Collaborative Research: Displacement history of the Pearya terrane, Ellesmere Island - evaluating a strike-slip origin for the Canadian Arctic margin

合作研究：埃尔斯米尔岛 Pearya 地体的位移历史 - 评估加拿大北极边缘的走滑起源

• 批准号: 1650022
• 负责人: Jane Gilotti
• 金额: $ 27.34万
• 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: 2017
• 资助国家: 美国
• 起止时间: 2017-05-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1650022&HistoricalAwards=false
• 关键词: Collaborative; Research; Displacement; history; Pearya

This project is a structural, petrologic and geochronologic study of basement rocks that comprise the Pearya terrane of Ellesmere Island, which forms the northernmost landmass of North America. This tectonic terrane has geologic affinities with continental crust in Svalbard and Greenland. It is postulated that the Pearya terrane is the best example along the Canadian Arctic margin of a crustal fragment that has been displaced by plate tectonic processes. A proposed tectonic model for the origin of the Pearya terrane (the Paleozoic Northwest Passage model) postulates that many exotic or far-travelled geologic terranes that make up the northwestern Cordillera (e.g. Alaska) originated in the Caledonian orogenic belt shared by Greenland and Scandinavia, and subsequently traveled westward on a strike-slip fault to their current location about 400 million years ago. The lack of documentation on the timing and movement sense of the Pearya terrane severely limits understanding of the tectonic evolution of the Arctic margin of North America, leaving room for recent models that claim Pearya was stationary and was not the result of tectonic displacement. This project includes field observations and sample collection from remote southern boundary of the Pearya terrane that will be used to test these models. The project is part of the 2017 Circum-Arctic Structural Events Expedition organized by the German Federal Institute for Geosciences and Natural Resources, who will provide logistical support for the fieldwork. The project will involve international collaboration with scientists from five countries. In addition to the scientific contributions of the project, the study will contribute to training of graduate and undergraduate students in an important science, technology, engineering and mathematics (STEM) discipline, which is important in contributing to the enhanced compatibility of the U.S. workforce. The project will also contribute to broadening of underrepresented groups in STEM. Research results will be shared with the public through lectures and will be published in the peer reviewed scientific literatures and presentations at professional society meetings. Understanding the geological evolution of the North American Arctic margin is critical to informing important scientific, political and economic issues associated with the Arctic region. This award is cofunded by the NSF Office of International Science and Engineering.The ultimate goal of this project is to establish a stratigraphic, structural and metamorphic framework for the evolution of the complex southern boundary of the Pearya terrane. The study entails integrated kinematic, petrochronologic and argon-argon thermochronologic analysis of the crystalline basement and major faults at the southern Pearya terrane margin; and detailed stratigraphic comparison across the terrane boundary through sandstone petrography, detrital zircon uranium-lead and hafnium analysis, and major, trace element and neodymium isotope geochemistry on mudstone. Although the Canadian Arctic margin is often cited as an example of large magnitude terrane translation, little is known about the structures that may have accommodated such profound displacement. The project will evaluate possible strike-slip tectonics in light of structures associated with transpression, which may reconcile the earlier observations of straight contraction. The results of this study will provide critical timing on the age of metamorphism and the early ductile history of the shear zones in order to see through the pervasive overprinting. The principal investigators will also evaluate the stratigraphy of the overlap assemblage in different fault blocks to determine whether it is a single assemblage or, in fact, time correlatives of spatially separate depositional systems. By producing a robust data set tied to the geology, this project will help discriminate among the disparate models that currently exist for the Pearya terrane and the larger tectonic development of the Arctic.

