It is designed to sample
east-dipping, submarine sedimentary strata just offshore from the Transantarctic Mountains, South Victoria Land.
The CRP-1 core was drilled from floating sea ice off Cape Roberts in the Ross Sea during October 1997. The
core penetrated 148 meters below the sea floor (mbsf) through an early Miocene and Quaternary section,
before drilling was terminated. Anticipated Paleogene sediments were never encountered.
Department of Geosciences, University of Arizona, Tucson, Arizona, U.S.A.
1 RR2, Box 186C, Fayetteville, Texas 78940, U.S.A.
Key cored intervals in wells located in Union Parish, Louisiana, combined with cuttings samples
from nearby wells provided the primary framework for this zonation. A tentative Valanginian age is
characterized by the LAD of a new species of
Druggidium. This interval is typically seen in the lower
Hosston Formation. A provisional Berriasianage is recognized by the LAD of a new spore that marks the top of
the Cotton Valley Formation in this area. Down dip this new spore is associated with a well preserved
and diverse marine assemblage that includes Achomosphaera
neptunii, Dichadogonyaulax, Gonyaulacysta
diutina, Kleithriasphaeridium,
Systematophora and several undescribed dinocysts. The Tithonian is marked by a
new species of Ellipsoidictyum. The LAD of
Subtilisphaera? paeminosa marks the CottonValley-Bossier
transition and is interpreted as the Tithonian-Kimmeridgian boundary. Species commonly observed with, or
just below Subtilisphaera? paeminosa, include
Subtilisphaera? inaffecta, Ctenidodinium? chondrum
and a new species of Kraeuselisporites. The oldest consistent dinoflagellate LAD in the basal Bossier to
Haynesville transition is Gonyaulacysta
jurassica.
2 Dept. Estratigrafia i Paleontologia, Universitat de Barcelona, Spain
Palynomorph assemblages have been defined based on ecological affinities:
Savanna: Poaceae, charred cuticles,
Aizoaceae, Brachystegia,
Berlinia..., Mangrove: Rhizophora,
Acrostichum aureum, Avicennia and Swamp forest:
Crudia, Ipomea, Symphonia..., Semi-decidous forest:
Celtis, Nauclea, Commiphora and Pionner Forest:
Alchornea..., Rain Forest:
Sapotaceae, Meliaceae, Croton,
Randia, Amanoa, Mussaenda....No Montane taxa have been founded for upper Miocene.
Palynofacies signature (relative proportions in Amorphous Organic Matter, Structured Plant
Debris and Cuticles, Coals and Woody Debris) can be interpreted in terms of sequence stratigraphic
approach. Higher values of AOM fits with TST, plants debris and cuticles maximums occur during LST and HST.
Ecological evolution is characterized successively by a decrease of Savanna, an occurrence of
Pionnier Forest, an increase of Rain Forest followed by a maximum of Mangrove. This succession fits
with sequential interpretation.
Some events have been pointed out:
Dinocysts and mangrove events are interpreted as a change in the Congo channel direction.
Peaks of Brigantedinium spp are interpreted as high nutrient level indicators.
The base of the studied interval is characterized by upper Miocene reworkings probably due to
LST wedge.
In both areas, high bioproductivity is inferred in the lowermost Toarcian sediments
(Dactylioceras tenuicostatum ammonite Zone) on the basis of the relationships between the Hydrogen Index
and phytoplankton abundance/diversity. This was caused by a sea level rise which increased the
available palaeoecological niches and promoted mutual exchange via marine currents between high and
low latitudes. The compositional variations of the phytoplankton assemblages and the type of
preserved organic matter indicates a gradual stratification of the water column which led to an expansion of
the oxygen-minimum zone in the Boreal seas. This is responsible for the higher TOC values recorded at
high palaeolatitudes related to major eutrophication indicated by the dominance of green algae. In both
areas, the oxygen deficiency interval is also marked by a 'blackout' of calcareous nannofossils and
dinoflagellate cysts. The overcoming of these stressed conditions led to a phytoplankton renaissance. Due to
marked provincialism at this time, different marker species are observed in the two regions which exhibit
similar palaeoecological preferences and occupied comparable niches.
A palynological study of these stratigraphic units is based in 71 core samples from 6 wells drilled
in these basins. Gray shales with intercalated sandstones and eventual pyrite and evaporite
laminae compose the Castellanos Formation. This lithology supports an interpretation of a lacustrine system
for this unit. The Migues Formation is predominantly composed by red sandstones intercalated
with centimeter thick beds of brown/red shales attributed to fluvial deposits. Both formations have
a transitional contact and interfinger laterally.
The poor albeit diversified palynofloral association, and the small number of fossiliferous samples
did not allow to establish a more accurate biostratigraphic zonation. However, based on the known
stratigraphic ranges of some palynomorphs, an Albian age was assigned to this fossiliferous
stratigraphic interval. These forms include: Striatopollis reticulatus, Stellatopollis barghornii, Klukisporites
variegatus, Eucomiidites troedssonii, Equisetosporites ambiguus, Stephanocolpites
sp. and Cyclocristella senticosa.
Together with more abundant species and guides for Albian deposits, such as:
Cycadopites, Classopollis, Exesipollenites tumulus, Spheripollenites scabratus, Steevesipollenties, Podocarpidites, Gamerroites
and Retitriletes, which are also
frequent in the neighboring Cretaceous basins of Argentina. This interval is correlated with
the Petrobras P280 Zone established for the Brazilian, Cretaceous marginal basins.
In samples from the wells situated closer to the ancient basin margins, occur a great variety of
spore species of the Cicatricosisporites genus, and other palynomorphs related to bryophytes and
pteridophytes, characterizing a more humid environment in these areas. As it is common in the Albian sediments of
the cratonic basins in South America, Europe, Africa and Asia,
Botrhyococcus spores are also abundant in
this association.
*Contribution of the Project of FAPESP n 96/7090-8 "The Continental Upper Cretaceous
Sedimentar of the Portion Austral from the South America".
The strobilus presented in this paper is elongated, 38 cm long as preserved, and 7 cm wide in the
widest middle region. It is incomplete at both apical and basal ends. It was studied under reflected light. A
few pieces were prepared by using routine techniques for studying the details under high magnifications
with compound research microscope and with SEM facility.
