The Dynamics of UHP Tectonism: Does the Western Gneiss Region Consist of Multiple (U)HP Blocks With Different Histories?

超高压构造运动的动力学：西部片麻岩地区是否由多个具有不同历史的（超）高压块体组成？

• 批准号: 0911485
• 负责人: Bradley Hacker
• 金额: --
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0911485&HistoricalAwards=false
• 关键词: Dynamics; UHP; Tectonism; Does; Western

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The margins of continents have been subducted to profound depths (more than 100 km) deep within Earths interior many times throughout the last 500 million years; this process has likely had a major influence on the composition and evolution of the continents and underlying mantle. Understanding how such rocks form and are returned to Earths surface continues to be one of the outstanding questions about plate tectonics. This research uses an enormous region of high-pressure rocks in Norway to understand whether such regions form from one large piece or from many smaller pieces. The impact of this research should be considerable within the earth sciences community because the Norwegian terrane is an archetypal example of continental subduction.The research approach is two-pronged: U-Pb zircon dating of eclogite to assess whether crustal blocks with different ages exist, and structural petrology to characterize shear zones between the blocks. Following careful petrology, eclogite-facies zircon genesis will be assessed by optical and back-scattered electron petrography, cathodoluminescence, trace-element abundances, and Raman spectroscopy. After reconnaissance secondary-ion mass spectrometry and laser-ablation multi-collector inductively coupled-plasma mass spectrometry dating, single zircon grains and grain fragments will be analyzed by high-precision U-Pb thermal-ionization mass spectrometry (TIMS) and chemical-abrasion thermal-ionization mass spectrometry. The strength of this approach lies in its use of state-of-the-art zircon geochronology and petrology, collaboration with researchers at cutting-edge facilities, and our familiarity with other ultrahigh-pressure orogens.

该奖项是根据2009年《美国复苏和再投资法》(公法111-5)资助的。在过去的5亿年里，大陆的边缘多次被俯冲到地球内部深处(100多公里)；这一过程可能对大陆和地幔的组成和演化产生了重大影响。了解这些岩石是如何形成并返回地球表面的，仍然是关于板块构造的悬而未决的问题之一。这项研究使用了挪威一个巨大的高压岩石区域，以了解这些区域是由一大块岩石还是由许多较小的岩石块形成的。这项研究的影响在地球科学界应该是相当大的，因为挪威地体是大陆俯冲的典型例子。研究方法是双管齐下的：榴辉岩的锆石U-Pb测年，以评估不同时代的地壳块体是否存在，以及构造岩石学，以表征块体之间的剪切带。经过仔细的岩石学研究，榴辉岩相锆石的成因将通过光学和背散射电子岩石学、阴极发光、微量元素丰度和拉曼光谱进行评估。经勘察二次离子质谱仪和激光烧蚀多收集器电感耦合等离子体质谱测年后，采用高精度U-Pb热电离质谱(TIMS)和化学磨蚀热电离质谱仪(TIMS)对单颗锆石颗粒和颗粒碎片进行分析。这种方法的优势在于它使用了最先进的锆石年代学和岩石学，与尖端设施的研究人员合作，以及我们对其他超高压造山带的熟悉。