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Transverse Ranges. Satellite image of Transverse Ranges. Animation. Eastern Transverse Ranges. View of San Gabriel Mountains looking east. Mt. San Antonio. Cross section through Mt. San Antonio. Vincent Thrust – San Gabriel Mountains. Lower plate rocks
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Vincent Thrust – San Gabriel Mountains • Lower plate rocks • complex of metamorphosed sedimentary and volcanic rocks known as the Pelona Schist, a rock unit whose pre-metamorphic protolith consisted of Mesozoic (Jurassic and Cretaceous?) marine deep-water sand, silt, and calcareous and siliceous mud locally interlayered with basaltic flows. • Upper plate rocks • the crystalline-rock complex that directly overlies the Vincent Thrust consists mainly of gneissic (layered) metamorphosed plutonic rocks and associated metasedimentary rocks that have been complexly deformed under deep-seated ductile metamorphic conditions that locally yielded mylonite as the end product.
Miocene Monterey Formation • Deposited 12-23 million years ago • Exposed throughout coastal California • Source rock for most of California’s petroleum • Composed of deep water sediments with little to no terrestrial input • Siliceous sediment mostly diatomite • Also contains porcelanite and dolomite
Salton Trough • Formed 5-6 million years ago by fracturing of the continent by the East Pacific Rise • Bounded on northeast by San Andreas fault and on southwest by Imperial fault • Volcanic activity occurs in the south – Obsidian Buttes • Transpression along transform faults forms hills such as Durmid, Mecca, and Indio Hills