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中元古代造山带，即纳马夸-纳塔尔-莫德带，记录了约 100 年前的高级变质作用和大陆与大陆碰撞。 1090 和 1060 Ma。南极洲东部的 Dronning Maud 陆地的主要部分是 1000 Ma 卡拉哈里板块的一部分。最近提出了两种截然不同的喀拉哈里重建方案。一种将卡拉哈里解释为劳伦大陆的压头，另一种将卡拉哈里解释为西澳大利亚沿线。在劳伦大陆东部（格伦维尔造山带）和澳大利亚西部，都发生了c。 1080 Ma 高篦岩石符合 1080 Ma 左右与喀拉哈里沙漠的大陆-大陆碰撞。 1080马。然而，无论是构造数据还是古地磁数据都无法明确确定卡拉哈里是否与其中之一发生碰撞。在西澳大利亚，只有一条非常狭窄的地带c。 1080 Ma 的古老岩石被保存下来，即平贾拉造山带，其中大部分可能被后来的裂谷所肢解。因此，如果卡拉哈里曾经附属于西澳大利亚，那么靠近 Dronning Maud 地任何新元古代缝合带的 Dronning Maud 地中元古代沉积岩应该表明典型的澳大利亚锆石年龄群体。因此，在该项目中，将对 Dronning Maud 地变沉积岩中的碎屑锆石进行测年，以测试卡拉哈里是否与劳伦西亚、西澳大利亚发生碰撞，或者两者都不发生碰撞。