Paleozoic tectonics of the Ouachita Orogen through Nd isotopes
- Univ. of Arizona, Tucson, AZ (United States). Dept. of Geosciences
A combined isotopic and trace-element study of the Late Paleozoic Ouachita Orogenic belt has the following goals: (1) define changing provenance of Ouachita sedimentary systems throughout the Paleozoic; (2) constrain sources feeding into the Ouachita flysch trough during the Late Paleozoic; (3) isolate the geochemical signature of proposed colliding terranes to the south; (4) build a data base to compare with possible Ouachita System equivalents in Mexico. The ultimate aim is to constrain the tectonic setting of the southern margin of North America during the Paleozoic, with particular emphasis on collisional events leading to the final suturing of Pangea. Nd isotopic data identify 3 distinct groups: (1) Ordovician passive margin sequence; (2) Carboniferous proto-flysch (Stanley Fm.), main flysch (Jackfork and Atoka Fms.) and molasse (foreland Atoka Fm.); (3) Mississippian ash-flow tuffs. The authors interpret the Ordovician signature to be essentially all craton-derived, whereas the Carboniferous signature reflects mixed sources from the craton plus orogenic sources to the east and possibly the south, including the evolving Appalachian Orogen. The proposed southern source is revealed by the tuffs to be too old and evolved to be a juvenile island arc terrane. They interpret the tuffs to have been erupted in a continental margin arc-type setting. Surprisingly, the foreland molasse sequence is indistinguishable from the main trough flysch sequence, suggesting the Ouachita trough and the craton were both inundated with sediment of a single homogenized isotopic signature during the Late Carboniferous. The possibility that Carboniferous-type sedimentary dispersal patterns began as early as the Silurian has important implications for the tectonics and paleogeography of the evolving Appalachian-Ouachita Orogenic System.
- OSTI ID:
- 5808882
- 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
PALEOZOIC ERA
PLATE TECTONICS
APPALACHIAN BASIN
CARBONIFEROUS PERIOD
GEOCHEMISTRY
GEOLOGIC FORMATIONS
ISOTOPE RATIO
MEXICO
NEODYMIUM ISOTOPES
NORTH AMERICA
ORDOVICIAN PERIOD
OROGENESIS
TUFF
CHEMISTRY
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
LATIN AMERICA
SEDIMENTARY BASINS
TECTONICS
580000* - Geosciences