Antarctica within Rodinia: Testing the Laurentia Connection

这项研究评估了南极东部的小型Coats陆地地块是否是新元古代超大陆Rodinia内跨越造山缝合线连接卡拉哈里和劳伦蒂亚南部的构造示踪剂。一条泛非(~600 Ma)缝合线将小Coats陆块与主要Mawson克拉通分开，表明该地壳块体具有独立的前泛非历史。科茨岛基岩微小露头的现有数据为这一古地理位置提供了关键线索，表明劳伦蒂亚与卡拉哈里在格伦维尔-纳马卡/纳塔尔-莫德造山带相撞。科茨地块只有三小组基岩出露，两组形成双峰，第三组发生在悬崖表面。这两个Nunatak由花岗岩和流纹岩组成，与约1.1Ga Keweenawan、中大陆裂谷、劳伦蒂斯火山及其拟议的位于德克萨斯州埃尔帕索的西南延伸形成。此外，Coats陆地和Keweenawan岩石的铅同位素是相同的，古地磁数据广泛支持Coats陆地地块位于现今劳伦斯克拉通南缘附近。来自悬崖面裸露的变质岩在岩石学上类似于德克萨斯州埃尔帕索的基岩。这项拟议的研究将进一步对以前从Coats Land收集的样本和德克萨斯州埃尔帕索附近收集的新的和现有的岩石样本进行现有的地球化学和地质年代学研究，以进行详细的比较。分析方法包括锆石U-Pb定年和Hf、O同位素分析，全岩地球化学和铅、Sm-ND、Rb-Sr同位素分析。这项研究将最大限度地利用南极洲这一极其偏远地区的现有材料来验证这一假设。研究人员将与德克萨斯大学奥斯汀分校杰克逊地球科学学院的两个成熟的教育推广项目合作。本科生研究助理将从杰克逊学者计划(JSP)中招聘。研究人员将提供一个基于现场和实验室的研讨会，为JSP重建Rodinia，并将在GeoFORCE 12年级暑期学院期间与高中生一起进行研究。这项研究评估了南极东部的小Coats陆地地壳块体是否是古老的北美(劳伦蒂亚)的一部分，在古代罗迪尼亚超大陆形成期间，两个大陆在~1Ga碰撞和随后的分裂过程中转移到了南部非洲(Kalahari)。科茨大陆与邻近的南极莫森克拉通之间有约600 Ma的大陆缝合，表明科茨大陆在600 Ma之前具有独立的历史。科茨岛基岩微小露头的现有数据为古地理提供了关键线索，表明劳伦蒂亚与卡拉哈里相撞。科茨地块只有三小组基岩出露，两组形成双峰，第三组发生在悬崖表面。这两个Nunatak由花岗岩和流纹岩组成，与约1.1Ga Keweenawan、中大陆裂谷、劳伦蒂斯火山及其拟议的位于德克萨斯州埃尔帕索的西南延伸形成。此外，Coats陆地和Keweenawan岩石的铅同位素是相同的，古地磁数据广泛支持Coats陆地地块位于现今劳伦斯克拉通南缘附近。来自悬崖面裸露的变质岩在岩石学上类似于德克萨斯州埃尔帕索的基岩。这项拟议的研究将进一步对以前从Coats Land收集的样本和德克萨斯州埃尔帕索附近收集的新的和现有的岩石样本进行现有的地球化学和地质年代学研究，以进行详细的比较。分析方法包括锆石U-Pb定年和Hf、O同位素分析，全岩地球化学和铅、Sm-ND、Rb-Sr同位素分析。这项研究将最大限度地利用南极洲这一极其偏远地区的现有材料来验证这一假设。研究人员将与德克萨斯大学奥斯汀分校杰克逊地球科学学院的两个成熟的教育推广项目合作。本科生研究助理将从杰克逊学者计划(JSP)中招聘。研究人员将提供一个基于现场和实验室的研讨会，为JSP重建Rodinia，并将在GeoFORCE 12年级暑期课程期间与高中生一起进行研究。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Technical AbstractThis research evaluates whether the small Coats Land crustal block of East Antarctica is a tectonic tracer linking Kalahari and southern Laurentia within the Neoproterozoic supercontinent of Rodinia across an orogenic suture. A Pan-African (~600 Ma) suture separates the small Coats Land block from the main Mawson Craton indicating that this crustal block had an independent pre-Pan-African history. Existing data from the miniscule outcrops of bedrock in Coats Land provide critical clues to that paleogeography, suggesting that Laurentia collided with Kalahari across the Grenville-Namaqua/Natal-Maud orogen. The Coats Land block has only three small groups of bedrock exposures, two form nunataks and the third occurs in a cliff face. The two nunataks comprise granophyre and rhyolite contemporaneous with the ca. 1.1 Ga Keweenawan, mid-continent rift, volcanics of Laurentia and its proposed southwestern extension in El Paso, TX. Moreover, the Pb isotopes of the Coats Land and Keweenawan rocks are identical, and paleomagnetic data are broadly supportive of the Coats Land block having been located adjacent to the present southern margin of the Laurentian craton. Metamorphic rocks from the cliff face exposure lithologically resemble basement rocks of the El Paso, TX. The proposed research will further existing geochemical and geochronologic studies of specimens previously collected from Coats Land and new and existing samples of rocks collected near El Paso, Texas for detailed