Collaborative Research: Origin of the Alexander Terrane in the Arctic Realm?

合作研究：北极地区亚历山大地体的起源？

• 批准号: 0948359
• 负责人: William McClelland
• 金额: $ 12.07万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0948359&HistoricalAwards=false
• 关键词: Collaborative; Research; Origin; Alexander; Terrane

This project will test the hypothesis that much of southern Alaska formed along the Arctic margin of Canada, with transport to its present position only in the relatively recent geologic past. Such a displacement history is counter to the more traditional view that these rocks, and most other portions of western North America (e.g., Baja California), have moved northward along the continental margin. It also differs from previous suggestions that these rocks formed along the western margin of the paleo-Pacific and are truly exotic to North America. Fortunately, recent technological developments have provided a technique that will provide a robust evaluation of these possible displacement scenarios. The technique involves the determination of ages of zircon crystals in the displaced rocks and in potential correlatives in the western US, along the western margin of the paleo-Pacific, and in the Canadian Arctic. The occurrence of similar ages would suggest potential linkages, whereas the occurrence of different ages of zircon crystals in rocks of the same age would be inconsistent with geographic proximity. This project will provide opportunities for undergraduate and graduate students at two universities to participate in a research project that involves both field studies in frontier regions and laboratory analyses utilizing sophisticated instrumentation. Primary activities involved in this project will include:1. Conducting geologic field studies and collecting samples from Paleozoic strata of the Alexander terrane in southeast Alaska and the Pearya terrane in the Canadian Arctic. These studies will be based from zodiacs and a live-aboard boat (presently operated by the University of Arizona) in SE Alaska and with helicopter support in the Canadian Arctic.2. Determining U-Pb ages and Hf isotope ratios of detrital zircons utilizing a new Laser Ablation-ICPMS system (Nu HR ICPMS) and SEM system (Hitachi 3400N and Gatan Chroma CL) at the University of Arizona.3. Comparison of our new data with U-Pb ages and Hf isotope information from other assemblages in the circum-Pacific and circum-Arctic realms in an effort to test various possible displacement models for the Alexander terrane. Much of the field and lab research will be conducted by graduate students at the University of Arizona and the University of Iowa. Undergraduate students will be involved as field assistants, with possible senior-thesis-type projects available as appropriate.

这个项目将检验这样一个假设，即阿拉斯加南部的大部分地区是沿着加拿大北极边缘形成的，只有在相对较近的地质历史中才会被输送到现在的位置。这样的位移历史与更传统的观点相反，即这些岩石和北美西部的大多数其他部分(例如下加利福尼亚州)沿着大陆边缘向北移动。这也不同于之前的说法，即这些岩石形成于古太平洋的西缘，对北美来说确实是奇特的。幸运的是，最近的技术发展提供了一种技术，将对这些可能的流离失所情况提供强有力的评估。这项技术涉及确定美国西部、古太平洋西缘和加拿大北极地区置换岩石和潜在相关性中的锆石晶体的年龄。相似年龄的出现将暗示潜在的联系，而相同年龄的岩石中不同年龄的锆石晶体的出现将与地理上的接近不一致。该项目将为两所大学的本科生和研究生提供参与研究项目的机会，该研究项目涉及前沿地区的实地考察和利用尖端仪器进行实验室分析。该项目涉及的主要活动包括：1.对阿拉斯加东南部的Alexander地体和加拿大北极的Pearya地体的古生代地层进行地质实地研究并采集样品。这些研究将基于阿拉斯加东南部的生肖和一艘生活船(目前由亚利桑那大学运营)，并在加拿大北极提供直升机支持。利用亚利桑那大学新的激光烧蚀ICPMS系统(Nu HR ICPMS)和扫描电子显微镜系统(日立3400N和Gatan Chroma CL)测定碎屑锆石的U-Pb年龄和Hf同位素比值。将我们的新数据与环太平洋和环北极地区其他组合的U-Pb年龄和Hf同位素信息进行比较，以努力检验亚历山大地体各种可能的位移模式。大部分实地和实验室研究将由亚利桑那大学和爱荷华大学的研究生进行。本科生将参与作为现场助理，可能的高级论文类型的项目可适当提供。