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.

喀拉哈里板块被中元古代造山带纳马卡-纳塔尔-毛德带包围，该造山带记录了约1090-1060 Ma之间的高级变质作用和陆-陆碰撞。东南极的Dronning Maud陆地的主要部分是1000 Ma的卡拉哈里板块的一部分。最近，人们提出了两种截然不同的卡拉哈里重建方案。一种解释是卡拉哈里缩进了劳伦蒂亚，另一种解释是卡拉哈里沿着西澳大利亚。在东劳伦蒂亚(格伦维尔造山带)和西澳大利亚州，1080 Ma左右高花岗岩的产出符合1080 Ma左右与卡拉哈里的陆-陆碰撞。然而，无论是构造数据还是古地磁数据都不能明确地确定卡拉哈里是与其中之一相撞的。在西澳大利亚州，只有大约1080 Ma的一条非常狭窄的古老岩石被保存下来，这就是平贾拉造山带，它的大部分可能被后来的裂谷所肢解。因此，如果卡拉哈里曾经依附于西澳大利亚，那么靠近任何新元古代缝合带的Dronning Maud陆地中的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，在这个项目中，将对Dronning Maud陆地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碰撞，或者两者都不碰撞。