Earth and Planetary Sciences ETDs

Publication Date

12-1972

Abstract

A regional gravity survey has been conducted over the Mogollon Plateau, a mid-Tertiary volcano-tectonic complex 125 km in diameter located in southwestern New Mexico. The complete Bouguer gravity map (3 milligal contour interval) shows gravity values ranging form -167 milligals over an outcrop of Precambrian rocks near Silver City, on the southern rim of the Plateau to -251 milligals over an alluvium filled graben east of Reserve, in the northwestern part of the Plateau giving a maximum relief of 84 milligals. Gravity data show that in general the Mogollon Plateau is an area of low density rocks: gravity values within the Plateau are 10 to 15 milligals lower than values around the Plateau. Low relief of the gravity field within the Plateau shows that rocks there are horizontally homogeneous with respect to density. The observed gravity pattern is in agreement with the previously proposed geologic model of the Mogollon Plateau; that it is the surface expression of a ring-dike complex probably underlain by a pluton.

A low of -15 to -20 milligals is correlated with the Bursum cauldron. A low of at least -24 milligals, probably due to a near surface pluton, is associated with the southern end of the source cauldron of the Kneeling Nun Quartz Latite. The proposed Gila Cliff Dwellings cauldron has only a slight gravity expression. Gravity values within the San Agustin Plains are -25 milligals low with respect to the north side of the plains but about 12 milligals high with respect to the south side. A 25 milligal high associated with an area of complex structure and intense hydrothermal alteration is found o the southwestern margin of the Mogollon Plateau. A 10 hilligal high is correlated with the Santa Rita horst and a low of about -8 milligals is associated with the Mangas Trench.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

George Jiracek

Second Committee Member

Wolfgang E. Elston

Third Committee Member

Albert Masakiyo Kudo

Fourth Committee Member

Lee A. Woodward

Language

English

Document Type

Thesis

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