Date of Award

12-1982

Degree Name

Master of Science

Department

Geosciences

First Advisor

Dr. Raymond Freeman-Lynde

Second Advisor

Dr. William Harrison III

Third Advisor

Dr. John Grace

Access Setting

Masters Thesis-Open Access

Abstract

Limestones recovered from Bahama Escarpment dives (DSRV Alvin, 1978) were expected to contain shallow marine, freshwater, and deep marine cementation since the limestones had been fractured, bored, and cemented at depth. Magnesium and trace element concentrations, carbon-oxygen composition, cathodoluminescence, and petrographic study indicated the presence of all three cement types.

Lithification may have proceeded by allochem deposition, major shallow marine cementation, sparse freshwater cementation leaving porosity, fracturing, and final deep marine cementation leaving minor porosity. According to this interpretation, the pore space remained open for an unlikely 75-115 million years. In an alternative interpretation, pore space is occluded after freshwater cementation. Fracturing and minor dissolution prior to deep marine cementation may enable overlapping or equilibration of cement compositions so they are not distinct groups.

More detailed sampling is needed to distinguish generations of cements. The porosity and occlusion by deep marine cements has interesting implications for petroleum research.

Included in

Geology Commons

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