Publication Date

2015

Document Type

Dissertation/Thesis

First Advisor

Frank, Mark R.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Geology and Environmental Geosciences

LCSH

Geology; Geochemistry; Mineralogy; Porphyry--Research; Ore deposits--Research; Magmatism--Research

Abstract

Ore deposits are local and/or regional deviations from the country rock where desired minerals and/or metals are deposited in elevated concentrations. Porphyry ore deposits are those temporally and spatially associated with intermediate to felsic igneous intrusion(s) and commonly form via magmatic and hydrothermal components. In these systems, the MVP is thought to be the dominant transporter of desired elements (e.g. Cu, Au) towards sites of deposition. Commonly, the minerals that exist in porphyry deposits are sulfides (e.g. chalcopyrite, bornite, etc.), oxides and native elements. In this study, we conduct a fluid inclusion study to evaluate the concentration of metals (e.g. Fe, Cu, Zn, etc.) in each phase dominantly as a function of log f (sys/S2) to demonstrate the conditions under which the most metals could be transported in the MVP. The MVP were trapped as brines and vapor pairs or supercritical fluids in fluid inclusions during experiments conducted at fixed pressures of 100 MPa, f( sys/O2) buffered by Ni-NiO and temperature of 500, 600 and 700 °C. Logf(sys/S2) was varied from -11.0 (+/-1.0) to 0.6 (+/-4.0) bars to evaluate the importance of sulfur. The D(b/v/Cu) from 700 °C experiments decrease from 20.0 +/- 5.6 to 2.8 +/- 0.7 with increasing logf(sys/S2) (-5.6 +/- 0.1 to 0.6 +/- 0.4) while ?D( b/v/Fe) and D(b/v/Zn) had negligible changes. Among supercritical fluid data, the concentration of Fe, Cu and Zn are elevated in 600 °C experiments where log f( sys/S2) was -1.7 +/- 1.0 as opposed to 500 °C where log f(sys/S2) ranges from -11.0 +/- 1 to -9.2 +/- 0.6 , respectively.

Comments

Advisors: Mark R. Frank.||Committee members: Justin P. Dodd; James A. Walker.

Extent

80 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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Text

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