Late Jurassic plutonism in the southwest U. S. Cordillera 
Reference Number:
Publication Year:
Book Editors:
Wright, James E; Shervais, John W
Geological Society of America (GSA), Boulder, CO, United States (USA)
GeoREF Number:
2008-110000 (View Original Data File)
Barth, Andrew P; Wooden, Joseph L; Howard, Keith A; Richards, JoshuaL
absolute age; basins; batholiths; California; Cenozoic; chemicalcomposition; dates; fore-arc basins; geochemistry; intrusions; ionprobe data; Jurassic; magmatism; major elements; mass spectra;Mesozoic; Mojave Desert; North America; North American Cordillera;paleoenvironment; Paleogene; Paleozoic; Permian; plate tectonics;reconstruction; SHRIMP data; Southern California; Southwestern U.S.;spectra; subduction; Tertiary; thermal ionization mass spectra; traceelements; Transverse Ranges; U/Pb; United States; Upper Jurassic
Special Paper - Geological Society of America, vol. 438, pp.379-396,2008
Although plate reconstructions suggest that subduction was anapproximately steady-state process from the mid-Mesozoic through theearly Tertiary, recent precise geochronologic studies suggest highlyepisodic emplacement of voluminous continental-margin batholiths inthe U.S. Cordillera. In central and southern California and westernArizona, major episodes of batholithic magmatism are known to haveoccurred in Permian-Triassic, Middle Jurassic, and late Early to LateCretaceous time. However, recent studies of forearc-basin andcontinental-interior sediments suggest that Late Jurassic time wasprobably also a period of significant magmatism, although few datedplutons of this age have been recognized. We describe a belt of LateJurassic plutonic and hypabyssal rocks at least 200 km in length thatextends from the northwestern Mojave Desert through the TransverseRanges. The belt lies outboard of both the voluminous Middle Jurassicarc and the ca. 148 Ma Independence dike swarm at these latitudes. Theplutons include two intrusive suites emplaced between 157 and 149 Ma:a calc-alkaline suite compositionally unlike Permian-Triassic andMiddle Jurassic monzonitic suites but similar to Late Cretaceous arcplutons emplaced across this region, and a contemporaneous but notcomagmatic alkaline suite. The Late Jurassic was thus a time of bothtectonic and magmatic transitions in the southern Cordillera.
GeoRef, Copyright 2008, American Geological Institute.

Sample Summary:
Sample ID: Major Data: Trace Data: Isotope Data:
AM6 No No No
AM11 No No No
PN19 No No No
JW176 No No No
JW178 No No No
179 No No No
JW180 No No No
JW282 No No No
3438 No No No
JW273 No No No
3436 No No No
JW275 No No No
JW274 No No No
3422 No No No
3440 No No No
3435 No No No
3439 No No No
3504 No No No
3455 No No No
JW218 No No No