Earth and Planetary Sciences ETDs

Klyne Headley

Publication Date

10-1968

Abstract

The northwestern Guadalupe Mountains of southeastern New Mexico are part of a large regional cuesta that slopes gently northeast. The crest of the northern escarpment rises abruptly to more than 2,200 feet above Pinon Valley.

The rugged west-facing escarpment has been carved in an uplifted fault block composed entirely of Permian sedimentary rocks having an aggregate thickness of about 1,700 feet. Dark-red to buff siltstone, gray dolomite, and white to gray gypsum compose the Yeso Formation. Conformably overlying these rocks is the dark-brown limestone and dolomite sequence of the San Andres Formation. The Glorieta Sandstone which usually occurs between these two formations elsewhere in the Southwest was not distinguished in the report area. The marine shelf lithologic facies of these two formations grades laterally to the south into lithologies of the Delaware sedimentary basin. The changes noted were: decreased gypsum and limestone with increased dolomite in Yeso beds, and increased dolomite and decreased limestone in San Andres beds. Limestones of the San Andres Formation become more dolomitic toward the crest of the escarpment.

The Guadalupe Mountains are a tilted fault-block range bounded on the west by one or more high-angle normal faults that are downthrown to the west. The Guadalupe Mountain fault system can be divided into two structurally differ­ent provinces in the report area. The northern part contains one main fault with a minimum vertical displacement of 1,200 feet. The southern province is characterized by numerous normal faults. Stratigraphic displacements are generally 800 feet or less to the south.

Fold development is apparently directly related to the major episode of uplift that occurred during Plio-Pleistocene time. As uplift of range began a "structural gradient" was established that caused limestone beds of the San Andres Formation to slide downslope. Another mechanism causing deformation of bedding is differential solution of gypsum units in the Yeso formation. Hydration of anhydrite to gypsum may also have distorted bedding locally.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Vincent C. Kelly

Second Committee Member

Stuart A. Northrop

Third Committee Member

Lee A. Woodward

Language

English

Document Type

Thesis

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