Exploring the Significance of Na-Alkaline Magmatism in Subduction Systems, a Case Study From the Ross Orogen, Antarctica

探索俯冲系统中钠碱性岩浆作用的意义——以南极洲罗斯造山带为例

• 批准号: 1043152
• 负责人: John Cottle
• 金额: $ 31.14万
• 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: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1043152&HistoricalAwards=false
• 关键词: Exploring; Significance; Na; Alkaline; Magmatism

Intellectual Merit: Magmas generated during subduction of oceanic lithosphere beneath active continental margins typically have a calc-alkaline chemistry. However, igneous rocks with signatures usually associated with anorogenic magmatism are increasingly being found with calc-alkaline rocks in subduction zones. These enigmatic rocks provide insight into a variety of magmatic and structural processes that are fundamental to subduction zone dynamics but processes that lead to their petrogenesis remain a matter of debate. This project will investigate the Koettlitz Glacier Alkaline Province (KGAP) in the Transantarctic Mountains, which is a section through a Na-alkaline province bounded to the north and south by calc-alkaline magmatism. This province potentially contains key information on the thermo-mechanical processes leading to generation of Na-alkaline rocks in subduction systems. The PI will examine structures that bound the KGAP as well as intrusives and metasedimentary rocks contained within it to determine the tectonomagmatic history in the framework of two end-member hypotheses: the KGAP represents a crustal-scale extensional or transtensional domain in a subduction setting; or the KGAP formed in response to ridge subduction. Broader impacts: This study will train three graduate and three undergraduate students incorporating hands-on experience with state of the art instrumentation. Each summer, four high school students will be incorporated into various aspects of the laboratory-based research through the UCSB research mentorship program. This project will stimulate refinement of in-situ LA-ICPMS methods and development of collaborative linkages with Antarctic geologists at GNS Science in New Zealand. Results will be disseminated via papers and presentations at international conferences.

智力优点：在活性大陆边缘下方岩石圈俯冲期间产生的岩浆通常具有钙碱化学。然而，俯冲带中的钙碱岩石越来越多地发现了通常与厌食岩浆相关的签名的火成岩。这些神秘的岩石提供了对俯冲带动力学基础的各种岩浆和结构过程的洞察力，但是导致其石化的过程仍然是辩论的问题。该项目将调查跨北极山脉的Koettlitz冰川碱性省（KGAP），这是通过Colc-alsalline Magmatism界定向北和南部的Na-Alkaline省的一部分。该省有可能包含有关热机械过程的关键信息，从而导致俯冲系统中的Na-烷烃岩石产生。 PI将检查结合KGAP的结构以及其中包含的侵入物和沉积物岩石，以确定两个末端成员假设的框架中的构造经济学历史：KGAP代表在俯冲设置中的地壳规模的扩张或跨性别域；或响应山脊俯冲而形成的KGAP。更广泛的影响：这项研究将培训三名毕业生和三名本科生，并将动手经验与最先进的仪器结合在一起。每年夏天，将通过UCSB研究指导计划将四名高中学生纳入基于实验室研究的各个方面。该项目将刺激原位LA-ICPMS方法的完善，并与新西兰GNS Science的南极地质学家的协作联系发展。结果将通过国际会议上的论文和演讲来传播。