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

该项目将评价导致大陆地壳在科迪勒拉型岩浆弧中非稳定状态增长的过程。这些岩基是由于大洋岩石圈在会聚边缘的俯冲作用而形成的，但控制岩浆生成克里思的过程尚不清楚;即使在俯冲作用连续的弧中，岩浆活动也是强烈的幕式的（例如，Sierra内华达州岩基、Peninsular Ranges岩基、Central安第斯山脉）。短时期（1000 - 1500万年）的强烈岩浆活动或“爆发”可能产生多达90%的岩基总量，在中间的平静期几乎没有发生岩浆活动。地球化学和同位素特征表明，在耀斑期间产生的岩浆比平静期间形成的岩浆含有更多的上层板块物质。这一模式提出了一个问题，即大陆的岩浆增长是否主要是由俯冲洋板块的行为或大陆岩石圈在板块边缘的构造控制。 我们正在通过对不列颠哥伦比亚省南部海岸山脉岩石的综合地质、年代学和地球化学研究来调查这个问题。这个项目直接解决了地球科学中的一个基本问题：大陆是如何生长的？除了该项目的研究目标外，这一奋进还加强了对四个学术机构学生的科学教育和培训，这四个学术机构因其学生群体的多样性而受到认可。 学生参与实地考察，实验室分析，数据解释和结果展示为他们提供了对科学过程和职业选择的各个方面的见解，并提高了STEM领域的保留率。 该项目产生的样本和数据集正被用于设计调查人员授课的问题集和解释练习。 在此项目过程中产生的数据正在被添加到NSF资助的数据库，如NAVDAT，供更大的社区访问。

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.