--> Abstract: The Interplay between Tectonics and Sedimentation in the Late Cretaceous Sacramento Basin, California, by T. H. Nilsen; #91004 (1991)

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The Interplay between Tectonics and Sedimentation in the Late Cretaceous Sacramento Basin, California

NILSEN, TOR H., Independent Consultant, San Carlos, CA

Santonian, Campanian, and Maestrichtian deposystems of the Sacramento basin of California consist principally of deltaic, slope, deep-sea-fan, and basin-plain lithofacies that generally prograded southward and westward into the basin from magmatic-arc source areas located to the east in the Sierra Nevada and to the north in the Klamath Mountains area. The basin formed the northern part of the Late Jurassic to Late Cretaceous Great Valley fore-arc basin, filled

with more than 15 km of siliciclastic strata. Partly coeval accretionary-wedge units of the Franciscan complex to the west structurally underlie the fore-arc-basin deposits. Because the uppermost Cretaceous fill of the fore-arc basin produces large volumes of natural gas, abundant subsurface data, complemented by excellent outcrop data, are available to establish the relations between tectonics and sedimentation.

The eastern basin margin formed a stable, shallow, gently west-dipping shelf underlain by the Sierran magmatic-arc complex. The axial and western parts of the basin formed a more unstable, deep-marine, south-plunging trough underlain by ophiolitic basement rocks. The western basin margin was a submarine ridge underlain by the Franciscan accretionary wedge; underplating and tectonic uplift of this ridge resulted in arcward migration of facies and depocenters through time, accounting for the great thickness of accumulated sediment and the complex distribution of facies within the forearc. Downfaulting along the arc margin to the east formed a number of additional depocenters. Subsequent Tertiary thrusting and strike-slip-related tectonism produced most of the major structural traps in t e basin.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)