Tracing Ignimbrite Calderas and Provenance in Southern Peru

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The Central Andes represent one of the world's largest Miocene ignimbrite provinces. Knowing the location, size and tectonic regime of caldera structures and relating them to the (volume of) associated ignimbrite outflow sheets is important for two fundamental issues: First, the timing, cause, and location of "ignimbrite flare ups" are first-order processes during the evolution of the Central Andean orogen. Second, the volcano-tectonic structures and calderas with shallow intrusive or subvolcanic stocks are often related to mineralization of significant economic value. We plan to use (1) geochemical and isotopic fingerprinting to locate the provenance of ignimbrites, (2) Ar-Ar geochronology for temporal control of correlation of ignimbrites and the location of their caldera sources (3) remote sensing using ASTER SWIR reflectance data and an ASTER- and SRTM-derived DEMs for analysis in ENVI and (4) a DEM-based drainage net analysis to identify caldera structures using "Rivertools". We will concentrate our effort on southern Peru, which is still relatively little studied. However, we will integrate our results with literature data on ignimbrite flare-ups and tectonic evolution from the entire Central Andes in order to present a model for the relation between these flare ups and orogenic evolution.