The strobilus in appearance resembles a carboniferous lepidodendrid. The central axis bears in
close helicals sporophyll/sporangium complexes, with sporangium adhered adaxially on the upper surface
of the sporophyll.The lower units overlap the upper. Heel and keel are absent. Sporangia are in
situ, elongated and are filled with many spores having triradiate mark and measuring ca 50 microns each.
The strobilus is compared for its affinity with those known from the Late Devonian age. The big
size of the cone with woody appearance indicates arborescent habit of the plant on which it grew.
The dominant pollen group throughout the record was Cheno/Ams which ranged from 30 to 90%
of the total pollen and spores. This dominance most likely results from the sea of
Salicornia (glasswort) surrounding the core site for an average of 0.5 km in all directions. Because the
Salicornia is submerged daily at high tide, the Cheno/Ams were not used in the total of terrestrial pollen. As a result, obtaining
an accurate pollen percentage of other species required very high pollen counts.
The pollen analysis results show a major increase in Poaceae pollen around 2750 yr B.P. followed by
a subsequent contraction around 1750 yr B.P. This most likely indicates an expansion of grasslands
adjacent to the estuary, but it may also be indicative of the presence of the estuarine grass, California cord-
grass (Spartina foliosa), although this species does not presently occur in the estuary. Greater available
moisture is indicated after 2000 yr B.P. by increasing levels of cottonwood
(Populus sp.), lip fern (Cheilanthes
sp.), adder's tongue fern (Ophioglossum
californicum) and spike moss (Selaginella
bigelovii type). Microscopic charcoal in the sediments also increases around 2000 yr B.P. This change could be due to moister
climates causing greater continuity in the vegetative fuel, and/or changing burning practices by native
Californians who lived adjacent to the estuary.
Sediment deposition shows a gradual rise in the surface of the estuary, roughly keeping pace with
the late Holocene rise in sea level, until the settlement era when the apparent sedimentation rate increased
ten-fold. Historic portions of the sediment core were dated using sediment chemistry, fossil pollen,
and correlation with historical records. Post-settlement sediments in the top 65 cm of the core are indicated
by a rise the magnetic susceptibility and increases in pollen from exotic taxa such as storksbill
(Erodium sp.).
The reserve population of Torrey Pine
(Pinus torreyana), which is immediately adjacent to the estuary, is
one of only two natural stands in the world. The pine population appears to have been present at the site
throughout the 3600 year core record.
Principle gymnosperms are
Araucariacites, Alisporites,
Callialasporites (4 sp.), Cerebropollenites
, Chasmatosporites, Eucommiidites (several),
Ginkgocycadophytus, Ovalipollis,
Parvisaccites, Pityosporites,
Podocarpidites, Protopinus,
Spheripollenites, and Vitreisporites. Ferns and pre-ferns are
Auritulinasporites, Cibotiumspora,
Contignisporites, Cyathidites,
Densoisporites, Gleicheniidites,
Heliosporites, Leptolepidites, Lycopodiumsporites
(several), Matonisporites,
Murospora, Neoraistrickia,
Sestrosporites, Stereisporites,
Taurocusporites, and Todisporites.
A comparison is made with a similar age palynoflora, the Mistuskwia Beds of Ontario
(Bajocian-Bathonian), Fort Dodge beds of Iowa (Kimmeridgian-Portlandian or Early Cretaceous), and
palynofloras of the Gravelbourg Fm., Saskatchewan and Manitoba (Middle Jurassic) and Sawtooth Fm.,
Alberta (Middle Jurassic).
The Michigan "Red Beds" are comprised of red and gray-green shales, stringers and thin beds
of gypsum, and irregular pods and lenses of varicolored sandstones. These seem to have accumulated in
a large, inland playa with internal drainage on a broad, structurally controlled, intermittently
reactivated, shallow depression. Absence of acritarchs/dinoflagellates in all but one sample indicates
non-marine origin. However, a brief transgression of an epeiric sea through a restricted channel from both the
north or northwest, and development of a sabkha-like environment on a broad coastal plain of low-relief
is considered.
A dataset of fossil cysts from the Angola Basin was analyzed in order to test the models
developed for the present day on paleopalynological data. Statistical models of the ecological signals from
living cysts from the region had been developed, providing a modern analogue against which to compare
and interpret the fossil data spanning roughly the last 200,000 years. The objective application of
these models allowed the easy recognition downcore of the same ecological gradients known to exist in
the region at the present day. The aim of this project in the Angola Basin was to trace migrations of
the Angola Benguela Front, but it demonstrated that our statistical modelling methods could be
successfully applied downcore. The variations in the cyst signals over time matched closely with
signals produced by other fossil groups (eg., forams and diatoms) and suggested additional information
not detected by the other groups. For example, variations in the proportions of transitional cyst
types reflecting runoff from the Congo River plume, allowed the recognition of gradations of front
movement which were identifiable by other microfossil groups only through documenting presence/absence
of indicator species at a number of geographically spread core sites. The ability of our methods to
highlight similar changes, on the basis of one core, as those detected by other fossil groups using a minimum
of four cores, bodes very positively for the likelihood of using these methods to identify
ecological gradients influencing other paleopalynological datasets - e.g., those likely to be important for
sequence stratigraphy.
The stratigraphically highest
Subtilisphaera Biozone is characterized by abundant
Subtilisphaera spp., frequent
Phoberocysta neocomica, P.
lowryi, Muderongia microperforata, M.
aequicornus of Monteil (1991), and rare Systematophora
sp. cf. S. palmula (short, narrow processes). The
Tehamadinium Zone from the middle of the section is marked by the first downhole occurrences of
Tehamadinium dodekovae, T. daveyi,
consistent Systematophora palmula, and a decrease in
M. simplex. A new Muderongia species with a tabulate,
'lacy' periphragm is first recovered from within this zone and potentially can be used to further subdivide it.
The third and stratigraphically lowest
Batioladinium Biozone is defined by the first downhole occurrences
of common Batioladinium spp., occasional
Aprobolocysta varigranosum, and increases in
Muderongia nov. sp., S.
palmula, and T. daveyi.
The most important features of
Muderongia nov. sp., which resembles Muderongia
microperforata, are a discontinuous coarsely perforate to reticulate periphragm, which is typically better developed in the
horn areas, and the relatively high reticulate septa that define the plate boundaries. The reticulate
parasutural septa is sometime broken and may appear as low ornamental ridges to irregularly aligned
spines. Description of the species conforms to that of the genus
Muderongia.
