40 The western equatorial Pangea: Geological, geophysical, geochronological, and paleoecological insights on the youngest supercontinent assembly and breakup on Earth (Part 2)

This session welcomes studies in Mexico, southwestern North America, and northwestern South America investigating the Pangea’s supercontinent cycle from tectonic, stratigraphic, paleoecologic, geophysical, geochronologic, and paleogeographic perspectives to offer insights into its assembly and breakup.

Friday, 24 April 2026
1:30 PM - 5:30 PM
LMH, Isla Carmen

Is Paleomagnetism in Mexico a key to understanding the configuration and dynamics of the breakup of western equatorial Pangea?

Paper number: 40-10
Program: Technical Sessions
Time: 4:25 PM – 4:45 PM

Authors

Abstract

The configuration and breakup dynamics of western Pangea have been debated for more than fifty years. Since the introduction of the Pangea A-1 and A-2 models in the mid-1960s and early 1970s, the arrangement of peri-Gondwanan continental blocks northwest of Gondwana—primarily the terranes and blocks of Mexico, Colombia, Venezuela, and Central America—has remained unresolved. These blocks frequently overlap and (non-)deform in reconstructions of the assembly and breakup of western Pangea. The opening of the Gulf of Mexico provides essential information about the breakup dynamics east of Mexico during the Jurassic, particularly the counterclockwise rotation of the Maya block. However, the spatial and temporal configuration of central-western Mexican fragments, such as the El Fuerte, Mixteca, Oaxaquia, and Coahuila terranes, remains poorly understood during this extensional phase.

This study re-evaluates more than fifteen previous investigations across Mexico, incorporating data from over 250 paleomagnetic sites in Triassic and Jurassic units. During the breakup of western Pangea, the latitudinal displacement of Laurasia accelerated, particularly from the late Triassic to the mid-Cretaceous, making this interval promising for reconstructing the configuration and dynamics of continental fragments through paleomagnetic analysis. Site selection was based on the quality of paleomagnetic data, geographic distribution across key regions, and coverage of critical time intervals. The methodology included a systematic re-analysis of paleomagnetic data, correction for known biases in sedimentary rocks such as inclination shallowing, and a reassessment of paleosecular variation. Stratigraphy and unit ages were carefully reviewed, and potential remagnetization from post-Jurassic tectonic events was considered. Despite inherent biases, this approach improves the reliability of the conclusions and highlights new perspectives, challenges, and opportunities for applying paleomagnetism to Triassic–Jurassic rocks in Mexico and adjacent regions, with significant implications for understanding the configuration and breakup dynamics of western Pangea.

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

doi: 10.1130/abs/2026CD-410885

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