Field, Analytical, and Experimental Studies of Progressive Crustal Melting in the Himalaya

喜马拉雅地区地壳渐进熔融的现场、分析和实验研究

• 批准号: 9814497
• 负责人: Kip Hodges
• 金额: $ 29.17万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-15 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814497&HistoricalAwards=false
• 关键词: Field; Analytical; Experimental; Studies; Progressive

9814497HodgesThe metamorphic core region of the Himalaya displays spectacular exposures of leucogranites produced by partial melting of the continental crust. These melts were produced over a wide range of pressure and temperature conditions as the orogen evolved through Late Oligocene to Middle Miocene time. This research will capitalize on the opportunity presented by the Himalaya to better understand the process of orogenic anatexis in time and space. Over a three-year period, an integrated field, petrologic, and geochemical study of multiple generations of leucogranites in the Everest-Makalu region of eastern Nepal will be conducted. This project is unique, compared to previous studies of leucogranite petrogenesis, in that it features high-resolution geochronology designed to explore the rate and episodicity of the melting process. Since the successful dating of leucogranites relies on U-Th-Pb analyses of accessory minerals (zircon, monazite, xenotime, and uraninite), one key to understanding leucogranites is understanding the behavior of accessory minerals during the anatectic process. This requires direct and continual feedback between experimental studies and field/analytical studies of geologic examples. The experimental component of this proposal builds on current research by Watson and associates at the Rensselaer Polytechnic Institute by focusing on xenotime solubility in granitic melts.

9814497 Hodges喜马拉雅变质核区展示了大陆地壳部分熔融产生的浅色花岗岩的壮观暴露。这些熔体产生在广泛的压力和温度条件下的造山带通过晚渐新世到中中新世的时间演变。这项研究将利用喜马拉雅山提供的机会，更好地了解造山深熔作用的时间和空间的过程。在三年的时间里，将对尼泊尔东部珠穆朗玛峰-马卡鲁地区的多代浅色花岗岩进行综合实地、岩石学和地球化学研究。该项目是独特的，与以往的研究相比，浅色花岗岩的岩石成因，因为它具有高分辨率的地质年代学，旨在探索熔融过程的速率和偶发性。由于浅色花岗岩的成功定年依赖于副矿物（锆石、独居石、磷钇矿和晶质铀矿）的U-Th-Pb分析，因此了解浅色花岗岩的关键之一是了解副矿物在重熔过程中的行为。这需要在实验研究和地质实例的实地/分析研究之间进行直接和持续的反馈。该提案的实验部分建立在伦斯勒理工学院的沃森和同事目前的研究基础上，重点关注花岗岩熔体中磷钇矿的溶解度。