37 Cordilleran Margin Evolution and Supercontinent Tectonics: From Pangea Assembly to North American Orogenesis (Posters)

This session integrates tectonics, petrology, geochronology, stratigraphy, and paleontology to illuminate how Paleo-Pacific plates drove subduction dynamics, crustal evolution, and paleogeographic reconstructions across the complex geological architecture of the American Cordilleras.

Friday, 24 April 2026
8:00 AM - 5:30 PM
LMH, 5th Floor Chapel

Paleogene reactivation and recent activity of the Tamaulipas Golden Lane - Chiapas Fault (TGLCF) in the Tehuantepec Isthmus, Southern Mexico.

Paper number: 37-5
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

The complex structural framework of southern Mexico has been heavily influenced by episodic reactivations of faults bounding lithospheric blocks since at least the Permian. The Tamaulipas Golden Lane - Chiapas Fault (TGLCF) likely represents one such reactivation during the Middle Jurassic. Geophysical data indicates that this fault separates continental crust to the west from oceanic crust to the east. Historically, this structure accommodated hundreds of kilometers of dextral displacement, facilitating the rotation of the Yucatán block during the opening of the Gulf of Mexico. Despite its regional importance, systematic surface studies of its southern continuity have been limited, largely because the fault is buried beneath Neogene infill in the Veracruz Basin.

In this study, we document evidence of this structure in the central Tehuantepec Isthmus through detailed geological-structural mapping and kinematic analysis. We identified three subparallel shear zones: (1) the Chivela Shear Zone, (2) the Hierba Santa Fault, and (3) the Paso de Buques Fault. These structures align with the SE projection of the TGLCF, following a general NW-SE orientation. Observations indicate that these faults widen and exhibit deformation mechanisms consistent with higher metamorphic grades toward the south.

Kinematic analysis and cross-cutting relationships suggest at least three distinct episodes of activity since the Late Cretaceous: initial dextral displacement, followed by sinistral transpression, and finally, north-directed extension. These events localized deformation along the primary faults and resulted in high-angle block tilting without significant folding. The intense faulting observed in the Tehuantepec Isthmus supports the southern projection of the Jurassic-Cretaceous TGLCF and its subsequent reactivations. Regionally, these structural reactivations may correlate with the final stages of the Mexican Orogeny and the migration of the Chortis block along the Pacific margin.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-410860

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