Abstract

The Miocene turbidite system exposed in the beach cliffs at San Clemente State Beach, California, has been used by industry and academia alike as a field laboratory. It has been used as an analog for petroleum reservoirs in the Los Angeles Basin and other areas. We interpret the turbidite system at San Clemente State Beach to represent the fill of a single turbidite channel that aggraded subvertically. This interpretation is based on construction of a detailed photomosaic, mapping of three-dimensional facies distributions, measurement of representative sections, and collection of new paleocurrent data; we also extended this analysis to outcrops not previously described in the literature. The channel had a minimum width of 1 km and a paleotransport direction toward the northwest. Our new paleocurrent measurements indicate an average transport direction of 321° for the channel deposits, approximately perpendicular to previously published paleocurrent data. Our paleocurrent data are in agreement with the trend of the channel as defined by facies mapping. The lateral and vertical facies changes along the sea cliffs at San Clemente are a result of interfingering between axial and marginal facies within a single turbidite channel. We interpret the turbidite channel to have been cut into a low-gradient continental slope (less than 1°), rather than representing a channel on a submarine fan. We propose that the Gollum channel system is a modern analog of the turbidite system at San Clemente State Beach.

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