A COMPLETE SEDIMENTARY RECORD FROM LAST GLACIAL TERMINATION TO EARLY HOLOCENE IN MIDWESTERN DUNE FIELD

One of the most important climate shifts during the last 100 kyrs is the abrupt climate change from the last glacial termination to the Holocene period. The Greenland ice core record indicates that the cold Heinrich stadial 1 (HS1) from 17.7 kyrs was followed by the abrupt Bølling-Allerød (B/A) warming at 14.5 kyrs, then by the Younger Dryas stadial (YDS) cold snap at 12.9 kyrs, and finally by the Holocene warming at 11.7 kyrs BP. One prominent feature of the last deglacial warming is the exceptionally large melting event, which led to a sea-level rise of 20 meters in less than 500 years. Fresh water forcing affected the global thermohaline circulation, setting the stage for the YDS cold period. However, near the southern front of the Laurentide ice sheet (LIS), these abrupt climate changes and the phase relationship between the B/A warming and the meltwater flood have not been fully observed in any sedimentary record. Here, we present a dune-paleosol succession in the middle Illinois River Valley with radiocarbon (¹⁴C) and optical stimulated luminescence (OSL) dates to show the equivalent climatechronozones. Using the age-depth model and characterization curves of the gray scale (L*), rubification (a*), yellow index (b*), and matrix carbonate content, the sedimentary boundaries were implicitly defined, and these climatechronozones nearly perfectly matched the GISP2 d¹⁸O record since the last glacial termination to the Holocene period.