Clockwise block rotations in the Perija Mountains, Venezuela

Conference · Mon Feb 01 04:00:00 EST 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5939792

Gose, W A ^[1]; Perarnau, A ^[2]; Castillo, J ^[3]

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1. Univ. of Texas, Austin (United States)
2. Intevep, Los Teques (Venezuela)
3. Universidad Simon Bolivar, Caracas (Venezuela)

Paleomagnetic analyses of Mesozoic sedimentary rocks (8 sites, 115 samples) from the Perija Mountains, Venezuela, yield well-grouped directions of both polarities. Fold tests imply that the magnetization of the Jurassic La Quinta Formation is pre-mid-Cretaceous in age and that the Lower Cretaceous Cogollo Group acquired its magnetization prior to its mid-Tertiary deformation. These data as well as the results from the Cretaceous Apon and La Luna Formations yield consistent northeast or southwest declinations and inclinations corresponding to the present latitude of the sampling area. The clockwise rotations indicated by these data are interpreted to be the result of rotation of fault-bounded blocks in a left-lateral strike-slip zone. Faults such as the Cogollo, La Ge, and Totumo faults which intersect the Perija-Tigre fault at low angles, had initially a north-northwest strike. The Late Oligocene northwest-southeast compression which initiated the uplift of the Perija Mountains rotated these faults to their present north-northeast orientation imparting the observed left-lateral slip. Our paleomagnetic data measure the corresponding rotation of the fault-bounded blocks. Model calculations suggest that a displacement on these faults of less than ten kilometers would be sufficient to cause the observed approximately 45[degrees] clockwise rotations.

• OSTI ID: 5939792
• Report Number(s): CONF-930306--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 77:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
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58 GEOSCIENCES
580000 -- Geosciences
AGE ESTIMATION
CENOZOIC ERA
COMPRESSION
CRETACEOUS PERIOD
DEFORMATION
DEVELOPING COUNTRIES
GEOGRAPHICAL VARIATIONS
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
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MAGNETISM
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MESOZOIC ERA
MOTION
MOUNTAINS
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PALEOMAGNETISM
ROCKS
ROTATION
SEDIMENTARY ROCKS
SLIP
SOUTH AMERICA
SURVEYS
TERTIARY PERIOD
VARIATIONS
VENEZUELA