Thermal and structural history of the San Emigdio Mountains, southern San Joaquin basin, California, based on fission-track analysis

Conference · Fri Mar 01 04:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:7075414

White, L A ^[1]; Kelley, S A ^[2]; Corrigan, J ^[3]

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1. Arco Oil and Gas Co., Plano, TX (United States) Univ. of Texas, Austin (United States)
2. Southern Methodist Univ., Dallas, TX (United States)
3. Univ. of Texas, Austin (United States)

The thermal and structural history of the San Emigdio Mountain area, southern San Joaquin basin, California, was studied using inverse modeling and geohistory analysis of new fission-track (FT) data from 32 apatite samples from five wells and two outcrop traverses. Apatite composition was determined by microprobe analysis on eight of the samples in order to select appropriate kinetic parameters for modeling. Modeling of seven Eocene to Oligocene samples and a single basement sampled along the Pleito Creek traverse shows that the base of the sequence began to cool from {approximately} 115 {plus minus} 10C during the late Mohnian ({approximately} 13-7 Ma). Ten Eocene to Oligocene samples and a single basement sample along the San Emigdio Creek traverse cooled below {approximately} 85 {plus minus} 20C during latest Mohnian to early Pliocene ({approximately} 8-4 Ma). Assuming paleogeothermal gradients of {approximately} 25 to 30C/km, these data indicate that the San Emigdio Mountains experienced {approximately} 2 km of denudation from the late Mohnian to Pliocene at rates less than 0.5 mm/yr, and {approximately} 1.5 km of Pliocene to Recent denudation at rates less than 1 mm/yr. The study also shows that the area was affected by Miocene heating, probably associated with Tecuya Formation volcanism (22.5 Ma). In addition, ten new zircon FT dates indicate a Sierra Nevada-type provenance from Eocene to Miocene. The apatite microprobe analyses indicate decreasing numbers of chlorine-rich grains from Eocene to Miocene, suggesting a change in the geochemistry of apatite in the source region over time.

• OSTI ID: 7075414
• Report Number(s): CONF-910403--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:3
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
152004* -- Geothermal Data & Theory-- Isotope & Trace Element Studies
58 GEOSCIENCES
580000 -- Geosciences
AGE ESTIMATION
APATITES
CALIFORNIA
CENOZOIC ERA
CHEMICAL ANALYSIS
CHEMISTRY
DEVELOPED COUNTRIES
FISSION TRACKS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOTHERMAL GRADIENTS
GEOTHERMOMETRY
ION MICROPROBE ANALYSIS
MICROANALYSIS
MINERALS
MOUNTAINS
NONDESTRUCTIVE ANALYSIS
NORTH AMERICA
OROGENESIS
PARTICLE TRACKS
PHOSPHATE MINERALS
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
TECTONICS
TEMPERATURE GRADIENTS
TERTIARY PERIOD
USA