Graphic correlation of middle Ordovician graptolite shale, southern Appalachians: An approach for examining the subsidence and migration of a Taconic foreland basin
Journal Article
·
· Geological Society of America, Bulletin
- California State Univ., Long Beach, CA (United States)
- Raymond M. Alf Museum, Claremont, CA (United States)
- Oak Ridge National Lab., TN (United States)
Graptolite-rich shale in the Valley and Ridge province of Alabama, Georgia, Tennessee, and Virginia records subsidence and migration of the Sevier foreland basin, which formed in response to arc-continent collision during the Middle Ordocician Blountian phase of the Taconic orogeny. Rapid, tectonically induced subsidence of what had been a shallow carbonate platform led to pelagic deposition of graptolite shale in a deep basinal setting. The contact of the shale with the underlying carbonate rocks is a distinct record of initiation of subsidence. Graptolites were collected extensively and systematically from the shale at 50 localities in the southern Appalachians. Biostratigraphic datas from 22 localities were amenable to analysis by graphic correlation. Recorrelation of each of the 22 measured sections with the composite standard reference section allowed the stratigraphic base of the shale in each section to be expressed in terms of composite standard units, and such correlations permitted the diachronism of the basal shale contact to be measured with much greater precision than with zonal biostratigraphy. In addition, age differences of the basal shale contact between sections can be expressed in terms of time. With the temporal information provided by the composite standard reference section and original distances between sections determined from a palinspastic reconstruction, the rate of migration of the foreland basin as recorded in the diachronous basal shale contact was determined. 70 refs., 15 figs., 1 tab.
- OSTI ID:
- 420908
- Journal Information:
- Geological Society of America, Bulletin, Journal Name: Geological Society of America, Bulletin Journal Issue: 3 Vol. 108; ISSN BUGMAF; ISSN 0016-7606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Graptolite biostratigraphy and depositional history of Middle Ordovician shales, southern Appalachians
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Conference
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Thu May 01 00:00:00 EDT 1986
· Am. Assoc. Pet. Geol., Bull.; (United States)
·
OSTI ID:5311140
Increasing influence of exotic terranes as sources of shales from the Sevier and Taconic Foreland basins : Evidence from Nd isotopes
Conference
·
Mon Feb 28 23:00:00 EST 1994
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:7059934
Taconic foreland basin evolution: Sedimentology and cement stratigraphy of the Black River Group limestones in the Champlain Basin
Conference
·
Sun Feb 28 23:00:00 EST 1993
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:5934204