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Clay mineralogy of Devonian shales in the Appalachian basin

Journal Article · · Geol. Surv. Open-File Rep. (U.S.); (United States)
OSTI ID:5236131
A study of the clay mineralogy of the Devonian black shales of the Appalachian basin was undertaken to help predict areas for potential gas resources. Illite (2m) recrystallized during diagenesis is more or less uniformly present throughout all shale units. Chlorite formed during low grade metamorphism is least abundant in the younger units and more abundant in the older units. Illite-smectite mixed-layer clay, which supplied the material for the formation of chlorite, is most abundant in the younger units and least abundant in the older units. Illite-chlorite mixed-layer clay occurs as a trace in all shale units. Kaolinite, the only unaltered detrital clay mineral, occurs in ca. 25 to 30% of the samples. The source of the kaolinite appears to have been to the east and northeast of the basin of deposition. The color of the shale units is primarily due to the organic content; however, those shales that contain calcite are darker than those that do not for equal amounts of organic carbon. 24 references.
OSTI ID:
5236131
Journal Information:
Geol. Surv. Open-File Rep. (U.S.); (United States), Journal Name: Geol. Surv. Open-File Rep. (U.S.); (United States) Vol. 81-585; ISSN GSORD
Country of Publication:
United States
Language:
English