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

智力优势：在活动大陆边缘之下的大洋岩石圈俯冲过程中产生的岩浆通常具有钙碱性化学。然而，通常与非造山岩浆作用有关的火成岩与俯冲带中的钙碱性岩一起被越来越多地发现。这些神秘的岩石提供了各种岩浆和构造过程的洞察，这些过程是俯冲带动力学的基础，但导致它们岩石成因的过程仍然存在争议。该项目将调查横跨北极山脉的科特利茨冰川碱性省(KGAP)，这是一个南北被钙碱性岩浆活动包围的钠碱性省的一部分。该省可能包含导致俯冲系统中钠碱性岩石生成的热机械过程的关键信息。PI将研究KGAP的边界构造以及其中包含的侵入岩和变质沉积岩，以确定在两个终端成员假说的框架内的构造岩浆历史：KGAP代表俯冲背景下的地壳规模的伸展或拉张区域；或KGAP响应海脊俯冲而形成。更广泛的影响：这项研究将培训三名研究生和三名本科生，他们将结合最先进的仪器设备的实践经验。每年夏天，四名高中生将通过UCSB研究导师计划被纳入以实验室为基础的研究的各个方面。该项目将促进改进现场LA-ICPMS方法，并与新西兰GNS Science的南极地质学家建立协作联系。结果将通过论文和在国际会议上的陈述来传播。

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.