Rift systems at continental margins: A case study of facies evolution and provenance of the sedimentary-volcanic facies evolution of the Permotriassic Mitu Group (Central Andes, Peru)

大陆边缘裂谷系统：二叠纪米图群（秘鲁安第斯山脉中部）相演化及沉积-火山相演化物源实例研究

• 批准号: 299483040
• 负责人: Professor Dr. Hans Heinrich Bahlburg
• 金额: --
• 依托单位: Institut für Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/299483040?language=en
• 关键词: Rift; systems; continental; margins; case

The Permian-Jurassic Mitu Rift System in the Peruvian Andes marks the crucial transition from an accretionary (Neoproterozoic-Paleozoic) to the modern Andino-type continental margin, which exists since the Jurassic. Despite its geodynamic importance the Mitu Rift System is not well studied and understood. Consequently it remains unclear in which way basin structures, and the thicknesses and distribution of the basin fill have influenced Andean mountain building. Centered in the Urubamba valley near Cusco the proposed project combines a detailed analysis of volcanisedimentary facies with provenance analytical studies of single- and multi-grain heavy mineral samples including petrography, geochronology, geochemistry and isotope geochemistry. This will result, for the first time, in geographically resolved maximum depositional ages of different basin parts as well as the determination of variable inputs from different source areas. This will induce an enhanced temporal and spatial resolution of the units building the basin fill architecture. The combination of facies and provenance data will allow for deciphering temporal and spatial variations in the depositional development, and consequently of the basin itself. Finally, these data will constrain the influence of structures and sedimentary fill of the Mitu basin on mountain building of the Andean chain.

秘鲁安第斯山脉的二叠纪-侏罗纪米图裂谷系统标志着从增生期（新元古代-古生代）到自侏罗纪以来就存在的现代安迪诺型大陆边缘的关键转变。尽管米图裂谷系统具有地球动力学重要性，但尚未得到充分研究和理解。因此，目前尚不清楚盆地结构以及盆地填充物的厚度和分布以何种方式影响安第斯山脉的形成。拟议项目以库斯科附近的乌鲁班巴山谷为中心，将火山沉积相的详细分析与单粒和多粒重矿物样品的来源分析研究（包括岩相学、地质年代学、地球化学和同位素地球化学）结合起来。这将首次在地理上解决不同盆地部分的最大沉积年龄以及来自不同源区的可变输入的确定。这将提高构建盆地填充结构的单元的时间和空间分辨率。相和物源数据的结合将有助于破译沉积发育的时间和空间变化，从而破译盆地本身的时间和空间变化。最后，这些数据将限制米图盆地的构造和沉积充填对安第斯链造山的影响。