Date of Award

2013-01-01

Degree Name

Doctor of Philosophy

Department

Geology

Advisor(s)

Richard P. Langford

Second Advisor

Diane I. Doser

Abstract

This Dissertation consists of two different projects. The first project describes the results of an outcrop based sequence stratigraphic study of the Albian Cox Sandstone in the Indio Mountains of west Texas. The depositional environment of the Cox Sandstone ranges from shallow marine to the coastal plain deposited in four sequences where sequence 1 and sequence 2 consists of transgressive system tracts (TST) followed by highstand system tracts (HST). The highstand system tract (HST) is missing in sequence 3 and the transgressive systems tract is missing in sequence 4. The Cox changes in thickness from 320 m in the northern end of the outcrop belt to 365 m in the southern end. This thickness change is accommodated during transgression where shales drape topography that is actively being shaped by faults and block rotation recorded in exposed growth strata. During Highstand, coarse fluvial-deltaic systems truncate shales on topographic high levelling the topography. Systems tracts and sequences change thickness due to block rotation and erosion as well as deposition from a point source near the center of the outcrop belt. The second project involves the integrated study of gravity and well log data in the northern Hueco bolson. The objective of this study is to demarcate subsurface faults that appear to control the locations of fresh and brackish water. In this study 28 gravity anomalies were identified that correlate with previously mapped (Collins and Raney, 2000) and new faults, and some of them can be extended further south to south east to join with previously mapped faults by Collins and Raney (2000) and Marrufo (2011). Structural cross sections of well logs also suggest that at least some faults are present between them. The four depositional environments inferred from the gamma log responses and their stacking patterns are consistent with the previous interpretation of Doser and Langford (2006) and Marrufo (2011).

Language

en

Provenance

Received from ProQuest

File Size

124 pages

File Format

application/pdf

Rights Holder

Pawan Budhathoki

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