comparison. Analyses include zircon U-Pb dating and Hf and O isotope analysis, and whole rock geochemistry and Pb, Sm-Nd and Rb-Sr isotope analysis. This research will make maximum use of existing material from this extremely remote part of Antarctica to test this hypothesis. Researchers will collaborate with 2 well-established education-outreach programs in the Jackson School of Geosciences at The University of Texas at Austin. Undergraduate research assistants will be recruited from the Jackson Scholars Program (JSP). Researchers will provide a field- and lab-based seminar on reconstructing Rodinia for the JSP and will conduct research with high school students during GeoFORCE 12th grade summer academy. Non-technical AbstractThis research evaluates whether the small Coats Land crustal block of East Antarctica is a piece of ancestral North America (Laurentia) that was transferred to southern Africa (Kalahari) during ~ 1 Ga collision, and subsequent breakup, of the two continents during the formation of the ancient supercontinent of Rodinia. Coats Land is separated from the adjacent Mawson Craton of Antarctica by ~600 Ma continental sutures indicating that Coats Land had an independent history prior to 600 Ma. Existing data from the miniscule outcrops of bedrock in Coats Land provide critical clues to that paleogeography, suggesting that Laurentia collided with Kalahari. The Coats Land block has only three small groups of bedrock exposures, two form nunataks and the third occurs in a cliff face. The two nunataks comprise granophyre and rhyolite contemporaneous with the ca. 1.1 Ga Keweenawan, mid-continent rift, volcanics of Laurentia and its proposed southwestern extension in El Paso, TX. Moreover, the Pb isotopes of the Coats Land and Keweenawan rocks are identical, and paleomagnetic data are broadly supportive of the Coats Land block having been located adjacent to the present southern margin of the Laurentian craton. Metamorphic rocks from the cliff face exposure lithologically resemble basement rocks of the El Paso, TX. The proposed research will further existing geochemical and geochronologic studies of specimens previously collected from Coats Land and new and existing samples of rocks collected near El Paso, Texas for detailed comparison. Analyses include zircon U-Pb dating and Hf and O isotope analysis, and whole rock geochemistry and Pb, Sm-Nd and Rb-Sr isotope analysis. This research will make maximum use of existing material from this extremely remote part of Antarctica to test this hypothesis. Researchers will collaborate with 2 well-established education-outreach programs in the Jackson School of Geosciences at The University of Texas at Austin. Undergraduate research assistants will be recruited from the Jackson Scholars Program (JSP). Researchers will provide a field- and lab-based seminar on reconstructing Rodinia for the JSP and will conduct research with high school students during GeoFORCE 12th grade summer academy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.