HR: 1340h
AN: PP43A-1000    [Abstracts]
TI: Base-level Response to Holocene Climate Change in the Central Appalachian Mountains of North America: Preview of Global Warming?
AU: * Springer, G S
EM: springeg@ohio.edu
AF: Department of Geological Sciences, Ohio University, 316 Clippinger Laboratories, Athens, OH 45701, United States
AU: Rowe, H D
EM: hrowe@uky.edu
AF: Department of Geological Sciences, University of Kentucky, 101 Slone Research Bldg, Lexington, KY 40506, United States
AU: Cocina, F G
EM: frankcocina@gmail.com
AF: Department of Geological Sciences, Ohio University, 316 Clippinger Laboratories, Athens, OH 45701, United States
AU: Hardt, B
EM: ben_hardt@comcast.net
AF: Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, United States
AU: Cheng, H
EM: cheng021@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, United States
AU: Edwards, R L
EM: edwar001@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, United States
AB: Global Warming is expected to bring about substantive changes in global precipitation patterns, which will lead to altered stream hydrologies. The directions and magnitudes of streamflow changes can be inferred from climate projections, but changes in stream architecture and base level are open questions. We address base level response to climate change by reconstructing river behavior during the mid- to late Holocene, including the Hypsithermal when peak Holocene temperatures were achieved. We reconstruct the climate of the Greenbrier River watershed of the central Appalachian Mountains of North America using the stable isotope geochemistry of a stalagmite, cave sediments, and published pollen data. Independently, we construct a history of base level position using cave sediments deposited by the river. Stalagmite values of δ¹⁸O and δ¹³C are heavy during the Hypsithermal, which pollen results indicate was warm and dry compared to the rest of the Holocene. Cave sediments deposited by the Greenbrier River record base level as having been below the cave during the early and late Holocene, but above the cave during the Hypsithermal. The mid-Holocene base level rise is attributed to infilling of the channel with as much as 4 m of sediment, presumably a response to changes in storm frequency and stream hydrology. Global Warming will cause temperatures to exceed those of the Hypsithermal. Flood zones will extend to higher elevations and flood risks and vulnerabilities will increase dramatically if Appalachian rivers respond to Global Warming as the Greenbrier River did to the Hypsithermal.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1807 Climate impacts
DE: 1825 Geomorphology: fluvial (1625)
DE: 4914 Continental climate records
DE: 4958 Speleothems
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting