Field trips are a time-honored venue for geologists to showcase paradigms of geologic mapping, especially to elucidate models of deposition and landsystem analysis. We are planning to lead a post-meeting field trip on November 8-9 originating from Indianapolis in conjunction with the Annual meeting of the Geological Society of America. The stops highlight recent efforts in Will County, Illinois, mapping Quaternary deposits in three-dimensions for the Great Lakes Geologic Mapping program, as well as work done as part of the STATEMAP program. One stop, highlighted below, is at a creek highbank that shows a nearly full glaciogenic sedimentary sucession from distal – proximal outwash, proglacial lacustrine, and subglacial diamicton deposits that locally form the Tinley Moraine. Additional stops will reveal subjacent stratigraphic units of the Lemont Formation. A featured stop will be at Eagle Lake (an informal name), a breached linear basin that appears to have formed by collapse of a tunnel channel. We have obtained numerous Cone Penetrometer Test profiles that help to flesh out the geometry of the sedimentary facies across the basin. We will also visit two ice-walled lake plains that have yielded fossil plant fossils to help constrain the minimum age of the Valparaiso Morainic System. The ages just precede well-founded dates associated with breaching of the Marseilles Morainic System 18,900 cal yr BP by the Kankakee Torrent.
|Original language||English (US)|
|State||Published - 2018|