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Comparisons of 210Pb and Pollen Methods for Determining Rates of Estuarine Sediment Accumulation

Published online by Cambridge University Press:  20 January 2017

Grace S. Brush
Affiliation:
Department of Geography and Environmental Engineering, Johns Hopkins University, Baltimore, Maryland 21218 USA
E. Ann Martin
Affiliation:
United States Geological Survey, Corpus Christi, Texas 78411 USA
Ruth S. DeFries
Affiliation:
Indian Institute of Technology, Bombay, 400076, India
Cynthia A. Rice
Affiliation:
United States Geological Survey, Corpus Christi, Texas 78411 USA

Abstract

Comparisons of sedimentation rates obtained by 210Pb and pollen analyses of 1-m cores collected throughout the Potomac Estuary show good agreement in the majority of cores that can be analyzed by both methods. Most of the discrepancy between the methods can be explained by the analytical precision of the 210Pb method and by the exactness with which time horizons can be identified and dated for the pollen method. X-radiographs of the cores and the distinctness of the pollen horizons preclude significant displacement by reworking and/or mixing of sediments. Differences between the methods are greatest where uncertainties exist in assigning a rate by one or both methods (i.e., 210Pb trends and/or “possible” horizon assignments). Both methods show the same relative rates, with greater sediment accumulation more common in the upper and middle estuary and less toward the mouth. The results indicate that geochronologic studies of estuarine sediments should be preceded by careful observation of sedimentary structures, preferably by X-radiography, to evaluate the extent of mixing of the sediments. Time horizons, whether paleontologic or isotopic, are generally blurred where mixing has occurred, precluding precise identification. Whenever possible, two methods should be used for dating sediments because a rate, albeit erroneous, can be obtained isotopically in sediments that are mixed; accurate sedimentation rates are also difficult to determine where the time boundary is a zone rather than a horizon, where the historical record does not provide a precise date for the pollen horizon, or where scouring has removed some of the sediment above a dated pollen horizon.

