Collaborative Research: Using Well-dated Paleomagnetic Poles from the Kalahari and Congo Cratons to Constrain Rodinia Configurations and the Assembly of Central Gondwana

合作研究：利用来自卡拉哈里和刚果克拉通的年代清楚的古磁极来约束罗迪尼亚构造和中部冈瓦纳的组装

• 批准号: 0510690
• 负责人: Wulf Gose
• 金额: $ 7.85万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0510690&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; Well; dated

A collaborative team of U.S. and African scientists are acquiring well-constrained paleomagnetic poles from two of the major building blocks of the African continent, the Congo and Kalahari cratons in central and southern Africa (Namibia and Tanzania). Both study areas contain a variety of igneous rocks emplaced 850-700 million years ago, which is a critical time frame in Earth history. During this interval, the ancient supercontinent of Rodinia was beginning to break apart, setting the stage for subsequent rearrangement of continental land masses to form the younger Gondwana supercontinent. The team is carrying out paleomagnetic studies on an extensive suite of samples from selected rock units in the Kalahari and Congo cratons in order to constrain the original relative positions of the two cratons during breakup of Rodinia and prior to assembly of Gondwana. This work is coupled with a detailed program of isotopic dating, designed to produce rigorous constraints on the age of magnetization in the rocks and to determine whether the primary magnetization has been disturbed by subsequent thermal events. The Congo and Kalahari cratons formed the keystone of central Gondwana, which was assembled about 550 million years ago as different parts of the present-day southern continents collided. Acquisition of well-dated poles from both cratons will allow testing of competing models for Gondwana assembly: were the Congo and Kalahari cratons separated by a wide ocean basin before formation of Gondwana or were the two cratons already in roughly their present-day relative positions. The latter scenario would imply that the central part of Gondwana was inherited from the earlier Rodinia supercontinent, about which little is known. The project is collaborative in nature and involves workers at Texas Christian University, Massachusetts Institute of Technology, and the University of Texas at Austin in the US, and at the University of Cape Town in South Africa, the Geological Survey of Namibia, and the University of Dar es Salaam in Tanzania. Students from both the US and Africa are involved in the field and laboratory work.

一个美国和非洲科学家的合作团队正在从非洲大陆的两个主要建筑区，刚果和南部非洲（纳米比亚和坦桑尼亚）的刚果和卡拉哈里·克拉通（Congo和Kalahari Cratons）那里获取良好约束的古磁极。这两个研究区域都包含了850-7亿年前出现的各种火成岩，这是地球历史上的关键时间。在此间隔中，罗迪尼亚的古老超大陆开始崩溃，为随后重新排列大陆土地群体奠定了基础，形成了年轻的冈瓦纳超大陆。该团队正在对卡拉哈里和刚果克拉通的选定岩石单元的广泛样品套件进行古磁研究，以限制罗迪尼亚分裂期间和冈瓦纳（Gondwana）汇编之前的两个cratons的原始相对位置。这项工作与同位素约会的详细程序相结合，旨在对岩石中的磁化时代产生严格的限制，并确定是否因随后的热事件而干扰了主要的磁化。刚果和卡拉哈里的克拉通构成了冈瓦纳中部的基石，大约5.5亿年前，随着当今南部大陆的不同部分碰撞。从两个cratons中获取良好的杆子将允许测试冈瓦纳组件的竞争模型：刚果和卡拉哈里克拉一次是在形成冈瓦纳之前被宽阔的海盆隔开的刚果和卡拉哈里克拉一次，或者是已经大致是其当今相对位置的两个craton。后一种情况将暗示冈瓦纳的中央部分是从较早的Rodinia Supercontinent继承的，几乎没有人知道。该项目在自然界是合作的，涉及得克萨斯州基督教大学，马萨诸塞州理工学院和美国奥斯汀大学的工人，南非的开普敦，纳米比亚地质调查局以及坦桑尼亚的达尔斯萨拉姆大学。来自美国和非洲的学生都参与了现场和实验室工作。