Applying European and Australian dinoflagellate ranges, for species such as
Tehamadinium dodekovae, T.
daveyi, Perisseiasphaeridium sp. A (pers. obs.),
Systematophora palmula, Systematophora
sp. cf. S. areolata, and Batioladinium
varigranosum, the studied section is placed in the Lower Valanginian, and tentatively
correlated to the Be 8 to Va 3 sequences of the Sequence Stratigraphy of European Basins chart, SEPM Spec. Pub.,
of Hardenbol and others (in press).
Sarah R. De La Rue and Francisca E. Oboh-Ikuenobe
The biosiliceous Eocene interval experienced some periods of upwelling, which is reflected in
the sporomorph:dinocyst ratios, and types of dinocysts. Such periods of upwelling have
low sporomorph:dinocyst ratios, and are characteristically richer in protoperidinioid dinocysts. Samples
from the Middle Eocene interval, which experienced a high sedimentation rate, have a higher diversity
of sporomorphs and dinocysts than other samples, probably as a result of an increase in the influx
of palynomorphs from the coastal and neritic environments into the deep bathyal environment. One
Middle Eocene sample with the highest sporomorph:dinocyst ratio correlates with a slight increase in the
amount of black debris, which are more commonly observed in channel and other nearshore deposits.
Rodolfo Dino
According to quantitative analyses of the palynological assemblages, the flora consisted chiefly
of cheirolepidacean conifers and gnetophytes, followed by pteridophytes and angiosperms as
minor components. Stratigraphic index fossils confirm that the Alagamar Formation (and therefore the
Alagoas Stage) are Aptian in age. Ages of the palynological units have been assessed and correlated
with palynological sequences from other basins in Brazil and overseas. Comparisons with
plant-microfossil assemblages from other continents support the concept of W.A.S.A. microfloristic belt.
Palynological data imply that the Aptian climate in the Potiguar Basin was warm to hot, arid to
semi-arid, and that the depositional environments were dominantly fluvial-deltaic-lacustrine. These
conclusions agree with previous paleontological and sedimentological studies and are consistent with the
high paleolatitudes commonly proposed for this area in the Aptian.
Lucy E. Edwards
The major finding for the stratigraphy of the Coastal Plain is that a simple "layer-cake" model does
not apply. It has long been recognized that rapid facies changes occur, formations are hard to trace,
and stratigraphic terminology is confusing at best. Although gradual pinchouts of stratigraphic units do
occur, most stratigraphic units thicken, thin, or disappear entirely from one drillhole to another in a
more complex pattern. Dinocysts in these Coastal Plain sediments are generally well preserved.
Distinctive forms, many of which are undescribed, aid in recognizing correlative deposits, and in
distinguishing among similar, noncorrelative deposits.
Most of the cores analyzed to date have at least three Paleocene units: one of early Paleocene age,
one near the early/late Paleocene boundary, and one rather heterogeneous unit of broadly late Paleocene
age. Overlying these are middle Eocene sediments. In contrast, a relatively updip drill hole in
Orangeburg County has thick lower Eocene deposits directly overlying "mid" Paleocene sediments. The bulk of
the expected upper Paleocene deposits are simply not there, and sediments of early Eocene age are found
in their place.
Erosion, in general, and selective erosion, in particular, should not be underestimated. Upper
Paleocene deposits are found elsewhere in both updip and downdip directions. Lower Eocene deposits
were probably widespread (evidenced by reworked early Eocene material) but are missing in all but
localized areas. The selective downcutting and subsequent fill could be result from erosion in an ancient
river channel or from submarine scour.
These paleo-erosional paths have important hydrologic implications where an upper
Paleocene confining unit is cut out.
The LRM pollen record indicates open forest and dry conditions during the early Holocene,
culminating in a xeric interval ca. 8,500-7,000 14C yr. B.P. where rates of pollen deposition, particularly pine,
were greatly reduced compared to earlier Holocene samples and recent deposits. Microscopic
charcoal evidence suggests that fires played an important ecological role in the early Holocene environment.
After ca. 5,000 yr. B.P., increases in Abies and decreases in understory pollen taxa indicate the development
of modern mixed conifer forest with increased effective moisture. The pattern of Holocene vegetation
change seen at LRM is consistent with that recorded at other eastern Sierra Nevada sites.
Radiocarbon dates on several WL cores show that deposition in the historic meadow began by at
least 5,500 14C yr. B.P., with an average of one meter of deposition across the meadow since that time.
High abundance of Artemisia pollen suggests drier-than-modern conditions at WL in the mid-Holocene. By
ca. 3,000 yr. B.P. the meadow had expanded to cover most of its present area. The highest rates of
basin sedimentation occur during two periods of tephra deposition in the meadow: ca. 4200-3800 14C yr.
B.P. and ca. 1820 14C yr. B.P. The 1820 yr. B.P. event coincides with human occupation of the valley
as evidenced by abundant chipped stone lithic debitage directly underlying the tephra at the valley margins.
The preliminary data from the WL and LRM cores demonstrate the potential of the upper Rush
Creek drainage basin for paleoecological investigations. This basin provides a unique laboratory for
studying Holocene biogeography, as well as the effects of volcanic events on plant succession and on
prehistoric human populations. At least three distinct volcanic ash layers are present in most of the cores,
including probable Mono Craters and possible Mazama tephras. Associated with these deposits are
apparent successional shifts in taxa such as Salix, Alnus, and Poaceae. Environmental shifts and increased
charcoal abundance after ca. 2,000 yr. B.P. may be associated with intensified human use of the basin.
3 Geo-Strat, Inc., 1718 Triway, Houston, TX 77043
Standard Overall
Suite Caryapollenites
%Diff(Avg) Vit. Ref. measured
Sample
S-1 0.22/0.32/0.40 0.24/0.30/0.34 0.02 surface
The vitrinite reflectance measurements were made using the "through the cover glass technique."
Algal cysts or palynomorphs that are anonymously dark, such as fungal spores, were not measured. The
results given here, based on Grayson's standards, show that within the margin of error overall estimates
of maturation (primarily from terrigenous palynomacerals) are similar to those based on a specific
pollen genus.
