PALYNOLOGICAL RECOGNITION OF A CRETACEOUS-TERTIARY BOUNDARY SECTION FROM THE GUAYAQUIL FORMATION, ECUADOR

G. W. Barker, A. Aleman, W. S. Hale-Erlich, J. A. Stein, G. D. Wood, D. T. Pocknall, Carol S. Kazmer and Steve F. Barrett

Amoco Production Company, P.O. Box 3092, Houston, Texas 77253

A palynologically delineated Cretaceous-Tertiary boundary section has been recognized in an exposure of the Guayaquil Formation, Ecuador. The section consists of silicified limestones, tuffs, siliceous tuffs and tuffaceous shales exposed south of the Via Perimetral overpass at Via Daule, east of the city of Guayaquil.
Key dinoflagellate taxa delimiting the boundary include, oldest to youngest, Manumiella druggii, Cassidium fragile and Trithyrodinium evittii. An acme of Manumiella druggii marks the uppermost Maastrichtian. The first occurrence of Cassidium fragile signifies the base of the Danian. The first occurrence of Trithyrodinium evittii is approximately six meters higher in the section.
This sequence is extremely similar to that from the Cretaceous-Tertiary boundary of the Laidmore Formation, exposed at the Middle Waipara River section on the South Island of New Zealand. Within the Laidmore Formation the uppermost Isabelidinium superzone is marked by the last abundant occurrence of Manumiella druggii. The decrease in M. druggii abundance and development of Cassidium fragile acme zone with rare specimens of Trithyrodinium evittii delineates the base of the Tertiary.

LOWER (IBEXIAN) AND MIDDLE (WHITEROCKIAN AND MOHAWKIAN) ORDOVICIAN PALYNOMORPHS AND CONODONTS FROM THE MICHIGAN BASIN: EXPLORATION ASPECTS OF BIOSTRATIGRAPHY, THERMAL MATURITY, AND PALEOENVIRONMENTAL ANALYSES

Stig M. Bergström1, Merrell A. Miller2, Gordon D. Wood2, Gary W. Barker2, H. R. Lane2, Sheree Thompson2 and Holly Benson2

1 Department of Geological Sciences, The Ohio State University, Columbus, Ohio 43210
2 Amoco, P.O. Box 3092, Houston, Texas 77253

Samples from fifty-one Michigan Basin wells (cores and cuttings) and one outcrop (682 samples total) were investigated to support Amoco's central Michigan exploration and southern Michigan stratigraphic play. The study required integration of conodont and palynomorph data because these microfossils are essentially confined in the carbonate and siliciclastic facies, respectively.
A complete or nearly complete Lower Ordovician (Ibexian, conodont faunas C through E) and Middle Ordovician (Whiterockian) succession is present in the Michigan Basin. In the central part of the Michigan Basin, the Sauk-Tippecanoe cratonic sequence boundary occurs before the Archeognathus and Multioistodus faunas. At the southern margin of the Michigan Basin, this sequence boundary occurs at an unconformity between the Lower Ordovician (conodont faunas C or D) and the uppermost Whiterockian or lower Mohawkian. This significant sequence boundary (probably eustatically controlled) has correlation potential throughout the area of the warm-water faunal province and may be useful for correlating with the cold-water faunal province (Gondwana).
Two palynomorph assemblages have been recovered. The youngest was isolated from the Glenwood Formation (Middle Ordovician) and equivalents and is identified by new species of Conochitina and Villosacapsula. An older assemblage was also recovered from the Whiterockian consisting of new genera. A similar assemblage has been recovered from the Simpson Group (Oil Creek and McLish) of Oklahoma. Both assemblages have been recognized in most of the wells studied, and allowed reinterpretation of lithological correlations.
Conodonts (e.g., Leptochirognathus, Multioistodus, Paraprioniodus) and palynomorphs (e.g., abundant spheromorphs) indicate that the Whiterockian and Ibexian rocks were deposited in very shallow marine water (e.g., intertidal to subtidal) settings. The diversity of the Mohawkian assemblages from the Glenwood Formation indicates a normal marine depositional environment.
CAI and/or TAI indicate that the Middle Ordovician sediments in the basin center and western margins are peak to past peak for gas and past peak for liquids. The southernmost wells indicate peak generation for liquids.

POLLEN IN CLAMS, FLOCS, AND PELLETS: LESSONS FROM A TREK ON A DUTCH TIDAL FLAT

Gail L. Chmura

Department of Geography, McGill University, 805 Sherbrooke St. W., Montreal, Quebec H3A 2K6 Canada

Pollen in water and surface sediments from a tidal flat of the Dollard Estuary was analyzed to examine controls on transport and deposition. Pollen types important in both water and sediment samples were Ericaceae, Alnus, Betula, Chenopodiaceae, Corylus, Gramineae, Polypodiaceae, and Pinus. In the water samples, concentrations of pollen were compared to that of the mineral fraction. Pollen which are aerially dispersed in early spring, or by water, do not correlate to mineral fractions, yet those pollen types which are dispersed in warmer months do significantly correlate to the suspended mineral fraction. In warmer periods increased biological activity in the estuarine environment reduces concentrations of dissolved carbohydrates which are suspected to be the "glue" of micro-flocs. The seasonality of pollen production probably causes certain pollen types to be preferentially incorporated into flocs in the Dollard waters. Pollen analysis may provide a tool to elucidate temporal mechanisms of floc formation in other systems.
Analysis of tidal flat sediments indicates that pollen concentrations increase in troughs between ripples and at lower elevations where finer grain sizes accumulate. There is minimal evidence of selective sorting of pollen types. Ordination (using Principal Components Analysis) of pollen from sediments indicates that elevation and distance from the estuary mouth influence concentrations of all pollen, but have only minimal influence on percentages of individual types. Pollen deposition is probably affected by incorporation of pollen into fecal pellets which have relatively high settling velocities, thus reducing the occurrence of sorting during deposition. Analysis of stomach contents of locally common bivalves provides support for this hypothesis.
Thus, transport and deposition of pollen types cannot generally be predicted on the basis of hydraulic properties of individual grains, as floccules and pellets have variable densities and settling velocities. Pollen may be deposited with sediments coarser than would be expected based on the size and density of individual grains; thus caution should be taken when utilizing decanting in processing to assure that pollen incorporated into pellets are not discarded with sands.

MODERN DISTRIBUTION OF POLLEN AND
DINOFLAGELLATE CYSTS ALONG A NEARSHORE TRANSECT IN LOUISIANA COASTAL WATERS

Gail L. Chmura1, Quay Dortch2, Nancy N. Rabalais2 and R. Eugene Turner3

l Dept. of Geography; McGill Univ.; 805 Sherbrooke St. W; Montreal, Quebec H3A 2K6, Canada
2 Louisiana Universities Marine Consortium, 8124 Highway 56, Chauvin, Louisiana 70344
3 Department of Oceanography and Coastal Sciences and Coastal Ecology Institute, Louisiana State University, Baton Rouge, Louisiana 70803

Distribution of palynomorphs in surface sediments were examined along a river-to-sea water gradient of the Mississippi River mixing plume. This was a pilot study to determine if relative abundances of pollen and spores, dinoflagellate cysts, and foram test linings can be used to reflect the mixing of marine and fluvial waters along the Louisiana coast. Samples of surface sediments (1 cm) were taken in water depths of 12 to 20 m and processed with conventional palynological techniques, but excluding acetolysis. During the sampling period in July 1992, surface water salinities ranged from 26 to 32 ppt. Although sample sites fall along a general salinity gradient, ratios of pollen abundance to that of dinoflagellate cysts or forams do not reflect this trend.
The most important identifiable pollen types are Quercus, Pinus, Cheno-Am, and TCT which reflect components of the regional flora, but high abundances of reworked pollen in all samples suggest that fluvial sources are important throughout the transect. Cyst assemblages are generally characteristic of that expected in warm estuarine waters, and no direct relationship to salinity is noticeable among the thirteen cyst types identified. Interestingly, the most common and abundant cyst is Lingulodinium machaerophorum, yet its thecate equivalent, Gonyaulax polyedra, is seldom observed during monitoring of living dinoflagellate populations in these coastal waters. As sedimentation rates are exceptionally high in this area, sediments may be reflecting short-term variations in supply and transport of pollen, encystment of dinoflagellates and flow of the river plume.

POTENTIAL USES OF DNA TECHNOLOGY
IN ARCHEOBOTANY

Karen Clary

Botany Department, University of Texas at Austin, Austin, Texas 78712

Over the past decade, tremendous strides have been made using DNA technology. One significant breakthrough has been the development of the polymerase chain reaction (PCR) which permits miniscule amounts of DNA to be replicated millionfold. "Amplified" DNA can be used to obtain DNA "fingerprints" and from these, variation between taxa can be identified. The technique has been widely applied, from the identification of the DNA of individuals in forensics to the study of cladistic relationships of all living organisms. This technology has great potential to help solve longstanding archeobotanical and paleobotanical questions including the positive identification of micro-remains of cultivars and plant fragments from packrat middens. The presentation will focus on the potential use and problems of applying DNA technology to traditional pollen and macro- botanical studies.

THE LATE PLEISTOCENE DEVELOPMENT OF SAGEBRUSH STEPPE IN THE EASTERN GREAT BASIN

Owen K. Davis

Department of Geosciences, University of Arizona, Tucson, Arizona 85721

Fifteen wells drilled to bedrock in the Great Salt Lake, Utah, by Amoco Production Company, have provided the first record of Miocene - Pleistocene vegetation change for a single locality in North America. Pollen preservation is excellent and the concentration ranges from 200,000 - 20,000 grains cm-3 in the upper core, from 20,000 - 2000 grains cm-3 in the lower core.
Pine, fir, and Sarcobatus dominate the Miocene pollen assemblage and the pollen of aquatic plants and planktonic algae are rare. Few modern analogs exist for this assemblage. Miocene aridity is suggested by the high percentages of Sarcobatus and low percentages of aquatic pollen types. The pollen of "Tertiary exotics (elm, hickory, Shepherdia, Ostrya-Carpinus)" is rare but persistent.
The advent of modern plant communities is marked by increased percentages of Chenopodiaceae-Amaranthus and Artemisia during the Pliocene and early Pleistocene. However, modern analogs are primarily at low altitude south of the Great Salt Lake. Abundant (> 100% of upland) pollen of sedges (Cyperaceae), cattail (Typha), and other littoral taxa indicate a shallow freshwater marsh in the northern lake basin. These probably were fed by streams that were later captured by the Snake River, north of the GSL basin.
Dominance by sagebrush (Artemisia) and pine (Pinus) signals the modern distribution of plant communities, beginning ca. 0.9 Ma. Contemporary analogs for these late Pleistocene assemblages can be found in the Great Salt Lake Basin. Low percentages of aquatic pollen types mark the development of the contemporary drainage patterns in the basin.
Glacial-interglacial cycles are superimposed on the long-term vegetation sequence. During the Pliocene and early Pleistocene, Chenopodiaceae-Amaranthus (interglacial) and Artemisia (glacial) alternate. During the late Pleistocene the regular fluctuations are between basin-floor taxa (Cupressaceae, Sarcobatus, Gramineae) during interglacials versus montane conifers (Picea, Abies, Pseudotsuga) during full-glacials. Percentages of aquatic types are highest during interglacial-glacial transitions, when lake levels are intermediate and stream runoff greatest.

FINDING A NEEDLE IN A HAYSTACK: A COMPARISON OF METHODS

Glenna Dean

Archeobotanical Services, 7485 Sagebrush Road, Santa Fe, New Mexico 87505

Traditional palynology is aimed at characterizing the most common palynomorphs in a preparation, usually by means of a 200-grain count. When research questions require the finding of less common palynomorphs, however, the 200-grain count is inappropriate. Other methods used to find rare palynomorphs include screening to segregate the sample residue by size, and specialized microscopy such as scanning at lower magnification. These methods have the potential to present rare palynomorphs to the microscopist, but the researcher usually is unable to characterize them in other than descriptive terms that are unsuitable for numerical manipulation.
Intensive Systematic Microscopy (ISM) was developed to target rare palynomorphs while retaining the ability to describe the results in numerical terms. This goal is met by taking advantage of the presence of marker grains added to the sample during laboratory extraction, and by shifting the goal of the microscopy from counting palynomorphs to counting marker grains.
ISM uses ordinary laboratory extraction and slide-making procedures; sets the goal of the microscopy (number of marker grains) in advance, based on parameters set by the microscopist (x rare palynomorphs/unit of sample); allows the microscopist to predict how much time it will take to reach that pre-determined number of marker grains in a given sample, using estimates derived from the examination of 10% of the slide; allows the microscopist to predict the maximum potential number of rare palynomorphs/unit of sample in the unexamined sample, using observations gained from a single negative slide; and is applicable to the search for any rare microscopic item, provided that marker grains are used.

