Provenance characterization of Appalachian clastic wedges from sandstone petrography and clast compositions
- Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Science
- Kutztown Univ., PA (United States). Dept. of Physical Science
- Univ. of Maryland, College Park, MD (United States). Dept. of Geology
- State Univ. of New York, Stony Brook, NY (United States). Dept. of Earth and Space Science
- Australian National Univ., Canberra (Australia)
Sandstones in the Taconic, Acadian and Alleghanian clastic wedges in the Appalachian Orogenic Belt provide evidence for changing provenances during the late Ordovician through pennsylvanian, Neoproterozoic-Early Cambrian, synrift sandstones are predominantly feldspathic arenites, whereas quartz arenites typify sandstones in the Cambrian passive-margin prism. In contrast, sandstones in the overlying foreland-basin clastic wedges typically are lithic arenites and occupy the quartzose to lithic recycled fields on QmFLt diagrams. Mid-Ordovician lithic arenites (Knobs, Bays Fms.) are dominated by a variety of sedimentary rock fragments including feldspathic and quartz arenites, limestone, dolomite and chert. Conglomerates in the Bays Formation similarly are dominated by recycled sedimentary clasts; gneiss clasts are only rarely observed. Above a regional unconformity in the middle Tuscarora formation, a succession of quartz arenites (upper Tuscarora, Rose Hill and Eagle Rock Fms.) developed in response to prolonged reworking. Overlying lithic arenites (Middle Devonian-Pennsylvanian) contain a variety of metamorphic rock fragments including quartz-mica schist, strained and polycrystalline quartz, and detrital mica. Sandstone petrography and clast compositions thus indicate that the Taconic orogeny involved uplift of the older passive-margin prism in a fold-and-thrust belt or accretionary prism. Coarse-grained sedimentary rocks provide no evidence of an arc to the east. Mature Silurian sandstones record an inter-orogenic, quiescent phase of the Appalachian Orogeny.
- OSTI ID:
- 6786085
- Report Number(s):
- CONF-9404221--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 26:4; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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