Date of Award

4-2016

Degree Name

Master of Science

Department

Geosciences

First Advisor

Dr. Joyashish Thakurta

Second Advisor

Dr. Robb Gillespie

Third Advisor

Dr. Mohamed Sultan

Access Setting

Masters Thesis-Open Access

Abstract

This study characterizes the following rock units in Marquette County, Michigan in terms of geochemistry and petrology: (1) Presque Isle Peridotite, (2) Deer Lake Peridotite, (3) Yellowdog Peridotite, and (4) Black Rock Point Gabbro. Analyses were conducted to determine if any petrological or geochemical relationships exist between these units, and to assess the potential of these units to host magmatic sulfide deposits.

The generated data and chosen geotectonic proxies indicate that Black Rock Point Gabbro and Deer Lake Peridotite crystallized from unrelated magmas, probably during the formation of the Great Lakes Tectonic Zone (2.7-1.85 Ga). No evidence was found which suggest that either unit hosts a magmatic sulfide deposit.

Investigation has also revealed a great deal of similarity between the Presque Isle and Yellowdog Peridotite units. Trace element comparisons, along with the use of geotectonic proxies (when considered in conjunction with Yellowdog Peridotite's known age of 1107.2 Ma ± 5.7Ma) suggest the possibility that both units crystallized from a similar parent magma during the Midcontinent Rift event (1.1 Ga). Microprobe analysis revealed comparable Ni-depletion in both units. These findings suggest the possibility that Presque Isle Peridotite may be regarded as a prospective location for a magmatic sulfide deposit similar to that hosted by the Yellowdog Peridotite.

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