Detailed Lithostratigraphic Characterization Of The Monterey Formation At Chico Martinez Creek, CA

Abstract

Chico Martinez Creek in the Temblor Range exposes one of the thickest Miocene successions in California and is often cited as the type section of the Monterey Formation for the San Joaquin basin. Nonetheless, no published detailed description of the section exists in the public literature. In this new study, the 6012-foot Monterey Formation succession at Chico Martinez Creek is characterized at high spatial resolution by spectral gamma-ray data in 2-foot increments, 5-foot lithologic descriptions, and qualitative XRD and FTIR analysis. Based on these data, the 4 Monterey members–the Gould, Devilwater, McDonald and Antelope shales–are subdivided into 7 distinctive lithofacies. New paleomagnetic data, combined with industry-provided biostratigraphy establishes a chronostratigraphic framework and allows determination of linear sediment accumulation rates. Condensed sedimentation at the onset of McDonald deposition (∼14 Ma) is also observed in correlative members in the Pismo, Santa Maria and Santa Barbara basins. This regional event is associated with eustatic regression from the Mid-Miocene highstand related to formation of the East Antarctic Ice Sheet and ongoing local thermotectonic basin subsidence. A surge in linear sediment accumulation rates in the siliceous upper McDonald and Antelope (∼10.4 Ma) is attributed to a regional increase in diatom productivity.

AAPG Datapages/Search and Discovery © 2014 Pacific Section AAPG, SPE and SEPM Joint Technical Conference, Bakersfield, California, April 27-30, 2014