Southern and Central Mexico: Basement Framework, Tectonic Evolution, and Provenance of Mesozoic–Cenozoic Basins

This volume furthers our understanding of key basins in central and southern Mexico, and establishes links to exhumed sediment source areas in a plausible paleogeographic framework. Authors present new data and models on the relations between Mexican terranes and the assembly and breakup of western equatorial Pangea, plate-tectonic and terrane reconstructions, uplift and exhumation of source areas, the influence of magmatism on sedimentary systems, and the provenance and delivery of sediment to Mesozoic and Cenozoic basins. Additionally, authors establish relationships between basement regions (sediment source) in the areas that supplied sediment to Mesozoic rift basins, Late Cretaceous foreland systems, and Cenozoic basins developed in response to Cordilleran events.
Petrogenesis of the crystalline basement along the western Gulf of Mexico: Postcollisional magmatism during the formation of Pangea
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Published:December 09, 2021
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CiteCitation
Henry E. Coombs, Andrew C. Kerr, James Pindell, David Buchs, Bodo Weber, Luigi Solari, 2021. "Petrogenesis of the crystalline basement along the western Gulf of Mexico: Postcollisional magmatism during the formation of Pangea", Southern and Central Mexico: Basement Framework, Tectonic Evolution, and Provenance of Mesozoic–Cenozoic Basins, Uwe C. Martens, Roberto S. Molina Garza
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ABSTRACT
The supercontinent of Pangea formed through the diachronous collision of Laurussia and Gondwana during the late Paleozoic. While magmatism associated with its formation is well documented in the Variscan orogeny of Europe and Alleghanian orogeny of the United States, little is known about the Sonora orogeny of northern Mexico. This paper reports geochronology (U-Pb zircon), whole-rock geochemistry, and Lu-Hf zircon isotope data on basement cores from the western Gulf of Mexico, which were used to develop a tectonomagmatic model for pre- to post-Pangea amalgamation. Our results suggest the existence of three distinct phases of magmatism, produced during different stages of continental assembly and disassembly. The first phase consists of Early Permian (294–274 Ma; n = 3) granitoids with geochemical signatures indicative of a continental arc tectonic setting. This phase formed on the margins of Gondwana during the closure of the Rheic Ocean, prior to the final amalgamation of Pangea. It likely represents a lateral analogue of late Carboniferous–Early Permian granitoids that intrude the Acatlán and Oaxacan Complexes. The second phase of magmatism includes Late Permian–Early Triassic (263–243 Ma; n = 13) granitoids with suprasubduction geochemical affinities. However, Lu-Hf isotope data indicate that these granitoids formed from crustal anatexis, with εHf values and two-step Hf depleted mantle model ages (TDM[Hf]) comparable to the Oaxaquia continental crust into which they intrude. This phase of magmatism is likely related to coeval granitoids in the Oaxaca area and Chiapas Massif. We interpret it to reflect late- to postcollisional magmatism along the margin of Gondwana following the assembly of Pangea. Finally, the third phase of magmatism includes Early–Middle Jurassic (189–164 Ma; n = 2) mafic porphyries, which could be related to the synchronous suprasubduction magmatism associated with the Nazas arc. Overall, our results are consistent with Pangea assembly through diachronous collision of Laurussia and Gondwana during subduction of the Rheic Ocean. They suggest that postorogenic magmatism in the western termination of the Rheic suture occurred under the influence of a Panthalassan subduction zone, before opening of the Gulf of Mexico.
- absolute age
- Acatlan Complex
- Atlantic Ocean
- basement
- chemical composition
- diachronism
- Gondwana
- granites
- Gulf of Mexico
- I-type granites
- ICP mass spectra
- igneous rocks
- isotope ratios
- Jurassic
- Laurussia
- Lu/Hf
- magmatism
- major elements
- mass spectra
- Mesozoic
- nesosilicates
- North Atlantic
- orthosilicates
- paleogeography
- Paleozoic
- Pangaea
- Permian
- plate collision
- plate tectonics
- plutonic rocks
- Rheic Ocean
- S-type granites
- silicates
- spectra
- tectonics
- trace elements
- U/Pb
- zircon
- zircon group