Time-temperature-burial significance of Devonian anthracite implies former great (approx. 6. 5 km) depth of burial of Catskill Mountains, New York

Journal Article · Mon Feb 01 00:00:00 EST 1982 · Geology; (United States)

OSTI ID:5427977

Friedman, G M ^[1]; Sanders, J E

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1. Rensselaer Polytechnic Inst., Troy, NY

Specimens of coalified plant debris in Tully-correlative strata of the Gilboa Formation (uppermost Middle Devonian) within the eastern Catskill Mountains of New York State have been converted to anthracite having a vitrinite reflectance of 2.5%. This implies a level of organic metamorphism (LOM) of 16. The specimens are about 350 m.y. old; if 200 m.y. is taken as the duration of the time of exposure to the maximum geothermal temperature, then the LOM of 16 and other thermal indicators imply a maximum temperature of 190/sup 0/C. Using a geothermal gradient of 26/sup 0/C.km/sup -1/ (17/sup 0/F.1,000 ft/sup -1/), a former depth of burial of 6.5 km is implied. Such former deep burial is not usually inferred for the Catskills, but it is consistent with the idea that the thick (about 6.4 km or 21,000 ft) Carboniferous strata of northeastern Pennsylvania formerly extended northeast far enough to bury the Catskills. The lack of metamorphism of the Paleozoic strata lying about 4.5 km beneath the Tully-correlative rocks and exposed in the adjacent Hudson Valley places low limits on the former geothermal gradient; this supports the concept of great depth of former burial of the Catskills. For example, 6.5 km of former burial and a geothermal gradient of 26/sup 0/C.km/sup -1/ imply a temperature of 307/sup 0/C for the base of the Paleozoic. By contrast, only 1 km of former burial requires a geothermal gradient of 170/sup 0/C.km/sup -1/, which would have subjected the base of the Paleozoic to a temperature of 955/sup 0/GAMMA, which is far higher than the 600 to 650/sup 0/C recently inferred for the Acadian-age metamorphism of the Taconic allochthon in southwestern Massachusetts and adjoining areas.

• OSTI ID: 5427977
• Journal Information: Geology; (United States), Vol. 10:2
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
01 COAL, LIGNITE, AND PEAT
ANTHRACITE
ORIGIN
DEVONIAN PERIOD
GEOLOGIC HISTORY
GEOTHERMAL GRADIENTS
METAMORPHISM
NEW YORK
SEDIMENTARY ROCKS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
BLACK COAL
CARBONACEOUS MATERIALS
COAL
ENERGY SOURCES
FEDERAL REGION II
FOSSIL FUELS
FUELS
GEOLOGIC AGES
MATERIALS
NORTH AMERICA
PALEOZOIC ERA
ROCKS
TEMPERATURE GRADIENTS
USA
580100* - Geology & Hydrology- (-1989)
011000 - Coal
Lignite
& Peat- Reserves
Geology
& Exploration