Northeastern Section - 47th Annual Meeting (1820 March 2012)
Paper No. 52-5
Presentation Time: 8:00 AM-12:00 PM

A 4,000 YEAR RECORD OF LONG ISLAND SOUND ENVIRONMENTS OBSERVED THROUGH XRF-CORE SCANNING

WARREN, Courtney E., Geology & Geophysics, Yale University, 210 Whitney Ave, New Haven, CT 06511, courtney.warren@yale.edu, VAREKAMP, J.C., Department of Earth & Environmental Sciences, Wesleyan University, 265 Church Street, Middletown, CT 06459, THOMAS, Ellen, Geology and Geophysics, Yale University, P O Box 208109, New Haven, CT 06520-8109, and MEYERS, Stephen R., Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton St, Madison, WI 53076

Many estuaries, including Long island Sound (LIS) have seen major environmental changes over the last millennia. Commonly these changes have been influenced by increases in human population along the coasts, and the direct or indirect effects of this growth on the coastal environment. These effects include changes in aquatic food extraction, contaminant and nutrient input, increased fresh-water run-off through changes in land use, and the release of effluent from wastewater treatment plants. As there is no written history available for most of this time period, we must rely on the sediment record to evaluate environmental changes and their impact on biota over time. For this study we used sediment cores representing different hypoxic regimes in western and central LIS, dated using Hg-pollution profiles, 210Pb - 137Cs, and 14C, and spanning the past ~2,000 to ~4,000 years. With the use of an Avaatech XRF (X-ray Fluorescence) core scanner with a Rhodium source, we have derived high-resolution records of elemental concentrations to assess variability in sediment composition over the last millennia. XRF-scanners are powerful tools in paleo-environmental analysis because they provide non-destructive and relatively fast analyses of large numbers of data points from very thin (cm to mm) sediment slices, reflecting a high temporal resolution. XRF scanners measure the chemical composition of sediments as element intensities in total counts, which are proportional to the chemical concentrations. We have measured the concentration of major and trace elements (Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Rh, Zn, Br, Rb, Sr, Y, Zr, Mo, Pb, U, Ag, Sn, Te, I and Ba), and calibrated these measurements through traditional XRF analysis (WDXRF, Bruker S4 Pioneer) on discrete, fused beads and dry powder samples in order to calibrate the semi-quantitative XRF-core scanner measurements. We have evaluated the potential to use the elemental variability in sediments from these complex, multi-source estuarine settings as indicators for changes in salinity, oxygenation and biotic productivity over time.

Northeastern Section - 47th Annual Meeting (1820 March 2012)
General Information for this Meeting
Session No. 52--Booth# 58
Human Impacts on Estuaries (Posters)
Hartford Marriott Downtown: Ballrooms A & C and Ballroom Pre-function Area
8:00 AM-12:00 PM, Tuesday, 20 March 2012

Geological Society of America Abstracts with Programs, Vol. 44, No. 2, p. 117

© Copyright 2012 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.