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-侏罗纪米图裂谷系标志着从增生(新元古代-古生代)向自侏罗纪以来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重要的地球动力学意义，但人们对它的研究和了解还不够深入。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了安第斯山脉的建造。该项目以库斯科附近的乌鲁班巴山谷为中心，结合了对火山沉积相的详细分析和对单颗粒和多颗粒重矿物样品的来源分析研究，包括岩石学、地质年代学、地球化学和同位素地球化学。这将第一次产生不同盆地部分的地理分辨最大沉积年龄，以及确定来自不同物源区的可变输入。这将提高建造盆地填充建筑的单位的时间和空间分辨率。相和物源数据的结合将能够破译沉积发育过程中的时空变化，从而破译盆地本身的变化。最后，这些数据将制约米图盆地构造和沉积充填对安第斯链造山的影响。