Large-scale Terrane Displacement in the Arctic: Evidence from Faults in the Northern Yukon

北极大规模地体位移：来自育空北部断层的证据

• 批准号: 1624130
• 负责人: William McClelland
• 金额: $ 17.32万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1624130&HistoricalAwards=false
• 关键词: Large; scale; Terrane; Displacement; Arctic

The shapes of the continents are modified over time by a variety of tectonic processes including large-scale horizontal transport of crustal fragments. This project explores the idea that this process was important in shaping the current configuration of the North American Arctic region. The research team will investigate a major fault system - the Kaltag-Porcupine fault system - in northern Yukon, Canada to determine if it accommodated horizontal movement of a large portion of the Arctic region and, if so, when this occurred. This research project will not only further our understanding of large-scale transport of crustal fragments along continent-scale strike-slip systems, but also provide new insights into the tectonic evolution of the poorly understood Arctic region of North America, a region important for its natural resources. The study will promote international collaboration between academic researchers at two U.S. institutions, two Canadian and German universities, and government research agencies in both Germany, Canada, and the United States. The collaborative international effort will also generate research opportunities and training for undergraduate and graduate students at both Dartmouth College and the University of Iowa, as well as a series of public lectures and a new museum exhibit in the Upper Valley of New England.Recent models for the Paleozoic tectonic evolution of the Arctic highlight significant, yet poorly understood, margin-parallel transport of crustal fragments relative to the North American craton; however, very little is known about the hypothetical structures that accommodated these displacements. The goal of this research project is to study the Kaltag-Porcupine fault system of Yukon, Canada, a craton-bounding structure that potentially accommodated the displacement of Arctic Alaska and other Arctic terranes across the northern margin of Laurentia. The fault system was probably reactivated during the Mesozoic and Tertiary, but may be a much older early Paleozoic structure. The research team aims to determine if the structure separates geologic units with different histories and paleogeographic origins and if there is any evidence for Paleozoic displacement on the structure. This project will involve: 1) development of a large, stratigraphically-constrained provenance data set, consisting of sandstone petrography, large-N detrital zircon U/Pb geochronology and hafnium isotopes, and major and trace element geochemistry and neodymium isotopes on mudstone, from previously collected and new samples of late Neoproterozoic-Silurian strata in the North Slope subterrane and Yukon block of northwestern Canada; and 2) a detailed structural and geochronological examination of the Kaltag-Porcupine fault system in northern Yukon, Canada. This multidisciplinary project will fundamentally inform tectonic models for the evolution of the Arctic and northwestern margin of North America.

随着时间的推移，大陆的形状因各种构造过程而改变，包括地壳碎片的大规模水平迁移。该项目探讨了这一过程在塑造北美北极地区当前格局方面的重要性。研究小组将调查加拿大北方育空地区的一个主要断层系统--Kaltag-Porcupine断层系统，以确定它是否适应北极地区大部分地区的水平运动，如果是的话，何时发生。这一研究项目不仅将进一步加深我们对地壳碎片沿着大陆尺度走滑系统的大规模搬运的理解，而且还将为了解北美北极地区的构造演化提供新的见解，北极地区是一个对其自然资源非常重要的地区。这项研究将促进美国两个机构、加拿大和德国两所大学的学术研究人员以及德国、加拿大和美国的政府研究机构之间的国际合作。这项国际合作努力还将为达特茅斯学院和爱荷华州大学的本科生和研究生提供研究机会和培训，以及一系列公开讲座和在新英格兰上谷的一个新博物馆展览。北极古生代构造演化的最新模型突出了重要的，但知之甚少的，地壳碎片相对于北美克拉通的边缘平行运输;然而，对容纳这些位移的假设结构知之甚少。本研究项目的目标是研究加拿大育空地区的Kaltag-Porcupine断层系统，这是一个有可能容纳北极阿拉斯加和其他北极豪猪穿过劳伦特北方边缘的位移的构造。断裂系统可能在中生代和第三纪期间被重新激活，但可能是一个更古老的早古生代构造。研究小组的目的是确定该结构是否将具有不同历史和古地理起源的地质单元分开，以及是否有任何证据表明该结构上有古生代位移。该项目将涉及：1）从加拿大西北部北坡次陆块和育空地区地块的新元古代-志留纪晚期地层中先前收集的和新的样品中，开发一个大型的、受地层学约束的物源数据集，包括砂岩岩石学、大氮碎屑锆石U/Pb年代学和铪同位素、泥岩上的主要和微量元素地球化学和钕同位素;对加拿大北方育空地区Kaltag-Porcupine断裂系进行了详细的构造和年代学研究。这个多学科项目将从根本上为北极和北美西北边缘的演变提供构造模型。