Magnetofabrics of shear zones and ultrahigh-pressure rocks from the Chinese Continental Scientific Drilling (CCSD)

中国大陆科学钻探（CCSD）剪切带和超高压岩石的磁组构

• 批准号: 22115417
• 负责人: Privatdozent Dr. Jens Carsten Grimmer
• 金额: --
• 依托单位: Abteilung für Geothermie und Reservoir-Technologie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/22115417?language=en
• 关键词: Magnetofabrics; shear; zones; ultrahigh; pressure

The Chinese Continental Scientific Drilling (CCSD) in Donghai intersected crustal and mantle ultrahigh-pressure (UHP) rocks from the Triassic-Jurassic Sulu-UHP-orogen in eastern China. The CCSD provides a 5.1 km vertical section of stacked UHP-rocks separated by shear zones. The intersected rocks mainly comprise eclogites, amphibolites, gneisses, and minor peridotites. Coesite inclusions in garnet and zircon from eclogites and gneisses indicate that the intersected rocks were subducted to upper mantle depths (>80 km) and subsequently exhumed. Rock magnetic studies on drill core samples provide a unique chance to monitor vertical changes of structural elements, strain gradients, fluid-rock interactions, and changes of oxygen fugacities especially across ductile shear zones. A focus will be placed on rock magnetic properties (anisotropy of and temperature dependent magnetic susceptibility, magneto-mineralogy) of peridotites, eclogites, and high-grade shear zones in gneisses. The susceptibility tensor comprises two fabric components which can be isolated and which recorded the same or different and thus possible polyphase or progressive deformation. Rock magnetic studies contribute to questions related with structural geology, petrology, mineralogy, and geochemistry, and thus may contribute to a better understanding of exhumation processes by its multidisciplinary approach.

中国大陆科学钻探（CCSD）东海段主要研究中国东部三叠纪-侏罗纪苏鲁超高压造山带的壳幔超高压岩石。CCSD提供了一个由剪切带分隔的5.1 km的超高压岩石叠加垂直剖面。榴辉岩主要由榴辉岩、角闪岩、片麻岩和少量橄榄岩组成。榴辉岩和片麻岩中的石榴石和锆石中的柯石英包裹体表明榴辉岩俯冲到上地幔深度（>80 km），随后折返。对岩芯样品的岩石磁性研究提供了一个独特的机会，以监测结构元素的垂直变化，应变梯度，流体-岩石相互作用，特别是在韧性剪切带的氧逸度的变化。重点将放在岩石磁性（各向异性和温度依赖的磁化率，磁性矿物学）的橄榄岩，榴辉岩，和高级剪切带的片麻岩。磁化率张量包括两个组构成分，这两个组构成分可以被分离，并且记录相同或不同的，因此可能是多相或渐进变形。岩石磁学研究有助于解决与构造地质学、岩石学、矿物学和地球化学相关的问题，从而通过其多学科方法有助于更好地理解折返过程。