Episodic dike intrusions in the northwestern Sierra Nevada, California: Implications for multistage evolution of a Jurassic arc terrane
- Univ. of California, Davis (USA)
- NASA, Houston, TX (USA)
In the northwestern Sierra Nevada, California, volcanic and plutonic rocks of the Smartville and Slate Creek complexes, both fragments of a Jurassic arc terrane, are tectonically juxtaposed against ophiolitic and marine rocks that represent late Paleozoic-early Mesozoic oceanic basement. This oceanic basement is intruded by Early Jurassic dikes that are coeval with hypabyssal and plutonic rocks within the Smartville and Slate Creek complexes. These dikes have geochemical characteristics reflecting a depleted and metasomatized source, as commonly observed in modern fore-arc settings and incipient volcanic arcs, and are interpreted to be the conduits for the Early Jurassic arc volcanism, which was built on and across the disrupted oceanic basement. Late Jurassic sheeted dikes intruding the Smartville complex have basaltic compositions compatible with an intra-arc or back-arc origin and indicate that a spreading event occurred within the arc in early Late Jurassic time. These interpretations support models for a complex multistage evolution via episodic magmatism and deformation within a singly ensimatic Jurassic arc terrane west of the North American continent.
- OSTI ID:
- 5796388
- Journal Information:
- Geology; (USA), Vol. 19:2; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALIFORNIA
GEOLOGIC FORMATIONS
MAGMATISM
BASEMENT ROCK
CONTINENTAL CRUST
DEFORMATION
DIKES
GEOCHEMISTRY
GEOLOGY
JURASSIC PERIOD
OCEANIC CRUST
PLUTONIC ROCKS
TECTONICS
VOLCANIC ROCKS
VOLCANISM
CHEMISTRY
EARTH CRUST
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC STRUCTURES
IGNEOUS ROCKS
MESOZOIC ERA
NORTH AMERICA
ROCKS
USA
580000* - Geosciences