Segmentation and thrusting along the offshore Newport-Inglewood-Rose Canyon zone of deformation

Conference · Fri Feb 01 04:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5199944

Mills, G I; Fischer, P J ^[1]

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1. California State Univ., Northridge (United States)

The offshore Newport-Inglewood-Rose Canyon (NI-RC) zone of deformation is a 106-km-long, linear zone of folds and faults that extend from Newport Beach to La Jolla. Using seismicity and high-resolution and digitally processed seismic reflection data, three distinct fault segments are defined. These segments control the position and trend of shelf break: (1) the Laguna Beach segment (Corona Del Mar to San Mateo Point), a right-stepping zone with activity decreasing southward to San Mateo Point, where the latest activity was middle Holocene. (2) The San Onofre segment (San Mateo Point to Oceanside), where a major, 2-km-wide, left-stepping break occurs near the center of this segment opposite San Onofre; it is associated with an apparent basement discontinuity, a major blind thrust ramp and bowing of the continental slope. Shoreward of the NI-RC zone a 20-km-long synclinal fold trends subparallel to the zone. (3) The La Jolla segment (Oceanside to La Jolla), north of Encinitas, overlapping, left-stepping fault splays are associated with folding and thrusting. Preliminary earthquake focal mechanism studies suggest that right-lateral faulting, with a minor reverse component, is dominant along the NI-RC Zone. Earthquake foci do not seem to be related to the thrust faults. Compressional deformation along the zone is thought to be a direct result of relative North American/Pacific plate motion direction changes at 4 Ma. Deformation was concentrated near the left-stepping break in the San Onofre segment, perhaps producing a detached block or flake. Mapped structures suggest the NI-RC is dislocated by the blind' thrust ramp.

• OSTI ID: 5199944
• Report Number(s): CONF-9103128--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:2
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CALIFORNIA
CONTINENTAL MARGIN
CONTINENTAL SHELF
DEFORMATION
DEVELOPED COUNTRIES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
NORTH AMERICA
OFFSHORE SITES
PACIFIC OCEAN
SEAS
SEDIMENTATION
SEISMIC SURVEYS
SEISMICITY
SUBMARINE CANYONS
SURFACE WATERS
SURVEYS
USA