Masters Theses

Abstract

"Bitumen in the form of oil blebs from the Magmont West orebody of the Viburnum Trend was examined and analysed in an attempt to relate hydrocarbon distribution and origin to ore genesis. Hydrogen, carbon, nitrogen, sulfur and oxygen percentages were determined by elemental analyses. Trace element composition was determined by emmission spectroscopy and the composition of the bitumen was calculated with respect to aromatic hydrocarbons, saturated hydrocarbons and NSO (nitrogen-sulfur-oxygen) components. The bitumen and kerogen from associated shale samples were evaluated by Rock-Eval pyrolysis and pyrolysis-gas chromatography.

The bitumen was calculated to be approximately 40 to 50 percent aromatic and is considered to be a polymerized normal crude oil. Polymerization, which was probably caused by water-washing and mild biodegradation, caused hardening of the bleb surfaces and appears to have frozen the blebs during primary migration from the local source beds. A comparison of the bitumen to kerogen in local shale beds confirms that the oil is almost certainly derived locally. The polymerized oil blebs are considered to have been derived from an oxidized type II (marine) kerogen.

Textural analyses indicate that oil migration occurred after lead-zinc mineralization and at temperatures that exceed normal ancient or present geothermal gradients. The following sequence of events is postulated for the Magmont West orebody.

1. Generation of hydrogen sulfide and methane during diagenesis of a normal organic-rich carbonate sequence.

2. "Introduction of pulses of hot, metal-rich fluids that result in the following sequence of events:
a. Lead-zinc mineralization by the following reaction: Me++ + H2S = MeS + 2H+
b. Solution of carbonates as result of excess acid produced during above reaction.
c. Brecciation of the host-rock in some cases.

3. Passage of the pulse resulted in:
a. Carbonate buffering of system to alkaline conditions.
b. Precipitation of dolomite.
c. Slight temperature drop.

4. Eventually the high temperatures caused oil generation and primary migration began.

5. Water-washing and mild biodegradation altered the blebs to their present composition"--Abstract, pages ii-iii.

Advisor(s)

Laudon, Robert C.

Committee Member(s)

Hagni, Richard D.
Hufham, James B.

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geology and Geophysics

Publisher

University of Missouri--Rolla

Publication Date

Fall 1984

Pagination

x, 122 pages

Note about bibliography

Includes bibliographical references (pages 93-111).

Geographic Coverage

Southeast Missouri

Rights

© 1984 Mark Alan Marikos, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 5151

Print OCLC #

11705480

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Thesis Location

 
COinS