Collaborative Research: Evaluating the Influence of Crustal Deformation on Episodic Magmatism: Southern Coast Mountains Batholith, British Columbia

合作研究：评估地壳变形对幕式岩浆作用的影响：不列颠哥伦比亚省南部海岸山脉基岩

• 批准号: 1347375
• 负责人: George Gehrels
• 金额: $ 13.21万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1347375&HistoricalAwards=false
• 关键词: Collaborative; Research; Evaluating; Influence; Crustal

This project will evaluate processes responsible for the non-steady-state growth of continental crust in Cordilleran-type magmatic arcs. These batholiths develop as a result of subduction of oceanic lithosphere at convergent margins, but the processes that control the tempo of magma production are unclear; even in arcs where subduction is continuous, magmatism is strongly episodic (e.g. Sierra Nevada batholith, Peninsular Ranges batholith, Central Andes). Short periods (10-15 million years) of intense magmatism or 'flare-ups' may generate as much as 90% of total batholithic volumes, with little magmatism occurring during intervening lulls. Geochemical and isotopic signatures indicate that magmas produced during flare-ups incorporate more upper plate material than magmas formed during lulls. This pattern raises the question of whether continental growth by magmatic addition is controlled primarily by the behavior of the subducting oceanic plate or by the tectonics of the continental lithosphere at the plate margin. We are investigating this question through an integrated geologic, geochronological and geochemical study of the southern Coast Mountains Batholith in British Columbia. This project directly addresses a basic question in earth science: how do continents grow? In addition to the research goals of this project, this endeavor is enhancing the scientific education and training of students at four academic institutions recognized for the diversity of their student populations. Engagement of students in fieldwork, laboratory analysis, data interpretation and presentation of results are providing them with insights into all aspects of the science process and career options, and increase retention in STEM fields. Samples and datasets generated as a result of this project are being used to design problem sets and interpretive exercises for classes taught by the investigators. Data generated during this the course of this project is being added to NSF-funded databases, such as NAVDAT, for access by the larger community.

该项目将评估科迪勒拉型岩浆弧中大陆地壳非稳态生长的过程。这些岩基是由于海洋岩石圈在汇聚边缘俯冲而形成的，但控制岩浆产生速度的过程尚不清楚；即使在俯冲连续的弧中，岩浆作用也是强烈的偶发性（例如内华达山脉岩基、半岛山脉岩基、安第斯山脉中部）。短时期（10-1500 万年）的强烈岩浆活动或“爆发”可能会产生多达 90% 的岩岩总量，而在间歇期几乎不会发生岩浆活动。地球化学和同位素特征表明，爆发期间产生的岩浆比平静期间形成的岩浆包含更多的上层板块材料。这种模式提出了这样一个问题：岩浆添加引起的大陆生长是否主要受俯冲海洋板块的行为控制，还是受板块边缘大陆岩石圈的构造控制。 我们正在通过对不列颠哥伦比亚省南部海岸山脉基岩的综合地质学、年代学和地球化学研究来调查这个问题。该项目直接解决了地球科学中的一个基本问题：大陆如何生长？除了该项目的研究目标外，这项努力还加强了四个因其学生群体多样性而闻名的学术机构的学生的科学教育和培训。 学生参与实地考察、实验室分析、数据解释和结果呈现，可以让他们深入了解科学过程和职业选择的各个方面，并提高 STEM 领域的保留率。 该项目生成的样本和数据集用于为研究人员教授的课程设计问题集和解释练习。 该项目过程中生成的数据将被添加到 NSF 资助的数据库（例如 NAVDAT）中，以供更大的社区访问。