PALYNOFLORA FROM AN INDONESIAN MIOCENE LIGNITE, AND AN INTEGRATED PALEOENVIRONMENTAL RECONSTRUCTION

Thomas D. Demchuk1 and Timothy A. Moore2

1 Amoco Exploration and Production Technology, Biostratigraphic Support and Development, P.O. Box 3092, Houston, Texas 77253-3092
2 Coal Research Association of New Zealand, P.O. Box 31-244, Lower Hutt, New Zealand

Three palynofloral assemblages are recognized within a thick Miocene lignite from East Kalimantan, Indonesia. These three assemblages likely represent ecological evolution in the original coal-forming vegetation as peat accumulated and the geochemical and edaphic conditions within the mire changed through time. Recovered palynoflora can be ascribed to vegetation which are present and abundant in the modern-day coastal mires of Indonesia. Pollen of Calophyllum, Melanorrhea and Dactylocladus are present in all three of the assemblages.The first assemblage, characteristic of the lower portion of the seam, is composed of Calophyllum, Melanorrhea, Dactylocladus, Dacrydium, Palaquium, Polypodium and pollen of Malvaceae. This is interpreted as a mixture of mire floras and regional pollen. The second assemblage is comprised of Palaquium, Ilex, Elaeocarpus, Polypodium, Casuarina, Oncosperma and Brownlowia. This diverse assemblage is interpreted as representative of a bog-forest. The mangrove elements present are likely allochthonous in nature, but represent proximity of this bog-forest to a shoreline. The third assemblage, from the upper portion of the seam, is characterized by Shorea and other dipterocarpaceous pollen characteristic of a well-advanced, mature, bog-forest. Coal petrographic study reveals that most of the lignite is dominated by huminite macerals, with little inertinite and liptinite. This abundance of huminite is consistent with abundant woody angiosperm vegetation as identified from the palynoflora. The distinct lack of inertinite indicates that periods of peat oxidation and degradation were non-existent, suggesting a continued high water table within the original mire. From coal geochemistry, low sulphur values indicate terrestrial environments with no marine influence. This would be consistent with the interpretation of a bog-forest paleo- environment, with the mangrove pollen being allochthonous to the mire.

ALBIAN­CENOMANIAN PALYNOMORPHS FROM THE EAST TIBA-1 WELL IN THE NORTHWESTERN DESERT OF EGYPT

Nabil M. Aboul Ela1 and Hussein A. R. Mahrous1,2

1 Department of Geology, Cairo University, Egypt
2 Current address: CENEX, Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803

Palynological analysis of eleven ditch cutting and two core samples from the East Tiba-1 Well, Wadi Natrun Basin located in the northern Western Desert of Egypt, yielded rich assemblages of pollen grains, spores and dinoflagellates of Albian to Cenomanian age. The studied interval includes Abu Roash (G. Member), Bahariya and the top of Kharita Formations. The study stressed marine dinocysts because the pollen and spores were previously studied. Twenty-seven dinocyst species were identified. The ratio of marine and non-marine palynomorphs was calculated in order to discriminate palaeoenvironments. Six new palynological zones (Xiphophoridium alatum-Coronifera oceanica, Dinopterygium cladoides, Florentinia spp., Odontochitina rhakodes-Xenascus plotei, Odontochitina ancala, Oligosphaeridium spp.) were proposed based on the stratigraphic distribution of specific dinocysts. The previously studied late Albian, Cretacaeiporites scabratus Sub Zone was fixed at the Cenomanian-Albian border, while the late Albian was defined by the first downhole appearance (extinction) of Odontochitina ancala. The results of the study were correlated with mid-Cretaceous dinocyst assemblages recovered from other localities in Tethyan realm, Gulf of Mexico and North American, as well as the previously studied miospore assemblages from the East Tiba-1 well. A transgression began during the late Albian changed the depositional environment from lacustrine/fluvial (middle-late Albian) to inner neritic (earliest Cenomanian). This was followed by a brief regression to peat swamp conditions during middle early Cenomanian. During the late early Cenomanian a major transgression changed the depositional setting to middle-outer neritic as indicated by maximum diversification of dinocysts, followed by a regression to inner-middle neritic with fresh water influx during middle-late Cenomanian. The sharp changes in depositional environments through the studied sequence of East Tiba-1 Well may be related to the global sea-level fluctuations, associated with tectonic activity and sea-floor spreading during the mid-Cretaceous.

OCEAN DRILLING PROGRAM: RECENT AND
FUTURE EXPEDITIONS, WITH A SUMMARY
OF PALYNOLOGICAL RESULTS SINCE 1990

John Firth, Philip D. Rabinowitz, Timothy J.G. Francis, Jack G. Baldauf, Jamie Allan, Peter Blum, Peter Clift, Adam Klaus, Jay Miller, and Carl Richter

Ocean Drilling Program, Texas A&M University, College Station, Texas 77845

The Ocean Drilling Program (ODP) has now completed 58 internationally staffed expeditions and ten years of scientific ocean drilling. During the past year, ODP has operated in the Atlantic Ocean. Leg 153 cored on the lower crust and upper mantle in the MARK area of the Mid-Atlantic Ridge, studying a variety of tectonic, petrological, hydrothermal, and geophysical problems. Leg 154 piston cored a depth transect across the Ceara Rise to study the Cenozoic history of deep water flow in the Atlantic, and the relationship between deep water circulation, chemistry and Earth's climate. Leg 155 studied the sedimentary facies of the Amazon Fan, and their relationship to sea- level change. Leg 156 drilled a number of instrumented holes through the decollement zone and across the deformation front of the North Barbados Ridge accretionary prism, to define the interrelationship of deeply sourced fluids, tectonic features and geochemical signatures. Leg 157 studied the development of the Canary Basin in terms of the history of volcanic activity in the Canary Hotspot, the detailed evolution of the islands of Gran Canaria and Tenerife, and the formation and filling of the Madeira Abyssal Plain. Leg 158 investigated the fluid flow, geochemical fluxes and associated alteration and mineralization, and the subsurface nature of an active hydrothermal system on a slow-spreading ridge (TAG area).
After a drydock period, future expeditions include Leg 159 which will core an equatorial Atlantic transform margin to document its structure and deformation history, and the Cretaceous to Cenozoic history of the equatorial Atlantic oceanic gateway between the Central and South Atlantic. Legs 160 and 161 are a two-leg program to investigate the tectonic and paleoceanographic history of the Mediterranean Sea. Leg 160 focuses on the collisional tectonics between southern Europe and northern Africa, and processes associated with the origin of sapropels, while Leg 161 focuses on the evolution of the Alboran Sea as well as the origin of sapropels. Leg 162 is the second of a two- leg program to investigate Atlantic-Arctic gateways with the aim of reconstructing the temporal and spatial variability of the oceanic heat budget and the record of variability in the chemical composition of the ocean. Leg 163 will core on the Blake Ridge - Carolina Rise area to investigate one of the world's most laterally extensive gas hydrate fields.
Since 1991, palynologic research published in ODP Proceedings volumes has concentrated on Neogene and Quaternary pollen analysis and Cretaceous dinoflagellate biostratigraphy of the southern ocean, Australian margin, and western Pacific. Several Paleogene sections recovered on recent ODP legs in the North Atlantic will help to improve Paleogene palynologic stratigraphy.

A PRELIMINARY REPORT OF SELECTED SHARED MIOSPORES FROM THE PERMIAN AND EARLY TRIASSIC OF RUSSIA AND AUSTRALIA

C.B. Foster1, A.V. Gomankov2, O.P. Yaroshenko2, G.V. Dyupina3, and I.Z. Faddeeva4

1 Australian Geological Survey Organisation, P.O. Box 378, Canberra, Australia 2601
2 Geological Institute, Russian Academy of Sciences, Pyzhevskii Per. 7, Moscow, 109017, Russia
3 Institute of Geology and Geochemistry, Urals Branch, Russian Academy of Sciences, Ekaterinburg, 620219, Russia
4 All Union Scientific Research Geological Institute (VSEGEI), Sredny pr., 74, St. Petersburg, 199026, Russia

Spores and pollen which appear to be the same have been reported from both Russian and Australian Permian and Early Triassic assemblages. Plant megafossils, however, suggest that each country belonged to distinctly different floral provinces; Gondwanan (Australia) and Euramerian/Angaran (Russia). Therefore, do the shared taxa reflect migration of the parent plants, or parallel evolution?
Plant megafossil evidence suggests that at least four distinct phytogeographic provinces existed during the Late Paleozoic: Angaran, Euramerian (both recognized in Russia and the former Soviet Union), Cathaysian, and Gondwanan (Australia and other Gondwanan countries). Despite the megafloral differences, the palynofloral record from each of these areas contains some apparently similar taxa. Most obvious of these are the striate pollen of presumed gymnospermous origin. Such grains have been produced by at least three distinct parent plant groups, thus fueling the argument for parallel evolution, and downgrading the use of spores and pollen for intercontinental correlation.
Pollen which appears common to Permian palynofloras of the Salt Range, Pakistan, Australia (and other Gondwanan countries), and Russia, for example, include members of Weylandites Bharadwaj & Srivastava 1969 (as Vittatina pars), Lueckisporites Potonié & Klaus 1954, Scheuringipollenites Tiwari 1973, Protohaploxypinus Samoilovich 1952, and monosaccate pollen. We are able to confirm, however, that Gondwana Weylandites is structurally distinct from Russian taxa assigned to Vittatina. Similarly, more detailed observations on certain members of Protohaploxypinus and Striatopodocarpites Sedova 1956 from the Tatarian (Late Permian) of the Russian Platform show differences with Gondwanan forms assigned to these genera.
We have reexamined other Russian Permian taxa from the Urals and Siberian Platform which have been assigned to either Gondwana species or genera, and identified other conspecific Gondwanan forms, such as Microbaculispora tentula Tiwari 1965 [=Turrisporites trimodius (Andreeva) Drjagina 1988] from the Late Permian of the Kuznetsk and Tungus Basins. Turrisporites resistens Luber, which from published illustrations seemed similar to the Australian index form Pseudoreticulatispora pseudoreticulata (Balme & Hennelly) Bharadwaj & Srivastava 1969, is morphologically distinct, and unrelated to P. pseudoreticulata.
The early Triassic palynofloras appear more cosmopolitan, with the almost universal appearance of lycopod spores ( Aratrisporites spp., and Densoisporites spp.) and of spores of the Limatulasporites complex. Plant migration, particularly in the Early Triassic would account for the widespread occurrences of shared taxa.
The questions of either reflected plant migration or of parallel evolution, from the appearance of shared taxa, and the subsequent use of palynology for interregional correlation, will only be answered through continuing joint studies through interchange of samples and specimens, and studies of in situ spores and pollen.

A NEW SCRIPPSIELLA-LIKE CYST-FORMING
DINOFLAGELLATE

Julie K. Garrett1, 2, Jan H. Landsberg2, and Earnest W. Truby2

1 Current address: Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803
2 Florida Marine Research Institute, Department of Environmental Protection, 100 Eighth Avenue Southeast, St. Petersburg, Florida 33701

During June of 1993, the Florida Marine Research Institute staff investigated a non-specific fish fill that occurred in a man-made estuary in northeastern Tampa Bay. A bloom of a Scrippsiella- like species of dinoflagellate colored water in the area brown. Cysts and live dinoflagellates were identified in water samples collected from the estuary. Preliminary study of the theca indicated that the dinoflagellates was a Scrippsiella-like species with a plate formula of Po, x, 4', 2a, 7", 6c, 5s, 5''', 2''''. The pore plate is the characteristic Scrippsiella - Ensiculifera type. The cysts appear to be of the Pentapharsodinium type. Although the composition of the cysts have yet to be determined, they appear to be permanent, fossilizable cysts with a calcareous or "sporopollenin" wall. Further study is necessary to determine the exact taxonomy of this dinoflagellate species.

PALYNOLOGY OF A PORTION OF THE UPPER MANNING FORMATION (LATE EOCENE), TEXAS

Judith Gennett

Department of Geology, Texas A&M University, College Station, Texas 77843-3115

A core drilled through part of the Upper Manning Formation (Jackson Group, Upper Eocene) of Texas contains several transgressive-regressive cycles. Palynological analysis of one of these cycles supports environmental interpretations made without benefit of paleontology.
Momipites coryloides, Caprifoliipites tantulus, and Cupuliferoipollenites sp. are the most common palynomorphs in all but one sample. Finely sculptured monocolpates (mostly Arecipites sp.), likely representing plants in the palm family, dominate a mudstone sample believed to represent a swamp. One grain of Nypa occurs in the lowermost sample of the sequence, also a mudstone thought to represent a swamp. Disregarding the sample dominated by monocolpates, only a few significant percentage fluctuations occur. Notable are peaks of Nyssa sp., C. tantulus, and total spores near the center of the transgressive sequence. Dinoflagellates are very rare.
The sample from the monocolpate-dominated "swamp" mudstone has a relatively low (.45) Simpson diversity. Otherwise, diversities are uniformly high (.86-.91). Total palynomorph concentration is highest in the monocolpate-dominated sample, and lowest in the well-sorted transgressive sand above it. There are only moderate, seemingly random, differences in total concentration among the remaining samples. Reciprocal Averaging (Correspondence Analysis) segregates the fine-grained monocolpates on the first axis. A continuum with Quercoidites microhenricii, Sabal sp., and Salixipollenites sp. at one end and Cyrillaceaepollenites sp., Nyssa sp., and Ailanthipites berryi at the other forms the second axis. Momipites coryloides plots near the center of the second axis.

