Tectonic setting of Talladega belt olistostromal sequences, Alabama appalachians

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6273308

Tull, J F; Telle, W R

Olistostromal sequences are common in parts of the Lay Dam Formation (LDF) in the Alabama Talladega slate belt. The LDF occurs in low-angle unconformable contact above metamorphic equivalents of the Cambrian-Ordovician carbonate bank facies, and is Silurian (.) to early Devonian in age. Units above and below the LDF can be stratigraphically linked to cratonal North America. Olistostromal deposits form an arcuate belt 40-50 km in length and are found within a thick (up to 3 km) sequence of lower greenschist facies metaclastic rocks. Single deposits range up to 500 m in thickness and consist of unsorted, unbedded polymictic diamictites containing clasts (up to 2m) of carbonate, pelite, quartzite, chert, felsic plutonic and high-grade metamorphic rocks; mafic and ultramafic clasts are absent. Olistrostromal units are interbedded with metagraywacke and feldspathic metasandstone, rhythmically layered and graded metasiltstone, and massive metapelite. Lithologies, lithologic associations and unit geometries indicate derivation of olistostromal sequences through gravity flow in a submarine fan/delta complex. Distribution of diamictites and clast sizes and types indicate major nearby Grenville basement-cored uplifts on the SE. with deposition of the LDF fan/delta complex upon a tilted and rapidly foundering shelf block. Shelf uplift, collapse, and LDF deposition were followed rapidly by volcanism and major Acadian dynamothermal activity, and are interpreted to be a response to initial subduction along the shelf margin during the middle Paleozoic.

• Research Organization: Florida State Univ., Tallahassee (USA)
• OSTI ID: 6273308
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201 -- Geophysics-- Seismology & Tectonics-- (1980-1989)
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ALABAMA
CARBONATE ROCKS
CONTINENTAL MARGIN
CONTINENTAL SHELF
DEVONIAN PERIOD
FEDERAL REGION IV
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
LITHOLOGY
METAMORPHIC ROCKS
METAMORPHISM
NORTH AMERICA
PALEOZOIC ERA
PETROLOGY
PLATE TECTONICS
ROCKS
SCHISTS
SEDIMENTARY ROCKS
SILURIAN PERIOD
STRATIGRAPHY
SUBDUCTION ZONES
TECTONICS
USA
VOLCANISM