The Importance of Glaciofluvial Features within Michigan's Port Huron Moraine

Abstract

Abstract Evidence based on topographic quadrangles, aerial photographs, soils maps, and extensive fieldwork indicates that the Inner and Outer Port Huron moraines in the northwestern part of Michigan's Southern Peninsula represent a mega-assemblage of related glaciofluvial formations marking successive marginally stagnant glacial termini. Surficial sediments consist of ice-contact stratified drift and proglacial sand and gravel. Diamictons are very limited in extent and usually occur in the form of flow till. Uppermost sediments within the intervening Mancelona Plain show a transition from coarse, poorly sorted proximal deposits dominated by longitudinal bars to distal, fine-textured, well-sorted braided-stream deposits displaying sandy bedforms. Paleocurrent indicators show that meltwater streams first flowed directly away from the ice margin and then turned 90 degrees to the right (southwest) to flow parallel to the sandur's trend. Based on these data, we propose that what were previously mapped as the ...