Pliocene Palynomorph Census Data from the Pinecrest Beds (Tamiami Formation) in Quality Aggregates Phase 6 Pit, southwestern Florida by Debra A. Willard Mail Stop 970 U.S. Geological Survey Reston, Va. 22092 U.S. Geological Survey Open-File Report 93-563 INTRODUCTION The U.S. Geological Survey is conducting a long-term study of the climatic and terrestrial conditions of the Pliocene. One of the major elements of the study involves the estimation of vegetational composition and abundance from palynomorph assemblages and the estimation of terrestrial paleotemperatures based on vegetational abundance and distribution. Many samples will be analyzed during the project, resulting in a large volume of raw census data. In addition, it is likely that all or some of the census data from individual sites will be incorporated into analyses for more than one report over the course of the project. Therefore we have decided to make the raw census data available in a series of open-file reports that will provide basic data for future work. In this report, raw census data is presented for 47 palynomorph assemblages from the Pinecrest Beds (Tamiami Formation) of southwestern Florida (Fig. 1). FIGURE 1. Location of Quality Aggregates Phase 6 Pit (QA6). [Editor's note: This figure depicts the state of Florida, with the location of QA6 marked. QA6 is located on the west side of the penninsula south and east of Tampa Bay. Because it simply shows the location and contains no other information, this figure was not converted to a more portable format. It is embedded in the original report, which is contained in the self-extracting archive file of92-563.sea.hqx in the Derived section; the report is presented there in Microsoft Word format.] GEOLOGICAL SETTING The Pinecrest Beds of the Tamiami Formation consist of coarse sands with an extremely diverse molluscan fauna, which has been studied intensively by paleontologists (Allmon, et al., 1991; Jones, et al., 1991). These units are exposed particularly well in the Quality Aggregates Phase 6 Pit (Lat. 27 degrees 21'45" N, Long. 82 degrees 26'23" W) near Sarasota, Florida, hereafter referred to as QA6. The Pinecrest Beds range from about 2 Ma to more than 3.5 Ma (Jones, et al., 1991), and they have been subdivided informally into eleven units based on molluscan composition (Petuch, 1982). Of these eleven units, six are exposed at QA6 (Fig. 2), and these were sampled intensively to establish the composition of the regional vegetation throughout the time period, to determine how variable the vegetation was during mid- to Late Pliocene time, and to estimate Pliocene temperatures and precipitation. A detailed interpretation of the vegetational history of the site is provided in Willard, et al. (1993). [Editor's note: Location is 27.3625 degrees North, 82.439722 degrees West, specified to nearest second of latitude and longitude.] METHODS Samples were collected at 20 cm intervals at four sampling sites in QA6 in order to maximize stratigraphic coverage. The relative locations of these sites, the units sampled, and the sample intervals are illustrated in Fig. 2. Samples weighing about 80 grams were collected for pollen preparation. Sediments first were screened through an 850 um mesh to remove shelly debris. Then, samples were decalcified using hydrochloric acid and demineralized using hydrofluoric acid. The neutralized residue was suspended in a dilute detergent solution to keep clay-sized particles in suspension and filtered through an 8 µm nylon mesh to remove the clay- sized particles. Organic and mineral matter then were separated using a heavy-liquid flotation with zinc chloride (specific gravity =2.0). Organic material was removed, washed, and stained with Bismarck Brown before being mixed with warm glycerine jelly and mounted on microscope slides. For most samples, 300 palynomorphs (excluding pollen of aquatic angiosperms and spores of lower vascular plants) were counted; for samples with relatively sparse pollen, data were included if at least 100 palynomorphs were counted. Raw counts for taxa (genera and families) contained in each sample are provided in Table 1. Table 1. Raw counts of palynomorphs in samples from the Pinecrest Beds (Tamiami Fm.), Quality Aggregates Phase 6 Pit, near Sarasota, Florida. "P" indicates that the taxon was present in the sample but not included in the count. [Editor's note: Table 1 is included separately in the file Core/raw/table1.txt] ACKNOWLEDGEMENTS I thank T. Cronin and S. Ishman for reviewing this manuscript and G. Belair for assistance with sample preparation. I also thank W. Allmon, T. Cronin, D. Jones, K. Ketcher, R. Portell, and L. Wingard for field assistance. This report is a product of the PRISM (Pliocene Research, Interpretation, and Synoptic Mapping) Project. REFERENCES Allmon, W.D., Rosenberg, G., Portell, R.W., and Schindler, K.S., 1993, Diversity of Atlantic Coastal Plain mollusks since the Pliocene, Science, v. 260, p. 1626-1629. Jones, D. S., MacFadden, B.J., Webb, S.D., Mueller, P.A., Hodell, D.A., and Cronin, T.M., 1991, Integrated geochronology of a classic Pliocene fossil site in Florida: linking marine and terrestrial biochronologies, Journal of Geology, v. 99, p. 637-648. Petuch, E.J., 1982, Notes on the molluscan paleoecology of the Pinecrest Beds at Sarasota, Florida with the description of Pyruella, a stratigraphically important new genus (Gastropoda: Melongenidae), Proceedings of the Academy of Natural Sciences of Philadelphia, v. 134, p. 12-30. Willard, D.A., Cronin, T.M., Ishman, S.E., and Litwin, R.J., 1993, Terrestrial and marine records of climatic and environmental changes during the Pliocene in subtropical Florida, Geology, v. 21, p. 679-682. (end)