Paper No. 4
Presentation Time: 2:05 PM
THE ACATLÁN COMPLEX, SOUTHERN MEXICO: RECORD OF THE ASSEMBLY, DURATION AND BREAKUP OF PANGEA
New structural, geochronological and geochemical data from the Acatlán Complex of southern Mexico shows it to preserve a complete history of Pangea assembly, duration and breakup. Previously interpreted to be a vestige of the Iapetus suture, the Acatlán Complex records a history that can be sequentially linked to the Rheic Ocean, the paleo-Pacific and the Gulf of Mexico. This record is interpreted to reflect: (1) the development of a rift/passive margin on the southern flank of the Rheic Ocean in the Cambro-Ordovician; (2) the formation of either an arc or an extensional regime along the formerly active northern margin of Gondwana throughout the Ordovician; (3) closure of the Rheic Ocean documented by subduction-related eclogite facies metamorphism and exhumation during the Late Devonian-Mississippian; (4) Permo-Triassic convergent tectonics on the paleo-Pacific margin of Pangea; and (5) the overriding of a Jurassic plume associated with the opening of the Gulf of Mexico. The new data additionally show the Acatlán Complex to preserve the largest fragment of the Rheic Ocean in North America.