Masters Theses

Alternative Title

Geology and mineralogy of the Iron Mountain mine, St. Francois County, Missouri

Abstract

"The Iron Mountain mine represents one of six known major iron deposits in the Southeast Missouri Iron Metallogenic Province. The deposit is in the form of an unusual, inverted cup-shaped body, contains a skarn-like mineralogy that is unique to the Missouri iron deposits, and is hosted by trachytic volcanic flows of Middle Proterozoic age. The ore occurs as massive veins and matrix between brecciated host rock. Hematite and Magnetite are the main ore minerals. Ore textures indicate that the original ore mineralization was composed entirely of magnetite that has subsequently been extensively martized. Intimately associated with the ore is actinolite and apatite which exhibit a phenocrsyt-like habit and distribution throughout the ore. The orebody shows distinct mineral zonation - the eastern portion consists of magnetite, actinolite, and apatite, and the western portion contains martite, andradite, and apatite. Late crustiform, fracture-filling minerals include quartz, specular hematite, calcite, epidote, chlorite, dolomite, fluorite, and a second generation of magnetite, actinolite, and andradite. New minerals identified include titanite, anatase, potassium feldspar, tellurobismuthite, and nickelliferous pyrite. Ore textures, Lineation of the actinolite and apatite, and lack of pervasive wallrock alteration, suggest a magmatic origin, i.e., the deposit formed from the intrusion of an iron-oxide rich melt. Alteration and oxidation of the early ore/silicate mineralization probably resulted from interactions with a high temperature magmatic hydrothermal fluid that probably evolved from the main magnetite body or ore system. Through cooling, the ore system eventually evolved into a hydrothermal-dominant system composed of residual mineralizing fluids and volatiles unused in the early ore/silicate crystallization"--Abstract, p. iii

Advisor(s)

Hagni, Richard D.

Committee Member(s)

Wronkiewicz, David J.
Miller, F. Scott, 1956-

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geology and Geophysics

Publisher

University of Missouri--Rolla

Publication Date

Spring 1998

Pagination

xi, 184 pages

Note about bibliography

Includes bibliographical references (pages 178-183)

Rights

© 1998 Mark Anthony Dudley, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Thesis Number

T 7491

Print OCLC #

39632227

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