PEDIASTRUM ASSEMBLAGES IN TRIBUTARIES OF THE MISSISSIPPI RIVER

Colleen Gillespie and Gail Chmura

Dept. of Geography, McGill Univ., 805 Sherbrooke St. W, Montreal, Quebec H3A 2K6, Canada

A preliminary investigation into assemblages of Pediastrum has been conducted on water sampled from five tributaries of the Mississippi River (the Upper Mississippi, Missouri, Ohio, Illinois and Minnesota Rivers). Samples were taken as part of the USGS Mississippi River Project in the fall of 1991 on a cruise of the RV Acadiana. Three species were identified in our samples, P. boryuanum, P. simplex, and P. duplex and, whenever possible, identification to specific varieties was made. Among the most striking results were the differences in absolute concentrations of Pediastrum coenobia in the rivers; waters from the Missouri, upper Mississippi and Minnesota all contain roughly 25 coenobia per litre, and concentrations in waters of the Ohio and Illinois are an order of magnitude lower. The reason for this difference is as yet unclear, but could be due to variation in productivity and nutrient availability of source lakes, or simply differences in rainfall prior to sampling.
Species assemblages and diversity of Pediastrum vary between rivers. We assume differences in ecological requirements of individual species are the major control on distribution, although the nature of these differences is as yet unclear. Preliminary analyses indicate species patterns are related to neither differences in land use nor agricultural chemical influx. Review of prior research on Pediastrum suggests that pH and nutrient levels may be important, but the extent of empirical evidence on Pediastrum ecology is limited. We are presently investigating these and other parameters, such as regional lake chemistry and population density (which can have an impact on nutrient levels), which could explain variations in Pediastrum assemblages.

THE TRANSWESTERN PIPELINE EXPANSION PROJECT POLLEN ANALYSIS

Jannifer W. Gish

Quaternary Palynology Research, 150 Lisbon Ave. SE, Rio Rancho, NM 87124, and the Department of Anthropology, University of New Mexico, Albuquerque, New Mexico 87131

The Transwestern Pipeline Expansion Project (TPEP), which extended 97 miles from Bloomfield to Gallup, New Mexico, and then 200 miles west across Arizona, involved pollen analysis of 1178 samples from 90 archaeological sites and geomorphological study localities. This analysis was conducted over a two-year period, and depended on a number of special methods to meet the tight time constraints and the research goals of the archaeologists. Field methods included specifically structured sampling designs in order to initiate analysis of sites while excavations were ongoing. In-field pollen washes were used for mortuary finds in accordance with Native American memoranda of agreement. Sample analysis methods included slit counts, large-fraction scanning of Archaic samples, and attempts *unsuccessful) at accelerator mass spectrometry dating of pollen. Special research topics were addressed, such as dietary ethnicity in an Historic gold-mining town, the nature of pollen assemblages from traditional crop Navajo gardens, and the distinctiveness of tobacco (Nicotiana) pollen among Southwestern Solanaceae genera. The TPEP pollen results provided insight into Archaic , Anasazi, Senega, Navajo, and Historic Anglo subsistence practices, and environmental changes in Arizona and New Mexico.

THE USE OF BLEACH FOR EXTRACTION OF ARID SOUTHWESTERN POLLEN SAMPLES

Richard G. Holloway1, Philip Dering.2, and Vaughn M. Bryant, Jr..2

1 Quaternary Services, 9705 Toltec Rd. NE, Albuquerque, New Mexico 87111-4839
2 Department of Anthropology, Texas A&M University, College Station, Texas 77843-4352

Six soil samples were collected from Site LA 80377 in McKinley County, New Mexico. These were tested for fossil pollen using several extraction techniques. A sample of 26g of soil was used and three Lycopodium tablets were added to each sample to enable us to conduct pollen concentration studies of each sediment sample. All samples were initially processed by the same procedure. The final step was a heavy density separation using zinc bromide. Following this step, the samples were split in a 60/40 ratio using a graduated pipet. The 40% fraction was treated with acetolysis, washed, stained, and mounted in glycerine. The 60% fraction was bleached for 30 seconds, washed, stained, and mounted on slides for analysis. The remaining portion was exposed to bleach for an additional 30 seconds, washed, stained, and mounted in glycerine. A minimum 200- grain pollen count was made on each sample for each of the three treatments. In addition to the individual taxa, categories reflecting deterioration (such as broken, thinning, etc.) were recorded for pine (Pinus) and corn (Zea). Confidence Limits were calculated and the concentration values between techniques, by samples, were compared using Maher's Nullconc program to determine if the concentration values were similar. Initial results suggest significant differences in the concentration values obtained from the samples representing different techniques. In addition, smaller grains appear to decrease in number in the bleached samples while both corn and pine pollen are also more broken. This suggests that the use of bleach on arid southwestern samples has certain disadvantages and should be avoided whenever possible.

PRELIMINARY POLLEN ANALYSIS OF TEREBINTH RESIN FROM A LATE BRONZE AGE SHIPWRECK

Maria Jacobsen1 and Vaughn M. Bryant, Jr.2

1 Institute for Nautical Archaeology, P.O. Drawer H.G., College Station, Texas 77841-5137
2 Palynology Laboratory, Texas A&M University, College Station, Texas 77843-4352

During the excavation of a 1300 B.C. shipwreck, discovered in the Mediterranean near Uluburun, Turkey, archaeologists found samples of resin, believed to have been part of the original ship's cargo. Solid lumps of resin were found inside 120 amphoras, and chemical analyses of some of these samples have established that the resin came from the sap of Pistacia terebinthus trees, a species of pistachio indigenous to the Mediterranean region.
Studies of ancient texts reveal that terebinth resin was used as an aromatic, and was in great demand, especially in Egypt where it was burned as an incense during religious ceremonies. Reports also indicate that the resin was used in Egypt during the mummification process, and for pharmaceutical purposes. During the Bronze Age terebinth resin was an important cultural and economic product that was used by inhabitants in areas of the Mediterranean. Nevertheless, little is known about where the resin was produced, or how it was harvested.
Our preliminary study of the pollen, contained in some of these terebinth resin samples, demonstrates that it is possible to retrieve palynomorphs, even when resin has been submerged for more than 33 centuries under the sea. To date, we have identified more than 15 pollen taxa in the resin samples. We believe that continued pollen studies may enable us to determine where, when, and perhaps how these resins were produced.

PALYNOLOGICAL ANALYSIS OF THE GONDAR (ETHIOPIA) HANGING

David M. Jarzen

Palynology Laboratory, Canadian Museum of Nature, Ottawa, Ontario, Canada K1P 6P4

The restoration and conservation strategies for the Gondar Hanging, a late seventeenth or early eighteenth century card-woven silk hanging of religious, artistic importance, incorporated the results of palynological examination. Pollen grains associated with the hanging support historical evidence of the origins of the hanging within Ethiopia and subsequent movement to North America. Well-preserved grains referable to Olea and Justicia, native to Ethiopia, indicate that the hanging was, during its history, in Ethiopia. Pollen of Acer, Fagus, Fraxinus, Populus, Ulmaceae and others are considered contaminants, associated with the hanging subsequent to its removal from Ethiopia. Although a few fungal spores and hyphae were recovered from the associated debris, evidence of fungal attack or damage to the silk fibers was not seen, supporting other evidence that the hanging could withstand a thorough washing in preparation for an Ethiopian art exhibit.

TECHNIQUES IN MELISSOPALYNOLOGY

Gretchen D. Jones1 and Vaughn M. Bryant, Jr.2

1 USDA, CIPMRU, 2771 F&B Road, College Station, Texas 77845
2 Palynology Laboratory, Texas A&M University, College Station, Texas 77843-4352

Melissopalynology is the study of pollen identifiable in honey. By identifying and quantifying the pollen found in honey samples, one can determine the range of plant taxa utilized by honey bees and rate plant taxa as foraging resources.
Although there are standard techniques for pollen analyses of honey, the extraction techniques vary. There is considerable controversy over not only the amount of liquid needed to dilute honey for processing, but also the speed and the length of the centrifugation time needed for honey samples.
Historically, the liquid medium used to dilute honey is water. Because pollen in honey can have a specific gravity less than one, we examined the use of a low specific gravity liquid, ETOH, for honey dilution. We examined ten samples using two different centrifuge times, and compared water and alcohol as dilution agents for honey.
Pollen concentrations of alcohol-diluted samples were significantly higher than those of water- diluted samples. There was no significant difference in the number of pollen taxa recovered between the water long-spin technique and the alcohol long-spin technique. However, there was a significant difference between pollen recovery of the water short-spin technique versus the alcohol short-spin technique.
A new technique for extracting pollen from honey by filtration noted that non-filtration extraction methods used in melissopalynology produced serious inaccuracies. We compared five samples using first the alcohol dilution technique and second, the new filter technique. No significant difference was found in pollen recovery or in pollen concentration values between the two techniques. With both techniques, pollen counts of 400 or 500 pollen grains yielded significantly more taxa than lesser counts. Taxa in each frequency class remained constant for most pollen types between 200 and 500 grain counts.

ARE ALL SLIDES MADE FROM THE SAME POLLEN RESIDUE CREATED EQUAL?

Gretchen D. Jones1, and Vaughn M. Bryant, Jr.2

1 USDA, Crop Insect Pests Management Research Unit, 2771 F&B Road, College Station, Texas 77845
2 Palynology Laboratory, Texas A&M University, College Station, Texas 77843-4352

Many assume that slides made from a thoroughly mixed pollen residue are equal in pollen concentration values and in the number of taxa. To test this assumption we examined five separate microscope slides, each prepared with one drop of pollen residue from the same pollen-rich honey sample. We prepared a 500 grain count for each slide by first counting 200 grains and then counting three consecutive sets of 100 grains, for a total of 500 per slide. We prepared pollen concentrations, percentages, and taxon frequency classes for each of the counts, and noted the total number of taxa per count.
Differences in pollen concentration values among the four different pollen counts on the same slide (i.e., 200, 100, 100, 100) were not significant. For each of the five separate slides, each prepared from the same pollen residue, the calculated pollen concentration values, based on 500 grain counts, varied from a low of 265,984 per 10 g of honey to a high of 502,222 per 10 g of honey.
The total number of taxa found during the 500 grain counts of each slide varied from a low of 34 in one, to a high of 75 in another. We also noted that with each successively higher count (200+100+100+100), we found significantly more taxa. Overall, differences in the number of taxa found per count, per slide, were the most uniform between the 300-400 grain counts.
The five separate slides were not the same in regards to the number of taxa each contained. The difference in the number of taxa found among the five different prepared slides was greater than we expected. When combined, the total diversity of taxa found in the pollen residue, during the total count of 2,500 grains (500 from each of the five slides) totalled 130. Of this total number, none of the individual 500 grain counts accounted for more than 60% of the total number of taxa. We found four taxa occurred in only one slide count: Cardiospernum corindum, Polygonum sp., Liquidambar styraciflua, and Acer sp.
Berchemia scandens was classified as a secondary pollen type (i.e., 15-45%) in all five counts, and in all of the individual 200 and 100 grain counts, except for the 300, 400, and 500 grain counts made from one of the five slides. Rhamnus caroliniana and Toxicodendron radicans were important minor pollen types (i.e., 3-15%) in all five slides, and in all of the individual counts of each slide.

THE USE OF ENTOMOPALYNOLOGICAL TECHNIQUES IN THE POLLEN ANALYSES OF BOLL WEEVILS

Gretchen D. Jones, Pete D. Lingren, and Thomas M. O'Neil

USDA-Areawide Pest Management Research Unit (AWPMRU), 2771 F&B Road, College Station, Texas 77845

Previous pollen analyses of boll weevils, Anthonomus grandis Boheman (Coleoptera: Curculionidae), have been conducted by examining the midgut portion of the alimentary canal. In this study, the exoskeleton of five boll weevils were examined using scanning electron microscopy (SEM) to determine where pollen might be located on their bodies. We found attached pollen primarily on the head region. Thereafter, we examined the heads of 43 boll weevils, collected from pheromone traps in the Brazos River bottom, Burleson Co., Texas between 18 April and 5 June 1994. Pollen was found on 58% of the boll weevils examined. A total of 29 floral taxa were identified. Quercus sp. (oak) was found most frequently (13% of the samples). (black willow) and Prunus sp. (plum) were both found in 11% of the samples. To our knowledge, this is the first time that entomopalynological techniques have been applied to pollen analyses of the exoskeleton of boll weevils. This technique resulted in faster and more accurate identification of boll weevil pollen than previous techniques. As a result of this research, we believe the feeding behavior of boll weevils can be easily and rapidly ascertained.

