Graduation Semester and Year

2018

Language

English

Document Type

Thesis

Degree Name

Master of Science in Earth and Environmental Science

Department

Earth and Environmental Sciences

First Advisor

Merlynd K Nestell

Abstract

In the Apache Mountains of West Texas, Middle Permian (Guadalupian) strata a portion of the Delaware Basin part of the Capitan Reef is well exposed in many canyons that cut through the northern escarpment in the eastern part of the mountains. In Panther Canyon, the massive part of the Capitan Reef is well exposed and overlain by a stratigraphic sequence of lagoonal carbonate deposits referred to the Yates and Tansill Formations. At the entrance to Panther Canyon, two sections of these stratified carbonate rocks have been measured and described: the PC7 section, 31.8 meters thick, with eight distinct packages and the PC8 section, 86 meters thick, with 18 packages. Faunal assemblages consisting of algae, sponges, brachiopods, ostracodes, bryozoans, and foraminifers, are Capitanian (Late Guadalupian, Middle Permian) in age. Fusulinids present are Codonofusiella extensa, Yabeina texana, Paradoxiella pratti, and Reichelina lamarensis and the ranges of these genera enable these sections to be biostratigraphically correlated to extensively studied sections in the nearby Guadalupe Mountains to the north (Skinner and Wilde, 1955; Tyrrell, 1962; Nestell and Nestell, 2006; Wilde et al., 1999). Microfacies analysis has revealed the stratified carbonate rocks were generated within reef, proximal back-reef, and lagoon depositional environments. The environmental conditions were controlled by the eustatic condition during the time of deposition. Lagoon rocks appear to contain two distinct microfacies: (1) Biomicrite containing dasycladacean green algal remains was deposited on the lagoon floor in calm, marine water. A barrier reef would disrupt any wave action and protect the lagoon allowing for the deposition of fine carbonate mud amongst the skeletal remains of the lagoon inhabitants. (2) Bioclastic intrasparite was deposited in barrier wash-over fans generated by storm events. Large, storm generated, high energy waves could wash over the barrier reef and disturb the fine carbonate lagoonal sediment and transport it out of the barrier inlets. Reef detritus generated by wave action can mechanically erode the fore-reef structure and be transported shoreward and deposited within the lagoon. The resultant allochemical composition of the rocks would be fore-reef derived carbonate intraclasts amongst lagoonal faunal and floral components.

Keywords

Carbonate, Lagoon, Apache Mountains, Delaware Basin, Permian, Biostratigraphy, Carbonate petrology, Capitanian, Guadalupian, West Texas

Disciplines

Earth Sciences | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

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