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

大陆的形状随着时间的推移被各种构造作用所改变，包括大规模的地壳碎片的水平运输。该项目探讨了这一过程在形成北美北极地区当前格局方面的重要作用。研究小组将调查加拿大育空地区北部的一个主要断层系统-卡尔塔格-豪猪断层系统，以确定它是否容纳了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加深我们对沿大陆规模的走滑系统的地壳碎片大规模运输的了解，而且还将为了解北美北极地区的构造演化提供新的见解，该地区对其自然资源非常重要。这项研究将促进两个美国机构、两个加拿大和德国大学的学术研究人员与德国、加拿大和美国政府研究机构之间的国际合作。合作的国际努力还将为达特茅斯学院和爱荷华大学的本科生和研究生提供研究机会和培训，并在新英格兰上谷举办一系列公开讲座和新的博物馆展览。最近的北极古生代构造演化模型突出了地壳碎片相对于北美克拉通的重要但鲜为人知的边缘平行运输；然而，人们对容纳这些位移的假设结构知之甚少。这项研究项目的目标是研究加拿大育空地区的卡尔塔格-豪猪断裂系统，这是一个以克拉通为边界的构造，可能会容纳北极阿拉斯加和其他北极地体在劳伦西亚北缘的位移。断裂系统可能在中生代和第三纪重新激活，但可能是一个更古老的早古生代构造。研究小组的目标是确定该构造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构造存在古生代位移。该项目将涉及：1)开发一个大型的、受地层约束的物源数据集，其中包括砂岩岩石学、大N碎屑锆石U/Pb年代学和Hf同位素，以及泥岩中的常量和微量元素地球化学以及泥岩上新元古代晚期-志留纪地层的新样品；2)对加拿大育空地区北部的卡尔塔格-波丘派斯断裂系统进行详细的结构和地质年代学研究。这一多学科项目将从根本上为北极和北美西北缘的演化提供构造模型。

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.