Masters Theses


"The Ohio and Mt. Baldy Mining Districts near Marysvale, Utah occupy a cauldron complex in the Bullion Canyon Volcanics. This complex contains three rock groups of three volcanic episodes. The oldest is a volcanic cone framework series of lahars. The middle group is represented by lava flows, ash flows, and breccias which represent intra-caldera fill. The upper group consists of a local vent complex and the Delano Peak Tuff Member both of which may be related to ring fracture activity.

The stages of veining in the area include in order of gradational deposition: (1) early quartz veins, (2) pre-productive main stage quartz veins, (3) productive precious metal bearing main stage quartz veins, (4) productive base metal bearing main stage quartz veins, and (5) alunite veins. The initial fissures and veining probably accompanied resurgent doming of the Delano Peak Tuff Member and older rocks. A period of quiescence of about 7 m.y. occurred between Delano Peak Tuff Member deposition and base metal mineralization (Steven and others, 1977). Fissure deepening and vein mineralization was contemporaneous with magmatic doming. Trace amounts of Mo deposition increased with fissure deepening.

The earliest stage of hydrothermal alteration is that of alteration activity that formed K-silicate minerals. This preceded veining activity. Pervasive sericitization and argillization accompanied vein stage (1). Advanced argillic, sericitic, argillic, and propylitic alteration zones accompanied vein stages (2) through (5) and envelope those veins in a zonal fashion in the sequence listed.

The dome margins were intensely silicified sometime during vein stages (2) through (3). This fringe area developed stockwork fractures and open fissures after silicification. Vein solutions during vein stage (5) oxidized to sulphuric acid near the water table. K and Al, probably leached from the hot volcanic wall rock, reacted with the acid vein solutions to deposit alanite in the stockworks and fissures soon after base metal deposition"--Abstract, page ii.


Proctor, Paul Dean, 1918-1999

Committee Member(s)

Grant, S. Kerry
Spokes, Ernest M., 1916-1995


Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geology


University of Missouri--Rolla

Publication Date



ix, 112 pages, 2 maps

Note about bibliography

Includes bibliographical references (pages 88-91).

Geographic Coverage

Marysvale, Piute County, Utah


© 1979 Lawrence M. Nuelle, All rights reserved.

Document Type

Thesis - Restricted Access

File Type




Subject Headings

Geology -- Utah -- Piute County
Mines and mineral resources -- Utah -- Piute County

Thesis Number

T 4511

Print OCLC #


Electronic OCLC #


Link to Catalog Record

Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.

Nuelle_Lawrence_1979-Plate_1.TIF (145695 kB)
Geology, Mineralization and Alteration - Ohio and Mt. Baldy Districts, Piute County, Utah

Nuelle_Lawrence_1979-Plate_2.TIF (143747 kB)
Distribution of Trace Element Anomalies - Ohio and Mt. Baldy Districts, Piute County, Utah

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