POLLEN AND PHYTOLITHS: NATURAL COMPLEMENTS FOR ENHANCED DATA RECOVERY

John G. Jones and Dolores R. Piperno

Smithsonian Tropical Research Institute, Balboa, Republic of Panama

Phytolith research has long been recognized as an important paleo-research tool which can independently provide detailed information on prehistoric environmental conditions. When conducted in tandem with pollen studies, phytolith analysis can serve to greatly augment our knowledge of a region's past environmental conditions. Unique properties of biosilicate phytoliths make the determination of grassland and forest composition possible, areas where pollen analysis usually falls short. Further, phytoliths are frequently preserved in sediments where pollen grains have been lost through degradation. Stratigraphic palynologists should investigate this promising avenue of investigation.

FURTHER APPLICATION OF MICROWAVE TECHNOLOGY IN PALYNOLOGICAL PREPARATION

Rae Anthony Jones

Centre for Palynological Studies, University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom

Prior to the application of microwave heating, rapid digestion of rock samples for palynological analysis was extremly hazardous, envolving open vessel heating of 60% hydrofluoric acid. In the case of bituminous samples (e.g. North Sea Kimmeridge Clay), adequate rapid oxidation of kerogen prior to analysis was impossible using existing techniques.
Although pressurized microwave digestion systems have helped in solving the problems associated with rapid silicate digestion and rapid oxidation, they have not been well received commercially due to concerns about safety, sample quality and user-friendliness.
Preliminary investigations of a non-pressurized microwave digestion system have shown it to be more applicable to palynological processing than traditional pressurized systems. The system is particularly attractive for well site work where safe, rapid digestion, and oxidation of samples are required, especially during monitoring of directional drilling.
Other preliminary work suggests possible future benefits from the system will be automated sample digestion and oxidation, and the use of alternative and milder, less concentrated, reagents.

PALYNOLOGY OF A MARGINAL MARINE AND TERRESTRIAL PROGRADING DELTA SYSTEM, UPPER CRETACEOUS (TURONIAN), CENTRAL-WESTERN, NEW MEXICO

Kurtis C. Kelly1 and Aureal T. Cross2

1 914 Burchwood Dr., Washington, Illinois 61571
2 Department of Geological Sciences, Michigan State University, East Lansing, Michigan, 48824-1115

The Atarque and Moreno Hill formations, Zuni Basin, western New Mexico, represent lower Upper Cretaceous marginal marine and mainly non-marine sedimentary rocks, respectively, between Mancos Shale below and unconformable Tertiary strata above. This coal-bearing terrestrial sequence interdigitates northeastward with tongues of Mancos Shale. The Atarque Formation is a regressive series of coastal barrier bars which prograded northeastward into the Mancos seaway. Cuttings from three coal-test wells, and type locality roadside and canyon outcrops of the Moreno Hill Formation, and other outcrops were sampled for the study. Problems had to be overcome because palynomorphs in outcrop samples were partially restricted in diversity and quality due to deep weathering, and cuttings were contaminated with a Lower Cretaceous age drilling mud. Raw species data were grouped in 16 categories and subjected to Cluster Analysis. The 16 groups were a mix of key genera (Exesipollenites, Phimopollenites), families (Gleicheniaceae, Liliaceae, etc.), major groups (acritarchs, dinoflagellates, other gymnosperms, etc.), and morphological forms. Five pollen-spore assemblages were recognized.
Assemblage No. 1 characterizes the Rio Salado Member, (offshore marine) with Classopollis most abundant, of the prominent gymnosperm assembly, and increasing in abundance of Classopollis offshore; angiosperms common, gymnosperms and marine microplankton less common. Assemblage 2, dominated by marine microfossils, mainly dinoflagellates, represents nearshore and brackish water shales and siltstones, mostly Atarque and lowermost Moreno Hill Formations. Assemblage 3 is fern-dominated with Cyathidates comprising 30% to 40% of the population, mainly in gray or carbonaceous shales. Assemblage 4, also in gray or carbonaceous shales, is angiosperm-dominated. Ferns and gymnosperms are generally common and diverse. These palynomorphs represent freshwater overbank muds and flooded marshes. Assemblage 5 identifies coal and coaly shales. It is also dominated by angiosperms with greater abundance of large reticulate tricolpate pollen (e.g., Tricolpites sp.), common fern spores (e.g., Cyathidites), bryophytic spores (e.g., Stereisporites), some lycophytes, and generally fewer gymnosperms.

THE PROBLEM OF GAPS IN LATE CENOZOIC POLLEN RECORDS FROM ORGANIC SEDIMENT SEQUENCES IN AUSTRALIA

A. Peter Kershaw, Ann Bohte and Guy Holdgate

Centre for Palynology and Palaeoecology, Department of Geography and Environmental Science, Monash University, Clayton, Victoria 3168, Australia

The high degree of climatic variability and prevalence of fire in Australia should be major sources of concern to palynologists attempting to reconstruct continuous past vegetation records from accumulations of organic sediments. Permanent lakes are relatively rare and the majority of studies have to be undertaken from swamp deposits vulnerable to drying out and catching fire. Evidence for peat burning is recorded throughout the late Cenozoic and particularly well documented from historical evidence within the last 200 years. Despite this, little account, until recently, has been taken of this problem and where potential gaps have been suspected, particularly in recent sediments, there has been a desire to look for alternative explanations such as major changes in rates of sedimentation in inaccurate dating. In studies of older organic sediments, gaps have seldom been suspected.
Here, we examine a number of sequences from a variety of ages that serve to demonstrate the extent to which gaps can mislead stratigraphic, vegetational and environmental interpretation of pollen records. They include the substantial thicknesses of organic sediments composing the Miocene brown coal seams of the Latrobe Valley in Victoria, glacial volcanic crater swamp sediments in tropical northeastern Queensland and Holocene swamp sequences in southeastern Australia.

PALYNOSTRATIGRAPHY IN THE FORMER
SOVIET UNION

Judith K. Lentin

Lentin International Biostratigraphic, Suite 700, 665 8th Street SW, Calgary, Alberta, Canada T2P 3K7

Palynostratigraphy and the study of palynomorphs has been a popular scientific pursuit in the Former Soviet Union (FSU) for decades. Oddly, when compared to the rest of the world, most of the palynologists in the FSU are women. In the past there has been a strong concentration on knowing all there is to know about a single type section, with little extension of this information into a coherent correlation framework. This is partly due to the fact that many palynologists in the FSU have little or no background in geology. Indeed many of the palynologists were trained as sociologists before becoming magically transformed into "scientists" by transfer to a geology department for graduate research. Graduate research in the FSU is not accompanied by classroom training, which has perpetuated the "palynology as an independent science" attitude which restricts real application. A poor understanding of geological processes results in zonation schemes which are impossibly complex with floral zones based on a single outcrop.
Many western oil company palynologists now find themselves examining samples from the Tymen Pechora, West Siberian Basin, Moscow Basin, Pericaspian Basin, etc., and need a correlation framework with which to work. In the Tymen Pechora, Moscow Basins and the Pericaspian Basin, the dinoflagellate correlation frameworks from the North Sea have worked very well for the Mesozoic and Cenozoic. In the Paleozoic, the spore zonations of Britain and France are extremely useful. The North Sea correlations are not so viable in the West Siberian Basin (WSB) where the sediments are more related to those found in western and Arctic Canada. Although Paleozoic rocks form the basement complexes, particularly around the margins of the WSB, most of the reservoirs are Mesozoic, which results in an emphasis on Mesozoic and Cenozoic stratigraphic correlations.
Using a combination of Russian literature and Canadian literature on palynology, a framework for correlation has been created for the West Siberian Basin. Paleogeography plays an important role in understanding the changes seen across the Basin. However, a major challenge to the western palynologist is combating the preconceived notions of the Russian joint-venture partners "that real men don't do palynology."

A MIOSPORE (POLLEN AND SPORES) BIOZONATION MODEL FOR THE LATE CRETACEOUS TO MIDDLE EOCENE SUCCESSION OF AJIRE-1 WELL, ANAMBRA BASIN

F. A. Lucas

R & D, Nigerian National Petroleum Corporation, 49 Moscow Road, Port Harcourt, Nigeria

Biostratigraphically significant miospores recovered from Ajire-1 Well are used to establish a biozonation model for the Late Cretaceous to the middle Eocene succession of Anambra Basin. Ten assemblage biozones are recognized and designated A through J in the order of decreasing geologic age. These zones are: Leiotriletes triangulus, proxapertites cursus, Retidiporites magdalenesis, Monocolpites marginatus, Ctenolophonidities costatus, Straitricolpites catatumbus, Syncolporites corrugatus, Monocolpites baculatus, Anacolosidites sp. and Grimsdalea polygonallis.
Five Eocene diagnostic miospores (Mauriitidites crassiexinus, Grimsdalea Polygonallis, Forma 'C', Psilatricolpites okeziei and Proteacidites otamirinesis), originally described from the Upper Eocene Ogwashi-Asaba formation by Jan du chene, Onyike, and Sowunmi (1978) have their first stratigraphic occurrences in the lower Eocene section of the biozonation model.
The biozones are introduced for the first time in the southern Nigeria and have potential for the recognitions of major geologic boundaries in the basin.

THE PERMIAN­EARLY TRIASSIC HISTORY OF
THE FINNMARK PLATFORM, BARENTS SEA: PALYNOSTRATIGRAPHY & PALEOENVIRONMENT

Gunn Mangerud

Norsk Nydro a.s., Research Centre, 5020 Bergen, Norway

From Late Paleozoic time, sediments have been deposited over most of today's Barents Shelf. Along the northern margin of the Fennoscandian Shield, on the inner part of the Finnmark Platform, close to the present coast of Norway, condensed sections of the Upper Paleozoic-lowermost Triassic succession occur in a relative shallow position. During 1987 and 1988 IKU Petroleum Research cored most of this succession revealing excellent material for a.o. biostratigraphic studies. Exploration wells aiming at Paleozoic play models are later drilled further north on this platform.
The present study demonstrates diverse palynological assemblages ranging from Kungurian to earliest Triassic (Griesbachian) in age. Based on comparison with assemblages elsewhere in the present Arctic region, palynological correlations and ages are given for the following 3 palyno- zones: a Dyupetalum sp. - Hamiapollenites bullaeformis Assemblage Zone of ?Kungurian - Ufimian age, a Scutasporites sp. cf. S. unicus-Lunatisporites sp. Assemblage Zone of Kazanian - Tatarian age and a Lundbladispora obsoleta - Tympanicysta stoschiana Assemblage Zone of earliest Triassic (Griesbachian) age. The documentation of these datings and correlations will be discussed, followed by general outlines of the paleoenvironment in this area during the same period.

PALYNOLOGICAL EVIDENCE FOR TIME OF
EMPLACEMENT OF DIAMOND-BEARING KIMBERLITES, NORTHWEST TERRITORIES, CANADA

David J. McIntyre

Institute of Sedimentary and Petroleum Geology, Geological Survey of Canada, Calgary, Alberta T2L 2A7, Canada

Mudstone xenoclasts incorporated in the diatreme facies of several diamond-bearing kimberlite pipes in the Lac de Gras region (Slave Province), Northwest Territories, contain pollen spores and dinoflagellates. The palynological assemblages range in age from Lower Cretaceous (Albian) to Early Tertiary (Paleocene). Kimberlites that are now encased in Precambrian metamorphic rocks must have penetrated a succession of Albian to Paleocene strata resting on the Precambrian during Early Tertiary time. The date of emplacement is generally confirmed by a rubidium-strontium isochron age of 52+/-1.2 million years from phlogopite and whole rock samples from diatreme facies. The nearest known Cretaceous and Early Tertiary strata are some 300 km west of Lac de Gras. The palynomorphs preserved in the kimberlites show that Lower Cretaceous to Early Tertiary sediments were deposited as far east as the Lac de Gras region and the extent of the Cretaceous seas was greater than presently mapped. The sedimentary rocks were probably removed by Quaternary glaciations.

FORENSIC PALYNOLOGY: SOME CASE STUDIES FROM CRIMINAL AND CIVIL TRIALS IN NEW ZEALAND

D.C. Mildenhall

Institute of Geological and Nuclear Sciences, P.O. Box 30 368, Lower Hutt, New Zealand

In 1980 Colin Gary Christoffersen was convicted of receiving stolen property, namely deer antlers. This was the first time in New Zealand that palynological evidence had been used in court, and in this trial it formed a substantial part of the prosecution's evidence. This case received much publicity within New Zealand and led to an increase in the use of forensic palynological evidence. Since then about 80 Police investigations have involved forensic palynology, of which about 10 have resulted in court appearances by New Zealand forensic palynologists. In many other cases the forensic palynological evidence has been accepted in the courts without challenge. On occasions no evidence is obtained from our forensic studies.
The types of investigation in which forensic palynological evidence is useful are as varied as the number of investigations. Further; violent assault, including rape; theft, burglary, and breaking and entering; importation, cultivation, sourcing, and supplying of illicit drugs; location of missing persons; disproving or proving alibis; and smuggling are all examples of situations in which forensic palynological evidence has been used. While forensic palynology will rarely prove that an individual perpetrated a crime, it is occasionally useful in connecting items or individuals to the crime scene. It is also useful in providing the Police with direction, i.e., where to look for the original source of items or people involved in some way with a criminal activity; even then the evidence obtained is not firm enough to be useful in a court of law.
Ideally forensic palynology should be used in conjunction with other forensic geology or isotopic techniques. In practice, the cost of using all these techniques together is such that what is usually used is the least expensive method coupled with the technique that is most likely to give a result. For example, the spores and pollen, and the morphology of sand grains found on the abandoned clothing of a missing (murdered) person indicated that the body was most likely to be found close to the banks of a river. The Police had been looking previously on the surrounding hillsides, where the clothing was originally found. The forensic geology information was not available to the Police at the time they were searching so the search was abandoned before the body could be found. However, the palynological evidence was in a very small way instrumental in obtaining a murder conviction without the existence of a body.
Many other aspects of the use of forensic palynology can be demonstrated.

