Implications of Latest Pennsylvanian to Middle Permian Paleontological and U-Pb SHRIMP Data from the Tecomate Formation to Re-dating Tectonothermal Events in the Acatlán Complex, Southern Mexico

Permian-Carboniferous arc magmatism and basin evolution along the western margin of Pangea: Geochemical and geochronological evidence from the eastern Acatlan Complex, southern Mexico

“…Apart from abundant quartz veins, thin granitoid dikes are localized to an area south of Santo Domingo Tonahuixtla. Though lithologically identical to the Tecomate Formation type area in the central Acatlán Complex (Ortega-Gutiérrez, 1978), reconnaissance geochronological analyses of Tecomate Formation metasedimentary rocks from the fi eld and the type area, respectively (Keppie et al, 2004b;Sánchez-Zavala et al, 2004), have yielded distinct detrital zircon age populations, suggesting contrasting sources for the two units.…”

“…288 and ca. 263 Ma in another, fossiliferous limestone horizons in the type Tecomate Formation in the central Acatlán Complex range from latest Pennsylvanian to early Middle Permian (Keppie et al, 2004b) and middle Pennsylvanian (Kazimovian = 306-304 Ma) to Early Permian. Thus, the Tecomate Formation may be a composite unit, collectively spanning the middle Pennsylvanian-Early Permian, but of different ages in different locations.…”

“…Conglomerates in the Tecomate Formation in the study area contain granitic pebbles (Keppie et al, 2004b), suggesting a potential linkage between magmatism and basin evolution. However, based on the available data, it is unclear whether the Tecomate Formation, which has been mapped on the basis of lithologic comparison, is the same age in different locations.…”

New insights into the history and origin of the southern Maya block, SE México: U–Pb–SHRIMP zircon geochronology from metamorphic rocks of the Chiapas massif

“…Igneous crystallization ages of 1.2-1.25 Ga, which are also present in the Custepec sample (a minor population of three grains), are common in Oaxaquia and they have been interpreted as the age of arc magmatism (Weber and Kö hler 1999;Lawlor et al 1999;Lopez et al 2001;Keppie et al 2001). The~1.5-Ga zircons cannot come from Oaxaquia if this microcontinent evolved as a juvenile island arc 1.35-1.2 Ga ago (Keppie et al 2004). Even if this arc is 1.4-1.5 Ga (Weber and Kö hler 1999;Weber and Hecht 2003), the source for the 1.5-Ga zircons must be different from Oaxaquia because most of the zircons of this age are of metamorphic origin.…”

New geological and geochronological data of the Placer de Guadalupe uplift, Mexico: a new piece of the Late Triassic–Jurassic Nazas Arc?

“…During the Palaeozoic, the study area was part of the southern Pangea passive margin (Sanchez-Zavala et al 1999;Keppie et al 2004). Palaeozoic and Permian sedimentary formations were deposited on the continental platform from subtidal to deep ocean conditions (Centeno-García 2005).…”