Structural style and tectonic evolution of the marathon thrust belt, west Texas

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

OSTI ID:6456392

Hickman, R G; Varga, R J; Altany, R M; Witmer, R J

A balanced cross section indicates that the basal Dugout Creek thrust is strongly folded and that the Marathon facies rocks overlie a folded and thrusted sequence of late Paleozoic strata. Shortening in the allochthonous sequence is >80%. Extreme shortening across anticlinoria requires upper level detachments. These appear to have been duplex zones connected to the basal fault by steep imbricates. Progressive deformation folded the imbricates and the roof thrusts of these zones. Individual units have distinct deformational styles. Folds in the Caballos Fm. are tight, high-amplitude concentric folds with wave-lengths of 0.5 to 1.7 km. Pre-Caballos units are characterized by smaller wavelength box and chevron folds and imbricate faults. The overlying Tesnus Fm. is exposed in broad synclines. High strain within the cores of the synclines was accommodated by development of cleavage and axial-parallel pencil lineation. The pre-Mississippian part of the Marathon sequence represents slope deposits developed along a divergent continental margin. The Mississippian was marked by flysch sedimentation (Tesnus Fm.) which heralded the beginning of collision of Gondwanaland. Much of this sediment was derived from Devonian and older strata of Gondwanaland. The Tesnus Fm. was deposited on the slope sequence and is entirely allochthonous. By Atokan-Virgilian times, the slope/Tesnus sequence overrode the miogeoclinal sequence of North America. Permian foreland and taphrogenic basins formed within shelf areas north of the Marathon region during continued compression. Deformation progressed from SE to NW during a period of about 70 million years.

• Research Organization: Union Oil Science and Technical Division, Brea, CA (USA)
• OSTI ID: 6456392
• 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)
ANTICLINES
CROSS SECTIONS
DEFORMATION
DEPOSITION
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
GEOMETRY
MATHEMATICS
MECHANICS
MISSISSIPPIAN PERIOD
NORTH AMERICA
PALEOZOIC ERA
PLATE TECTONICS
ROCK MECHANICS
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
TECTONICS
TEXAS
USA