Implications of U-Pb zircon ages for the tectonic settings of the Smartville and Slate Creek complexes, northern Sierra Nevada, California
- Univ. of California, Davis (USA)
- Univ. of Kansas, Lawrence (USA)
U-Pb zircon ages combined with stratigraphic and structural data indicate that ca. 160 Ma arc rocks of the Smartville Complex were constructed across ca. 200 Ma arc rocks of the Slate Creek Complex, which were already juxtaposed against more easterly units in the northern Sierra Nevada. The Slate Creek Complex, an ophiolitic thrust sheet east of the Smartville Complex, is 200-210 Ma, which precludes previous correlations with ca. 160 Ma rocks of the Smartville Complex. The Slate Creek Complex tectonically overlies chert-rich Paleozoic-early Mesozoic units along a low-angle fault that is cut by 163-168 Ma and 158-161 Ma plutons. Seven new ages of 160-163 Ma for plutonic rocks in the Smartville Complex agree with previous ages from Smartville volcanic rocks, sheeted dikes, and other plutons. In addition, one tonalite is 198 Ma and is cut by a 163 Ma dike, thus providing the first evidence of the basement of the ca. 160 Ma rocks. The 198 Ma tonalitic basement is probably correlative with the Slate Creek Complex, which contains the only other ca. 200 Ma tonalite in the northern Sierra Nevada. Thrust emplacement of the Slate Creek Complex between 200 and 163 Ma was followed by locally extensional arc magmatism in the Smartville Complex at about 160 Ma, then by Nevadan contractional deformation, a sequence of Jurassic deformation similar to that in the Klamath Mountains. Nevadan deformation could be part of a noncollisional deformation or a long-lived arc (Slate Creek Complex) collision.
- OSTI ID:
- 6314784
- Journal Information:
- Geology; (USA), Vol. 17:11; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
Similar Records
Episodic dike intrusions in the northwestern Sierra Nevada, California: Implications for multistage evolution of a Jurassic arc terrane
New geochronologic constraints on Early, Middle, and Late Jurassic orogenesis in the Klamath Mountains
Related Subjects
CALIFORNIA
GEOLOGIC DEPOSITS
TECTONICS
BASEMENT ROCK
CHERT
DEFORMATION
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
ISOTOPE RATIO
LEAD ISOTOPES
MAGMATISM
MESOZOIC ERA
MOUNTAINS
PALEOZOIC ERA
STRATIGRAPHY
URANIUM ISOTOPES
ZIRCON
ACTINIDE ISOTOPES
FEDERAL REGION IX
GEOLOGIC AGES
ISOTOPES
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
USA
ZIRCONIUM COMPOUNDS
ZIRCONIUM SILICATES
580000* - Geosciences