Collaborative Research: United States-China Scientific Cooperative Project -- Subduction and Exhumation of Ultrahigh-Pressure Rocks: Field and Drilling Studies in Eastern China

0003276隆隆声该项目的重点是中国将在中国中东部的苏禄超高压（UHP）变质火山岩中钻探一个5公里长的钻孔。 该项目的目标是通过研究来自P-T条件“禁区”（即，非常高的P，非常低的T）。 需要解决的一些具体问题是：当大陆俯冲时，会发生什么类型的壳幔相互作用？有多少大陆块是以这种方式回收的？o流体-岩石相互作用的时间可以受到限制吗？超高压石榴石橄榄岩告诉我们什么关于“岩石构造”过程？ 超高压橄榄岩是如何侵位到地壳中的？ 它们在挖掘过程中是如何演变的？ 什么样的机制和上升率是必要的，以保持他们的高P，低T组合？o板坯含水相在回收利用中起什么作用？ 挥发物进入地幔我们能区分俯冲/碰撞 使用深地震剖面的年轻事件的造山带结构？ 超高压变质作用和随后的折返作用发生在什么样的构造环境中？ 大陆-大陆碰撞是必要的吗？主要研究人员将在研究中采用各种方法：1）制图和结构分析; 2）岩石学地球化学; 3）地质年代学; 4）东海钻探现场的地球物理学;以及5）地球动力学建模。

0003276RumbleThis project is focused on the area around a 5 km drill hole the Chinese are going to drill in the Sulu ultrahigh-pressure (UHP) metamorphic terrane in east-central China. The goal of the project is to understand the formation and exhumation of UHP rocks through study of ultramafic (mantle) rocks from a "forbidden zone" of P-T conditions (i.e., very high P, very low T). Some specific questions to be addressed are: o What type of crust-mantle interaction occurs when continents are subducted? o How much of continental mass is recycled in this manner? o Can timing of fluid-rock interactions be constrained? o What do the UHP garnet peridotites tell us about "petrotectonic" processes? o How were UHP peridotites emplaced into the crust? How did they evolve during exhumation? What mechanisms and rates of ascent are necessary to preserve their high P, low T assemblages? o What roles do slab hydrous phases play in recycling of volatiles into the mantle? o Can we tell the difference between subduction/collisional architecture of orogens from younger events using deep-seismic profiles? o In what tectonic settings does UHP metamorphism and subsequent exhumation occur? Is continent-continent collision required?The Principal Investigators will employ a variety of methods in their study: 1) mapping and structural analysis; 2) petrology & geochemistry; 3) geochronology; 4) geophysics at the Donghai drill site; and 5) geodynamic modeling.***