Affiliation:
1. United States Geological Survey, Denver, CO 80225, USA
2. Department of Geology, University of New Mexico, Albuquerque, NM 87131, USA
Abstract
Increased aridity throughout the Great Plains and Rocky Mountain region during the middle Holo cene has been documented from pollen records, aeolian proxy variables in lake cores, and active sand dune migration. Varve calibration provided by a continuously varved record of the Holocene from a core from Elk Lake, northwestern Minnesota, shows that the influx of aeolian clastic material increased beginning about 8 ka and ended about 3.8 ka, with peak aeolian activity at about 6 ka. If aeolian influx to Elk Lake corresponds in time to aeolian influx in other lakes and to maximum dune activity in Minnesota dune fields, then the varve calibration in Elk Lake provides precise time calibration of periods of peak aeolian activity in Minnesota. Palaeowind studies from the Minnesota dune fields show that the dominant wind direction when the dunes were active was from the northwest, the same as the dominant wind direction in dune fields throughout the Great Plains and Rocky Mountains. If the mid-Holocene aeolian activity in Minnesota was driven by an increase in westerly zonal winds, then the varve calibration can be extended to more precisely determine the timing of activity of dunes over a much broader area. We suggest that an increase in the westerly zonal wind field might have a solar-geomagnetic cause.
Subject
Paleontology,Earth-Surface Processes,Ecology,Archaeology,Global and Planetary Change
Reference114 articles.
1. Ahlbrandt, T.S. and Fryberger, S.G. 1980: Eolian deposits in the Nebraska Sand Hills. US Geological Survey Professional Paper 1120A.
2. The Dynamic Holocene Dune Fields of the Great Plains and Rocky Mountain Basins, U.S.A.
3. Possible connection between surface winds, solar activity and the Earth's magnetic field
4. — 1993: The varve chronometer in Elk Lake: record of climatic variability and evidence for solar-geomagnetic-14C-climate connection. In Bradbury, J.P. and Dean, W.E., editors, Elk Lake, Minnesota : Evidence for rapid climate change in north-central United States, Boulder, Colorado: Geological Society of America, Special Paper 276, 45-67.
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