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Date Permissions Signed

5-14-2018

Date of Award

Spring 1983

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Wodzicki, Antoni

Second Advisor

Babcock, R. Scott (Randall Scott)

Third Advisor

Suczek, Christopher A., 1942-2014

Abstract

The Little Squaw gold mines are located in the Chandalar Mining District, which is in the Brooks Range, 200 miles north of Fairbanks, Alaska. Country rock in the Little Squaw area consists of Devonian clastic and volcanic rocks which were subjected to two periods of upper greenschist facies metamorphism during the Cretaceous. A penetrative schistosity developed during the first metamorphic event, and thrust faulting and the development of a non-penetrative cleavage occurred during the second.

Gold-bearing quartz veins in the Little Squaw area crystallized along high angle normal faults which post date thrust faulting and cross-cut the non-penetrative cleavage. Data obtained from the study of fluid inclusions from the gold-bearing quartz were used to determine physical and chemical conditions of ore deposition. It was found that the gold-bearing quartz veins in the Little Squaw area crystallized at about 275°C and 825 bars from boiling fluids containing an average of .18 mole % CO2. Thermodynamic calculations suggest Au(HS)2- was the predominant gold transporting agent and transport as AuCl2- was insignificant. The presence of arsenopyrite, stibnite, and CO2-rich fluid with the gold suggests that arsenothio, antimonothio, and carbonate complexing may have contributed to the transport of gold.

A drop from lithostatic to hydrostatic pressure, resulting from tectonic uplift and hydraulic fracturing, induced boiling of the hydrothermal fluids. The physiochemical changes that took place during boiling caused gold to precipitate. The search for additional ore shoots should center on locating the zone of boiling within post- metamorphic quartz-bearing structures in the Little Squaw area.

Type

Text

Keywords

Gold deposits, Little Squaw Mines, Chandalar mining district

Publisher

Western Washington University

OCLC Number

1080953457

Subject – LCSH

Gold ores--Alaska--Little Squaw Region; Quartz--Alaska--Little Squaw Region; Gold mines and mining--Alaska--Little Squaw Region; Geology--Alaska--Little Squaw Region

Geographic Coverage

Little Squaw Region (Alaska)

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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1983ashworthkathrynthesismapreduced.pdf (1079 kB)
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