An Integrated Study of the Chuacus Metamorphic Belt (Guatemala): A UHP Terrane Along the North America-Caribbean Plate Boundary?

Chuacus 变质带（危地马拉）的综合研究：沿北美-加勒比板块边界的超高压地体？

• 批准号: 0510325
• 负责人: Juhn Liou
• 金额: --
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0510325&HistoricalAwards=false
• 关键词: Integrated; Study; Chuacus; Metamorphic; Belt

This project that is jointly supported by the Division of Earth Sciences and the Office of International Science and Engineering, is designed to study a recently discovered Chuacus terrane in Guatemala. This terrane was developed in a subduction - collision of continental microplate environment, and opens an excellent opportunity to address this problem at the southern margin of the North-American plate in the Caribbean region. The formation and exhumation of deeply subducted rocks to mantle depths has been one of the most exciting problems in the field of continental dynamics for the last two decades. This project undertakes an integrated petrochemical-geochronological study, and the specific tasks involve field study along orogen-perpendicular traverses, petrochemical characterization of eclogitic and gneissic rocks to constrain thermobaric structures, and dating of subduction, collision and exhumation of continental materials by U-Pb SHRIMP and 40Ar-39Ar methods. The proposed research provides basic information concerning the age, protolith, HP-UHP metamorphism and tectonic evolution of a continental-affiliated terrane. This gneissic terrane, with mafic eclogitic layers, contrasts with the oceanic-affiliated HP terranes to the south of Motagua Valley. The subparallel occurrence of continental-derived and oceanic-derived eclogitic terranes in central Guatemala is unique, and provides a challenge for geosciences for their formation and juxtaposition. Spatial and temporal relations of oceanic subduction followed by subudction and collision of continent may have been involved in the early development of the Caribbean plate. This project supports research of a Ph.D. student from Colombia, a Japanese post-doc, Stanford faculty members and undergraduates and personnel from both Guatemala and Mexico. An essential part of this collaborative research with local scientists will involve training young Mexican and Guatemalan scholars in scientific writing and in research methods and techniques to which they lack access at the present time. Such tri-national cooperative project will enhance mutual friendship, exchanges, and both scientific cooperation and educational training.

该项目由地球科学部和国际科学与工程办公室联合支持，旨在研究最近在危地马拉发现的丘阿库斯地体。该地体是在大陆微板块俯冲-碰撞环境下发育的，为解决加勒比地区北美板块南缘的这一问题提供了极好的机会。深俯冲岩石的形成和折返到地幔深处是近二十年来大陆动力学领域最令人兴奋的问题之一。该项目进行了岩石化学-地质年代学的综合研究，具体任务包括沿造山带垂直导线的野外研究，榴辉岩和片麻岩的岩石化学特征以约束温压结构，以及用U-Pb SHRIMP和40Ar-39Ar方法测定大陆物质的俯冲、碰撞和折返的年龄。该研究提供了大陆附属地体的年龄、原岩、高压-超高压变质作用和构造演化的基本信息。该片麻状地体具有镁铁质榴辉岩层，与莫塔瓜河谷以南的海洋附属HP地体形成对比。危地马拉中部陆源和洋源榴辉岩区的次平行产状是独一无二的，这对地球科学的形成和并置提出了挑战。大洋俯冲、大陆俯冲和碰撞的时空关系可能参与了加勒比海板块的早期发展。该项目支持来自哥伦比亚的一名博士生、一名日本博士后、斯坦福大学的教职员工以及来自危地马拉和墨西哥的本科生和人员的研究。与当地科学家合作进行的这项研究的一个重要部分将涉及对墨西哥和危地马拉的年轻学者进行科学写作以及研究方法和技术方面的培训，而这些研究方法和技术目前是他们无法获得的。这样的三国合作项目将增进相互友谊和交流，增进科学合作和教育培训。