Graduation Term

10-5-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Department of Geography-Geology: Hydrogeology

Committee Chair

David H. Malone

Abstract

U-Pb isotopic ages were determined for zircons extracted from granitic and related rocks in the Tiskilwa till to determine their origin. Crystalline cobbles (n = 750) were collected at localities from each of the four of the sub-lobes of the terminal Wisconsin moraines. Two sites were chosen from the Decatur, Peoria, and Princeton sub-lobes with one sample taken from the Harvard sub-lobe. Each sample was then individually processed, the zircons handpicked (n = 301), and geochronology conducted using LA-MC-ICPMS at the University of Arizona Laserchron Center. A Kolmogorov-Smirnov (K-S) statistical analysis show that all samples have identical zircon age spectra with the populations being dominated by Archean age (>2.5 Ga) grains and peak age being 2.7 Ga. The dominance of Archean grains indicate a source located in the Superior Province, with the Hudson Bay Terrane (3.36 – 2.69 Ga) being the most likely source area for the granite clasts. In successfully utilizing granite clasts to determine provenance, this study could provide further insight into glacial transport systems.

DOI

http://doi.org/10.30707/ETD2016.Meister.P

Page Count

61

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