Metamorphic evolution and tectonic significance of high-P metamorphic rocks in the Palaeoproterozoic: the Nagssugtoqidian Orogen, South East Greenland.

古元古代高磷变质岩的变质演化及其构造意义：格陵兰岛东南部纳格苏格托奇甸造山带.

基本信息

批准号：
239661242
负责人：
Professorin Dr. Annika Dziggel
金额：
--
依托单位：
Institut für Geologie, Mineralogie und Geophysik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/239661242?language=en
关键词：
Metamorphic evolution tectonic significance metamorphic

项目摘要

This project aims to investigate the pressure-temperature-time-deformation evolution of high-pressure metamorphic rocks in the Palaeoproterozoic Nagssugtoqidian Orogen in South-East Greenland. The Nagssugtoqidian Orogen is unique in that it is one of a few Palaeoproterozoic collisional orogens, in which high-pressure metamorphic rocks have been preserved. Relict eclogites and/or high-P granulites occur within mafic dykes in the orthogneiss-dominated core of the orogen. Mineral assemblages of garnet and clinopyroxene as well as clinopyroxene-plagioclase symplectites indicate PT-conditions outside the plagioclase stability field. Preliminary work to this project indicates that the rocks underwent retrogression at medium-to high-pressure granulite facies grades, but it is currently unknown from which crustal depth these rocks were exhumed. In collaboration with the Geological Survey of Denmark and Greenland (GEUS), the research will combine pressure-temperature-time paths obtained from pseudosection modelling and U-Pb dating of minerals such as zircon, rutile, and titanite with detailed kinematic investigations of shear zones to the north and south of the high-P domain. The data will not only give new insights into the tectonic evolution and exhumation history of high-pressure rocks in the Nagssugtoqidian Orogen, and will also provide constraints on the geodynamic processes during the formation the supercontinent Nuna in the mid Palaeoproterozoic.

该项目旨在研究格陵兰岛东南部古元古代纳格苏格托奇甸造山带高压变质岩的压力-温度-时间-变形演化。那格苏格托旗造山带的独特之处在于，它是少数保存有高压变质岩的古元古代碰撞造山带之一。残余榴辉岩和/或高磷麻粒岩出现在造山带以正片麻岩为主的核心的镁铁质岩脉内。石榴石和单斜辉石以及单斜辉石-斜长石的矿物组合表明斜长石稳定场之外的 PT 条件。该项目的初步工作表明，岩石在中高压麻粒岩相级别经历了退变，但目前尚不清楚这些岩石是从哪个地壳深度挖掘出来的。该研究将与丹麦和格陵兰地质调查局 (GEUS) 合作，将通过锆石、金红石和钛矿等矿物的伪剖面建模和 U-Pb 测年获得的压力-温度-时间路径与剪切带的详细运动学研究相结合高 P 域的北部和南部。这些数据不仅将为纳格苏格托旗造山带的构造演化和高压岩石折返历史提供新的认识，也将为古元古代中期努纳超大陆形成过程中的地球动力学过程提供约束。