RUI: Tectonic Investigations of Proterozoic Sedimentary Rocks in Central Madagascar and Implications for Late Precambrian Paleogeography

9814945Cox超大陆冈瓦纳是在元古代晚期形成的，当时地球的大气、气候和生物圈发生了根本性的变化。马达加斯加位于冈瓦纳大陆的中心，是由前寒武纪地壳组成的，在冈瓦纳大陆聚集期间，地壳发生了变质和变形。马达加斯加中部伊特雷莫群沉积岩提供了提取前造山沉积和古地理的可能性，以及与组合相关的构造。本研究结合沉积学和岩石学分析，对伊特雷莫群露头带进行了详细的岩石和构造作图，目的是限制物源、沉积物扩散模式、沉积环境和事件年龄，从而建立马达加斯加中部的古地理和构造模型。研究结果有望提供马达加斯加元古代陆架环境的信息，并有助于了解冈瓦纳前古地理和冈瓦纳融合。＊＊＊

9814945Cox The supercontinent Gondwana was being assembled during the late Proterozic, a time when fundamental changes were taking place in the earth's atmosphere, climate and biosphere. Madagascar, then in the center of Gondwana, is composed of precambrian crust that was metamorphosed and deformed during the assembly of Gondwana. Sedimentary rocks of the Itremo Group of central Madagascar offer the possibility to extract pre-orogenic sedimentation and paleogeography in addition to assembly-related tectonics. This study involves defailed lithogic and structural mapping of the Itremo Group outcrop belt in association with sedimentologic and petrologic analysis, with the aim of constraining provenance, sediment dispersal patterns, environments of deposition and ages of events so that a paleogeographic and tectonic model for central Madagascar can be constructed. Results are expected to provide information on the proterozoic continental shelf environment of Madagascar and will contribute to understanding pre-Gondwana paleogeography and the amalgamation of Gondwana. ***