Tectonic implications of paleomagnetic data from Early Jurassic Dunlap Formation, west-central Nevada

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

OSTI ID:6644825

Callian, J T; Geissman, J W; Oldow, J S

Improved understanding of the kinematics of Mesozoic convergence in the western Basin and Range province is possible by paleomagnetic evaluation of rotations of layered rocks, as has been demonstrated in other fold/thrust belts. Hematitic clastic and shallow marine carbonate strata of the Early Jurassic Dunlap Formation were deposited within and around a successor basin formed after accretion of a Permian arc terrane. Because of their hematitic nature, Dunlap Formation strata may contain a magnetization which survived Late Cretaceous remagnetization. The authors have sampled eleven localities in upper and lower plates of major east-west oriented thrusts, from the western Excelsior to the southern Cedar Mountains. Site sample magnetizations (RM) are usually well-grouped, single component in character, and of normal polarity. They infer, by fold and conglomerate tests, a penecontemporaneous Early Jurassic age of RM acquisition. AF and thermal demagnetization and rock magnetic tests indicate that the RM resides largely in hematite. After simple correction for local tilt, locality mean inclinations are not statistically different from those expected for the craton for Early Jurassic time. Latitudinal translation relative to the craton, since RM acquisition, is not indicated. Locally, mean declinations, on the other hand, are often statistically discordant and imply considerable clockwise rotation of strata during thrust impingement.

• Research Organization: Univ. of New Mexico, Albuquerque (USA)
• OSTI ID: 6644825
• 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
580100 -- Geology & Hydrology-- (-1989)
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
CARBONATE ROCKS
CHALCOGENIDES
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
HEMATITE
IRON COMPOUNDS
IRON ORES
IRON OXIDES
JURASSIC PERIOD
MAGNETISM
MESOZOIC ERA
MINERALS
NEVADA
NORTH AMERICA
ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PALEOMAGNETISM
PLATE TECTONICS
ROCKS
SEDIMENTARY ROCKS
TECTONICS
TRANSITION ELEMENT COMPOUNDS
USA