Collaborative Research: Comparative Studies of Circum-Arctic Neoproterozoic-Paleozoic Terranes

合作研究：环北极新元古代-古生代地体的比较研究

• 批准号: 1049368
• 负责人: William McClelland
• 金额: $ 19.52万
• 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: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1049368&HistoricalAwards=false
• 关键词: Collaborative; Research; Comparative; Studies; Circum

Current tectonic models for the Cretaceous opening of the Amerasia Basin are controversial due to our poor understanding of circum-Arctic geology. This uncertainty is derived from a lack of field-based observations and data from remote portions of the North American Arctic continental margins. A better understanding of circum-Arctic geology is also critical to testing hypotheses related to the origin and evolution of exotic crustal fragments now incorporated within the Cordilleran orogen of North America. Some of these "suspect" terranes have Paleozoic and Neoproterozoic basement that record completely different evolutionary histories in comparison to the western margin of Laurentia (western North America). The elusive origination of these crustal fragments has remained a longstanding question in the geological literature. In addition to a number of previously proposed models for the origin of these exotic terranes, it has recently been proposed that they were born in the Baltic and eastern Laurentian realm and subsequently migrated to western Laurentia as a result of their entrainment in a mid-Paleozoic Caribbean/Scotia-style subduction system that formed between northern North America and Siberia. Of these displaced terranes, Pearya (Northern Ellesmere Island) and Arctic Alaska are the closest to their putative homeland in the Baltic realm. We are currently integrating detailed stratigraphic, paleontological, geochemical, and geochronological studies on Neoproterozoic and early Paleozoic rocks from northern Ellesemere Island, Arctic Alaska, and the Yukon to provide tests for: 1) The recently proposed model for the Paleozoic northwest passage of exotic terranes from their formation in Baltica; 2) The SAYBIA-Rubia hypothesis, which posits that the southern half of Arctic Alaska formed a ribbon continent with other "suspect" terranes that was exotic to North America until accretion in the Cretaceous; and 3) A North American origin for Arctic Alaska. Ultimately, the characterization of the Neoproterozoic and Paleozoic geology in Pearya and Arctic Alaska will constrain models for the origins of exotic Cordilleran terranes and will provide the geological background for reconstructing the Cretaceous opening of the Amerasian Basin. The project is a collaborative effort between researchers at Harvard University and the University of Iowa. The Mineralogical and Geological Museum at the Harvard Natural History Museum (HNHM) hosts one of the premier meteorite and mineral collections in the United States. HNHM is visited annually by approximately 33,000 school children in groups, presenting a unique forum to introduce students to the Geosciences. An exhibit on the geology of the Arctic is currently being developed at the HNHM. The exhibit will include: 1) photographs from expeditions in the Alaska National Wildlife Reserve of the NW Brooks Range, Northern Ellesmere Island, and on Arctic Icebreakers; 2) rock samples from formations at each of these localities including the North Slope oil source and reservoir rocks; and 3) educational displays about the geological evolution of the Arctic. The HNHM will provide a kid friendly microscopes and a Microsoft touch-table that will enable students to interact with animations of Arctic plate tectonic reconstructions and zoom in on Arctic satellite and geological data. Beyond mineralogy, expanding the MGM?s educational displays to the integrative and exciting nature of modern Geosciences, particularly the geological evolution of the Arctic, has the potential to influence a portion of the 33,000 students who visit the HNHM to pursue studies in the Geosciences. The project is also contribute to the training of two Ph.D. students, one at Harvard and one at the University of Iowa, and is providing support for training of undergraduate students at both universities.

由于我们对北极地质学的不良理解，目前用于白垩纪开放的白垩纪开放的构造模型引起了争议。这种不确定性源于缺乏基于现场的观察结果和来自北美北极大陆边缘的偏远地区的数据。 更好地理解北极地质地质的理解也至关重要，这对于与现在纳入北美山脉造山带中的外来地壳碎片的起源和演变有关的假设至关重要。 这些“可疑”地形中的一些具有古生代和新元古代地下室，与劳伦蒂亚（Laurentia）（西部西部）相比，记录了完全不同的进化史。这些地壳碎片的难以捉摸的起源在地质文献中仍然是一个长期存在的问题。除了许多先前提出的有关这些异国情调式人境的起源模型外，最近有人提出，它们出生于波罗的海和东部劳伦特人领域，随后由于他们夹其中中部加勒比海/Scotia式的俯冲系统而迁移到西劳伦蒂亚，这是他们属于北部北部美国北部北部和西伯利亚之间的。在这些流离失所的地形中，皮亚（北埃尔斯米尔岛）和北极阿拉斯加是波罗的海领域中最接近其假定的家园。我们目前正在整合来自北埃莱瑟米尔岛，北极阿拉斯加北部埃莱瑟米尔岛和早期古生代岩石的详细地层，古生物学，地球化学和年代学研究，以及育空地区，以及育空地区，为以下测试提供了：1）最近提出的模型，用于古生代西北的古生代西北塔师的外来式塔里奇（Terric of Terric of tortic tortic）的形式， 2）Saybia-Rubia假设认为，阿拉斯加北极的南半半就与其他“嫌疑人”地面形成了丝带大陆，这对北美充满异国情调，直到白垩纪积聚。 3）北美阿拉斯加北美。最终，在Pearya和Arctic Alaska中，新元古代和古生代地质的表征将限制外来山脉底层的起源模型，并将提供地质背景，以重建阿米拉群岛盆地的白垩纪开口。该项目是哈佛大学研究人员与爱荷华大学研究人员之间的合作努力。哈佛大学自然历史博物馆（HNHM）的矿物学和地质博物馆是美国的主要陨石和矿产收藏之一。大约33,000名小学生每年访问HNHM，并提出一个独特的论坛，向学生介绍地球科学。 HNHM目前正在开发有关北极地质的展览。展览将包括：1）来自西北布鲁克斯山脉，北埃尔斯米尔岛的阿拉斯加国家野生动物保护区的探险照片以及北极破冰船； 2）来自这些地区的地层的岩石样品，包括北坡油源和水库岩石； 3）关于北极地质演变的教育展示。 HNHM将提供一个儿童友好的显微镜和Microsoft Touch-Table，这将使学生能够与北极板块构造重建的动画进行互动，并放大北极卫星和地质数据。除了矿物学外，将米高梅的教育展示扩大到现代地球科学的综合性和令人兴奋的性质，尤其是北极的地质进化，有可能影响访问HNHM的33,000名学生中的一部分，以从事地球科学进行研究。该项目还有助于培训两项博士学位。学生，一名在哈佛大学，在爱荷华大学，正在为两所大学的本科生培训提供支持。