Collaborative Research: Laurentian and Non-Laurentian (Baltican) Components of Terranes in NW Washington?

合作研究：华盛顿西北部地体的劳伦系和非劳伦系（波罗的海）成分？

• 批准号: 1242939
• 负责人: George Gehrels
• 金额: $ 6.3万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1242939&HistoricalAwards=false
• 关键词: Collaborative; Research; Laurentian; Non; Baltican

Growth of the ancient North American continent (Laurentia) along its western margin in Paleozoic times occurred by addition of materials of both local and exotic origins: a sedimentary apron derived from erosion of the western flank of the continent (the miogeocline), and also a complex of accreted terranes displaced by plate tectonics from other parts of the globe and faulted into the continent. Research of this study will examine the history of the accreted Chilliwack terrane in northwest Washington about which preliminary studies suggest that at least parts came from northwestern Europe. A primary tool in our work is acquisition of U-Th-Pb ages of zircon grains in igneous and sedimentary rocks. Preliminary data from igneous rocks in the Chilliwack terrane yield ages not known in western North America, but common in ancient Scandinavia (Baltica). In sedimentary rocks, age distributions of zircons are in some rocks similar to North America and in other rocks point to an exotic (European or other) homeland. Additional zircon ages will clarify these possible correlations. Further Hf isotopic data from zircons will be used to test possible derivation of parts of the Chilliwack terrane from a primitive oceanic island arc, specifically the early Paleozoic Alexander arc terrane accreted in southeast Alaska, as opposed to evolved continental crust (Laurentian or other). Field mapping of rock units will evaluate the genetic and structural relationship among parts of the Chilliwack terrane that have North American vs. exotic affinities. The fundamental goal of the project is basic knowledge of mechanisms of plate tectonics and processes of formation of an active continental margin.The research plan is designed to address the scientific issue described above, and also to enhance the education and training of students and elevate interest and understanding of earth history of the Pacific Northwest in the general public. Project funds will support undergraduate students as assistants in the field and laboratory, and pay for students to attend a professional meeting. Student research on the project will likely form the basis of senior theses. Knowledge gained from this study will be incorporated into course work in the classroom, on field trips, and off-campus Pacific Northwest field courses taught at Western Washington University. With respect to the broader community, and aside from technical publications and lectures, results of the proposed study will be integrated into and will enhance frequently occurring field trips for professional groups, such as the Geological Society of America, National Association of Geology Teachers, and Northwest Geological Society. The public lands of the San Juan Islands and Cascades are global tourist destinations, presenting opportunity for reaching a broad audience through geologic displays in parks and in popular geologic literature. The scale of continental margin tectonics on display in western Washington is fascinating at any level of knowledge.

古代北美大陆（Laurentia）在古生代时期的西部边缘的增长是通过添加了局部和异国源头的材料而发生的：一种源自大陆西侧（MioGeocline）的侵蚀（MioGeocline）的沉积围裙，也是由板块从其他部分中取代的Globe和Globe和Disected and Disceent and Protected tectected Terranes的复合体。 这项研究的研究将研究华盛顿西北部的奇利瓦克地座的历史，初步研究表明至少部分来自西北欧洲。 我们工作中的主要工具是在火成岩和沉积岩中获取U-Th-PB年龄。来自北美西部辣椒岩地层产量年龄的火成岩的初步数据，但在古代斯堪的纳维亚半岛（Balcota）中很常见。 在沉积岩石中，锆石的年龄分布在一些类似于北美的岩石中，而在其他岩石中则指向异国情调（欧洲或其他）家园。额外的锆石年龄将阐明这些可能的相关性。来自锆石的进一步的HF同位素数据将用于测试来自原始的海洋岛弧的奇利瓦克地座的可能推导，特别是阿拉斯加东南部的早期古生代亚历山大弧形地面，与Evolded Continental Crust（Laurentian或其他）相反。 岩石单元的现场图将评估具有北美和异国亲和力的辣椒地形部分之间的遗传和结构关系。该项目的基本目标是对板块构造机制的基本知识和积极的大陆边缘的形成过程。研究计划旨在解决上述科学问题，还旨在增强学生的教育和培训，提高对西北太平洋西北公众地球历史的兴趣和理解。项目资金将支持本科生作为现场和实验室的助手，并为学生付费参加专业会议。该项目的学生研究可能构成高级论文的基础。从这项研究中获得的知识将在课堂上，实地考察和西北校园外野外野外课程中纳入课程工作。关于更广泛的社区以及技术出版物和讲座，拟议的研究的结果将融入并将加强用于专业团体的经常发生的实地考察，例如美国地质学会，全国地质教师协会和西北地质学会。圣胡安群岛和喀斯喀特郡的公共土地是全球旅游胜地，为通过公园和流行地质文学中的地质展览提供了吸引广泛观众的机会。华盛顿西部展出的大陆边缘构造规模在任何知识水平上都令人着迷。