Subduction and Exhumation of Ultrahigh-Pressure Rocks: Field and Drilling Studies in Eastern China

超高压岩石的俯冲和折返：中国东部的野外和钻探研究

• 批准号: 0810969
• 负责人: Juhn Liou
• 金额: $ 15.35万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0810969&HistoricalAwards=false
• 关键词: Subduction; Exhumation; Ultrahigh; Pressure; Rocks; Subduction; Exhumation; Ultrahigh; Pressure; Rocks

The ICDP Chinese Continental Scientific Drilling project, completed in 2005, targeted an ultrahigh pressure (UHP) metamorphic terrane in eastern China. The UHP terrane resulted from subduction of the northern edge of the Yangtze craton to 150 km depth beneath the Sino-Korean craton. Several drill holes including the main hole (MH) (5158 m depth), pre-pilot holes PP1 (432 m), PP2 (1028 m) and PP3 (705 m) in Donghai, and 3 shallow holes (183-350 m) in ultramafic bodies in Rongcheng and Rizhao were completed. Core recovery was more than 85% of drilling depth including unweathered samples of gneisses, eclogites, garnet peridotites, dunite, and garnet clinopyroxenite. Encountering peridotites was expected based on occurrences in surface outcrops but no one predicted the bonanza that was found by drilling. The new drill core samples, now available for study, offer an unprecedented opportunity to advance understanding of the mantle and subduction processes. The Continental Dynamics program funded a multi-institutional, multidisciplinary investigation of ICDP-CCSD drill core samples led by JG Liou at Stanford University and has included colleagues from the Chinese Academy of Geological Sciences, Beijing, Carnegie Institution of Washington, Academia Sinica (Taiwan), Tokyo Institute of Technology and Waseda University. The PIs have worked closely with more than 30 Chinese scientists, and published 107 papers. The published work on CCSD cores is valued by the research community as recognized by the ranking of J.G. Liou as the tenth most cited geoscience author and R.Y. Zhang as within the top 50 during 1996-2007 according to Thomson?s ISI Web of Science. This award provides one additional year of support as an Accomplishment Based Renewal (ABR) to complete geochemical studies of core samples of garnet peridotite. Newly recognized sulfide minerals in garnet peridotites will be analyzed for Re-Os and Sulfur isotopes. Zircons, a rare but immensely informative mineral found in peridotites, will be analyzed for Lu-Hf isotopes. Analysis of peridotite silicate minerals for oxygen isotopes will be used to test for mantle vs. crustal origin. These new studies, combined with U-Pb ion microprobe analyses of zircon, will provide a detailed chronology of the formation of sub-continental mantle lithosphere and give new insights as to the role of subduction in contaminating the mantle with crustal material.

ICDP中国大陆科学钻探项目于2005年完成，针对中国东部的超高压力（UHP）变质地层。 UHP地座是由扬兹克拉顿（Yangtze Craton）北部边缘俯冲到中国克拉顿（Craton）下方150公里的深度。几个钻孔，包括主孔（MH）（5158 m深度），Preot孔PP1（432 m），PP2（1028 m）和Donghai中的PP3（705 m），以及Rizhao的超镁杆菌的3个浅孔（183-350 m）。核心恢复占钻孔深度的85％以上，包括未经来说的片麻岩，eclogites，石榴石橄榄岩，Dunite和Garnet Clinopyroxenite。基于表面露头中的出现，预计会遇到橄榄岩，但没有人预测通过钻孔发现的大发。现在可以进行研究的新钻芯样品提供了前所未有的机会，可以提高对地幔和俯冲过程的了解。大陆动力学计划资助了由斯坦福大学JG Liou的ICDP-CCSD钻核样本进行的多机构，多学科调查，其中包括来自中国地质科学学院，北京，北京，卡内基华盛顿州华盛顿州卡内基研究所，台湾学术界，台湾大学理工学院的同事。 PI与30多位中国科学家密切合作，并发表了107篇论文。 J.G.的排名认可的研究界对CCSD核心的已发表著作进行了评价。 liou是第十名被引用的地球科学作者和R.Y.根据汤姆森（Thomson）的《科学》（Web of Science）的说法，张在1996 - 2007年期间排名前50位。该奖项提供了一年的支持，作为基于成就的续签（ABR），以完成石榴石橄榄岩核心样品的地球化学研究。石榴石橄榄岩中新认识的硫化物矿物质将分析Re-OS和硫同位素。 锆石是在橄榄岩中发现的一种罕见但信息丰富的矿物，将分析LU-HF同位素。 氧气同位素的橄榄岩硅酸盐矿物质的分析将用于测试地幔与地壳起源。 这些新研究，结合了锆石的U-PB离子微探针分析，将提供详细的年表，以形成次大陆地幔岩石圈，并就俯冲在污染地幔用外壳材料污染地幔中的作用提供新的见解。