Collaborative Research: Elucidating the Geologic Record of Late Paleozoic Subduction Initiation Along the Southwestern Margin of Laurentia, Southern California and Sonora, Mexico

合作研究：阐明南加州劳伦西亚和墨西哥索诺拉西南缘晚古生代俯冲起始的地质记录

• 批准号: 1322035
• 负责人: Nancy Riggs
• 金额: $ 11.41万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1322035&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; Geologic; Record

The principle aim of this project is to document the timing and response of the southwestern Laurentian margin to the initiation of subduction during late Paleozoic time. Although the recycling of lithosphere at subduction zones is a fundamental part of plate tectonic theory, the manner by which subduction zones initiate is a poorly constrained process, largely because there are few modern examples and ancient examples are largely not recognized or well preserved. Unique sequences of sedimentary and volcanic rocks exposed in southern California (El Paso Mountains region) and northern Mexico (Carborca Block) will be investigated in order to better understand how subduction inception is recorded in stratigraphic successions and how the paleogeography of continental margins evolves in response to the onset of plate convergence. We propose that continental margin successions recording subduction initiation will have predictable deepening and shallowing trends and distinct changes in sand composition and detrital zircon provenance through time reflecting the changing paleogeography of source regions. An additional geochemical and geochronologic investigation of volcanic sequences and coeval intrusions will be used to constrain the timing and petrogenesis of magmatic products, which we suggest will record conditions unique to cold, nascent continental arc settings. Results of this project may contribute significantly to global models of the birth and development of subduction zones. This project is a multi-disciplinary and collaborative effort between researchers at California State University - Northridge and Northern Arizona University, which are both minority-serving institutions. In addition to the science goals of the project, this research will provide training and mentorship for masters level and undergraduate students and promote the involvement of underrepresented groups in STEM research. Sample collections and study results will be used for the development of resources for teaching, community outreach, and further research.

该项目的主要目的是记录劳伦斯西南部边缘在晚古生代开始俯冲的时间和响应。尽管俯冲带岩石圈的再循环是板块构造理论的一个基本部分，但俯冲带启动的方式是一个缺乏约束的过程，这在很大程度上是因为现代例子很少，古代例子大多没有被认识到或保存得很好。将对加州南部(埃尔帕索山脉地区)和墨西哥北部(Carborca地块)出露的独特的沉积和火山岩序列进行调查，以便更好地了解俯冲开始是如何记录在地层序列中的，以及大陆边缘的古地理如何随着板块会聚的开始而演变。我们认为，记录俯冲开始的大陆边缘序列将具有可预测的加深和变浅趋势，砂岩成分和碎屑锆石来源随时间发生明显变化，反映了源区古地理的变化。对火山序列和同时代侵入体的额外地球化学和地质年代学调查将用于限制岩浆产品的时间和岩石成因，我们认为这将记录寒冷、新生的大陆弧环境所特有的条件。该项目的结果可能会对俯冲带的诞生和发展的全球模型做出重大贡献。这个项目是加州州立大学北岭分校和北亚利桑那大学的研究人员之间的多学科合作努力，这两所大学都是为少数族裔服务的机构。除了该项目的科学目标外，这项研究还将为硕士和本科生提供培训和指导，并促进未被充分代表的群体参与STEM研究。样本收集和研究结果将用于教学、社区推广和进一步研究的资源开发。