Type
Research Article
Copyright
University of Washington

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References

Anderson, T.W. (1974). The chestnut pollen decline as a time horizon in lake sediments in Eastern North America. Canadian Journal of Earth Sciences 11. 678685.Google Scholar
Bazzaz, F.A. (1974). Ecophysiology of Ambrosia artemisifolia: A successful dominant. Ecology 55. 112119.Google Scholar
Benninger, L.K. (1976). The uranium-series radionuclides as tracers of geochemical processes in Long Island Sound. Ph.D. dissertation Yale University, New Haven, Connecticut.Google Scholar
Benjamin, J.R. Cornell, C.A. (1970). Probability, Statistics and Decision for Civil Engineers McGraw-Hill, New York.Google Scholar
Beyer, W.H. (1978). 25th ed. CRC Standard Mathematical Tables CRC Press, Boca Raton, Florida.Google Scholar
Biggs, R.B. (1970). Sources and distribution of suspended sediment in Northern Chesapeake Bay. Marine Geology 9. 187201.CrossRefGoogle Scholar
Bruce, P.A. (1896). Economic history of Virginia in the sixteenth century Macmillan Co, New York2 vol..Google Scholar
Brugam, R.B. (1978). Human disturbance and the historical development of Linsley Pond. Ecology 59. 1936.Google Scholar
Brush, G.S. DeFries, R.S. (1981). Spatial distributions of pollen in surface sediments of the Potomac Estuary. Limnology and Oceanography 26. 295309.CrossRefGoogle Scholar
Craven, A.O. (1925). Soil exhaustion as a factor in the agricultural history of Virginia and Maryland, 1606–1860. University of Illinois Studies in the Social Sciences 13. 9179.Google Scholar
Davis, M.B. (1976). Erosion rates and land-use history in Southern Michigan. Environmental Conservation 3. 139148.CrossRefGoogle Scholar
DeGroot, A.J. Salomons, W. Allersma, E. (1976). Processes affecting heavy metals in estuarine sediments. Estuarine Chemistry. Burton, J.D. Liss, P.S. Academic Press, New York. 131153.Google Scholar
Farmer, J.G. (1978). The determination of sedimentation rates in Lake Ontario using the 210Pb dating methods. Canadian Journal of Earth Sciences 15. 431437.CrossRefGoogle Scholar
Flynn, W.W. (1968). The determination of low levels of polonium-210 in environmental materials. Analytica Chimica Acta 43. 221227.Google Scholar
Froomer, N.L. (1978). Geomorphic change in some Western Shore estuaries during historic times. Ph.D. dissertation Johns Hopkins University, Baltimore.Google Scholar
Goldberg, E.D. Gamble, E. Griffin, J.J. Koide, M. (1977). Pollution history of Narrangansett Bay as recorded in its sediments. Estuarine Coastal Marine Sciences 5. 549561.Google Scholar
Hirschberg, D.J. Schubel, J.R. (1979). Recent geochemical history of flood deposits in the Northern Chesapeake Bay. Estuarine Coastal Marine Sciences 9. 771784.Google Scholar
Höhndorf, A. (1969). Bestimmung der Halbwertszeit von Pb-210. Zeitschrift für Naturforschung 24A. 612.Google Scholar
Hunter, J.F. (1914). Erosion and sedimentation in Chesapeake Bay around the mouth of the Choptank River. U.S. Geological Survey Professional Paper 90-B. 715.Google Scholar
Koide, M. Soutar, A. Goldberg, E.D. (1972). Marine geochronology with lead-210. Earth and Planetary Science Letters 14. 442446.Google Scholar
Koide, M. Bruland, K.W. Goldberg, E.D. (1973). Th-228 Th-232 and Pb-210 geochronologies in marine and lake sediments. Geochimica Cosmochimica Acta 37. 11711187.Google Scholar
Martin, E.A. Rice, C.A. (1981). Sampling and analyzing sediment cores for 210Pb geochronology. U.S. Geological Survey Open-File Report 81-983.Google Scholar
Mason, W.T. Flynn, K.C. (1976). The Potomac Estuary: Biological resources, trends and options. Interstate Commission for the Potomac River Basin Technical Bulletin 76-2. 7074.Google Scholar
Nichols, M.M. (1972). Sediments of the James River Estuary, Virginia. Environmental Framework of Coastal Plain Estuaries. Nelson, B.W.Geological Society of America Memoir 133. 189212.Google Scholar
Nittrouer, C.A. (1978). The process of detrital sediment accumulation in a Continental Shelf environment: An examination of the Washington Shelf. Ph.D. dissertation University of Washington.Google Scholar
Olsen, C.R. Simpson, H.J. Bopp, R.F. Williams, S.C. Peng, T.H. Deck, B.C. (1978). A geochemical analysis of the sediments and sedimentation in the Hudson Estuary. Journal of Sedimentary Petrology 48. 401418.Google Scholar
Rawls, C.K. (1964). Aquatic plant nuisances, problems of the Potomac Estuary. Interstate Commission for the Potomac River Basin Proceedings 1964-1. 5156.Google Scholar
Richard, G.A. (1978). Seasonal and environmental variations in sediment accretion in a Long Island Salt Marsh. Estuaries 1. 2935.Google Scholar
Robbins, J.A. (1978). Geochemical and geophysical applications of radioactive lead isotopes. Biogeochemistry of Lead. Nriagu, J.O. Elsevier, Amsterdam/New York. 285293.Google Scholar
Robbins, J.A. Edgington, D.N. (1975). Determination of recent sedimentation rates in Lake Michigan using lead-210 and cesium-137. Geochimica Cosmochimica Acta 39. 285304.Google Scholar
Robbins, J.A. Edgington, D.N. Kemp, A.L.W. (1978). Comparative 210Pb, 137Cs, and pollen geochronologies of sediments from Lakes Ontario and Erie. Quaternary Research 10. 256278.Google Scholar
Schubel, J.R. Hirschberg, D.J. (1977). 210Pb-determined sedimentation rate, and accumulation of metals in sediments at a station in Chesapeake Bay. Chesapeake Science 18. 379382.Google Scholar
Snedecor, G.W. Cochran, W.G. (1967). 6th ed. Statistical Methods Iowa State University Press, Ames.Google Scholar
Solomon, A.M. Buell, M.F. (1969). Effects of suburbanization upon airborne pollen. Bulletin of the Torrey Botanical Club 96. 435445.Google Scholar
Thomson, J. Turekian, K.K. McCaffrey, R.J. (1975). The accumulation of metals in and release from sediments in Long Island Sound. Estuaries Research. Cronin, E.L. Vol. 1. Academic Press, New York. 2844.Google Scholar