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.

该奖项根据 2009 年美国复苏和再投资法案（公法 111-5）提供资金。在过去 5 亿年里，大陆边缘多次俯冲到地球内部深处（超过 100 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。了解这些岩石如何形成并返回地球表面仍然是板块构造学的突出问题之一。这项研究利用挪威巨大的高压岩石区域来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。这项研究在地球科学界的影响应该是相当大的，因为挪威地体是大陆俯冲的典型例子。研究方法有两个方面：对榴辉岩进行 U-Pb 锆石测年，以评估是否存在不同年龄的地壳块体，和构造岩石学来表征块体之间的剪切带。经过仔细的岩石学研究，将通过光学和背散射电子岩相学、阴极发光、微量元素丰度和拉曼光谱来评估榴辉岩相锆石的成因。经过勘察二次离子质谱和激光烧蚀多接收器电感耦合等离子体质谱测年后，将通过高精度 U-Pb 热电离质谱 (TIMS) 和化学磨损对单晶锆石颗粒和颗粒碎片进行分析热电离质谱法。这种方法的优势在于它利用了最先进的锆石地质年代学和岩石学、与尖端设施的研究人员的合作以及我们对其他超高压造山带的熟悉。