The Latest Callovian, Early and Middle Oxfordian dinoflagellate cyst assemblages from throughout
the West Siberia have a lot of general taxa with coeval floras from the Russian Platform and different
regions of the norhwest Europe and Canada. Three dinoflagellate cyst zones have been recognized in this
interval. These are Wanaea thysanota,
Wanaea fimbriata and Rigaudella
aemula calibrated according to the Uppermost Callovian, Lower Oxfordian and Middle Oxfordian-the lowermost of Upper Oxfordian
in West Siberia. The Callovian/Oxfordian boundary stage is drawn at the base of dinozone
Wanaea fimbriata as well as the Russian Platform and northwest Europe.
The Kimmeridgian sediments in West Siberia yield a rich and very diverse dinoflagellate
cyst assemblage with abundant Rhinchodiniopsis
cladophora, Cleistosphaeridium spp.,
Stephanelytron spp. together with Endosrinium
luridum, Gonyaulacysta jurassica subsp.
jurassica, Scriniodinium
crystallinum, Chytroeisphaeridia spp.,
Prolixosphaeridum, Systematophora sp.,
Subtilisphaera? inaffecta and others, also
with rare typical boreal species Paragoniaulacysta
borealis and Valensiella magna.
On the North of East Siberia in the Upper Volgian sediments (now ?Boreal Berriasian) is established
the boreal dinozone Paragonyaulacysta
borealis, Tubotuberella
rhombiformis, which may be traced circumpolarly in coeval beds of northern Eurasia and Artic Canada. In more southern regions of
West Siberia, the Volgian dinocyst assemblages yield boreal
Paragonyaulacysta borealis and Valensiella
magna as know sub-boreal genera
Oligosphaeridium,
Perisseiasphaeridium and others.
The late Eocene (lower Amphitheatre Formation) fungal assemblage, recovered by controlled
oxidation, includes some distinctive forms like
Ampulliferinites axelheibergi, Ctenosporites
eskerensis, Pesavis tagluensis and quite a few spores, e.g.
Brachysporisporites infacetus, B.
pyriformis, Cercosporites salmonii,
Dictyosporites eccentricus, Pluricellaesporites
trichocladites, are found to be morphologically similar to
their modern equivalents. The common occurrence of many saprophytic fungal types, such as
Dicellaeporisporites poratus,
Dicellaesporites septoconstrictus,
D. mediocoloratus, D.
navicularis, Diporisporites
anklesvarensis, Dyadosporites incisus,
Exesisporites neogenicus and ascomyceteous ascocarps examplified by
Callimothallus pertusus, Paramicrothallites
canadensis, Phragmothyrites eocaenicus,
Plochmopeltinites cooksoniae is indicative of a marshy habitat with a warm and moist microclimate, and a mesothermal climate, without
freezing winter temperatures.
A comparison of the fungal flora from Amphitheatre Formation with the known floras from the
more northern Bonnet Plume Basin, Yukon Territories and Iceberg Bay Formation, Axel Heiberg
Island, Northwest Territories, suggests a similar floristic composition, although the assemblage from
the Amphitheatre Formation contains fewer taxa with lesser diversity. This is probably attributed to a shift
in the climatic conditions from the periods of maximum warmth, which persisted during the lower
and middle Eocene Bonnet Plume and Iceberg Bay formations, to fluctuating conditions during the
beginning of the Oligocene as recorded in the Amphitheatre Formation.
Tertiary dinoflagellates were recovered from various parts of the basin, but the present work
focused on two wells with almost continuous recovery of Eocene (?) to Pliocene microfossils. Three
dinoflagellate assemblages were recognized from Well BY7-1-1: Assemblage 1, Homotryblium tenuispinosum
-Hystrichosphaeridium tubiferum Ass., distributed in interval of the Enping Fm., is characterized by
low abundance and low diversity. Hystrichosphaeridium
tubiferum and Hystrichokolpoma
rigaudiae occur alternatively throught the interval. Assemblage 2, Homotryblium plectilum- Cordosphaeridium gracile
Ass., distributed in interval of the Zhuhai Fm, is the most abundant and diverse assemblage.
Homotryblium plectilum occurs continuously throughout the interval. This species together with many others such
as Cordosphaeridium gracile, Homotryblium
pallidum, Homotryblium abbreviatum, Chiropteridium
lobospinosum, Glaphyrocysta exuberrus have their LAD at or close to the top of the interval. Assemblage 3,
Polysphaeridium zoharyi- Lingulodinium machaerophorum Ass., distributed in interval of the middle and upper parts
of the Zhujiang Fm.. Fossil abundance and species diversity decrease tremendously, but
Polysphaeridium zoharyi increases its relative abundance due to the disappearence of 2/3 species of Assemblage 2 from
this assemblage. Lingulodinium
machaerophorum occurs continuously throughout the interval and increases
its content in comparison to the underlying assemblage. It was not possible to distinguish a
dinoflagellate assemblage for the interval above Zhujiang Fm. due to its very low abundance and diversity, and lack
of key species. The age of the three assemblages was assigned to Eocene-Oligocene, late Oligocene
and Miocene respectively based on some key species which have certain world wide ranges, and
confirmed by data from calcareous nannofossils and foraminifera.
The paleoceanic environments of the basin during the Tertiary were interpreted on data from all
groups of microfossils, but dinoflagellates played an important role, particularly for the interval between
Enping Fm. and Zhuhai Fm.. The first transgression started possibly during the Eocene and ended in the
late Oligocene, advancing from the south towards the north in a relatively small area, resulting in the
Zhu-2 Seg under littoral to inshore environment. The second transgression, initiated in the early Miocene
and terminated in the middle Miocene, and reached most of the basin. The study area underwent
environmental changes from warm offshore to cooler inshore during this period.
Pollen analyses of late-glacial sediments dated between 15,000-10,000 years BP are beginning to
reveal the paleo-vegetation and climate of the continental shelf during this interval of likely human
migration. Some of the study sites are now submerged by postglacial sea level rise, but correlate well with
on-shore sediments from the Queen Charlotte Islands. Deglaciated landscapes were initially colonized by
sparse herbaceous vegetation, soon followed by a mosaic of sedge and grass communities with abundant
willow and crowberry. This tundra-like plant cover gave way to coniferous forest around 12,000 years ago
with the spread of pine, followed by spruce and hemlock. Rapid sea-level rise "drowned" shelf landscapes
soon after 10,400 BP, truncating the fossil record in lowland bogs and lakes. Preliminary interpretations
suggest that between about 13,500 and 10,000 years ago, a productive vegetation cover would have
provided suitable habitat for terrestrial fauna and supplied basic plant resources for human migrants.
