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), Journal Name: Geology; (USA) Vol. 19:2; ISSN GLGYB; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580000* -- Geosciences
BASEMENT ROCK
CALIFORNIA
CHEMISTRY
CONTINENTAL CRUST
DEFORMATION
DIKES
EARTH CRUST
FEDERAL REGION IX
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
GEOLOGY
IGNEOUS ROCKS
JURASSIC PERIOD
MAGMATISM
MESOZOIC ERA
NORTH AMERICA
OCEANIC CRUST
PLUTONIC ROCKS
ROCKS
TECTONICS
USA
VOLCANIC ROCKS
VOLCANISM