Sources of the Early Cretaceous plutons in the Turtle and West Riverside Mountains, California

Journal of Petrology
By: , and 

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Abstract

Ages and initial isotopic ratios of Early Cretaceous (˜100 Ma) plutons of the Cordilleran Interior in the southern Turtle and West Riverside mountains distinguish them from Late Cretaceous plutons in surrounding ranges in the eastern Mojave Desert. Furthermore, the studied plutons have isotopic and geochemical characteristics more similar to plutons of Cretaceous age in the coastal batholiths (Peninsular Ranges and Sierra Nevada) than to most Mesozoic plutons in the Cordilleran Interior. The studied plutons are calcic, in contrast to the mostly cak-alkaline Mesozoic plutons of the eastern Mojave Desert. Distinctive isotopic signatures of the granitoids include lower initial 87Sr/86Sr of 0⋅705–0⋅710, δ18O of +6⋅3 to +7⋅7‰, 208Pb/204Pb of 38⋅3–39⋅5, and higher εNd of −3⋅86 to −9⋅60 than the Late Cretaceous plutons in the region. The distinctive characteristics of these Early Cretaceous plutons are probably both location and time specific and result from: (1) emplacement in a cold, untapped ‘Mojave-type’ Proterozoic upper crust, (2) a significant component of basaltic magmas partially melted from the asthenosphere or subcontinental lithosphere and (3) a magmatic component derived from Proterozoic, mafic, lower crust. They interacted less with their crustal hosts than did the later, more voluminous Late Cretaceous plutons.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Sources of the Early Cretaceous plutons in the Turtle and West Riverside Mountains, California
Series title Journal of Petrology
DOI 10.1093/oxfordjournals.petrology.a037270
Volume 36
Issue 6
Year Published 1995
Language English
Publisher Oxford Academic Press
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 26 p.
First page 1675
Last page 1700
Country United States
State California