Piedras Blancas and San Simeon Quadrangles California

CONTENTS Abstract_____-_-___--_--_-_---_-_---_-_-_- Introduction. -___-----_--_----_---------_-.-- General geology-__-__--__----------_----_--- Basement rocks.___-_--__--_--_---__--.- Ultramafic rocks____-___-_---.__-_- Franciscan Formation.-__-_-___----_. Metamorphic rocks.___-_-_-_--____.- Granitic rocks_.--______________._- Tertiary intrusive rocks.______.__-__- Superbasement sedimentary rocks.________ Paleocene <strong>and</strong> upper Mesozoic deposits- Middle <strong>and</strong> lower Miocene deposits-__. Volcanic rocks.____--_--______--__-_- Monterey Shale.____________________ Page Al 1 2 2 2 2 2 2 3 3 3 3 4 4 General geology Continued Superbasement sedimentary rocks Continued Pancho Rico Formation.___--_----_---_-___- Paso Robles Formation_____---_-_-_-___-_- Surficial deposits._____-----_-_-_-_-_-_--__- Structure.---_--__-_--__-_-_-_--__------__-_-_- Gravity data_____________________________________ Gravity survey-_-_----____-_-_-_-_-_-.-----_--- Gravity interpretation._ _-_______.___-_-_---__ Gravity anomalies.--__-___---_-_---_-_--__---_- Detailed survey of the Burro Mountain ultramafic body ___-___-_-_-_._-_-_-___-_-_-_-_-_-___-_- Regional survey._______________________________ References cited.__-___-___-_______-_-_____--_----_- P8RC -H 4 4 4 5 5 10 10 10 10 12 ILLUSTRATIONS Page PLATE 1. Complete Bouguer gravity <strong>and</strong> generalized geologic map of the Cape <strong>San</strong> Martin, Bryson, <strong>Piedras</strong> <strong>Blancas</strong>, <strong>and</strong> <strong>San</strong> <strong>Simeon</strong> quadrangles, <strong>California</strong> _-_____.._--.-__-_.__-_-__-__-____.__-.__-_--___-----._--_-- In pocl et FIGURE 1. Index map showing location of map area.______________________________________________________________ Al 2. Aeromagnetic profile through the Burro Mountain body__________________________________________________ 11 TABLES TABLE 1. Selected exploratory wells__ 2. Principal facts for gravity bases.-. 3. Principal facts for gravity stations . Page. A3 5 5 ra