LATE PLEISTOCENE PALYNOLOGY OF THE PETONE DRILLHOLE, LOWER HUTT VALLEY, NORTH ISLAND, NEW ZEALAND

D.C. Mildenhall

Institute of Geological and Nuclear Sciences Limited, P.O. Box 30 368, Lower Hutt, New Zealand

A mid to late Pleistocene coastal sedimentary sequence drilled to a depth of 311.2 m (299 m of which was composed of Quaternary sediments) at Petone, near Weelington, New Zealand, consists of fossiliferous sands, silts, clays, and occasional peaty and less carbonaceous horizons, and provides a discontinuous pollen profile extending from the Postglacial to possibly as old as 350,000 years ago. The sequence includes 4 major cold periods and 4 major warm periods with minor fluctuations recognized within some of these periods.
Major vegetation shifts from warm to cool in the Petone area were followed by major periods of erosion and/or deposition of coarse gravel resulting in major breaks between pollen-bearing sequences. Nine biozones can be recognized in the pollen profiles and these are related to the lithology, local and regional surface formations, local climatic stages, and tentatively correlated with oxygen isotope stages. Oxygen isotope stage 5 can be recognized because it contains taxa restricted today to the north of North Island, indicative of the maximum warmth recognized in the study. This comparison and the radiocarbon dated Postglacial form two tie points for an attempt at correlating the sequence with the oxygen isotope scale.
A discriminant function analysis of the complete sequence, using as an initial basis a comparison between the Postglacial and Last Glaciation spores and pollen assemblages, provides a graph indicating relative fluctuations in the vegetation, which bears a close similarity to the oxygen isotope scale for the same period of time. Abrupt changes in climate are indicated between and occasionally within each glacial and interglacial.

SURFACE EMBEDDING OF FOSSIL POLLEN FOR TIME- AND COST-EFFECTIVE ULTRAMICROTOMY (TEM) AND MULTIPLE MICROSCOPY (LM, SEM, TEM)
OF SINGLE GRAINS

Lynne A. Milne

Departments of Earth Sciences and Botany, The University of Queensland, Brisbane 4072, Australia

Transmission electron microscopy (TEM) is a valuable aid to pollen morphological studies and taxonomic comparison of fossil and modern pollen. Despite its applicability, TEM of pollen, in particular that of fossil pollen, is not common because of the time and expense involved. The general method for preparing pollen for TEM was originally devised for modern pollen, en masse. For fossil pollena and single grain studies, preparation has variously been modified to expedite grain location in the resin block, and to minimize specimen loss when trimming down to the grain. Pollen surface-embedding was developed to eliminate these problematic steps, so that small fossil pollen compressed in the plane to be sectioned, can be ultra-thin sectioned confidently, quickly, and inexpensively. Additionally, correct grain orientation is assured, and solution changes during preparation are simplified to prevent loss of specimens. The surface-embedding technique enables light microscopy (LM), scanning electron microscopy (SEM), and TEM, to be performed on the same pollen grain without the need for delicate grain manipulation between the three procedures.

CORRELATING PALYNOFACIES ASSEMBLAGES WITH SEQUENCE STRATIGRAPHY IN LATE CAMPANIAN SEDIMENTS OF THE BOOK CLIFFS, EAST-CENTRAL UTAH

Francisca E. Oboh

Department of Geology and Geophysics, University of Missouri-Rolla, 125 McNutt Hall, Rolla, Missouri 65401-0249

The Book Cliffs have been the subject of numerous sequence stratigraphic studies because of the excellent exposures of Cretaceous strata that can be traced for more than 100 miles through Utah and western Colorado. Sedimentological and palynological techniques were used to study the Kenilworth, Grassy and Desert Members of the Blackhawk Formation, and the Castlegate Sandstone (late Campanian) in east-central Utah, with a view to defining the diagnostic criteria for recognition of depositional environments and systems tracts. Eight sections were measured in a basinward direction from northwest to southeast, in several well documented and sequence stratigraphically constrained localities. Sedimentological criteria were used to establish depositional environments, parasequences and sequences.
Forty-eight samples yielded twelve categories of dispersed organic matter, including sporomorphs, fungal remains, marine palynomorphs, cuticle fragments, wood, black debris, degraded bundles, amorphous organic matter and resin. These were analyzed using multivariate statistical techniques. Six palynofacies assemblages, designated A-F, were identified from cluster analysis, and they were compared with five sample groups defined by both principal components analysis and detrendent correspondent analysis. Marine palynomorphs, degraded bundles, black debris, sporomorphs, and to a lesser extent, cuticle and resin played a greater role in defining the palynofacies assemblages. Based on the sample composition of the palynofacies assemblages, two diagnostic assemblages were recognized: palynofacies B was dominated (92%) by shoreface heteroliths and marine shales from the highstand systems tract, while palynofacies E was primarily composed (92%) of fluvial to fluvio-estuarine sediments from the lowstand systems tract.

LATE EOCENE AND EARLY OLIGOCENE PALEOFLORISTIC PATTERNS IN SOUTHERN
MISSISSIPPI AND ALABAMA

Francisca E. Oboh1, Carlos A. Jaramillo1, and Lisa M. Reeves Morris2

1 Department of Geology and Geophysics, University of Missouri-Rolla, 125 McNutt Hall, Rolla, MO 65401
2 404 Fairview Drive, Blue Springs, MO 64014

Five measured sections of late Paleogene strata in southern Mississippi and southwestern Alabama contain diverse palynofloras which have been used to interpret the vegetation pattern. Two localities contain exposures of the latest Eocene Shubuta Clay of the Jackson Group and the early Oligocene Red Bluff Clay of the Vicksburg Group. The other three localities comprise formations of the Vicksburg Group, and of these, the St. Stephens Quarry in southwestern Alabama is the most complete, with additional samples from the overlying Chickasawhay Limestone. Two hundred and sixty sporomorph taxa have been divided into eleven taxonomic groups on the basis of abundance, and they are spores, bisaccates, Sequoiapollenites-Cupressacites, Momipites, Carya, Quercoidities Fraxinoipollenities, Cupuliferoidaepollenites, Cupuliferoipollenites, Cyrillaceiopollenites, Siltaria. The objective of this subdivision was to identify any relationship between the taxonomic groups and stratigraphy.
The Oligocene boundary is marked by a slight increase in Momipites and Quercoidites whereas Sequoiapollenites decreases in abundance. During Vicksburgian time observed changes among the diverse taxa are related to sea-level fluctuations, facies changes and diagenesis. In southwestern Alabama and southeastern Mississippi, Sequoiapollenites-Cupressacites and Quercoidites are the most important components, the former being more prominent in transgressive and highstand deposits of Mint Spring Marl, Marianna Limestone and Glendon Limestone. The Floristic pattern in the Mint Spring and Glendon in southwestern Mississippi (where the Marianna Limestone has been replaced laterally by the Mint Spring) is different from that in the eastern part of the study area: Sequoiapollenites-Cupressacites taxonomic group is a minor element whereas spores and other gymnosperms are more prominent in the assemblage. The Byram palynofloras are similar to those of the Bucatunna and Chickasawhay in southwestern Alabama. In the Vicksburg Group, increases up to the order of 7-30% were recorded for Siltaria, Quercoidites and Cyrillaceiopollenites over their abundances in the Shubuta Clay. With the exception of its increase in the Red Bluff, Momipites is generally more abundant in the Shubuta Clay than other Vicksburg formations.
Presence-absence data from three sections which had at least nine samples were analyzed using average linkage cluster analysis, in order to identify any possible "ecological" groups in the samples. Out of two hundred and sixty taxa, five cluster groups containing eighteen taxa (or approximately 7%) are common to all three sections. Group A comprises two species of Sequoiapollenites; group B is composed of Carya simplex, Siltaria cf. S. scabriextima, Quercoidites microhenrici, Momipites coryloides and Ulmipollenites thompsonianus; group C comprises Laevigatosporites haardti, Cupuliferoidaepollenites cf. C. selectus, Cupuliferoidaepollenites liblarensis, Cupressacites hiatipites, Cupressacites sp. 1, Quercoidites inamoenus, Cyrillaceiopollenites megaexactus, Momipites microfoveolatus; group D is composed of Salixpollenites parvus and Cicatricosisporites dorogensis; and group E has Fraxinoipollenites spp. It is unclear at this time if these five groups represent true ecological communities. Overall results indicate there was no significant paleofloristic change from the latest Eocene to the early Oligocene.

UPPER JURASSIC (MIDDLE OXFORDIAN TO LOWER KIMMERIDGIAN) DINOFLAGELLATE CYSTS FROM THE NORTHEASTERN CHIRICAHUA MOUNTAINS, SOUTHEASTERN ARIZONA

Gary Olmstead1, William Cornell1, and Gerald Waanders2

1 Department of Geological Sciences, The University of Texas at El Paso, El Paso, Texas 79968
2 Waanders Palynology Consulting, Inc., 1611-Crancho Santa Fe Rd., San Marcos, California 92069

Eleven genera and nine species of dinoflagellate cysts have been described, for the first time, from the Upper Jurassic sequence exposed within the northeastern Chiricahua Mountains of southeastern Arizona. This sequence is approximately 900 m (2,700 ft) thick, of which 425 m (1,275 ft) is characterized by open marine facies consisting of intrabasinal turbidities, pelagic sediments and submarine volcaniclastics. This sequence is underlain unconformably by the Permian Concha Limestone and is thrusted to the southwest over the Cretaceous Bisbee Group. These marine strata were deposited during a period of active rifting accompanied by a northwest transgressive incursion into a half-graben depositional depression known as the Bisbee Basin. Progressive infilling of Cretaceous Bisbee Group sediments resulted in a succession of Upper Mesozoic strata that is unique to this region of the southwestern cordillera.
An age ranging from Middle Oxfordian to lower Kimmeridgian has been assigned to these marine strata based on key ammonite genera Dichotomosphinctes, "Discosphinctes", Ochetoceras, Phylloceras and Lytoceras. This age range is substantiated by coexisting species of Gonyaulacysta jurassica, Cribroperidinium granuligera, Sentusidinium rikoulti and Tubotuberella lurida.
The abundance and diversity of dinoflagellate cysts, in conjunction with Tethyan ammonites, indicates a time of normal-open marine conditions within this region. Thus, this raises questions as to the relationship between the opening of the Bisbee Basin and Hispanic corridor to that of the Yethyan and Pacific realms. This study combined with future research in southern Arizona and northern Mexico will provide invaluable information to help further our understanding of basin evolution, species diversification, as well as regional and intercontinental stratigraphic correlations for the Upper Jurassic.

COMMUNITY SUCCESSION IN THE CONTEXT OF CYCLIC SEA LEVEL CHANGE: AN EXAMPLE FROM THE EOCENE GULF COAST OF TEXAS

M. K. Phillips, A. Raymond, T. E. Yancey and J. A. Gennett

Deptartment of Geology and Geophysics, Texas A&M University, College Station, Texas 77843

Three Late Eocene parasequence-scale cycles of deposition are present in exposures of the Manning Formation in the Lake Somerville spillway section, each containing a lignite at the base of the cycle. The lowest lignite (and the three depositional cycles) overlies a sequence boundary which in turn overlies a paleosol with common large diameter root traces. The upper two lignites overlie exposure surfaces of apparent short duration, developed on shore-zone sandstones. In all three lignites, a Momipites-dominated palynomorph assemblage overlies either a fern-dominated or a fern-rich palynomorph assemblage found in the basal portion of the lignite seams.
Sandy mudstones with marine microfossils and a diverse trace fossil assemblage (including Planolites, Thalassinoides, Gyrolithes, and Paleophycus) deposited in a shallow shelf environment, overlie the two lower lignite seams. The upper lignite seam contains an interbedded lacustrine clay and in turn is overlain by probable lacustrine deposits. Varied marine microfossils (including the diatoms Coscinodiscus and Stephanopyxis, and sponge spicules) in the sediments overlying the lowest lignite seam suggest that the maximum flooding surface for the sequence occurs within the lowest parasequence. In lignites overlain by marine sediments, a palynomorph assemblage dominated by Cupuliferoipollenites is present in the highest part of the lignite, overlying the Momipites-dominated assemblage, suggesting that a salt-tolerant community produced the Cupuliferoipollenites assemblage. The Cupuliferoipollenites assemblage does not appear at the top of the upper lignite seam, which is probably overlain by lacustrine sediments.
At Lake Somerville spillway, fern-dominated assemblages, Momipities-dominated assemblages, and Cupuliferoipollenites-dominated assemblages appear to represent end-member assemblages along two ecological gradients, from disturbed shallow to deeper fresh water swamp communities (fern-Momipites) and from fresh to salt water (Momipite-Cupuliferoipollenites). Similar communities probably existed in the swamps that formed other Gulf Coast lignites of similar age such as the San Miquel lignite deposit. However, at San Miquel, the end-member assemblages are less distinct. The allogenic community succession may be very clear in the three Lake Somerville lignites due to rapid accumulation rates.

