Antarctica within Rodinia: Testing the Laurentia Connection

罗迪尼亚境内的南极洲：测试劳伦西亚连接

• 批准号: 2332108
• 负责人: Staci Loewy
• 金额: $ 34.33万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2332108&HistoricalAwards=false
• 关键词: Antarctica; within; Rodinia; Testing; Laurentia

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.

技术摘要本研究评估了东南极洲的小科茨地地壳块是否是穿过造山缝合线连接罗迪尼亚新元古代超大陆内的喀拉哈里沙漠和南劳伦大陆的构造示踪剂。泛非（~600 Ma）缝合线将小科茨地块与主要的莫森克拉通分开，表明该地壳块具有独立的前泛非历史。来自科茨地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穿过格伦维尔-纳马夸/纳塔尔-莫德造山带发生碰撞。 Coats Land 区块只有三小组暴露的基岩，其中两处形成努纳塔克火山，第三处出现在悬崖面。这两个努纳塔克岛由与大约同时期的花岗岩和流纹岩组成。 1.1 Ga Keweenawan，中部大陆裂谷，劳伦西亚火山及其在德克萨斯州埃尔帕索的拟议西南延伸。此外，Coats Land 和 Keweenawan 岩石的 Pb 同位素是相同的，古地磁数据广泛支持 Coats Land 区块位于现今劳伦克拉通南缘附近。悬崖面暴露的变质岩在岩性上类似于德克萨斯州埃尔帕索的基底岩石。拟议的研究将进一步对先前从科茨地采集的样本以及在德克萨斯州埃尔帕索附近采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，以进行详细比较。分析包括锆石 U-Pb 定年和 Hf 和 O 同位素分析，以及全岩石地球化学和 Pb、Sm-Nd 和 Rb-Sr 同位素分析。这项研究将最大限度地利用来自南极洲这个极其偏远地区的现有材料来检验这一假设。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完善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）中招募。研究人员将为 JSP 提供有关重建罗迪尼亚的现场和实验室研讨会，并将在 GeoFORCE 12 年级暑期学院期间与高中生一起进行研究。非技术摘要这项研究评估了东南极洲的小科茨地地壳块是否是祖先北美（劳伦西亚）的一块，在约 1 Ga 碰撞期间转移到南部非洲（卡拉哈里），并随后发生了两个大陆的分裂。古代超级大陆罗迪尼亚的形成。科茨地与邻近的南极洲莫森克拉通被约 600 Ma 大陆缝合线隔开，这表明科茨地在 600 Ma 之前就有独立的历史。来自科茨地基岩微小露头的现有数据为古地理提供了重要线索，表明劳伦大陆与卡拉哈里大陆发生了碰撞。 Coats Land 区块只有三小组暴露的基岩，其中两处形成努纳塔克火山，第三处出现在悬崖面。这两个努纳塔克岛由与大约同时期的花岗岩和流纹岩组成。 1.1 Ga Keweenawan，中部大陆裂谷，劳伦西亚火山及其在德克萨斯州埃尔帕索的拟议西南延伸。此外，Coats Land 和 Keweenawan 岩石的 Pb 同位素是相同的，古地磁数据广泛支持 Coats Land 区块位于现今劳伦克拉通南缘附近。悬崖面暴露的变质岩在岩性上类似于德克萨斯州埃尔帕索的基底岩石。拟议的研究将进一步对先前从科茨地采集的样本以及在德克萨斯州埃尔帕索附近采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，以进行详细比较。分析包括锆石 U-Pb 定年和 Hf 和 O 同位素分析，以及全岩石地球化学和 Pb、Sm-Nd 和 Rb-Sr 同位素分析。这项研究将最大限度地利用来自南极洲这个极其偏远地区的现有材料来检验这一假设。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完善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）中招募。研究人员将为 JSP 提供有关重建罗迪尼亚的实地和实验室研讨会，并将在 GeoFORCE 12 年级暑期学院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评估进行评估，认为值得支持。智力价值和更广泛的影响审查标准。