Earth and Planetary Sciences ETDs

Publication Date

5-2-1973

Abstract

The Halite II Member of the Permian Castile Formation in the Delaware Basin of Texas and New Mexico constitutes a 1778-year record of evaporite laminations. They are composed of rhythmic halite-anhydrite layers interrupted by four distinct carbonate-laminated beds of anhydrite. The average thickness of the varves is 2.3 cm for the halite-anhydrite couplets and 3.9 mm for the carbonate-laminated anhydrite couplets. They are correlative over distances of 70 miles (113 km). Halite occurs either as hopper crystals, grains, or as compact masses with many inclusions, bubbles, and vacuoles. Matrix crystals, rectangular crystals, nodules, and laths are the main petrographic types of anhydrite. Calcite occurs as ovoid grains with rhombohedral cleavage. Pyrite, zircon, and magnetic particles appear as minor accessory minerals. Most halite laminae have become recrystallized. Textural relationships indicate that halite has partially replaced anhydrite. Other diagenetic events of lesser importance show partial dolomitization of calcite and subsequent partial replacement of dolomite by anhydrite. Unit-time sampling and analysis furnished a means to measure the true associations of the various components at different frequencies of change within the system. The continuous record has been resolved into parallel and independent time-series of halite, calcium sulfate, calcium carbonate, organic matter, magnesium, strontium, potassium, and iron. Correlation of time-series for major components indicates little association among the rates of halite, calcium sulfate, and calcium carbonate deposition on a long-term basis. There are frequent cessations of halite deposition with little or no change in carbonate and sulfate deposition. Organic matter shows no correlation with other components. Analyses for magnesium, potassium, strontium, and iron reveal definite positive associations among the concentrations of these elements in calcite-anhydrite layers. The halite-anhydrite layers, however, exhibit low and fairly steady concentrations with only minor fluctuations. Potassium and iron concentrations are much lower than strontium and magnesium concentrations in the same sample. The time-series generally depict climatic oscillations of roughly 50, 100, 150, and 350 years, resulting from alternating environmental changes within or outside the basin.

Degree Name

Earth and Planetary Sciences

Level of Degree

Doctoral

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Roger Yates Anderson

Second Committee Member

Charles Troy Siemers

Third Committee Member

Sherman Alexander Wengerd

Fourth Committee Member

J. Paul Fitzsimmons

Language

English

Document Type

Dissertation

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