At the edge of the Laurentide Ice Sheet: Stratigraphy and chronology of glacial deposits in central Indiana
Henry M. Loope, José Luis Antinao, G. William Monaghan, Robert J. Autio, B. Brandon Curry, David A. Grimley, Sébastien Huot, Thomas V. Lowell, Thomas A. Nash, 2018. "At the edge of the Laurentide Ice Sheet: Stratigraphy and chronology of glacial deposits in central Indiana", Ancient Oceans, Orogenic Uplifts, and Glacial Ice: Geologic Crossroads in America’s Heartland, Lee J. Florea
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This field guide provides an updated synthesis of the stratigraphy and chronology of glacial deposits in central Indiana near the southern limit of glaciation in the midcontinent. Central Indiana contains evidence of multiple glaciations—deposits from the last two glaciations (Oxygen Isotope Stages [OIS] 2 [Wisconsin Episode] and 6 [Illinois Episode]) have been the focus of recent stratigraphic and chronologic investigation. New radiocarbon and optically stimulated luminescence (OSL) dating from outcrop and core has refined the timing of OIS 2 and OIS 6 ice sheet advances, outwash/slackwater aggradation, glacial lake formation, and eolian activity. Radiocarbon ages within or below late Wisconsin till from three sites within 5 km (3 mi) of the late Wisconsin maximum limit indicate an age of 24.0 k cal yr B.P. for maximum OIS 2 ice sheet extent in central Indiana, consistent with chronology from Illinois and Ohio. A subsequent >50 km (31 mi) readvance (21.6 k cal yr B.P.) across central Indiana came within 10 km (6 mi) of the maximum limit and in the western part of the field-trip area, terminated in glacial Lake Eminence. The start of outwash aggradation and associated slackwater sedimentation in the West Fork White River valley and tributaries began ca. 27 k cal yr B.P. and continued until ca. 20.5 k cal yr B.P., representing the timing of ice sheet advance into and out of the paleo–White River drainage basin. Ice sheet advance and retreat rates average ~40 m/yr before and after the global Last Glacial Maximum (ca. 26−21 k cal yr B.P.) when ice was within ~50 km of the late Wisconsin maximum. OSL dating of pre-Wisconsin outwash and glacio-lacustrine sediment return ages between ca. 218 and 127 ka, confirming deposition during OIS 6. These ages document spatially complex sedimentation in bedrock valleys beyond the Wisconsin limit.
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Ancient Oceans, Orogenic Uplifts, and Glacial Ice: Geologic Crossroads in America’s Heartland
This volume, prepared for the 130th Annual Meeting of the Geological Society of America in Indianapolis, includes compelling science and field trips in Indiana, Illinois, Kentucky, Michigan, and Ohio. A wealth of geologic and human history collides in the Midwest, a confluence that led to the growth of America's industry over the past two centuries. Guides in this volume depict this development from the establishment of New Harmony, the birthplace of American geology, through the construction of Indianapolis's modern skyline. Underpinning this growth were the widespread natural resources-limestone, coal, and water-that built, powered, and connected a growing nation. Take a journey through the Heartland to sand dunes, outcrops, quarries, rivers, caves, and springs that connect Paleozoic stratigraphy with the assembly of Gondwana, continental glaciation with Quaternary geomorphology and hydrology, and landscape with the human environment.