T71 The Changing Cordilleran Margin: Permian through Eocene Tectonism, Magmatism, and General Geology from Western Mexico through Northern California and Eastward

Sunday, 22 September 2024
1:30 PM - 5:30 PM
304A

RECONSTRUCTING NORTH AMERICAN CORDILLERA PLATE TECTONIC HISTORY ALONG WESTERN MEXICO TO CALIFORNIA FROM MANTLE CONSTRAINTS

Paper number: T71-2
Program: Technical Sessions
Time: 1:35 PM – 1:55 PM

Authors

Abstract

We present a reconstruction of subduction history along western Mexico and California since the Jurassic based on tomographic slabs. We map and structurally restore subducted slabs from multiple tomography models between Alaska to Central America. At the Californian margin, we reconstruct: (1) since at least the Jurassic to mid-Cretaceous, eastwards subduction of a now-vanished marginal sea; (2) at 100±7 Ma the Wrangellia Composite Terrane (WCT) collided along California to northern Canada and subsequently translated >2000 km northward during the Late Cretaceous to Eocene (i.e. Baja-BC); (3) from Late Cretaceous (~100-80 Ma) to Oligocene, eastwards subduction of the Farallon plate occurred. South of California, we reconstruct a relatively short (up to ~1000 km N-S) segment of intra-oceanic subduction along western Mexico during the Mesozoic; the associated intra-oceanic arcs accreted to Mexico during the Cretaceous and are attributed to the Alisitos and Guerrero terranes. Subduction along northern Mexico during the Late Cretaceous to Eocene was likely perturbed by subduction of a diffuse, slightly divergent Farallon-Vancouver plate boundary. We compare our predicted subduction history along California and western Mexico to published magmatic and surface geologic histories from the region.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-401338

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