Vertical movements of crust, uplift of lithosphere, and isostatic unroofing: case histories from the Ozark dome and northern Appalachians
Evidence of former deep burial of Ordovician to Devonian strata of the Ozark dome and northern Appalachians has been obtained from petrographic and geochemical studies of carbonates and coal-bearing rocks. In diagenetic minerals of the carbonate rocks, fluid inclusion homogenization temperatures and delta/sup 18/O values indicate paleotemperatures of 100 to 200/sup 0/C. The geothermometers used also include vitrinite reflectance, level of organic metamorphism (LOM), Staplin kerogen alteration index, and conodont alteration index (CAI). Maximum depths of burial were calculated from the estimated paleotemperatures assuming a geothermal gradient of about 25/sup 0/C/km. Strata of the Silurian of the northern Appalachian basin and of the Ordovician of the Ozark dome are interpreted to have reached maximum burial depths of 5 and 4.3 km, respectively; Devonian strata in the Catskill Mountains of New York had former burial depths of about 6.5 km; Lower Ordovician carbonate sequences of the northern Appalachian basin were buried to more than 7 km; Middle Ordovician strata from the same basin had paleodepths of approximately 5 km, and Devonian strata, 4.5 to 5 km. If these strata were formerly buried much more deeply than previously thought, then unexpectedly large amounts of uplift and erosion, ranging from 4.3 to 7 km, must also have occurred to bring these strata to the present land surface. The occurrence of such large-scale vertical movements of the crust and lithosphere needs to be recognized in paleogeographic reconstructions.
- Research Organization:
- Brooklyn College of the City Univ. of New York
- OSTI ID:
- 6221620
- Report Number(s):
- CONF-870606-
- Journal Information:
- AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Vol. 71:5; Conference: American Association of Petroleum Geologists annual meeting, Los Angeles, CA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
APPALACHIAN MOUNTAINS
CARBONATE ROCKS
COAL
GEOLOGIC HISTORY
PETROLEUM GEOLOGY
GEOCHEMISTRY
DEVONIAN PERIOD
GEOLOGIC FORMATIONS
KEROGEN
MACERALS
OPTICAL PROPERTIES
ORDOVICIAN PERIOD
SEDIMENTARY BASINS
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHEMISTRY
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
MATERIALS
MOUNTAINS
ORGANIC MATTER
PALEOZOIC ERA
PHYSICAL PROPERTIES
ROCKS
SEDIMENTARY ROCKS
020200* - Petroleum- Reserves
Geology
& Exploration