Species encountered indicate an age range of Late Eocene to Recent. Most fungal spores observed
were long ranging with the exception of Ornatisporites
inequalis. Ramanunjam & Rao 1978 (Miocene to
Pliocene), Tricellaesporinites triangularis Sheffy & Dilcher 1971 emend Elsik 1992 (Restricted in the Miocene)
and Curvularia sp Boedijn 1933 (Miocene to Recent) which occur within the age range of late Oligocene
to Recent using sporomorphs and dinocysts from the same well samples. (Singano et al 1991) The
fungal assemblages indicates deposition during warm-humid palaeoclimate.
The diversity of palynomorph assemblages indicates a varied flora throughout deposition of the
Karoo strata. The presence of Kerogen type III for all samples indicates a gas prone hydrocarbon source
rock potential.
1
The presence of Spinachitina
maennili in the Cabot Head Shale and Strophomorpha
ovata in the Power Glen Formation suggest a Rhuddanian (early Llandovery) age for these Medina Group units.
Strophomorpha ovata is restricted to
the Coronograptus cyphus Zone of late Rhuddanian age in the type area of
Wales. Comparison of the Medina Group palynomorph assemblage at the Niagara Gorge and the
Hamilton, Ontario, area shows the differences between a near-shore assemblage and a shelf assemblage. The
Cabot Head palynomorph assemblage is dominated by acritarchs, including numerous acanthomorph
species; whereas, the Power Glen is dominated by a cryptospore assemblage.
The Neagha acritarch assemblage is significant in that it is present at the base of Brett et al.'s
Sequence II-A of the lower Clinton Group. The palynomorphs are distinctive from Sequence I (Medina
Group) which contains Strophomorpha ovata and
Spinachitina maennili among other diagnostic
palynomorphs including numerous cryptospores. It is also distinguished from subsequences within the lower
Clinton. For example, Sequence II-B (Lower Sodus Shale) contains the first appearance of
Beromia rexroadii and Ammonidium spp. In western New York, the Lower Sodus Shale and Williamson Shale are separated
by a middle Clinton unconformity (represented by Sequence III strata to the east). The Williamson Shale
and Rockway Member of the Irondequoit Limestone are assigned to Sequence IV (upper Telychian)
and contain Gracilisphaeridium
encantador and Deunffia and
Domasia species and diverse representatives
of Oppilatala. Sequence IV represents a global eustatic sea level rise during the latest Llandovery.
Within western New York and southern Ontario acrtiarch characterization of Sequences is possible with
finer subdivisions recognizable in some cases.
The wetlands are ideal environments for the conservation of pollen grains, which are one of the
tools for paleoenvironmental reconstructions. In the Colorado River Delta two wetlands exist, Cienega
El Doctor, of natural origin, and Cienega Santa Clara, which was generated by human activities in the
1970s. The former site was selected to show the Holocene environmental changes, and the latter, for the
most recent past. Both wetlands were cored during the 1997 summer. 5 cores were obtained from Santa
Clara and 3 from El Doctor; the longest one was 180 cm depth. These sediments will be analyzed for pollen
and dated with radiocarbon.
Additionally, the hydrological changes that generated both wetlands, as well as the Delta itself,
are being studied through the existent bibliography. Human activity has been very important in the Delta
in the last hundred years, through the establishment of rural and urban activities that displaced the
former desert landscape. On the basis of this study, our aim is to know the paleoenvironmental changes that
took place in the region, giving rise to the present landscape.
María Cristina Peñalba2
Instituto de Ecología, UNAM, A.P. 1354, Hermosillo, Sonora C.P. 83000, México
The first new data set corresponds to a series of packrat middens collected at 700 m elevation in
northern Baja California, in the Sonoran Desert. Pleistocene pollen assemblages suggest a
pine-oak-juniper woodland; the present desert vegetation established at the middle Holocene. The second series
was collected at 1500 m elevation in southwestern New Mexico, in the northern Chihuahuan Desert.
Late-Pleistocene, and Early to Middle Holocene pollen assemblages also suggest a pine-oak-juniper
woodland, and the present desert vegetation established at the Late Holocene.
This data corroborates the expansion of woodlands to both lower latitudes and altitudes during
the glacial times, and their retreat at the interglacials. They also indicate that the Baja California
Sonoran Desert did not represent a large Pleistocene refugium area. Moreover, pollen assemblages suggesting
a desert vegetation at 10,000 BP were recorded at sites below 300 m elevation in the northern and
coastal Sonoran Desert (Cole, 1986; Anderson & Van Devender, 1994), that could represent regions that
were covered by a desert landscape during the successive stages of the Quaternary. Glacial refugia of
the Chihuahuan Desert vegetation, due to higher elevation, should be found in much more restricted areas.
Rock-eval pyrolysis of 32 samples distributed in all sedimentary palaeoenvironments was
performed in order to establish their organic richness. On the basis of their organic content (TOC) a set of 14
samples was selected to analyse the relative abundance of different organic components. Seven groups of
organic components were distinguished:
*The project DGICYT PB96-0000-CO2- 01 has provided financial support to the realisation of this study.
Graphic correlation plots of the most complete outcrop sections at Rio Lora, Rio Lobaterita, and
Rio Chama indicate the presence of significant hiatuses in time, resulting from a combination of
non-deposition and erosion (marked by the presence of reworked Paleocene and Cretaceous
palynomorphs). A significant Late Paleocene to Early Eocene unconformity, as well as several intra Middle
Eocene unconformities appear to be caused by a drop in base level (sea level plus structural subsidence)
forming incised valleys over much of the study area. Other unconformities are present in the upper Middle
Eocene and Late Eocene and represent ravinement surfaces caused by transgressive marine reworking of
pre-existing units. These surfaces are often marked by the presence of dinoflagellates within the Upper
Eocene Carbonera Formation.
The palynological study of the well identified a flora of dinocysts, pollen and spores
comprising approximately 44 taxa. Although rich, diverse and well preserved palynoflora occur in the
Plio-Pleistocene, low abundances and poor preservation were recorded in the Eocene to Miocene interval.
