Date of Award

4-1991

Degree Name

Master of Science

Department

Geosciences

First Advisor

Dr. David A. Barnes

Second Advisor

Dr. William Harrison III

Third Advisor

Dr. John Grace

Access Setting

Masters Thesis-Open Access

Abstract

The petrographic evolution of authigenic minerals in the St. Peter formation consists of: early marine cement, syndepositional dolomite, quartz overgrowth cement, pervasive dolomite replacement of precursor carbonate, dissolution of framework grains and carbonate cements, and late formation of authigenic chlorite and illite.

Variations in the diagenetic sequence were templated by variations in primary mineralogy related to depositional facies. Early intergranular carbonate cement, common in shelf facies, precluded early quartz cementation. Subsequent dissolution of dolomite and detrital grains may be temporally and chemically related to the precipitation of authigenic clay in dissolution pores. In peritidal facies, pervasive quartz cementation was locally terminated, before complete porosity occlusion, by the precipitation of late, pore-filling, burial dolomite. Subsequent dissolution of this dolomite, along with minor silicate framework grains, also resulted in formation of secondary pores with little late, authigenic clay.

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Geology Commons

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