India-Antarctica-Australia-Laurentia connection in thePaleo-Mesoproterozoic revisited: Evidencefrom new zircon U-Pb SHRIMP and monazitechemical age data from the Eastern GhatsBelt
India-Antarctica-Australia-Laurentia connection in thePaleo-Mesoproterozoic revisited: Evidencefrom new zircon U-Pb SHRIMP and monazitechemical age data from the Eastern GhatsBelt
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重新审视古中元古代的印度-南极洲-澳大利亚-劳伦大陆联系：来自东高止山脉新锆石 U-Pb SHRIMP 和独居石化学年龄数据的证据
DOI：
10.1130/b30336.1
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M.
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文献类型：
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作者：
Bose;S.;Dunkley;D.J.;Dasgupta;S.,Das;K.;and Arima;M.
我们目前的锆石和独居石U-Pb数据从超高温（UHT）变质正片麻岩和副片麻岩收集的关键地区的东高止山脉带，印度。结果表明，对比构造历史在不同的同位素领域的东高止山脉带，确定了以前的工人。特别重要的是发现了一个案例。南部1A区1760 Ma事件（协和年龄），被解释为早期超高温变质事件的年龄。这是其次是第二麻粒岩相变质事件和部分熔融约。1600 Ma.这个区域大概在1600 Ma左右与印度合并。的记录。东高止山脉带1A区1760-1600 Ma的事件使我们能够推测古元古代-中元古代的跨大陆对比模型。超大陆哥伦比亚的增生造山过程包括澳大利亚、南极洲、劳伦蒂亚和印度的部分地区。另一方面，东高止山脉带的中部（同位素域2）含有锆石，显示出约1000年的继承年龄。1880-1700 Ma，年龄组一致，约为1000 Ma。1760年。在时间跨度上有中度到强烈的不一致。1600-1100 Ma的区域2被解释为混合年龄的一个ca. 1030-900 Ma的构造事件影响了这个领域。推测该区域的早期超高温变质事件发生在约1000年。1030-990 Ma（独居石颗粒的化学年龄）。锆石记录了该区域最普遍的构造事件。980-900 Ma，与东南极Rayner造山带相关，是Rodinia形成的一部分。
We present zircon and monazite U-Pb data from ultrahigh-temperature (UHT) metamorphosed orthogneisses and paragneisses collected from key areas of the Eastern Ghats Belt, India. The results show contrasting tectonothermal histories in different isotopic domains of the Eastern Ghats Belt that were identified by previous workers. Of particular importance is the discovery of a ca. 1760 Ma event (concordia age) in the southern domain 1A, which is interpreted to be the age of an early UHT metamorphism event. This was followed by a second granulite-facies metamorphism event and partial melting at ca. 1600 Ma. This domain was presumably cratonized with India at around 1600 Ma. The record of the ca. 1760–1600 Ma events in domain 1A of the Eastern Ghats Belt allows us to speculate on modeling the Paleoproterozoic–Mesoproterozoic transcontinental correlation. The accretionary orogenic processes in the supercontinent Columbia encompassed Australia, Antarctica, Laurentia, and parts of India.The central part of Eastern Ghats Belt (isotopic domain 2), on the other hand, contains zircons showing inherited ages of ca. 1880–1700 Ma, with a concordant age group of ca. 1760 Ma. Moderately to strongly discordant ages in the time span of ca. 1600–1100 Ma in domain 2 are interpreted to be mixing ages as a result of strong overprint of a ca. 1030–900 Ma tectonothermal event(s) that affected this domain. An early UHT metamorphism event in this domain is inferred to have occurred at ca. 1030–990 Ma (chemical dating of included monazite grains). Zircon records the most pervasive tectonothermal event in this domain at ca. 980–900 Ma, which is correlative with the Rayner orogeny in East Antarctica as a part of the formation of Rodinia.