This made it difficult to establish a precise age for the majority of pre-Pleistocene intervals.
Homotryblium tenuispinosum and H.
oceanicum indicate the presence of the Eocene.
Thalassiphora fenestrata was used to identify the Early Oligocene. The Pliocene was recognised by
Stereisporites cf. steroides,
Compositoipollenites rhizophours, Abiespollenites
sp., Alnuspollenites sp., and Pinuspollenites
spp., and the Pleistocene indicated by Polysphaeridium
zoharyi, Spiniferites mirabilis,
and S. membranaceus. The Pliocene-Pleistocene
boundary was also recognised at 1,100 m, indicated by the presence of
Polysphaeridium zoharyi.
Despite the use of cutting samples, the quantitative palynofacies approach produced some
useful results. The overall palynofacies characteristics indicate that the Well corresponds a more
proximal setting, this agrees with the fact that the Well is situated futher to the East and closer to the sediment
source. The stratigraphic variation in palynofacies character clearly demonstrate a lower regressive (distal
to proximal) trend, and an upper transgressive (proximal to distal) trend. These trends are best indicated
by the plankton:sporomorph ratio, and the percentage of total phytoclasts (terrestrial plant debris), AOM
and total palynomorphs.
Constrained clustering of palynofacies data was used to identify 2 palynofacies and 7 subunits.
The most proximal (regressive) interval may be useful in correlation; it may correlate with the strong
Late Miocene relative sea level fall indicated on the Exxon global sea level curve.
The residue is preserved in a flask filled with glycerinated alcohol, which after a week presents a
color related to the organic matter's thermal evolution and oil production in the basin. Additionally, slides
are made with the traditional palynological residue (attack with hydrochloric and hydrofluoric acids
and Schulze Solution, and elimination of mineral matter by heavy liquid separation), and selected
organic palynomorphs are analysed in these.
Quantitative and qualitative data obtained from alcohol and residual constituents provide the basis
for our stratigraphic conclusions related to the reconstruction of the basin evolution and its
petroleum potential. Results allow us to:
The Late Paleocene/early Eocene transition is the boundary between two floras which differ
both qualitatively and quantitatively. However, the change is not sudden but stepped and gradual.
Paleocene taxa seem to be of pantropical distribution, whereas Eocene assemblages are more restricted to
the Neotropics. The elsewhere well-documented global warming is proposed as the major cause for
these changes. Diversity, mainly controlled by richness, follows the same general trends than isotopic
temperature recorded in temperate regions. The extinct parent plant of
E. trianguliformis is tentatively proposed to be non-tolerant to higher temperatures, because of its absence during the early Eocene warm phase.
Palaeoecologically, although marsh and back-mangrove swamps dominated both Late Paleocene
and early Eocene assemblages, their taxonomic composition were different, especially in the inland
marsh forests. Mangrove components are scarce or absent through the whole sequence studied, suggesting
the absence of these communities during the time-interval analysed. A palaeoecological subdivision
into assemblage zones was not possible; instead, a recurrent pattern suggesting palynological cycles
was observed.
The cyclic pattern was studied using two different methodologies: palynocycles and ecologs.
Several palynological cycles were recorded and correlated with third-order global eustatic cycles. A
high-frequency cyclicity of ca. 220,000 year period was also found and related to Milankovitch
cyclicity (eccentricity). Both methodologies used were able to record the same cyclic patterns, and can be
considered complementary. Ecologs are easier to use, but have less interpretative potential. Palynocycles are
more complex, but also more descriptive, and help to detect small hiati. Diversity values showed their
maxima in the cycle boundaries, and their minima in the middle of the cycles. This has been interpreted in
terms of the different sources for palynomorphs in the two situations.
Pollen samples were obtained from herbarium material and field collections. The acetolysis
method was used in the preparation of nearly all material. The residues were mounted in glycerine jelly slides
and examined in light microscope.
The majority of taxa in the genus are characterized by 8-12 colpate, oblate monad pollen grains,
with echinate exine sculpturing. However, the variation observed in their morphology appears useful
for studies of species groups within the genus. The more important parameters in this study were the size
of equatorial diameter and the colpi number.
During the summer of 1990, we collected 40 surface samples in and adjacent to the Big Bend
National Park. These samples form the basis for our current study that adds a new dimension to the
understanding of pollen dispersion and distribution patterns over the Big Bend National Park region. Our study
also compares the advantages of using GIS, spatial modeling, and kriging to predict modern pollen
distributions over large geographical regions.
The palynological assemblages observed, present changes that are here related to the
sedimentary evolution. Integrated analyses of palynology, lithology and well logs are the basis for the
reconstruction of the sedimentary evolution in the area. The oldest marine sediments in this section correspond to
the uppermost part of the Lower Zuni Megacycle and contain a maximum flooding surface, correlative
with that dated as 111 Ma old. The rest of the sequence represents a major transgressive-regressive cycle
(Upper Zuni) and contains seven sequences correlative with global eustatic cycles. The Turonian
transgression dated as 91.5 Ma is the most important marine transgression in the entire section, and the
Maastrichtian-Paleocene sequence boundary dated as 68 Ma is clearly recognized.
Formely, Carboniferous strata of the Itararé Subgroup were considered to be in the Sakmarian C
age, corresponding to the informal "G" interval of the Neopaleozoic Paraná Basin classical
palynostratigraphical subdivision. Radiometrial data are missing, specially to the Carboniferous sequence. Furthermore,
there are no clear reference-levels with chronologically significant elements, which could permit wide
correlation and a more accurate age calibration among the available biostratigraphical schemes.
However, recently published papers have registered the presence of many important
biostratigraphical taxa which, back then were unknown in this basin. Although these taxa were unknown there, they
are common in assemblages from Gondwana and extra-Gondwana areas, mainly those ones from
neighbouring basins, whose Carboniferous succession is more complete. The most important species are:
Anapiculatisporites argentinensis,
Reticulatisporites muricatus,
Foveosporites hortonensis,
Granulatisporites varigranifer,
Raistrickia densa, R.
rotunda, R. paganciana,
Stenozonotriletes clarus, Cristatisporites
inordinatus, C. menendezii,
Ahrensisporites cristatus,
Plicatipollenites spp.,
Potonieisporites spp., and
Caheniasaccites spp.
