Greater-than-present wet conditions from 14.6 to 10.2 cal ka yr BP in the southwestern Great Lakes area, North America

B. Brandon Curry, E. Grimm, J. W. Gonzales, G. Filippelli, Keith C. Hackley, Shari E. Fanta, B. Panno

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A 9-m sediment core from Crystal Lake, Illinois (U.S.A.) has yielded pollen, ostracode, and ostracode biogeochemical records dating from 16.1 cal ka to the present. Crystal Lake has yielded a nearly continuous ostracode record spanning the Bølling, Allerød, Younger Dryas, and early Holocene; coeval sediments from other local deep-lakes are barren of ostracodes. Preservation of ostracode valves in the Crystal Lake record is attributed to a leaky basin, a moisture budget that includes about 50% groundwater input, watershed geology composed of dolomite-rich till and outwash, and water residence time of < 1 yr. Published reconstructions of past seasonal moisture and temperature based on an expanded response surface technique of no-analogue pollen spectra indicate excessive moisture (primarily as winter snow) from 14.2 to 11.5 cal ka-1. The biogeochemistry of adult valves of Candona ohioensis and other ostracode species supports these conclusions. Particularly sensitive is Sr/Cam, a proxy for alkalinity and salinity in hard-water lakes that do not precipitate aragonite. Modern analogs indicate that mid-Holocene total dissolved solids (TDS) averaged about 500 mg/L suggesting that Younger Dryas values were about 200 mg/L, approximately the calcite saturation level (below which calcite dissolves). Modern analogs of the mid-Holocene ostracode assemblages from Crystal Lake indicate a total dissolved solid (TDS) value of about 500 mg/L. Today, Crystal Lake’s TDS is about 450 mg/L. Sr/Cam values suggest TDS values at or below 200 mg/L for the interval 13.77-9.25 cal ka. The evidence in the core of fresher water, and hence, greater-than-modern P-E is supported by very low valve counts, barren zones, low ostracode diversity, and modern analog reconstructions of salinity. -1 Gonzales et al., 2009. doi:10.1016/j.quascirev.2009.09.005
Original languageEnglish (US)
Title of host publicationXVII International Quaternary Association Congress, Bern, Switzerland, Abstract no. 2667. Poster
StatePublished - 2011

Keywords

  • ISGS

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