| Summary: | <p> The 752 meter section of the Miocene Monterey exposures between Point Dume and Paradise Cove is described in detail using meter-by-meter Spectral Gamma Ray data, lithologic descriptions, sandstone analysis (percent sandstone and thin section petrography) and X-ray diffraction data. Samples were analyzed to determine total organic carbon (% TOC) and diatom assemblages. The stratigraphic section is subdivided into four distinct members and is portrayed in a new stratigraphic column. In stratigraphic order, the members are the Dolomitic Phosphatic Shale Member, the Porcelanite and Shale Member, the Mixed Clastics Member and the Cherty Diatomite Member. High TOC values in the Dolomitic Phosphatic Shale range between 4.2 and 7.5%. Opal-CT phase silica occurs in cherts and porcelanite and biogenic Opal-A phase silica occurred in the diatomites. Rocks showing a complete diagenesis to Quartz phase silica are not in the section. Bedding confined fractures and joint sets between different siliceous rocks are abundant in the Porcelanite and Shale Member. The base of the Mixed Clastics member has high energy deposits indicating down-slope movement with major sandstones and conglomerates. The top of the section contains the Cherty Diatomite member and consists of rhythmically bedded pure diatomite, “speckled” beds, muddy diatomites, siliceous/calcareous mudrocks and Opal-CT chert. Dolostone forms a significant component of the rock type throughout the section. The Monterey Formation is found throughout Coastal California and in most of the Neogene sedimentary basins in the State. It is highly petroliferous, forming both the source and reservoir rock. Understanding the exposures in Malibu, CA contributes to the understanding of this economically important formation.</p>
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