HR: 09:35h
AN: GP41B-05    [Abstracts]
TI: Multi-proxy Analysis of Lake Sediments from Western Connecticut Reveals Changes in Past Environments and Land-use
AU: * Geiss, C E
EM: christoph.geiss@trincoll.edu
AF: Trinity College, 300 Summit St, Hartford, CT 06106 United States
AU: Abrams, J L
EM: jeffrey.abrams@trincoll.edu
AF: Trinity College, 300 Summit St, Hartford, CT 06106 United States
AU: Sultan, R S
EM: ryan.sultan@trincoll.edu
AF: Trinity College, 300 Summit St, Hartford, CT 06106 United States
AB: Mudge Pond (lat. 41.90 deg. N, long 73.48 deg. W) is a small glacial lake in the highlands of western Connecticut. Our analyses of a transect of eight piston cores aim at reconstructing the combined effects of past climatic changes and human land use practices on the chemical, biological and physical properties of lake sediments. Magnetic analyses (magnetic susceptibility, hysteresis loops, remanence parameters and low-T analyses) characterize the terrigenous components of all cores and allow for correlation between sites. Sediments deposited prior to 10 ka B.P. are poor in organic carbon and its magnetic properties are dominated by paramagnetic minerals, leading to low remanence values and high values of magnetic susceptibility. Low lake levels during part of the Holocene, as reconstructed from sedimentary facies changes along our transect of cores, led to erosion and partial redeposition of these sediments in the deepest part of the lake. Late Holocene sediments are composed of Marl, which is only weakly magnetic and displays a magnetic remanence carried by large MD and PSD-sized ferrimagnets. The onset of Euroamerican settlement in New England led to increased erosion rates, which are reflected in higher concentrations of magnetic minerals. Analyses of macroscopic charcoal show that, despite extensive logging activities in the watershed, the severity of forest fires did not change noticeably compared to pre-settlement times. Our magnetic and sedimentological studies are supplemented by a palynological analyses, which confirm our reconstruction of past environmental change and help to clarify the onset of Euroamerican settlement and it's influence on the watershed of Mudge Pond.
DE: 1512 Environmental magnetism
DE: 1540 Rock and mineral magnetism
DE: 1625 Geomorphology and weathering (1824, 1886)
DE: 3344 Paleoclimatology
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly