Latest Cretaceous sedimentation on Peninsular Ranges block
The Peninsular Ranges block is dominated by a Late Jurassic-middle Cretaceous batholithic belt that extends from the Santa Ana Mountains in southern California southward through the state of Baja California. From paleomagnetic evidence, the block appears to have moved north about 11/sup 0/ with respect to the North American craton since the Late Cretaceous. The Campanian-Maestrichtian sedimentary record along the western side of the block shows that sedimentation occurred contemporaneously with faulting. Dominantly coarse sediments were stripped off the batholithic complex, carried westward relatively short distances, and deposited in alluvial-fan, fluvial, fan-delta, and shelf environments as well as in submarine fans built into local, fault-created basins. The Peninsular Ranges block apparently moved northward in response to oblique subduction of the Farallon plate; it seemingly rode along on a reasonably even keel as transcurrent faulting wrenched pieces off its western side. The steady keel allowed the sedimentary record to reflect eustatic changes. Along the west side of the Peninsular Ranges block, the Campanian column typically has a retrogradational sequence lower in the section that is overlain by a progradational sequence. This pattern holds for the Santa Ana Mountains, San Diego, California, and Descanso, Salsipuedes, and El Rosario, Baja California. Eustatic sea level changes left a dominant imprint on the entire stratigraphic column, although local facies may be distinctly different because basins were created by contemporaneous faulting. The fault basins may have had a borderland-style topography, judging from their relatively small size, discontinuous and sporadic development, and apparently linear margins.
- Research Organization:
- San Diego State Univ., CA
- OSTI ID:
- 6931750
- Report Number(s):
- CONF-8604187-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 70:4; Conference: American Association of Petroleum Geologist Pacific Section convention, Bakersfield, CA, USA, 16 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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