50-9 Dynamic Subsidence of the Sierra Madre Oriental Foldbelt and Foreland During the Laramide Orogeny, Linares, Nuevo Leon, Mexico

Session: Latest Research Advances in Structural Geology and Tectonics

Presenting Author:

Authors:

Abstract:

The Mexican orogen differs markedly from other, coeval Cordilleran orogenic belts (Sevier-Laramide of North America; Andean of South America) as regards its history of subsidence and uplift, the geometry of its structural development, and the fact that it was an east-facing passive margin prior to deformation. The Sierra Madre Oriental formed coeval with regional subsidence of its foreland. It developed above a regional salt detachment, resulting in a wedge of folded Mesozoic carbonate platform strata beneath 4-6 km of now-eroded sedimentary cover. Maximum subsidence occurred in the distal toe of the foreland, not near the hinterland Guerrero terrane. The Guerrero terrane was an active uplift, and may have sourced detrital volcanic and carbonate grains found in Turonian to Paleogene foreland deposits. This geodynamically and structurally unique orogen may have resulted from flat-slab-engendered dynamic pull-down similar in magnitude to what is estimated to presently exist beneath the Mexican continent. The dynamic pull-down phase led to the storage of a huge quantity of sediment that was being delivered to this region from the Laramide and Mexican orogens to the north and west. This cache of sediment was then recycled into the Gulf of Mexico during the early and middle Cenozoic, as the crust began re-equilibrating to an Airy-type isostasy.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9620

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