These ones are some selected taxa from the previously described and they are illustrated in papers
from Monte Mor, Buri (coals) and Araçoiaba da Serra localities (São Paulo State).
Ahrensisporites cristatus,
Psomospora detecta (Buri) and
Spelaeotriletes balteatus (Paraná State) are just referred to in short communications.
The strata bearing these taxa are informally refered by some authors as the informal "Pre-G"
interval, underlying the "G" interval, the lowest in the Upper Paleozoic sequence. This fact evidences the
necessity to reformulate the present biostratigraphical scheme for the Brazilian Paraná Basin, of course, after a
better and more complete knowledge of its Carboniferous palynological succession. The suggested late
Carboniferous age (Westphalian and/or Stephanian ?) is corroborated by analysis of plants
(pre-Glossopteris flora), animal macrofossils (insects), and microfossils (foraminifera) data.
The palynological assemblages from these occurrences are generally characterized by a strong
diversification and abundancy of trilete spores, followed by monosaccate pollen grains with radial and
bilateral symmetry (striated are rare). These features are commonly verified in late Carboniferous
palynological assemblages from Australia, Africa and South America (Argentine) and are related to marine and
non-marine sequences with glacial influence.
The sequence was deposited on the eastern margin of the Cretaceous epeiric sea in the western
Tethyan realm. Three major hiatuses within the sequence indicate marine regression resulting in erosional
surfaces. The first hiatus is within the Cenomanian at the top of the Grayson/Del Rio Formations. The second
major hiatus is at the base of the Turonian over the top of the Lake Waco and Lower Eagle Ford (Britton
Member) Formations. The third hiatus is a minor one at the base of the Coniacian over the top of the South
Bosque/Arcadia Park Formations. Texan dinocyst assemblages have a worldwide correlation potential as
seas were interconnected with the circum-equatorial Tethys during the Late Cretaceous in a prevailing
warm environment.
Geological Survey of Canada, Calgary, 3303-33 Ave. NW, T2L 2A7, Canada
A combination of these palynological events and magnetostratigraphy provides a time
sensitive zonation for the Paleocene that can be applied regionally.
APTICORE in the Cismon Valley penetrated 131.8 m of limestones, marlstones and 'black shales',
with 100% recovery of good quality material.
Detailed multidisciplinary studies of the Cismon APTICORE, including integrated
biostratigraphy, magnetostratigraphy, cyclostratigraphy as well as organic, inorganic and stable isotope geochemistry,
have been undertaken by an Italian-American team of specialists and final results will be possibly published
in a comprehensive volume.
One hundred and fourty-six samples representing most of the marlstone and shale beds of the
Cismon APTICORE were processed and analyzed for palynomorphs: most of them yielded relatively rich
and fairly well preserved assemblages of both marine and terrestrially derived palynomorphs.
The present study focuses on the dinoflagellate cyst and acritarch fossil record.
The vertical distribution of 149 taxa is tabulated against the chronostratigraphy of the cored
section based on preliminary bio-magnetostratigraphic data and on lithostratigraphic correlations with
extensively studied outcropping sequences.
The biostratigraphic value of 33 selected species is discussed and compared with data known from
the Tethyan area. In particular, the FADs of Prolixosphaeridium
parvispinum and Odontochitina
operculata are confirmed as useful bioevents for the definition of a formal Lower/Upper Barremian boundary.
The acritarch Pinocchiodinium erbae
gen. et sp. nov. is described: due to its peculiar morphology
and significant abundance also in the 'black shales' of the anoxic Selli Level, it appears to be a good
marker species for the Aptian in the Tethys.
The dinoflagellate Nexosispinum hesperum brevis
subsp. nov. is described from the Upper
Hauterivian portion of the studied section and additional taxonomic remarks are made about other
dinoflagellate species, including the emendation of
Bourkidinium granulatum whose LAD well approximates
the Hauterivian/Barremian boundary.
The palynological results reveal a complete lack of marine palynomorphs on all sections, and
indicate that the ages of the samples are not older than late Eocene, nor younger than Pliocene. In some
sections, an early Miocene age can be assigned based on the presence of species such
as: Psilatricolporites
triangularis, Psilatricolporites
pachydermatus, Bombacacidites noremii,
Bombacacidites baculatus and Bombacacidites
brevis.
Optical evaluation shows structured organic matter, represented by well-preserved phytoclasts
of vascular plants. Thermal maturity analyses shows that the TAI ranges from 1+ to 2+, equivalent to
vitrinite reflectance values of 0.35 to 0.65, indicating an immature to slightly mature source rock. In the
subsurface, the thermal maturity are slightly higher, reaching a maximum of 3, equivalent to a reflectance of
0.9%. Complementary geochemical data from pyrolisis indicate that maturity levels range from immature
to early mature in the outcrop sections and mature (oil generation window) in the subsurface. The
biomarker %C29aa20S and
%C29bb20R also coincide with the information mentioned
As indicated in Van Krevelen plots, the kerogen is type II in the subsurface and type III in samples
from outcrops. This difference could be due to meteorization of the organic matter in the outcrop sections.
In spite of this probable change, the amount and quality of the organic matter in the rocks analyzed,
is adequate to consider them as possible oil source rocks. The abundance of oleanane and C29 steranes,
the isotopic values in the saturated and aromatic fractions, and other molecular parameters confirm
the terrigenous origin of the organic matter and present good geochemical correlation with some of the
oils studied. The source rocks in the outcrop sections did not generate the oils geochemically correlated to
these sources, but their equivalents in the subsurface reached better thermal conditions to expel oil into the basin.
ELF Exploration Production, CSTJF, 64018 - Pau Cedex, France
The data model is illustrated and described, and some technical solutions are exposed.
In addition to providing a record of local changes, the site proved useful in reconstructing
regional vegetation change. Variability in arboreal pollen types such as
Sequoia, Pinus, and
Quercus, as well as herbaceous types like Poaceae, Apiaceae, and Asteraceae are likely the result of catastrophic fires
and broader climatic changes. Vegetation transformation after European arrival is strongly marked
by declining levels of arboreal pollen and rapid increases of grass and mustard pollen.
