31 The western equatorial Pangea: Geological, geophysical, geochronological, and paleoecological insights on the youngest supercontinent assembly and breakup on Earth (Part 1)

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
8:00 AM - 12:00 PM
LMH, Isla Carmen

From assembly to breakup of Pangea: birth and death of a supercontinent

Paper number: 31-7
Program: Technical Sessions
Time: 10:00 AM – 10:30 AM

Authors

Abstract

The transition from supercontinent assembly to supercontinent breakup requires a major change in the global tectonic setting and the switch from general convergence to divergence. In the case of Pangea, the timing and cause of such a transition remain unclear. At present, we know that Pangea was formed by closure of the Rheic Ocean and consequent continental collision of Gondwana, Baltica and Laurentia during late Paleozoic time and that, by Middle Triassic time, rift basins were already forming at various sites of the supercontinent. Thus, the middle–late Permian sedimentary record is key for our understanding of the Pangea assembly-breakup transition.

We present stratigraphic, sedimentological and petrologic data from two poorly understood areas, the Matzitzi and Huayacocotla areas in southern and central Mexico, respectively. These are potentially the most iconic areas of the Pangea assembly-breakup transition in Mexico, exposing an almost complete early Permian–Jurassic stratigraphic record, including middle–upper Permian successions erroneously mapped as Mesozoic rocks. Available data suggest a tectonic history defined by 3 main stages. Stage 1 is represented by the early–middle Permian assembly of Pangea, which produced crustal thickening and cessation of arc magmatism in Gondwana after ~270 Ma. Stage 2 occurred during latest middle and late Permian time, when, after a main gap of ~ 8 m.y. in magmatism and sedimentation, a few extensional basins of limited extent and hosting local fluvial systems started to form on the thickened continental crust of Gondwana. Middle–late Permian extension was accompanied by magmatism, which is mostly represented by plutons and scarce volcanic rocks. During stage 3, between Triassic and Jurassic time, extension was propagated to other sites, favoring the opening of progressively larger rift basins hosting more regional-scale fluvial systems. Also during this stage, extension was accompanied by magmatism, which, however, was increasingly represented by volcanic rocks and subordinate intrusive bodies. Geochemical data indicate that magmatic rocks of stage 3 were emplaced during a main event of crustal thinning.

We explore the possibility that stage 2 may represent the lithospheric collapse that characterizes the latest phase of orogenic building during Pangea assembly. According to this scenario, Pangea collapsed a few million years after its consolidation, and such a collapse triggered the propagation of extension, which culminated in the breakup of the supercontinent.

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

doi: 10.1130/abs/2026CD-410909

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