Collaborative Research: Testing Precambrian Siberia-Laurentia Geologic Connections with U-Pb Geochronology

合作研究：用 U-Pb 地质年代学检验前寒武纪西伯利亚-劳伦西亚地质联系

• 批准号: 0310186
• 负责人: James Sears
• 金额: $ 11.61万
• 依托单位: University of Montana
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0310186&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Precambrian; Siberia

Abstract Reconstruction of a Siberia-west Laurentia craton, in accordance with paleomagnetic data, basement piercing points, and the best fit of the rift margins, aligns Proterozoic dike/sill swarms and juxtaposes Proterozoic basins. In this collaborative Russian-American project, the PI's test the restoration by examining the crystallization ages of igneous rocks and the stratigraphy and detrital zircon systematics of sedimentary rocks that are truncated at the west Laurentian and east Siberian cratonic margins. Specifically, they plan the following tests. 1) U-Pb dating of a dike-sill swarm that may link the Anabar massif of north Siberia with the Belt-Purcell basin and adjacent basement of southwest Montana and Wyoming.2) U-Pb dating of detrital zircons from clastic rocks of northern Siberia that may link to the well-dated Belt-Purcell Supergroup.3) U-Pb dating of sill swarms and flows in the middle Uy Group of southeast Siberian and Kingston Peak Formation of Death Valley that may have formed one large igneous province.4) U-Pb dating of detrital zircons from clastic rocks in the Uy and Yudoma groups of southeast Siberian and potentially correlative Kingston Peak Formation and Noonday Dolomite of Death Valley that may have comprised parts of one basin. Requested funds will cover reciprocal geological excursions to Death Valley and southeast Siberia, to be followed by U-Pb geochronological lab work. The PI's will also date samples previously collected by Russian geologists. The project will have significant geological impact should it conclusively demonstrate the validity of the Siberia-Laurentia restoration because this is a critical component of the broader Rodinia supercontinent hypothesis, and has implications for several geologic and geodynamic problems, including global ice ages, true-polar wander, formation of Gondwana, and the Cambrian metazoan revolution. Should the results prove negative, the study will remove one potential interpretation for Rodinia, and will also provide valuable new constraints for Siberian and Laurentian Proterozoic geological evolution. Broader impacts include the advanced training of geoscience students supported by the grant, the promotion of peace and advancement of science through international scientific collaboration, and support of the Russian scientific infrastructure.

根据古地磁数据、基底穿透点和裂谷边缘的最佳拟合，重建西伯利亚-西劳伦西亚克拉通，对齐元古代岩墙/岩床群，并置元古代盆地。在这个俄美合作项目中，PI通过检查火成岩的结晶年龄和沉积岩的地层学和碎屑锆石系统学来测试恢复，这些沉积岩在西劳伦特和东西伯利亚的西西伯利亚边缘被截断。具体而言，他们计划进行以下测试。1)对可能连接北西伯利亚Anabar盆地与Belt-Purcell盆地以及蒙大拿州西南部和怀俄明州相邻基底的岩墙-岩床群进行了U-Pb定年。2）对可能连接年代较好的Belt-Purcell超群的北方西伯利亚碎屑岩中的碎屑锆石进行了U-Pb定年。3）对可能连接北西伯利亚Anabar盆地与Belt-Purcell盆地以及蒙大拿州西南部和怀俄明州相邻基底的岩墙-岩床群进行了U-Pb定年对西伯利亚东南部Uy群中段和死亡谷的金斯顿峰组的岩床群和岩床流进行了Pb测年，它们可能形成了一个大的火成岩省。西伯利亚东南部Uy群和Yu群碎屑岩中碎屑锆石的Pb测年，以及可能与之相关的金斯顿峰组和死亡谷的正午白云岩，它们可能构成一个盆地的一部分。申请的资金将用于死亡谷和西伯利亚东南部的地质考察，随后将进行U-Pb年代学实验室工作。PI还将确定俄罗斯地质学家以前收集的样本的日期。该项目将产生重大的地质影响，如果它最终证明西伯利亚-劳伦提斯恢复的有效性，因为这是更广泛的罗迪尼亚超大陆假说的关键组成部分，并对几个地质和地球动力学问题，包括全球冰河时代，真正的极地漂移，冈瓦纳的形成，和寒武纪后生动物革命的影响。如果结果被证明是否定的，这项研究将消除Rodinia的一个潜在解释，也将为西伯利亚和劳伦特元古代地质演化提供有价值的新约束。更广泛的影响包括赠款支持的地球科学学生的高级培训，通过国际科学合作促进和平与科学进步，以及支持俄罗斯科学基础设施。