All analyses were conducted on essentially the same sample suite. Maturity of palynomorphs based
on Thermal Alteration Index is approximately 0.9-1.0%
Roe and this is corroborated by biomarker
(sterane 20S/20R, terpane Ts/Tm ratio) data. The biostratigraphically significant dinocyst
Muderongia sp. A of Davey 1979 is present in the core samples. This dinocyst has a first appearance datum (FAD) in the
Upper Kimmeridgian Gdi(e) dinocyst interval (base of
Rotunda boreal Ammonite Zone) and the last
appearance datum (LAD) within the Portlandian Dpa (b) dinocyst interval biozone (top of
Kerberus boreal Ammonite Zone). Application of graphic correlation techniques utilizing additional key taxa (e.g., LAD's
of Senoniasphaera jurassica, Prolixosphaeridium
granulosum and Oligosphaeridium
patulum) indicate that the cored interval is wholly of Middle Volgian age. Counts were made of
Leiosphaeridia (small and large categories),
Pterospermella spp., organic-walled microforamifera linings, dinocysts, scolecodonts,
spores and saccate pollen. There is an inverse relationship between prasinophytes
(Pterospermella sp.) and organic-walled microforam linings. This is believed a response to anaerobic and
dysaerobic/aerobic environmental variations The kerogen composition of the core samples is amorphous/degraded
terrestrial structured dominant with subordinate amounts of wood fragments and palynonmorphs.
Total Organic Carbon (% weight TOC) values range from 2.64 to 7.76. Hydrogen Indices (HI) were low
(123-210) a probable reflection of the high maturity samples studied. Major bacterial input within the cored
interval is suggested by the high relative abundance of C31-C35 terpane and high C35/C34 terpane ratio.
Pyrolysis GC of core samples showed the presence of phenols which indicate a terrestrial land plant input.
Core plugs were taken at
vertical-horizontal-450 angles within the same horizon and tested for P-wave,
S-wave and anisotropy using pulse transmission techniques.
As the organic content of a shale increases both the P-wave and S-wave velocity decreases linearly.
Also, as the organic richness increases so does the magnitude of both P-wave and S-wave anisotrophies.
These results aid in imaging a horizon of interest and mapping lateral velocity variations.
Anisotrophic variations can be tied to Amplitude Velocity Optimization (AVO) techniques and could aid in
documenting source rock 'quality'. The integration of these techniques offers an encouraging beginning
for developing tools and methodologies to aid in the study of regional source rock presence and potential.
The sections examined are exposed on the banks of the Rio Chapiza, Rio Cuzutaime and
Rio Numbaime. Ammonites, foraminifera and palynomorphs from the Rio Chapiza and Rio Cuzutaime
(the most complete exposures) indicate a Albian through Santonian/Campanian age range for the
samples examined. The ammonites present within the sections include
Manuanceras carbonarum, Oxytropidoceras
stenzeli, Knemceras attenuatum, Sharpeiceras
occidentale, Engonoceras bravoense, Kanabceras
septemseriatum, Prionocycloceras
guayabanum and Prionocycloceras
pitalensis. Formanifera include Globotruncana
linneiana, Anomalina redmondi, Clavihedbergella
roblesae, Spiroloculina cretacea, Rugoglobigerina
cretacea, Heterohelix planata,
Globergina portsdowniensis, Lenticulina
comanchensis, Haplophragmoides
ecuadorensis, Globigernia washitensis and
Globegerina planispira. Palynomorphs (pollen, spores and dinocysts) include
Araucariacites, Balmeisporites,
Callialasporites, Canningia,
Cicatricosisporites, Classopollis,
Concavisporites, Coronifera,
Cyathidites Cyclonephelium,
Dingodinium, Diphyes,
Elaterosporites, Ephedripites,
Gabonisporis, Galeacornea,
Klukisporites, Leptolepidites,
Matthesisporites, Rousesisporites
and Sofrepites. The presence of
Elaterosporites, Galeocornea and
Sofrepites indicate that part of the Napo Formation can be assigned to the Albian-Cenomanian
Elaterate Province that approximates a paleoequatorial distribution.
An in-depth geochemical screening using Rock Eval/TOC (wt %) parameters was performed on
several samples samples for the Rio Chapiza section. TOC and HI ranged as high as 9.0% and 577,
respectively. The highest TOC values were complemented by elevated HI values indicating a oil prone
organic assemblage. S1 (thermally extracted
hydrocarbons obtained during Rock-Eval pyrolysis prior to the
onset of true pyrolysis; free hydrocarbons) and
S2 (hydrocarbons generated by kerogen decomposition
during Rock-Eval pyrolysis; kerogen cracking or pyrolyzate peak) values were also elevated for the high
TOC/HI samples.
Concurrent with drilling, initial palynologic studies were conducted at the Crary Science and
Engineering Laboratory, McMurdo Station, Ross Island. Rapid. Environmentally safe palynologic sample
processing was made possible by the use of a focused microwave digestion unit that scrubbed acid fumes.
In-situ and/or reworked dinoflagellate cysts (dinocysts), acritarchs (e.g., leiospheres and acanthomorphs),
and prasinophyte phycoma are present in 35 samples. Most of the in-situ palynomorphs are undescribed
taxa that currently have little biostratigraphic value. Diatom, paleomagnetic and strontium isotope
studies indicate the core is early Miocene and Quaternary in age.
The core can be divided into three intervals based on their palynomorph assemblages (Quaternary,
0-43.55mbsf; early Miocene, 43.55-99.10mbsf; and early Miocene, 99.10-147.69mbsf). Few
palynomorphs were found in the Quaternary section. Overall, the distinctive palynomorph assemblages are
interpreted to reflect deteriorating climatic conditions up-section at the time of deposition.
Although not age diagnostic in the CRP-1 core, the dinocysts are important because they are the
first in-situ Quaternary and Miocene dinocysts reported from East Antarctica, and the first recovered from
any firmly dated Neogene section in Antarctica. They demonstrate that cyst-producing dinoflagellates
were present in Antarctic waters during the Neogene and Quaternary.
Also significant are the acanthomorph acritarchs recovered from the CRP-1 core. They closely
resemble the cysts of extant, Antarctic autotrophic sea ice dinoflagellates. It is possible that some of
these acanthomorphs are actually dinocysts of sea ice dinoflagellates, and could be used as indicators of
such sea ice conditions. Overall, the CRP-1 assemblages are similar to Arctic marine palynomorph
assemblages that are used there as ice margin indicators.
