Doctoral Dissertations

Keywords and Phrases

Exploration; geochemistry; iocg; isotope; la-icp-ms; magnetite

Abstract

"Iron-oxide-copper-gold (IOCG) deposits are poorly understood mineral systems. For example, we do not know why Cu- and Co-rich IOCG deposits typically occur proximal to Fe ore deposits that are notably Cu and Co-poor, such as Iron Oxide Apatite (IOA) deposits. To better understand the formation of IOA and IOCG deposits in Missouri, USA, this PhD thesis examines the genesis of the Kratz Spring IOA and the Boss Central Dome IOCG deposits. This study presents the first constraints on formation conditions and fluid sources in the studied deposits using integrated petrographic, mineral composition, and Fe isotope analyses of oxide minerals. Observations show that the Kratz Spring deposit is primarily composed of magnetite with lesser hematite and can be sub-divided into two deposits: (i) a north deposit with magnetite formation temperatures of 650-850°C and (ii) a south deposit with magnetite formation temperatures of 350-500°C. Trace element and isotope data of oxides suggest that the two sub-deposits at Kratz Spring were formed from different fluid sources, i.e., the south deposit was formed by a juvenile magmatically exsolved fluid, while the north deposit’s had significant input of meteoric fluids. Oxide trace element chemistry and Fe isotopic analysis suggest that the magnetite ore in the Boss Central Dome deposit formed from a juvenile fluid at 300-600°C. Together, the data presented here suggest that the Kratz Spring South deposit mirrors the distant Boss Central Dome deposit more so than the adjacent Kratz Spring North deposit. This study supports linking Missouri’s IOA and IOCG deposits to a crustal-scale magmatic-hydrothermal system to explain their co-occurrence, and thereby helps to focus regional exploration efforts"-- Abstract, p. iv

Advisor(s)

Locmelis, Marek

Committee Member(s)

Awuah-Offei, Kwame, 1975-
Borrok, David M.
Hogan, John Patrick
Seeger, Cheryl M.
Wronkiewicz, David J.

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology and Geophysics

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2024

Pagination

xi, 262 pages

Note about bibliography

Includes_bibliographical_references_(pages 72, 102 and 260-261)

Rights

© 2023 Brandon James Sulivan, All rights reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12362

Electronic OCLC #

1478110247

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Geochemistry Commons

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