| Abstract: | Levels of thermal maturity are estimated for Paleozoic strata in five areas of the central Anadarko basin for times between the Paleozoic and the present, and depths of the oil window are plotted as a function of geologic time. Mean surface temperature assumed here for calculating Lopatin‘s time-temperature index of thermal maturity (TTl) in the central Anadarko basin declines from 80°F (27°C) to 60°F (16°C) from early Paleozoic time to the present. Shallow-water carbonates and lower paleolatitudes suggest warmer climates in the Paleozoic for this area. The geothermal gradient is assumed to equal 4.0°F/100 ft (7.3°C/100 m) in the Late Cambrian and to decay over a 100-m.y. period to the present regional gradient of 1.3°F/100 ft (2.4°C/100 m). Initial
basin formation was caused by crustal thinning. Accumulation of thick Pennsylvanian sediments in a foreland-style basin dominated by vertical lithospheric flexure represents a second major period of subsidence. An elevated geothermal gradient during this time is not assumed for TTl calculations, because mathematical models suggest time-invariant heat flows in such basins. TTl computations based on these assumptions indicate that oil could have been generated in the ancestral Anadarko basin >350 m.y. ago. By the end of the Pennsylvanian, significant volumes of kerogen were in the oil window (and perhaps beyond), and significant volumes have remained in the oil window up to the present day. These circumstances may partially explain the unusual richness of the Anadarko basin as a Paleozoic hydrocarbon province. |
| Genre: | Book chapter |
| ProdID: | 70044325 |
| Citation Author: | Schmoker, James W. |
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| Citation End Page: | 31 |
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| Citation Language: | English |
| Citation Larger Work Title: | Anadarko Basin symposium, 1988 (Circular 90) |
| Citation LatN: | 37.0 |
| Citation LatS: | 33.62 |
| Citation LonE: | -94.43 |
| Citation LonW: | -103.0 |
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| Citation No Pagination: | |
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| Citation Online Only Flag: | |
| Citation Phsyical Description: | 7 p. |
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| Citation Public Comments: | Proceedings of a symposium held April 5-6, 1988, at Norman, Oklahoma; cosponsored by the Oklahoma Geological Survey and the U.S. Geological Survey |
| Citation Publisher: | Oklahoma Geological Survey |
| Citation Series: | Circular |
| Citation Series Code: | CIR |
| Citation Series Number: | 90 |
| Citation Search Results Text: | Thermal maturity of the Anadarko Basin; 1989; Book chapter; CIR; 90; Other Government Series; Anadarko Basin symposium, 1988 (Circular 90); Schmoker, James W. |
| Citation Start Page: | 25 |
| Citation Volume: | |
| Citation Year: | 1989 |
| Type: | citation/reference |
| Text: | Thermal maturity of the Anadarko Basin; 1989; Book chapter; CIR; 90; Other Government Series; Anadarko Basin symposium, 1988 (Circular 90); Schmoker, James W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DOCUMENT): | http://www.ogs.ou.edu/pubsscanned/Circulars/Circular90.pdf |
| Date Other: | Tue, 1 Jan 2013 00:00 -0600 |
| Publisher: | Oklahoma Geological Survey |
