Tectonic Significance of Post-Accretion Rifting of a Mesozoic Island-Arc Terrane in the Northern Sierra Nevada, California

1989 ◽  
Vol 97 (4) ◽  
pp. 503-518 ◽  
Author(s):  
Yildirim Dilek
1988 ◽  
Vol 100 (3) ◽  
pp. 446-457 ◽  
Author(s):  
RICHARD E. HANSON ◽  
JASON B. SALEEBY ◽  
RICHARD A. SCHWEICKERT
Keyword(s):  

2020 ◽  
Vol 26 (1) ◽  
pp. 9-14
Author(s):  
R. Mark Bailey

ABSTRACT Naturally occurring asbestos (NOA) is being discovered in a widening array of geologic environments. The complex geology of the state of California is an excellent example of the variety of geologic environments and rock types that contain NOA. Notably, the majority of California rocks were emplaced during a continental collision of eastward-subducting oceanic and island arc terranes (Pacific and Farallon plates) with the westward continental margin of the North American plate between 65 and 150 MY BP. This collision and accompanying accretion of oceanic and island arc material from the Pacific plate onto the North American plate, as well as the thermal events caused by emplacement of the large volcanic belt that became today's Sierra Nevada mountain range, are the principal processes that produced the rocks where the majority of NOA-bearing units have been identified.


1996 ◽  
Vol 104 (4) ◽  
pp. 485-492 ◽  
Author(s):  
Olivier Blein ◽  
Henriette Lapierre ◽  
Richard A. Schweicker ◽  
Patrick Monié ◽  
Henri Maluski ◽  
...  
Keyword(s):  

1989 ◽  
Vol 26 (12) ◽  
pp. 2465-2478 ◽  
Author(s):  
O. Rouer ◽  
H. Lapierre ◽  
C. Coulon ◽  
A. Michard

The mid-Paleozoic volcanics of northern Sierra Nevada consist of the Sierra Buttes rhyolites, the Taylor basalts and andesites, and the Keddie Ridge basalt–latite–rhyolite suite. The Sierra Buttes calc-alkaline rhyolites display strong light rare-earth element enrichment and negative εNd values. The Taylor basalts and andesites in the northern Hough and Genesee blocks exhibit calc-alkaline affinities (REE rare-earth element patterns highly enriched in LREE), whereas in the southern Hough block they are tholeiitic (flat rare-earth element patterns). The abundance of silicic lavas, the low εNd values of both the Sierra Buttes and Taylor volcanics and the δ18O values of the Sierra Buttes rhyolite and Bowman Lake trondjhemite provide evidence that the northern Sierra Nevada island arc was continent based. The Keddie Ridge differentiated volcanics, characterized by high Zr, Y, Nb, K, and light rare-earth elements, are geochemically similar to a shoshonite suite. Their eruption at the end of the mid-Paleozoic volcanic episode suggests a reversal of subduction, uplift, and block faulting in the island arc.The mid-Paleozoic volcanics of the northern Sierra Nevada are thought to represent the remnant of a mature island arc because calc-alkaline rocks predominate over tholeiitic ones, the lavas display a K enrichment with time, and the volcanics are evolved in their isotopes, compared with rocks erupted in young or primitive island arcs.


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