MIOCENE PALYNOLOGY OF THE
GULF OF SUEZ, EGYPT

David T. Pocknall1 & Abu Bakr Abd-Elmoneim Ahmed2

1 Amoco Production Company, Houston, Texas
2 Gulf of Suez Petroleum Company, Cairo, Egypt

Lower and Middle Miocene rocks in the Gulf of Suez consist predominantly of marine shales and sandstones overlain by thick Middle and Upper Miocene evaporites. Previous analyses using foraminifera, nannofossils, and ostracodes have provided a biostratigraphic framework that has been applied successfully for oil and gas exploration in the gulf. The present study was designed to investigate whether palynomorphs (dinoflagellates, spores, and pollen) could help refine and enhance the existing biostratigraphy. Eight wells were studied; most contained diverse assemblages of palynomorphs, especially in the evaporitic section where foraminifera are not present. Dinoflagellates provide age calibration because many of them have age ranges that have been established from localities outside the Gulf of Suez region. Spores and pollen are abundant in some sections; however, their biostratigraphic value is unclear.
Dinoflagellates enhance the existing foraminiferal, nannofossil, and ostracode biostratigraphy in the Lower to Middle Miocene section, and they provide age information and facilitate well correlations in the Middle to Upper Miocene evaporites. Significant species are as follows: Cordosphaeridium cantharellum, Distatodinium craterum, Pentadinium laticinctum, Cribroperidinium tenuitabulatum, Palaeocystodinium golzowense, Selenopemphix brevispinosa var. brevispinosa, Labrynthodinium truncatum, Reticulatosphaera actinocoronata, Hystrichosphaeropsis obscura, and Spiniferites pseudofurcatus. Many new dinoflagellate species have been recorded but are yet to be formally described.
Lower to Middle Miocene lithostratigraphic units (Nukhul, Mheiherrat, Kareem, and Belayim formations) generally contain higher abundances of dinoflagellates than spores and pollen, and are considered to have been deposited in inner neritic to upper bathyal depths. Occasional influxes of the freshwater alga Pediastrum, indicates that freshwater plumes existed at times during the Early and Middle Miocene. In the Middle to Upper Miocene evaporitic section (South Gharib and Zeit formations), dinoflagellates are abundant, and shallow marine species such as Polysphaeridium zoharyi, Lingulodinium machaerophorum, and Tuberculodinium vancampoae predominate. Their presence, together with abundant spores, pollen, Pediastrum, and Botryococcus suggest marginal marine, brackish water, or lacustrine environments for much of the evaporitic section. Although pollen diversity is high, the most common groups are Gramineae, Cyperaceae, and Chenopodiaceae.

STEINKERNS AS POLLEN TRAPS

Fredrick J. Rich

Department of Geology and Geography, Georgia Southern University, Statesboro, Georgia 30460

The southeastern United States is host to a wide variety of sedimentary deposits. They range from Cretaceous to Holocene age, and many are richly fossiliferous. Establishing the strata depends increasingly upon the use of palynology. A disadvantage one faces is that the existing flora is very much like the ancient ones. The threat of contamination of ancient samples with pollen produced by living plants, and which are indistinguishable from the fossil pollen, requires very careful sample collection and preparation. Even the best field and laboratory procedures, however, cannot prevent natural contamination by stratigraphic leak, reworking, and other phenomena which are beyond the control of the palynologist. Recently, steinkerns, or sediment in-fillings of bivalves and gastropods have been investigated as sources of pollen-bearing sediment. Not only are the steinkerns abundant and productive of pollen (in some cases more productive than the surrounding sediment), but they have a finite (though probably undetermined) filling time, thus representing a sample which accumulated over a very limited time. They also provide pristine samples when the sample collection and storage history is suspect (i.e., when contamination of matrix might have occurred). Finally, they provide geochemically isolated samples which may have escaped oxidation or substantial changes in pH in a particular formation. Shells of Polinices, Crassostrea, Geukensia, Dinocardium, Ostrea, and Ecphora have all been used to interpret floras of Late Pliocene, Pleistocene, and Holocene age.

POLLEN AND SPORES AS STRATIGRAPHIC INDICES TO THE NORTH DAKOTA PALEOCENE

Eddie B. Robertson

Math and Science Division, Reinhardt College, Waleska, Georgia 30183

Seven pollen and spore assemblage zones, based on presence, absence and frequency acme, are established for the Paleocene of the Williston Basin. The stratigraphic controls for the study were part of the 1975 revision of the state geologic map prepared by the North Dakota Geological Survey. A composite section through the Tertiary from the Cretaceous Hell Creek to the Early Eocene upper member of the Golden Valley Formation was completed in the valley of the Little Missouri River. The Cretaceous is characterized by the Aquilapollenites Zone. Three sections cross the Hell Creek - Tullock boundary. In all three, and in two that also sample the base of the Tullock, a fern spike is detected that may represent the fern spike found elsewhere associated with the end of the Cretaceous. After a dramatic climatic deterioration, the sub-tropical flora of the Maestrichtian Hell Creek is replaced by a conifer flora dominated by members of the Taxodiaceae. The Early Paleocene Tullock is divided into a Kurtzipites-Syncolporites Zone and a Wodehouseia-Azolla Zone and is capped by the Triporopollenites-Reticuloidosporites Zone. The Wodehouseia zone is transitional and appears to be almost Danian in character. By the mid-Paleocene (early Tiffanian), the taxodiaceous flora of the early Paleocene is replaced by a transitional betulaceous-dominated hardwood mix. Elements of the betulaceous flora include representatives of Betula, Alnus, Corylus and Ostrya-Carpinus. The Lebo is characterized by the Tricolporopollenites kruschii Zone. The lowest 3/4 of the Tongue River is characterized by the Pistillipollenites Zone. The mid-Paleocene betulaceous flora is replaced by a more mesic juglandaceous-ulmaceous flora. Members of the flora include Carya, Pterocarya, Ulmus and Zelkovia-type forms. The upper 1/4 of the Tongue River, the Sentinel Butte and the lower member of the Golden Valley are characterized by the Momipites-Ulmoidiepites Zone. This juglandaceous climax lasts until the last of the Clarkforkian, when, in the Early Eocene (lower Wasatchian), it is replaced by a warmer-moister mix of tiliaceous hardwoods. The tiliaceous mix includes Tilia, Quercus and Platycarya. The tiliaceous climax recorded in the sediments within the upper member of the Golden Valley Formation is characterized by the Tiliaepollenites Zone.

CALCULATING THE CONCENTRATIONS OF PALYNOMORPHS : METHODOLOGICAL
CONSIDERATIONS AND SIGNIFICANCES FOR PALEOENVIRONMENTAL ANALYSIS

Marc Roche1 and Martine Hardy1, 2

1 Services Associes de Paleontologie, University of Liege, 7 Place du Vingt Aout, 4000 Liege, Belgium
2 Current address: CENEX, Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803

Palynological quantitative analysis is often based on the relative proportion of each taxon contained in an assemblage. Another way is to evaluate the palynomorph concentrations which are expressed as the number of palynomorphs per gram of sediment. Percentages are interdependent variables whereas concentrations are independently estimated. Results of our analyses of continental and marine coastal palynofacies are presented to illustrate that both parameters (relative percentages and concentrations) give complementary information. In many cases, however, palynomorph concentrations more clearly discriminate sedimentary facies.
The common processes used for calculating palynomorph concentrations are the volumetric method and the marker grain method. The volumetric method is based on a rigorous, time- consuming sample processing procedure that relates a specific volume of sample residue to a specific weight of sediment (X ml corresponds to Y g of sediment). The method using samples spiked with marker grains (Benninghoff, 1962) consists of adding a known quantity of exotic spores as a standard to which the indigenous palynomorphs are compared.
Both techniques are used in our processing routine. In our experience, the volumetric method shows an important underestimation of palynomorph concentration. Although various sources of imprecision are inherent in the volumetric method, it is an acceptable method for making a preliminary evaluation of taxa concentrations during sample processing.
Maher (1981) proposed a method using parametric statistics for assigning confidence limits to concentration measurements employing samples spiked with marker grains. Confidence limits take into account theoretical variance due to the counting technique, the sample weight error, and the error in estimation of the quantity of marker grains added to the sample. We have applied Maher's method to more than 230 samples, and approximately 95% yielded a coefficient of variation between 10 and 30%. Because of that error range, palynomorph concentrations can environmentally discriminate only those samples whose mean concentrations differ by at least a factor of 2.

Benninghoff W. S. (1962). Calculation of pollen and spores density in sediments by addition of exotic pollen in known quantities. Pollen and Spores, 4 : 332-333.
Maher, L. J. (1981). Statistics for microfossil concentration measurements employing samples spiked with marker grains. Review of Paleobotany and Palynology, 32 : 153-191.

ELECTRONIC COLOR ANALYSIS OF STAPLIN'S TAI STANDARDS

Karl W. Schwab1, Michael A. Smith1, 2, and Pieter van Gijzel3

1 Geo-Strat, Inc., 1718 Triway, Houston, Texas 77043
2 U.S. Minerals Management Service, 1201 Elmwood Park Boulevard, M.S. 5120, New Orleans, Louisiana 70123-2394
3 Gentiaanstraat 660, 7322 CT Apeldoorn, The Netherlands

Integrated Color Analysis (ICA) and Spectral Power Distribution (SPD) analysis are two new techniques which have been developed and designed to electronically measure the color of organic matter in transmitted illumination. Organic petrographers and palynologists now have the capability of producing highly accurate, reliable, and objective thermal maturity measurements from spores, pollen, and associated plant tissue fragments.
Using the ICA and SPD methods, Staplin's (1969) initial set of TAI Standards, slide series 1.2 through 4.8, have been analyzed, mathematically calibrated, and corrected into a "true" 1.0 to 5.0 scale. ICA and SPD thermal maturity values, based on hue and intensity readings, can be generated for organic constituents from all geologic ages, Precambrian to Recent. The data, produced in histogram and/or table format, is easily cross-correlated with estimated vitrinite reflectance (%Roe) values.
A comparison of ICA and SPD data with previously published information indicates that the technique is applicable over the entire range of thermal maturity from immature through metamorphosed (ie., 1.0 to 5.0 TAI and/or 0.30 to 5.00% Roe.)

ELECTRONIC TAI MEASUREMENTS USING THE ICA/SPD TECHNIQUE: A BETTER METHOD FOR DEFINING THERMAL MATURITY THAN VITRINITE REFLECTANCE

Karl W. Schwab1, Michael A. Smith1, 2, and Pieter van Gijzel3

1 Geo-Strat, Inc., 1718 Triway, Houston, Texas 77043
2 U.S. Minerals Management Service, 1201 Elmwood Park Boulevard, M.S. 5120, New Orleans, Louisiana 70123-2394
3 Gentiaanstraat 660, 7322 CT Apeldoorn, The Netherlands

Problems associated with the vitrinite reflectance (%Ro) technique, including suppression, anisotropy, calibration of the microscope system, preparation, and particle identification, make it increasingly clear that alternative methods that can accurately define thermal maturation levels throughout a basin are needed. Two new systems for measuring thermal maturity, based on the examination of trilete spores, pollen, and associated plant tissue fragments (including some algal debris) in transmitted illumination, are presented. Integrated Color Analysis (ICA) uses an advanced imaging system and a microscope with high-resolution optics. In Spectral Power Distribution (SPD) analysis, a spectral photometer is used in conjunction with high-resolution microscope in a manner similar to that of van Gijzel (1990). Both methods are calibrated with known standards. Hue and intensity values, based upon the percentages of red, green, and blue light components as detected by the spectral photometer, are used to define the thermal maturity index (TAI) and calculate estimated percent reflectance (%Roe). Thermal maturity values can be accurately calculated and reproduced according to several different scales including Staplin (1969), GeoChem Laboratories, Inc. (1976), Batten (1976), Robertson Research Spore Coloration Index (SCI), and Geo-Strat (1976).
ICA and SPD measurements are considerably more accurate than the visual TAI estimates based on the spore coloration method and can be used to define the level of maturity for organic material from all ages, Precambrian to Recent. The ICA/SPD technique also avoids the numerous problems found to be associated with vitrinite suppression and/or anisotropy as well as other difficulties associated with instrumentation and interpretation (e.g., see Dembicki, 1984; Wenger and Baker, 1987; and Lo, 1993). Because trilete spores, pollen, and plant tissue fragments are used in making ICA and SPD measurements, problems associated with particle identification, age, and derivation (in situ versus recycled debris) are generally not encountered. In the vitrinite reflectance technique few organic petrographers give any consideration to the origin and definition of vitrinite or to what material should be included or excluded among the macerals to be measured. However, explorationists continue to put their faith in vitrinite reflectance data for several reasons. First, vitrinite reflectivity is measured directly and has been fairly accurate, especially compared to indirect indicators such as Rock-Eval pyrolysis. Second, until now there has not been another method for electronically assessing the level of thermal maturation of organic matter. Finally, the computer hardware and software needed for ICA/SPD analysis did not even exist until a few years ago. Today, a new era is opening in the examination and assessment of kerogen. It is our considered opinion that once the ICA/SPD method has been used by and the resulting data tested by industry, it will be found to be more reliable and to have fewer problems than measurements based on vitrinite reflectance.

