14 Undergraduate Research Poster Session I (Posters)

Monday, 16 April 2018
8:00 AM - 5:30 PM
First Floor Lobby

FIELD MAPPING AND GEOLOGICAL HISTORY IN IGNEOUS ROCKS OF THE CENTRAL MINNESOTA BATHOLITH, WAITE PARK, MINNESOTA

Paper number: 14-24
Program: Theme Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Field work was conducted on a series of outcrops in the Early Proterozoic Central Minnesotan Batholith at the Radio Tower locality in Waite Park, MN. A range of igneous lithologies, some of which are mixed, as well as a series of variously-oriented fractures were mapped. From this, the relative age of each lithology and the inferred history of events has been determined. A series of outcrop maps partnered with collected samples show align with pre-existing trends in Minnesota. A total of four lithologies and three fracturing events have been identified. The oldest unit is a granodiorite, which is succeeded by a quartz alkali feldspar syenite. The first fracturing event on a north-south trend. Subsequently, is a pair of aplite dikes and a second east-west fracture set. Lastly, a basalt dike on-trend with those seen in the Central Minnesotan Batholith and a final north-south fracturing event. Glacial striations and polishing are absent from outcrops at the Radio Tower locality, compared to exposures at Quarry Park less than half a mile away. A complex history of deep chemical weathering and variable removal by ice probably accounts for this.

Geological Society of America Abstracts with Programs. Vol. 50, No. 4

doi: 10.1130/abs/2018NC-312342

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