A transect through the Alabama and southwest Georgia Appalachians
- Auburn Univ., AL (United States). Dept. of Geology
A transect across Alabama and southwest Georgia contains several occurrences that appear to be unique and are not accommodated in existing tectonic interpretations of the southern Appalachians. In the foreland, the Alleghanian orogeny was signaled by the Mississippian unconformity, Mississippian shelf collapse and flysch sedimentation followed by deposition of a >3,000 m thick Pennsylvanian molasse wedge. The Pottsville Formation itself is folded and faulted, documenting that deformation continued after Westphalian A deposition into the Late Pennsylvanian. The recent report of Early Mississippian plant fossils from the tectonically overlying, greenschist-facies Talladega slate belt indicates that metamorphism and deformation of these units occurred after ca. 360--352 m.y. and thus resulted from the Alleghanian event. To the south, a post-metamorphic thrust, he Hollins line fault system, emplaced amphibolite-facies eastern Blue Ridge units upon the slate belt. [sup 40]Ar/[sup 39]Ar cooling dates from the eastern Blue Ridge are hornblende ca. 334 Ma and muscovite 329 Ma indicating transport of the already metamorphosed and cooled units during Alleghanian thrusting. [sup 40]Ar/[sup 39]Ar metamorphic cooling dates from the sillimanite-zone rocks of the eastern Blue Ridge, Inner Piedmont, Pine Mountain, and Uchee belts document maintenance of 500 C temperatures from the Carboniferous into the Early Permian, contemporaneous with the Alleghanian orogeny recorded in the foreland and the Talladega slate belt.
- OSTI ID:
- 6785858
- Report Number(s):
- CONF-9404221-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 26:4; Conference: 43. annual meeting of the Southeastern Section of the Geological Society of America, Blacksburg, VA (United States), 7-8 Apr 1994; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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