PROCESSING POLLEN SAMPLES FROM SOUTHWEST ARCHAEOLOGICAL SITES, A COMPARISON OF LABORATORIES AND TWO PROCEDURES FOR INCREASING RECOVERY

Susan J. Smith

Laboratory of Paleoecology, Bilby Research Center, Northern Arizona University, Flagstaff, Arizona 86011

Three decades of Southwest contract archaeology have generated a daunting array of archaeological pollen data. Regional syntheses of archaeological pollen data presume individual studies are comparable. The processing procedures of six western pollen labs were compared to investigate one aspect of potential variability between pollen investigations. The majority of laboratories use heavy liquid floatation as the primary pollen recovery step. However, laboratories differ in the order and degree of standard chemical digestion steps, as well as ancillary treatments.
The order of hydrofluoric acid treatment was investigated with a set of 18 samples. Overnight treatment with hydrofluoric acid before the heavy liquid floatation step, as compared to after floatation, significantly increased pollen concentration.
Sediment samples from archaeological sites typically contain abundant charcoal, which is floated along with pollen during the floatation step. The recovered charcoal obscures pollen on slides, and in samples from contexts such as hearths or roasting pits, charcoal may dilute pollen to the point that counts are not practical. A sieving procedure, that separates micro-particulates from samples, significantly increased pollen counts per transect on a set of test samples. The procedure is inserted after acetolysis and consists of sieving samples through a nylon fabric (Nitex) with an eight-micrometer mesh opening.

MIDDLE ORDOVICIAN CRYPTOSPORES FROM SAUDI ARABIA: NEW EVIDENCE FOR A TRANSITIONAL TERRESTRIAL FLORA

Paul K. Strother1, Said Al-Hajri2 and Alfred Traverse3

1 Department of Geology & Geophysics, Boston College Weston Observatory, Weston, Massachusetts 02193
2 Saudi Aramco, P.O. Box 2141, Dhahran 31311, Saudi Arabia
3 Department of Geosciences, The Pennsylvania State University, University Park, Pennsylvania 16802

Macerations of Middle Ordovician (Llanvirnian) shales from Saudi Arabia yield an assemblage of spores of probable land plants (cryptospores), acritarchs and chitinozoa in addition to scolecodonts, tissue fragments, cuticles and cell clusters. The age of the Hanadir ranges from early Llanvirn to early Llandeila based on trilobite and graptolite correlation (Didymograptus murchisoni zone), chitinozoans and age-restricted acritarchs. We consider cryptospore tetrads and dyads in conjunction with cuticle-like fragments to be the remains of non-marine plants which were more further evolved than the algae and probably at a bryophytic grade of evolution. No trilete spores were found at this horizon, establishing unequivocally that obligate miospore tetrads occur stratigraphically before the earliest trilete spores.
Tetrad configuration varies considerably and the closeness of attachment varies from tightly pressed to loosely attached. Equatorial diameters of individual sporomorphs range from 15 to 34 µm; overall tetrad diameters extend to 48 µm. Membrane-enclosed tetrads are rare, but both Stegambiquadrella contenta and enclosed specimens of the dominant tetrad form occur. Numerous simple dyads, including Dyadospora spp., and other less tightly bound forms, occur. The presence of dyads in these earliest assemblages reinforces heterochronous miospore development as a possible evolutionary mechanism for the invasion of terrestrial habitats.
We propose that embryophytes evolved by Early Ordovician time, establishing, in conjunction with the nematophytes, a pre-vascular land flora, transitional between the earlier microbial communities and a Paleozoic plant biota, was eventually replaced by tracheophytes during later Silurian and Devonian time.

PHANEROZOIC PHYTOPLANKTON DIVERSITY IS DECOUPLED FROM MARINE INVERTEBRATE DIVERSITY

Paul K. Strother1, R.A. MacRae2, A. Fricker3, R.A. Fensome3, and G.L. Williams3

1 Department of Geology & Geophysics, Boston College Weston Observatory, Weston, Massachusetts 02193
2 Department of Geology & Geophysics, University of Calgary, Calgary, Alberta T2N 1N4, Canada
3 Atlantic Geoscience Centre, Geological Survey of Canada, Dartmouth, Nova Scotia B2Y 4A2, Canada

Four separately constructed curves of Phanerozoic acritarch/ prasinophyte generic diversity show a similar pattern of a mid-Paleozoic peak followed by severe depletion at the end of the Devonian with only moderate numbers remaining throughout the Phanerozoic. These data were combined with a dinoflagellate diversity curve to obtain an overall picture of organic-walled phytoplankton diversity over Phanerozoic time. The composite curve reveals a diversity low from the terminal Devonian decline to the rise in dinoflagellates during the Jurassic. This general pattern is unlike that of coeval benthic marine invertebrate who maintained elevated diversity through the remainder of the Paleozoic. At this scale of resolution, benthic invertebrate diversity appears to be decoupled from that of organic-walled phytoplankton.
Studies of modern suspension feeders indicate a moderate degree of food selectivity, implying that trophic partitioning is an important speciation mechanism in shallow marine habitats and, consequently, that there should be a correlation between phytoplankton and invertebrate diversity. Indeed, extinction scenarios commonly call for the demise of phytoplankton as a precursor to invertebrate decline. If benthic marine suspension feeders and phytoplankton are trophically coupled, this might indicate that a major phytoplankton group is missing from the fossil record during the lower Carboniferous through Permian interval.
Alternatively, the ability of typical suspension/filter feeders to survive on heterogeneous food sources implies only a very weak trophic link to primary producers and we should not expect a relation between phytoplankton diversity and marine invertebrate diversity. The trophic links between phytoplankton, zooplankton and nekton are more direct and may translate into a stronger diversity correlation. Thus, the decline in acritarch/prasinophyte diversity at the end of the Devonian may have been an important factor in the demise of agnathans and placoderms.

PALYNOLOGICAL INSIGHTS INTO THE LIMNOLOGY AND SEDIMENTATION OF THE EARLY OLIGOCENE PALEOLAKE FLORISSANT, COLORADO

Ralph E. Taggart and Aureal T. Cross

Department of Geological Sciences and Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824

Integration of stratigraphic, palynological, and geochemical data from the Florissant Fossil Beds National Monument has provided productive new insights into the nature and dynamics of 34 Ma Lake Florissant, a short-lived, inter-montane lake basin in the southern Colorado Rockies. The earliest sediments of the Florissant Formation (Unit Tf1) have been interpreted as a series of lahars, one of which may have dammed the paleodrainage system to create the lake. In contrast, the presence of abundant, well-preserved palynomorphs and their distribution patterns throughout the Tf1 sequence indicates that the unit is largely fluvio-deltaic and that a lake was present in the valley throughout much of Tf1 time, prior to the deposition of the laminated "Lake Shales" (Unit Tf2).
At about the 8 m level in the 11 m Tf1 sequence, lake level was drastically reduced by evaporation, based on oxygen isotope and geochemical data, exposing the Tf1 delta surface, which ultimately became colonized by forest trees. This forest persisted for several hundred to as much as 1000 years. Near or at the end of this interval, the bases of standing trees were buried by sediment and inundated by rising lake waters. Many of the tree stumps became permineralized. This layer, now variably exposed by erosion and excavation, represents the "Fossil Forest" horizon.
The rise in lake water level initiated a new phase in the history of the lake, marked by the deposition of the laminated diatomite/sapropel couplets, interbedded with ash and pumice, of the "Lake Shales" (Unit Tf2). While the lake has been interpreted as meromictic, palynological data suggest eutrophic conditions with seasonal, thermally-driven turnover. Palynological analysis of the lake flora and geochemical analysis of the sediments suggest that Lake Florissant evolved into a hard-water lake whose aerial extent and depth fluctuated greatly late in Tf2 time as a consequence of basin in-filling and variations in the volume of run-off from the relatively small-source watershed.

THE USE OF THREE-AXIS (TERNARY) DIAGRAMS IN STRATIGRAPHIC PALYNOLOGY

Ralph E. Taggart and Aureal T. Cross

Department of Geological Sciences and Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824

While the use of absolute pollen influx data has become common in Quaternary studies, much of the palynological work in older sediments continues to rely on the use of relative frequency pollen diagrams. In part this is due to the potentially confounding effect of highly variable rates of sedimentation exhibited in many stratigraphic sequences. The use of relative frequency data complicates ecological interpretation of pollen/spore diagrams due to the highly interactive relationship between dominant palynological elements, which may or may not reflect significant changes in the nature and distribution of the source vegetation mosaic.
We have found the use of three-axis (triangular or ternary) diagrams to be particularly useful in reconstructing patterns of vegetation dynamics from conventional pollen/spore data sets. The method permits the display of the interactions between any three elements of a pollen/spore suite, irrespective of the variability in other elements. The elements analyzed in a specific diagram can range from single taxa to composite aggregates consisting of multiple taxa. Three-axis diagrams are readily implemented in real-time, to evaluate the significance of various approaches to data clustering. Final diagrams, suitable for publication, are easily implemented using conventional CADD programs. Construction of three-axis diagrams will be demonstrated and examples drawn from Cenozoic floras will be used to emphasize the interpretive clarity provided by this type of data display.

THE DISTRIBUTION OF DINOFLAGELLATE CYSTS FROM A CORE OF EARLY TURONIAN TO EARLY CAMPANIAN (LATE CRETACEOUS) AGE FROM THE WESTERN BARENTS SEA

Bruce A. Tocher

Palynological Research Centre, Institute of Earth Studies, University of Wales, Aberystwyth, Dyfed SY23 3DB, United Kingdom

This paper discusses the stratigraphic distribution and abundance/diversity characteristics of dinoflagellate cysts recorded from a core collected by IKU Petroleum Research (Trondheim, Norway) as part of a detailed study of the Cretaceous and Tertiary erosional history of the western Barents Sea area. The core (7323/12-U-01) comprises 60.6m of sediment (representing 100% recovery).
Twenty-nine samples were analyzed for their palynological content, from which almost two hundred species and subspecies of dinoflagellate cysts were recorded. A comparison with published biostratigraphic data and unpublished industrial reports suggests that this core ranges from top early Turonian to early Campanian (Late Cretaceous) in age.
A study of the assemblage characteristics reveals that the Turonian samples contain abundant, diverse and well-preserved cysts, while the Coniacian interval is represented by much poorer assemblages. The Santonian-Campanian interval again generally contain abundant and diverse assemblages, although samples from the uppermost part of the sequence are less diverse and are dominated by Palaeoperidinium pyrophorum, Spongodinium delitiense and Chlamydophorella? grossa.
Overall the assemblages are dominated by peridinioid cysts such as Chatangiella, Isabelidinium, Trithyrodinium, and Palaeoperidinium, which are taken to indicate a boreal palaeogeographic setting. In addition, changes in the assemblage characteristics suggest a shallower water depositional environment for the latest Santonian-early Campanian sediments than for the underlying sequence.

POLLEN ANALYSIS OF ROMAN AND IRON AGE PLASTER FLOORS IN THE GREAT TEMPLE OF AMMAN, JORDAN

Peter Warnock1 and Michael Pendleton2

1 Department of Anthropology, University of Missouri, Columbia, Missouri 65211
2 United States Department of Agriculture, Agricultural Research Service, Food Animal Protection Research Laboratory, 2881 F & B Road, College Station, Texas 77845

Samples taken from two floors, one of Roman Age and one of Iron Age, from the Great Temple of Amman in Jordan were analyzed to determine if amurca (the sediment produced from processing olive oil) was used in these floors during their construction. Current research by the authors on olive oil produced in a reconstructed Roman Age press indicated that such oil contained olive (Olea europea) pollen grains. Minute amounts of olive pollen were also recovered from the Roman and Iron Age floor samples from the temple. Olive trees are wind pollinated and produce pollen in great quantities. Because other wind-dispersed pollen taxa were abundant in the floor samples, the presence of olive pollen in these samples may either represent wind-born contamination from nearby olive stands at the edge of the Jordan Valley or the use of olive oil during the construction of these al-Qual'a plaster floors.

