Apatite fission track evidence for post-Early Cretaceous erosional unroofing of Middle Pennsylvanian sandstones from the southern Appalachian Basin in Kentucky and Virginia
- Univ. of Texas, Austin, TX (United States). Dept. of Geological Sciences
Apatite fission track ages and mean etchable track lengths for 7 samples of Middle Pennsylvanian (Breathitt Formation) depositional age from the southern Appalachian Basin of KY and VA suggest that 3--4 km of erosional unroofing has occurred since the Early Cretaceous. The samples were collected over a 1,600 km[sup 2] area at the northern end of the Pine Mountain Overthrust southeast of Pikeville, KY. This new data set overlaps 8 published apatite fission track ages and 3 mean etchable lengths from the Cumberland Plateau and Valley and Ridge areas of WV. Because all of the apatite fission track ages are significantly younger than the depositional age, maximum burial temperatures in the area exceeded 125 C, such that fission tracks that formed in the detrital apatite prior to deposition have been totally annealed. Furthermore, mean etchable track lengths show considerable length reduction from initial values revealing that the samples resided in the zone of partial annealing on the order of 100 Ma following attainment of maximum temperatures. The burial history for these samples began with deposition and rapid burial of synorogenic sediments in front of the westward advancing Alleghenian deformation front. The fission track data are compatible with the hypothesis that maximum temperatures were attained during the Late Paleozoic as tectonically driven synorogenic fluids penetrated the foreland basin deposits. Slow erosional unroofing (< 15 m/Ma for a thermal gradient of 30 C/km) has occurred since the onset of Triassic-Jurassic rifting along the atlantic continental margin and continued into the Cenozoic.
- OSTI ID:
- 5810073
- Report Number(s):
- CONF-921058-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
APPALACHIAN BASIN
AGE ESTIMATION
EROSION
KENTUCKY
VIRGINIA
APATITES
CRETACEOUS PERIOD
FISSION TRACKS
GEOLOGIC HISTORY
RESERVOIR TEMPERATURE
WEST VIRGINIA
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
MESOZOIC ERA
MINERALS
NORTH AMERICA
PARTICLE TRACKS
PHOSPHATE MINERALS
SEDIMENTARY BASINS
USA
580000* - Geosciences