The majority of hydrocarbon resources in Bolivia are hosted within Carboniferous sedimentary rocks in the eastern part of the Andean fold-thrust belt and the Chaco foreland basin. It has been suggested on the basis of structural/stratigraphic relationships that these Carboniferous rocks were deposited in a foreland basin system that subsided as sediment eroded off a pre-Andean orogenic high. One proposed highland from which this sediment may have been derived is to the west, in the present-day Eastern Cordillera of southern Bolivia, where deeply-exhumed, low-grade metamorphic Ordovician sedimentary rocks are unconformably overlain by un-metamorphosed Mesozoic rocks. K-Ar ages of synkinematic illite in Ordovician rocks indicate that metamorphism occurred in the late Carboniferous (310-290 Ma); however, the timing of their exhumation is presently unconstrained. Our objective is to constrain the timing of this pre-Andean exhumation event, and to see how it relates temporally to deposition of Carboniferous hydrocarbon host rocks. Geologic mapping and a balanced cross-section through the eastern part of the thrust belt will be extended westward into the Eastern Cordillera. Raman spectroscopy on carbonaceous material and (U-Th)/He dating of zircon will be utilized to determine peak metamorphic temperatures and exhumation timing of Ordovician rocks in the Eastern Cordillera, and detrital (U-Th)/He zircon thermochronology will be performed on Carboniferous rocks from the frontal part of the thrust belt. We predict that if a regional, pre-Andean erosion event in the Eastern Cordillera was the source of Carboniferous rocks, then detrital thermochronologic ages from Carboniferous rocks should match the Ordovician bedrock cooling ages.