NEOGENE AND QUATERNARY PALYNOSTRATIGRAPHY OF NORTHERN YUKON TERRITORY AND ALASKA

J.M. White1, D.P. Adam2, T.A. Ager3, H. Jetté4, E.B. Leopold5, G. Liu6 and C.E. Schweger7

1 Geological Survey of Canada, Calgary, Alberta, T2L 2A7, Canada
2 U.S. Geological Survey, Menlo Park, California, 94025
3 U.S. Geological Survey, Denver, Colorado, 80225
4 Geological Survey of Canada, Ottawa, Ontario, K1A 0E8, Canada
5 Dept. of Botany, Univ. of Washington, Seattle, Washinton, 98195
6 Nanjing Inst. of Geology and Paleontology, Academia Sinica, Nanjing, People's Republic of China
7 Anthropology Dept., Univ. of Alberta, Edmonton, Alberta,
T6G 2H4, Canada

A Neogene and Quaternary pollen zone framework for Alaska and northern Yukon has been produced from sections whose ages have been determined by K-Ar, 39Ar/40Ar and fission track dates, or by correlation to sections where such age determinations are available. The zonation is compiled from sections north of the St. Elias Mountains and the Alaska Range and south of the Brooks Range and British Mountains.
The oldest record included in the study is estimated to be within the early Miocene (ca. 18 Ma). The late early and middle Miocene pollen assemblages, ca. 18 to 12.5 Ma, indicate a warm climate. Pollen taxa include Taxodiaceae-Cupressaceae-Taxaceae (T-C-T), Ilex, Carya, Juglans, Pterocarya, Fagus, Quercus, Castanea-type, Tilia-type, Ulmus-type and Ostrya/Carpinus. In the middle Miocene, at about 15 Ma, peak warm conditions are indicated by the abundance of T-C-T, Quercus, Fagus, Liquidambar and Nyssa pollen.
By ca. 12.5 Ma, most thermophilous elements disappeared from the palynological record, although Pterocarya, Tilia-type and Ulmus-type pollen were present until ca. 6 Ma. A minor abundance increase might indicate a climatic warming at ca. 6.6 Ma.
At 6 Ma, Sphagnum, Salix, Cyperaceae, Poaceae and Ericales pollen become common to abundant elements in the pollen record. This may be due in part to global climatic cooling and, in part, to the rise of the coast mountains and Alaska Range, which caused a more continental climate to the north. This orogenic event also probably caused distinctions to develop between the palynostratigraphic patterns of the southern coastal and northern continental areas. At ca. 2.5 Ma, or earlier, Artemisia and other Asteraceae pollen became consistent and common elements in the palynological record.

* Authorship alphabetical after White

THE IMPORTANCE OF REWORKED PALYNOMORPHS IN INTERPRETING DEPOSITIONAL AND THERMAL HISTORY: EXAMPLES FROM ARGENTINA, PAKISTAN AND SOUTH EAST ASIA

Gordon D. Wood1, John H. Wrenn2, Donald W. Engelhardt3, Brenda L. Claxton1, Jeffrey A. Stein1 and Gary W. Barker1

1 Amoco Exploration and Production Technology Group, P.O. Box 3092, Houston, Texas 77253
2 Department of Geology, Louisiana State University, Baton Rouge, Louisiana 70803
3 E.S.R.I., University of South Carolina, Columbia, South Carolina 29208

Recognition of reworking offers a unique perspective not accessible using vitrinite reflectance (%Ro) and traditional geochemical analyses (e.g., Rock-Eval. Biomarkers, Elemental Analyses). Bundled, these techniques can provide critical information germane to depositional and thermal history and hydrocarbon convertibility. Case history examples illustrating the importance of palynological reworking are discussed from studies in South America, Pakistan and Myanmar.
Core/cuttings samples were used to evaluate prospective hydrocarbon areas from the Permian of Chaco Basin, Argentina. Vitrinite reflectance measurements of several samples recorded bimodal organic populations indicative of massive reworking. Palynological analyses indicated recycled Devonian palynomorphs (e.g., Navifusa bacilla, Stellinium micropolygonale, Emphanisporites rotatus) were a major component of the assemblage. This reworked assemblage necessitated reassessment of exploration potential because the Devonian forms were not convertible to liquid hydrocarbons, a facet not identifiable using only source rock (wt%) analyses.
Samples from an approximately 4.5 ft thick outcrop of the Eocene Jatta Formation, of the Robat area, Pakistan were examined for palynology, vitrinite reflectance and a variety of geochemical parameters. Samples with high total organic carbon (TOC) values (up to 30%) possessed elevated hydrogen indices and were predominately amorphous kerogen. Samples with the lowest TOC had low hydrogen indices and were dominated by structures of mixed kerogen. Vitrinite reflectance measurements indicated a significant amount of reworking evident in the low TOC samples and this is corroborated by palynological analysis. Indigenous forms (e.g., Tiliapollenites spp., Retitricolpites sp., Muratodinium fimbriatum, Polysphaeridium zoharyi, Homotryblium tenuispinosum) are minor components in comparison to recycled Jurassic palynomorphs (e.g., Callialasporites dampieri, Gonyaulacysta jurassicia, Scrinodinium crystallinum, Nannoceratopsis pellucida, Omatia montgomeryi). This impacts the commonly held position that a single sample is adequate for characterizing a source rock.
The Upper Cretaceous through Plio-Pleistocene from the Chindwin Basin, Myanmar, was also afforded a multidisciplinary approach. Palynological examination indicates that the oldest rocks in the Chindwin contained abundant reworked Permian-Triassic. The oldest Tertiary included both recycled Cretaceous and Permo-Triassic organic microfossils. The youngest Tertiary yielded recycled Paleogene forms. These data were used to postulate prospective hydrocarbon area and provenance of the reservoir units.

THE IMPORTANCE OF PALYNOLOGIC PROCESSING TO THE EXPLORATIONIST

John H. Wrenn

Amoco Production Company, P.O. Box 3092, Houston Texas 77253
(Current Address:Center For Excellence in Palynology, Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803)

It is self-evident that high-quality palynologic analyses cannot be derived from poorly processed samples. And yet, poor quality processing is surprisingly common. The quality control of sample processing has never been more important to the oil industry than it is today. This is because many companies have eliminated palynologists from their staff and now require explorationists to oversee palynostratigraphic projects conducted outside the company.
The exploration experience of Amoco Production Company in Myanmar provides a good example of the importance of sample processing to the explorationist. The deposits in Amoco's Block B consist of Late Cretaceous through Cenozoic continental and near shore marine sediments. Studies of outcrop samples showed that palynomorphs were the only abundant, widely distributed fossils present. Only palynology could provide the biostratigraphic control for the exploration program.
One option considered for providing this control was contracting with a consulting company in Southeast Asia. The first step in selecting such a company was evaluating their palynologic sample processing. Duplicate cuts of 27 outcrop samples that had been previously prepared and studied by Amoco were submitted to three laboratories for processing and analysis. Two companies sent Amoco the microsope slides that they prepared and analyzed. All three companies provided photographic documentation of their results.
The preparations of all three companies were very poor compared to the cleaner preparations of Amoco, which contained abundant palynomorphs and were much easier to study. Even more important, poor sample processing resulted in erroneous and/or overly broad age determinations. Consequently, none of the consulting companies was selected to provide well control in Myanmar for Amoco.
Poor recovery may have been due to excessive oxidation, inadvertent disposal of palynomorphs, and/or poor sieving or heavy liquid separation techniques. The samples were apparently processed in an assembly-line fashion that overlooked differences in lithology, organic content, diagenetic history, etc.
This study demonstrates that: 1) high-quality processing is a prerequisite to high-quality palynologic analyses; 2) it is imperative to consider the quality of sample processing when assessing palynologic analyses; 3) in the long run, it is cheaper to spend more time and money producing clean, palynomorph rich slides, than it is to pay a palynologist to spend a long time studying dirty, palynomorph poor residues; and 4) it is necessary to assess consultant sample processing capabilities before contracting for biostratigraphic support of exploration efforts.
These points cannot be overemphasized. It is in the self-interest of consultants that sample processing be given the same attention to detail as is the palynologic evaluation of a sample.

FOSSIL EVIDENCE OF A RED TIDE IN THE LATE PLIOCENE PINECREST BEDS OF FLORIDA

John H. Wrenn1 & Steven D. Emslie2

1 Amoco Production Company, P.O. Box 3092, Houston Texas 77253
(Current Address: Center For Excellence in Palynology, Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803)
2 Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611
(Current Address: Western State College, Department of Sciences, Gunnison, Colorado 81230)

The late Pliocene Pinecrest "Beds" of central west Florida contain abundant, diverse molluscan, fish and mammal assemblages that indicate deposition occurred in a nearshore or lagoonal setting. Recently, a bed of late Blancan (2.4-2.0 Ma) age was discovered within the Pinecrest "Beds" in the Richardson Road Shell Pit, Quality Aggregates, Inc. of Sarasota, Florida. Thus far the bed has yielded more than 5,000 scattered bones and 130 articulated and semi-articulated skeletons of the extinct cormorant, Phalacrocorax sp. These skeletons indicate that death and burial of the cormorants occurred quickly.
Dinocysts were studied in four samples from this and adjacent beds to determine if a toxic red tide caused the mass kill of these fish-eating cormorants. Thirty dinocyst taxa were identified, including extant dinocyst species produced by bloom-forming dinoflagellates. By far the most abundant of all dinocysts in all samples was Polysphaeridium zoharyi (the cyst form of Pyrodinium bahamense). It is believed that a toxic bloom of Pyrodinium bahamense was responsible for the death of the cormorants.
According to some researchers, there are two varieties of P. bahamense (i.e., P. bahamense var. bahamense and P. bahamense var. compressa) and these have almost mutually exclusive geographic ranges in modern oceans. P. bahamense var. bahamense occurs primarily in the tropical-subtropical Atlantic Ocean and adjacent seas, whereas P. bahamense var. compressa occurs in the Indo-Pacific and Persian Gulf-Red Sea areas. The two varieties are only known to overlap off the west coast of Mexico. Only P. bahamense var. compressa causes toxic blooms today, particularly in the Indo-Pacific area.
The present day toxicity and distribution of the two varieties of P. bahamense create a problem for ascribing the Pliocene bird kill to a toxic bloom of that species. However, possible explanations include: 1) only one variety of Pyrodinium bahamense has ever existed and its toxicity is brought on by environmental pressures; 2) the toxicity of the Pyrodinium bahamense varieties (if two actually exist) may have been different during the Pliocene than it is today; or 3) P. bahamense var. compressa may have disappeared in the Atlantic Ocean and adjacent seas after the Pliocene closure of the Isthmus of Panama; or 4) P. bahamense var. compressa evolved in the Indo-Pacific area after closure of the Isthmus of Panama, whereas the toxicity of P. bahamense var. bahamense was lost or became dormant, perhaps in response to climatic cooling.

POLLEN-DOMINATED ASSEMBLAGES FROM THE LATE CARBONIFEROUS PALEOSUBTROPICS: PALEOPHYTOGEOGRAPHY AND EARLY CONIFER COMMUNITIES

Yu-Xing Zhou and Anne Raymond

Department of Geology and Geophysics, Texas A&M University, College Station, Texas 77843

Distinct climatic zones existed in the Late Carboniferous. The tropical rainy zone is represented by the belt of coal extending from the midwestern United States through Europe. The temperate rainy zones are indicated by the Siberian and Gondwana coals. The subtropical arid belts, located between the tropical rainy belt and the temperate belts, are represented by the evaporites and rise in latitude from west to east. With the known sensitivity of recent plants to climate, we should expect similar phytoprovincialism associated with climatic zonations in the Late Carboniferous. However, the generally accepted phytogeographic model for the Late Carboniferous based on plant macrofossils shows that the Euramerian province, characterized by arborescent lycopods in the early Late Carboniferous and pteridosperms, tree ferns and Cordaites in the late, Late Carboniferous, covers the tropical rainy zone and the northern subtropical arid zone. However, this situation reflects the lack of macrofloral information from the subtropical arid zone. Palynomorphs can play a key role in the recognition of the phytogeographic area which corresponds to the subtropical arid zone. A new phytogeographic province, the Tianural province, which is located along the 30šN paleolatitude, has been proposed based on pollen-dominated assemblage from the early-middle Late Carboniferous of Tian Shan, NW China, the Urals, and Arctic and NW Canada. Our recent study suggests that the Rocky Mountains also have pollen-dominated assemblages at least from the middle Late Carboniferous. The distribution of these pollen-dominated assemblages indicates that the paleosubtropical arid area had different plant communities from the paleotropical rainy area. In the latter, zonate spores like Lycospora dominate assemblages. In the paleosubtropical arid zone, the plant communities were most likely composed of conifers or conifer-like plants.