Provenance Analysis Of Granite Cobbles In The Tiskilwa Till Using U-Pb Geochronology
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 th...
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| Format: | Text |
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ISU ReD: Research and eData
2016
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| Online Access: | https://ir.library.illinoisstate.edu/etd/624 https://ir.library.illinoisstate.edu/cgi/viewcontent.cgi?article=1624&context=etd |
| Summary: | 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. |
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