US west coast revisited: An aeromagnetic perspective

Journal Article · Sun Apr 01 00:00:00 EST 1990 · Geology; (USA)

OSTI ID:6313835

Zietz, I; Johnson, P R ^[1]; Bond, K R ^[2]

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1. George Mason Univ., Fairfax, VA (USA)
2. Geological Survey, Reston, VA (USA)

A new compilation of magnetic data for the western conterminous United States and offshore areas provides significant information about crustal units and structures in the region. Features shown on the compilation include a magnetic quiet zone along the coast and two lineaments inland. The magnetic quiet zone correlates with the accretionary prism at the western edge of the North American plate and overlies subducted ocean crust; abrupt termination of ocean-floor magnetic anomalies at, or a short distance east of, the toe of the accretionary prism is an inferred effect subduction-induced low-temperature metamorphism of the ocean crust. The Puget Lowlands-San Joaquin lineament is an alignment of high-intensity magnetic anomalies that in the south, and possibly also in the north, are cause by bodies of mafic-ultramafic rocks accreted to North America during the Mesozoic and Tertiary. The lineup of the highs and the inferred lineup of the causative bodies may reflect fundamental structures that control Mesozoic and Tertiary evolution of the continental margin. The Mojave Desert lineament, a distinctive chain of short-wavelength magnetic anomalies in southern California, coincides partly with a zone of Mesozoic intrusions and the Cenozoic San Andreas fault system, but is likely to be older than both in origin and may reflect a Mesozoic or older crustal discontinuity.

• OSTI ID: 6313835
• Journal Information: Geology; (USA), Vol. 18:4; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
WEST COAST
AERIAL SURVEYING
MAGNETIC SURVEYS
CONTINENTAL CRUST
CONTINENTAL MARGIN
DESERTS
GEOLOGIC FAULTS
GEOLOGIC STRUCTURES
LINEAMENTS
MESOZOIC ERA
METAMORPHISM
OCEANIC CRUST
OFFSHORE SITES
PLATE TECTONICS
REGIONAL ANALYSIS
SUBDUCTION ZONES
TERTIARY PERIOD
USA
ARID LANDS
CENOZOIC ERA
EARTH CRUST
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOPHYSICAL SURVEYS
NORTH AMERICA
SURVEYS
TECTONICS
580000* - Geosciences