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History of burial diagenesis determined from isotopic geochemistry, Frio Formation, Brazoria County, Texas

Journal Article · · Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:5626939

Progressive burial diagenesis of the Oligocene Frio Formation in Brazoria County, Texas, has resulted in extensive reaction between pore fluids and sediment in a major shift toward water/rock equilibrium. Carbon and oxygen isotopic data, combined with fluid isotopic data from the literature, indicate that quartz cement formed at 75 to 80/sup 0/C and kaolinite at approximately 100/sup 0/C. The zone of most rapid albitization is near 150/sup 0/C. Authigenic carbonates formed over a wide range of temperatures, and those within the peak zone of hydrocarbon generation are depleted in /sup 13/C. At depths shallower than approximately 2600 m, quartz and carbonate cementation in primary intergranular pore spaces (passive diagenesis) dominated. Below 2600 m, within the geopressured zone, reaction of detrital components (active diagenesis) is the major process. Organic maturation, albitization, and the transition of smectite to illite are the processes that contribute most of the components required for precipitation of cements. Quartz cementation occurred quite early in the burial history of the Frio (beginning at approximately 1500 m of burial), when the rates of fluid expulsion were at a maximum and when little of the Frio sandstone section had reached the zone of albitization.

DOE Contract Number:
AC08-79ET27111
OSTI ID:
5626939
Journal Information:
Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 65-8; ISSN AAPGB
Country of Publication:
United States
Language:
English