该项目是对构成埃尔斯米尔岛皮尔亚地体的基底岩石进行结构、岩石学和地质年代学研究，埃尔斯米尔岛构成了北美最北端的陆地。该构造地体与斯瓦尔巴群岛和格陵兰岛的大陆地壳具有地质相似性。据推测，Pearya 地体是加拿大北极边缘因板块构造过程而移位的地壳碎片的最佳例子。 提出的皮尔雅地体起源构造模型（古生代西北通道模型）假设，构成西北科迪勒拉山脉（例如阿拉斯加）的许多奇异或遥远的地质地体起源于格陵兰岛和斯堪的纳维亚半岛共享的加里东造山带，随后沿着走滑断层向西移动到大约 4 亿年前的当前位置。 由于缺乏关于皮尔亚地体的时间和运动意义的文献，严重限制了对北美北极边缘构造演化的理解，这为最近声称皮尔亚是静止的、不是构造位移的结果的模型留下了空间。 该项目包括从 Pearya 地体偏远南部边界进行现场观察和样本采集，用于测试这些模型。 该项目是德国联邦地球科学和自然资源研究所组织的 2017 年环北极结构事件考察的一部分，该机构将为实地考察提供后勤支持。 该项目将涉及与来自五个国家的科学家的国际合作。除了该项目的科学贡献外，该研究还将有助于对研究生和本科生进行重要的科学、技术、工程和数学（STEM）学科的培训，这对于增强美国劳动力的兼容性非常重要。该项目还将有助于扩大 STEM 中代表性不足的群体。研究成果将通过讲座与公众分享，并将在同行评审的科学文献和专业协会会议的演讲中发表。了解北美北极边缘的地质演化对于了解与北极地区相关的重要科学、政治和经济问题至关重要。该奖项由美国国家科学基金会国际科学与工程办公室共同资助。该项目的最终目标是为皮尔亚地体复杂的南部边界的演化建立一个地层、结构和变质框架。 该研究需要对皮尔亚地体边缘南部的结晶基底和主要断层进行综合运动学、岩石年代学和氩-氩热年代学分析；通过砂岩岩相学、碎屑锆石铀-铅和铪分析以及泥岩的主量、微量元素和钕同位素地球化学，对地体边界进行详细的地层比较。 尽管加拿大北极边缘经常被引用为大规模地体平移的例子，但人们对可能容纳如此巨大位移的结构知之甚少。 该项目将根据与压扭相关的结构评估可能的走滑构造，这可能会与早期对直收缩的观察结果相一致。这项研究的结果将提供变质作用年龄和剪切带早期延性历史的关键时间，以便看清普遍的叠印现象。 主要研究人员还将评估不同断块中重叠组合的地层学，以确定它是否是单一组合，或者实际上是空间上分离的沉积系统的时间相关物。 通过生成与地质学相关的可靠数据集，该项目将有助于区分皮尔亚地体和北极更大的构造发育目前存在的不同模型。

项目成果

Zircon geochronology and geochemistry of the Ward Hunt pluton, Pearya terrane, Canadian High Arctic: Insights into its age, origin, and circum-Arctic Timanide connections

加拿大高北极地区皮尔亚地体沃德亨特岩体的锆石年代学和地球化学：深入了解其年龄、起源和环北极蒂马尼德联系

• DOI: 10.1007/s41063-020-00078-9
• 发表时间: 2020
• 期刊: Arktos
• 作者: Malone, S.J.;McClelland, W.C.
• 通讯作者: McClelland, W.C.

Neoproterozoic stratigraphy of the Southwestern Basement Province, Svalbard (Norway): Constraints on the Proterozoic-Paleozoic evolution of the North Atlantic-Arctic Caledonides

• DOI: 10.1016/j.precamres.2021.106138
• 发表时间: 2021-06
• 期刊: Precambrian Research
• 影响因子: 3.8
• 作者: V. T. Wala;G. Ziemniak;J. Majka;K. Faehnrich;W. McClelland;E. E. Meyer-E.;M. Manecki;J. Bazarnik;J. Strauss

P–T –t Path of Unusual Garnet–Kyanite–Staurolite–Amphibole Schists, Ellesmere Island, Canada—Quartz Inclusion in Garnet Barometry and Monazite Petrochronology

P – T – 异常石榴石之路 – 蓝晶石 – 十字石 – 角闪石片岩，加拿大埃尔斯米尔岛 – 石榴石气压计和独居石岩石年代学中的石英内含物

• DOI: 10.1093/petrology/egac068
• 发表时间: 2022
• 期刊: Journal of Petrology
• 影响因子: 3.9
• 作者: Kośmińska, Karolina;Gilotti, Jane A;McClelland, William C;Coble, Matthew A;Thomas, Jay B
• 通讯作者: Thomas, Jay B