Date of Award

Spring 1-1-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geological Sciences

First Advisor

Stephen J. Mojzsis

Second Advisor

Rebecca Flowers

Third Advisor

Kevin Mahan

Abstract

Quad Creek Paleoarchean quartzites (~3300 Ma) in Montana contain >3900 Ma detrital zircons. The outcrop-scale geological and geochemical context of these rocks is not well documented. New mapping reveals a suite of isoclinally folded, sheared and deformed chromite-rich banded, massive quartzites, garnet-bearing siliceous paragneisses, amphibolite, quartz-biotite schists and a suite of inter-bedded quartz+magnetite rocks. These data support the notion that the oldest crust tapped by the Quad Creek quartzites is comparable in age to the ca. 3960 Ma Acasta Gneiss Complex. This similarity suggests a linkage between the geology of the Wyoming Craton and the Western Slave Province. An ancient supercraton called Sclavia could provide the mechanism for this linkage. Sediment source(s) for some other Paleoarchean supracrustals were also contaminated by Hadean crust suggests that pre-3900 Ma zircons are present in similarly-aged basins elsewhere in North America and perhaps also remnants of Sclavia.

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