USGS

Open-File Report 97-0460

Preliminary Paleontologic Report on Cores 19A and 19B, from Russell Bank, Everglades National Park, Florida Bay

By G.L. Brewster-Wingard, S.E. Ishman, D.A. Willard, L.E. Edwards, and C.W. Holmes

This is a cover page. To go to the actual document, click on the title above.
 
The document is in PDF format (685 K). You will need Acrobat Reader to view and print. If you do not have Acrobat Reader, you will need to download the program.
 
Click here to download Adobe Acrobat 3.0, and follow the download and installation instructions provided. After downloading Acrobat, configure your browser to use Acrobat as a helper application.

Abstract

The fauna and flora preserved in two cores, 19A and 19B, from the south side of Russell Bank (N 25 03.831', W 80 37.486') in north-central Florida Bay, Everglades National Park, Florida, record a history of environmental change over the last century. The benthic foraminifera and molluscs indicate fluctuating salinities with increasing average salinity upcore in core 19B. Shifts from low salinity (12-15 ppt) to higher average salinity (30 ppt) occurred at 70-66 cm and 24-18 cm in core 19B (approximately 1937-1940 and 1975-1980). The inverse, shifts from periods of higher average salinity to periods of lower salinity, occurred at 140 cm, 90 cm, and 42 cm (approximately 1880, 1921, and 1960). Significant changes in the molluscan fauna indicative of specific substrate types occur at 88 cm, 68 cm, and 22 cm. The lower portion of the core is dominated by a mixture of sediment and grass dwellers, the middle portion by sediment dwellers, and the upper portion of the core by grass and finally grass and algae dwellers. Changes occur in the floral assemblages in core 19A, but the significance of these changes is unclear. Three subtle shifts occur in the pollen assemblages indicating the onshore vegetation was responding to some environmental factor. Two peaks in dinocyst abundance occur in core 19A, but the composition of dinocyst assemblages remains relatively stable throughout the core. Correspondence between changes in salinity and onshore vegetation changes is consistent with results from previous cores. The pattern of increased salinity upcore is consistent with patterns seen in core T24 from the mouth of Taylor Creek and in core 6A from Bob Allen mudbank.

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Information for ordering U.S. Geological Survey maps and reports
is available by calling 1-888-ASK-USGS. Information for ordering
USGS products also is available from the USGS home page on the
World Wide Web at URL http://www.usgs.gov/.

You can write to

USGS Information Services
Open-File Reports
Box 25286
Denver, CO 80225

Fax: 303-202-4695

Return to Geologic Mapping and Regional Geologic Studies in the Eastern United States
Return to Open-File Reports
Return to Geologic Information



<https://pubs.usgs.gov/pdf/of/ofr97460.html>
Maintained by John Watson
Last Updated 05.17.99