Constraints for Kalaharis position in Rodinia as derived from detrital zircon studies in highgrade metasedimentary rocks from Dronning Maud Land, East Antartica

根据对东南极洲 Dronning Maud 地高品位变沉积岩的碎屑锆石研究得出的罗迪尼亚卡拉哈里位置的限制

• 批准号: 5407946
• 负责人: Professor Dr. Joachim Jacobs
• 金额: --
• 依托单位: Institutt for geovitenskap
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2006-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5407946?language=en
• 关键词: Constraints; Kalaharis; position; Rodinia; derived

The Kalahari plate is rimmed by a Mesoproterozoic orogenic belt, the Namaqua-Natal-Maud Belt, that documents high-grade metamorphism and continent-continent collision between c. 1090 and 1060 Ma. A major part of Dronning Maud Land in East Antarctica is part of the Kalahari plate at 1000 Ma. Two very different reconstructions for Kalahari have recently been proposed. One interprets Kalahari as an indenter into Laurentia, the other places Kalahari along Western Australia. Both, in eastern Laurentia (the Grenville Orogen) and in Western Australia, the occurrence of c. 1080 Ma high-grate rocks would conform with a continent-continent collision with Kalahari at c. 1080 Ma. However, neither structural nor paleomagnetic data unequivocally resolve whether Kalahari collided with one or the other. In Western Australia, only a very narrow strip of c. 1080 Ma old rocks is preserved, the Pinjarra Orogen, the major portion of which probably dismembered by later rifting. Thus, if Kalahari was ever attached to Western Australia, Mesoproterozoic sedimentary rocks in Dronning Maud Land close to any Neoproterozoic suture zone in Dronning Maud Land shoud indicate a typical Australian zircon age population. In this project therefore, detrital zirkons from metasedimentary rocks in Dronning Maud Land will be dated in order to test whether Kalahari collided with Laurentia, Western Australia or neither of these.

喀拉哈里板块的边缘是一条中元古代造山带，Namaqua-Natal-Maud带，记录了约1090 - 1060 Ma之间的高变质作用和大陆-大陆碰撞。东南极洲的Dronning Maud陆地的主要部分是1000 Ma时喀拉哈里板块的一部分。最近提出了两种截然不同的对喀拉哈里沙漠的重建。一种解释是卡拉哈里是劳伦西亚的一个凹痕，另一种解释是卡拉哈里沿着西澳大利亚。在劳伦西亚东部（格伦维尔造山带）和西澳大利亚，c. 1080 Ma高栅岩的出现与c. 1080 Ma与喀拉哈里的大陆-大陆碰撞一致。然而，无论是构造数据还是古地磁数据都不能明确地说明喀拉哈里是与其中一个碰撞还是与另一个碰撞。在西澳大利亚，只有一条非常狭窄的约1080万年历史的岩石被保存下来，这就是平加拉造山带，它的主要部分可能被后来的裂谷作用肢解了。因此，如果Kalahari曾经附属于西澳大利亚，那么靠近Dronning Maud Land的任何新元古代缝合带的Dronning Maud Land的中元古代沉积岩应该表明典型的澳大利亚锆石年龄群。因此，在这个项目中，将对Dronning Maud地的变质沉积岩中的碎屑锆石进行测年，以测试卡拉哈里是否与西澳大利亚的劳伦西亚发生了碰撞，或者两者都没有发生碰撞。