TRACKING OF IGNEOUS AND METAMORPHIC GLACIAL ERRATICS IN CENTRAL OHIO FROM THE CANADIAN SHIELD USING SEM-EDS ANALYSIS

The Wisconsin Glaciation reached its last glacial maximum in Ohio approximately 24,000-26,000 years ago. Central Ohio has emplacements of Precambrian crystalline rock from the Canadian shield. The goal of this project is to correlate select deposits of glacial material to specific provinces of the Canadian Shield.

Cobble to boulder sized igneous and metamorphic erratics were collected from glacial till deposits within Delaware County, Ohio. Slab and trim saws were used to remove weathered material and shape the rock to a maximum side length of 5mm, after which the samples were polished using 60 to 600 grit powder on a glass plate. The chemical characterization of these erratics was determined using energy dispersive x-ray spectroscopy (EDS) techniques using a Zeiss EVO LS10 SEM and 50mm2 Oxford X-MAX EDS detector. The chemical character of the collected erratics will be correlated with the chemical characteristics of the provinces of the Canadian Shield gathered from Fahrig and Eade (1969). GIS techniques were used to estimate glacial pathways from the Canadian Shield to the central Ohio glacial till deposits.