HEAVY MINERAL ANALYSIS OF GLACIAL TILL IN NORTHERN AND SOUTH-CENTRAL INDIANA TO RECONSTRUCT PATH OF LAURENTIDE ICE SHEET
Heavy minerals from the 250-125 micron sand size in tills from cores and exposures in northern and southern-central Indiana were separated and point counted to create relative percentages of heavy minerals. Preliminary results show that tills from the Michigan and Huron-Erie lobes could be differentiated using heavy minerals. Possible Saginaw lobe samples, however, could not and had assemblages similar to the Huron-Erie lobe. Heavy mineral assemblages of till samples from near the terminal moraine in southern Indiana were consistent with other Huron-Erie lobe tills from northern Indiana.
The preliminary results of this study indicate that heavy mineral assemblages can differentiate between lobes of the Laurentide Ice Sheet in Indiana. Because till in south-central Indiana was likely from the Huron-Erie lobe, this lobe was probably more dominant across much of Indiana south and east of the Wabash River. Its southern margin may have been the ice front that deposited the terminal moraine in Indiana. Heavy minerals may also prove useful to determine provenance of pre-Wisconsin tills and test whether the path of older ice sheets were the same or different than during the late Wisconsin.