Structural and tectonic evolution of the Acatlán Complex, southern Mexico: Its role in the collisional history of Laurentia and Gondwana

Abstract

Correlation of deformational phases and thermal events in the Acatlán Complex permits definition of nine major tectonic events. Seven events are related to the evolution of the Iapetus and Rheic oceans. By the Early Ordovician, the Xayacatlán suite of Laurentian affinity was metamorphosed to eclogite facies and exhumed before colliding with the El Rodeo suite. From the Late Ordovician to Silurian, the Upper Ordovician Ixcamilpa suite with peri‐Gondwanan affinity was metamorphosed to blueschist facies, exhumed, and subsequently was overthrust by the Xayacatlán–El Rodeo block. Part of the Esperanza suite is an Early Silurian intra‐Iapetian continental arc that collided with and subducted beneath continental crust, generating a Silurian eclogitic event. By the Late Devonian, collision of the three high P/T suites closed the Iapetus Ocean. The resulting composite terrain was thrust over the Gondwana‐bordering Cosoltepec suite to close the Rheic Ocean. During the earliest Mississippian, the collision of the Acatlán Complex and the Oaxaca terrane uplifted and deformed the composite terrane. By the Early Permian, deposition of the Chazumba suite occurred in a pull‐apart basin. A latest Early Permian event produced thrust shear zones with N–S directed shortening. During the Middle Jurassic, plume rise caused regional doming, magmatism and amphibolite facies metamorphism. During the Late Cretaceous–Paleogene, folds and thrust faults overprint the Acatlán Complex. Most events in the Acatlán Complex correlate with events in the Appalachian chain, suggesting that the Acatlán Complex was located near the Appalachians until the Jurassic when it was displaced by the Gulf of Mexico opening.

Palaeozoic to Early Jurassic history of the northwestern corner of Gondwana, and implications for the evolution of the Iapetus, Rheic and Pacific Oceans

“…For contrasting views see Keppie et al (2012) and Vega-Granillo et al (2009), and references therein. CT: Cuyania Terrane (e.g.…”

“…Estrada-Carmona et al, 2012;Keppie et al, 2008Keppie et al, , 2012b, or (ii) Ordovician orogenesis and Ordovician to Silurian continental arc magmatism (e.g. Ratschbacher et al, 2009;Vega-Granillo et al, 2009;Solari et al, 2013). These strongly contrasting interpretations have been used to suggest that either the Rheic Ocean opened along the western margin of Gondwana, with its southern extent in front of present day Peru (e.g.…”

U–Pb geochronological constraints on the Triassic–Jurassic Ayú Complex, southern Mexico: Derivation from the western margin of Pangea-A

“…Despite the large amount of recently published geochemical and geochronological data for rocks of the Acatlán Complex (e.g. Talavera-Mendoza et al, 2005;Keppie et al, 2006b;Murphy et al, 2006;Keppie and Dostal, 2007;Middleton et al, 2007;Miller et al, 2007;Grodzicki et al, 2008;Hinojosa-Prieto et al, 2008;Morales-Gámez and Keppie, 2008;RamosArias et al, 2008;Dostal and Keppie, 2009;Galaz Escanilla et al, 2009;Morales-Gámez et al, 2009aOrtega-Obregón et al, 2009;VegaGranillo et al, 2009aVegaGranillo et al, , 2009bOrtega-Obregón et al, 2010), the interpretation of its geological development throughout the Paleozoic remain controversial (Talavera-Mendoza et al, 2005;Nance et al, 2006b;Keppie et al, 2008b;Vega-Granillo et al, 2009a). Although these authors disagree on the paleogeographic location (and hence the relationship of these rocks to the amalgamation of Pangea), they generally agree that the Late Paleozoic history of the Acatlán Complex records subduction-related arc magmatism dominated by the Permian Totoltepec pluton and the broadly synchronous deposition of clastic rocks of the Tecomate Formation in the eastern Acatlán Complex.…”

“…2. 2. Talavera-Mendoza et al (2005) inferred an Upper PennsylvanianLower Permian age for these rocks based on detrital zircon ages and inferred deposition in an oceanic basin that developed from an intracontinental pull-apart basin (Vega-Granillo et al, 2009a), prior to the break-up of Pangea. 3.…”

“…Böhnel (1999) infers the Mixteca terrane (black) to be located off eastern Canada along a dextral megashear zone (Pangea-B). b) the Acatlán Complex (Ac) and Oaxaquia (Ox) are placed on the western margin of Pangea (Pangea-A), V -position of the Permian-Triassic East Mexico arc, Coa -Coahuila, CA -Colombian Andes (after Elías-Herrera and Ortega-Gutiérrez, 2002;Keppie, 2004;Centeno-García, 2005;Weber et al, 2007); c) Vega-Granillo et al (2009a) place the Mixteca (Mx) and Oaxaquia (Ox) terranes within Pangea, between the Maya block and southern North America (Pangea-A). d) Main tectono-stratigraphic terranes and geologic provinces of Mexico.…”