Cenozoic plate tectonic history of southwestern Mexico; constraints from low temperature thermochronology

• Autores: Sarah Shoemaker, Mihai N. Ducea, Peter William Reiners, J.I. Garver, María Fernanda Campa U.
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 4, 2002 (Ejemplar dedicado a: INTERNATIONAL WORKSHOP ON FISSION TRACK ANALISIS: THEORY AND APPLICATIONS), págs. 137-138
• Idioma: inglés
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• Resumen

  • The southern coast of Mexico marks the southern margin of the North American plate, and the current position of Cenozoic eastward migration of the North American-Cocos-Caribbean triple junction. The chronology of the plate boundaiy movement is currently unclear. Contrasting hypotheses place the triple point either at the western end of the Xolapa terrane in the Oligocene-Miocene, or at the eastern end of the Xolapa prior to the Oligocene. The exhumation history of the Sierra Madre del Sur mountain range, whose southern reaches extend into the Xolapa terrane in southern Mexico, helps to resolve this problem, assuming that shallow crustal exhumation is related to the triple junction migration.

    Six N-S transects along the Xolapa terrane were sampled to better constrain the exhumation history of the southern Sierra Madre del Sur using two low-temperature thermochronometers, the apatite fission track and apatite (U-Th)/He systems. Preliminary data from one transect implies rapid cooling in the Oligocene, followed by relatively slow exhumation (-0.02 km/Myr) until ~ /2 Ma, with significantly faster exhumation rates aj'ter -12 Ma (-0.2 km/Myr).