Paleogeography and structural evolution of a Middle Mesozoic volcanic arc-continental margin: Sierra Nevada foothills, California

Thesis/Dissertation · Sun Jan 01 00:00:00 EST 1978

OSTI ID:5365603

Behrman, P G

Stratigraphic, structural and geochronometric features of Late Paleozoic to Middle Mesozoic metasedimentary and metaigneous rocks of the central Sierra Nevada foothills are an expression of the paleogeographic and paleotectonic evolution of the continental margin of western North America. Pre-Callovian rocks include Bear Mountains Ophiolite belt rocks and the siliceous strata of the Central belt. The Bear Mountains ophiolite is characterized by an epidote amphibolite grade of metamorphism, steep eastward dipping schistosity, and disrupted ophiolite stratigraphy. The siliceous strata of the Central belt are composed of four assemblages which consist of (1) interbedded sandstone and argillite; (2) chaotic deposits of chert, limestone and sandstone, and tectonized sandstone and argillite; (3) tightly folded argillite, sandstone, chert, and limestone; and (4) deformed ophiolitic rocks. Variably deformed Bear Mountains Ophiolite belt rocks and siliceous strata were probably part of the basement on which Callovian to Kimmeridgian strata were deposited. Callovian to Kimmeridgian volcanic, volcanicalstic, and epiclastic rocks are found in the Mother Lode, Central and Western belts, and comprise remnants of intertonguing volcaniclastic and epiclastic fan complexes, and volcanic centers. The presence of volcanism within the sedimentary basins, in conjunction with the petrologic character of the epiclastic strata, indicate that the Callovian to Kimmeridgian paleogeography consisted of a wide zone of arc volcanism which developed on submarine basin, slope, and continental shelf environments. The Callovian to Kimmeridgian paleogeographic regime was arrested during the Nevadan orogeny.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 5365603
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
SIERRA NEVADA COLORADO
ORIGIN
STRATIGRAPHY
VOLCANISM
CALIFORNIA
CONTINENTAL MARGIN
CONTINENTAL SHELF
DEFORMATION
LIMESTONE
MESOZOIC ERA
METAMORPHISM
PETROLOGY
SANDSTONES
SEDIMENTARY BASINS
STRATIFICATION
SUBMARINE CANYONS
TECTONICS
VOLCANIC ROCKS
CARBONATE ROCKS
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
IGNEOUS ROCKS
MOUNTAINS
NORTH AMERICA
ROCKS
SEDIMENTARY ROCKS
USA
580100* - Geology & Hydrology- (-1989)
580202 - Geophysics- Volcanology- (1980-1989)