Apatite U-Pb Thermochronology: A combined ID-TIMS and LA-ICP-MS study from southern Ecuador
Abstract
A combination of U-Pb LA-ICP-MS and ID-TIMS analyses of apatite has been used to investigate the high temperature (>450° C) thermal history of the Ecuadorian Andean margin. The rocks of the Eastern Cordillera of Ecuador evolved via terrane collision and accretion events, and active margin magmatism since the Early Jurassic. Low temperature (0.5) reveal periods of: i) rapid cooling (~240-220 Ma) through the Pb Partial Retention Zone (PRZ) shortly after crystallization, ii) residence at temperatures lower than the PRZ throughout the Jurassic, iii) reheating during 140-90 Ma, and iv) rapid cooling starting at 80-70 Ma. These findings corroborate conclusions based on geochronological and sedimentological data. Additional in-situ age transects and age-depth profiling of apatite are scheduled to determine the concentration distribution of radiogenic lead in the apatites, which will be used to constrain further the mechanisms of lead loss.
- Publication:
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EGU General Assembly Conference Abstracts
- Pub Date:
- April 2012
- Bibcode:
- 2012EGUGA..1414487C