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.

技术摘要这项研究评估了东南极洲东部的小毛皮陆地地壳是否是构造示踪剂，它将卡拉哈里（Kalahari）和南部劳伦蒂亚（Southern Laurentia）连接起来，在造山学缝隙中，罗丹尼亚（Rodinia）的新元古代上陆地上的laurentia是一个构造示踪剂。一个泛非（约600 mA）缝合线将小外套的陆地与主要的Mawson Craton分开，这表明该地壳块具有独立的前木制前历史。现有的数据来自大衣土地上基岩露头的现有数据为该古地理学提供了关键的线索，这表明Laurentia与Grenville-Namaqua/Natal-Maud造型的Kalahari相撞。 涂层块只有三个小组的基岩暴露，两种形式的nunataks，第三个出现在悬崖脸上。这两个Nunataks包括Granophyre和Ca的流纹岩。 1.1 Ga Keweenawan，中大陆裂谷，Laurentia的火山及其在德克萨斯州埃尔帕索的西南延期。此外，大衣土地和Kewionawan岩石的PB同位素是相同的，古磁数据广泛支持了与Laurentian Craton南部边缘相邻的外套土地块。来自悬崖的岩石岩石面部暴露在岩性上类似于德克萨斯州埃尔帕索的地下岩石。拟议的研究将进一步对先前从外套土地以及德克萨斯州埃尔帕索附近收集的岩石的新样品收集的标本进行现有的地球化学研究，以详细比较。分析包括锆石U-PB约会和HF和O同位素分析，以及整个岩石地球化学以及PB，SM-ND和RB-SR同位素分析。这项研究将最大程度地利用南极这一极为偏远的部分的现有材料来检验这一假设。研究人员将在德克萨斯大学奥斯汀分校的杰克逊地球科学学院与两个良好的教育式课程合作。本科研究助理将从杰克逊学者计划（JSP）招募。研究人员将为JSP重建Rodinia的基于现场和实验室的研讨会，并将在Geoforce 12年级夏季学院期间与高中生进行研究。非技术摘要这项研究评估了东南极洲东部的小型外套陆地地壳块是否是北美祖先的一块（laurentia），在〜1 GA碰撞期间被转移到南部非洲（Kalahari），以及随后的分手，在远古岛上的两个大陆构成Rodinia的古代超级中心。大约600 mA大陆缝合线与邻近的南极洲的Mawson Craton分开，这表明大衣土地在600 MA之前具有独立的历史。来自大衣土地上基岩露头的现有数据为该古地理学提供了关键的线索，这表明Laurentia与Kalahari相撞。涂层块只有三个小组的基岩暴露，两种形式的nunataks，第三个出现在悬崖脸上。这两个Nunataks包括Granophyre和Ca的流纹岩。 1.1 Ga Keweenawan，中大陆裂谷，Laurentia的火山及其在德克萨斯州埃尔帕索的西南延期。此外，大衣土地和Kewionawan岩石的PB同位素是相同的，古磁数据广泛支持了与Laurentian Craton南部边缘相邻的外套土地块。来自悬崖的岩石岩石面部暴露在岩性上类似于德克萨斯州埃尔帕索的地下岩石。拟议的研究将进一步对先前从外套土地以及德克萨斯州埃尔帕索附近收集的岩石的新样品收集的标本进行现有的地球化学研究，以详细比较。分析包括锆石U-PB约会和HF和O同位素分析，以及整个岩石地球化学以及PB，SM-ND和RB-SR同位素分析。这项研究将最大程度地利用南极这一极为偏远的部分的现有材料来检验这一假设。研究人员将在德克萨斯大学奥斯汀分校的杰克逊地球科学学院与两个良好的教育式课程合作。本科研究助理将从杰克逊学者计划（JSP）招募。研究人员将向基于现场和实验室的JSP进行基于现场和实验室的研讨会，并将在Geoforce 12年级夏季学院期间与高中生进行研究。这项奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准来通过评估来支持的。