Exhumation of Two Contrasting High-Pressure Metamorphic Belts in Venezuela: Implications for Caribbean Tectonics

小行星9706521 与俯冲作用有关的高压变质岩的隆升和折返是一个经典的、尚未解决的地质问题。 高P/低T组合一般被认为是在俯冲带中形成的，但由于各种可能的机制被带到地表，导致两种“类型”--一种以逆行的、近似等温的减压作用为特征，在委内瑞拉北方有两次高P/T波出现，它们是同一时代的低T变质带，并被认为与同一俯冲带有关。 然而，一个是“方济各型”和其他的“阿尔卑斯型”。 本项目将试图利用这种情况，并分离导致不同类型的隆起和上升机制，并将涉及对每个矿点的广泛结构和岩石学研究。 这些结果有可能对俯冲带深处变质岩石的隆起和暴露提供相当多的线索。

9706521 Sisson The uplift and exhumation of high-pressure metamorphic rocks related to subduction is a classic, unsolved geologic problem. High P/low T assemblages are generally thought to have formed a t great depth in subduction zones, but brought to the surface by a variety of possible mechanisms, resulting in two "types"- one characterized by retrograde, approximately isothermal decompression, and the other by a decompression path parallel to their prograde P/T path. In northern Venezuela there are two occurrences of High P/low T metamorphic belts of the same age and thought to be associated with the same subduction zone. However one is of the "Franciscan-type" and the other of the "Alpine-Type". This project will attempt to exploit this circumstance and isolate the mechanisms of uplift and ascent leading to the different types, and will involve extensive structural and petrologic study of each occurrence. Results have the potential for shedding considerable light on the uplift and exposure of rocks metamorphosed deep in subduction zones.