| 东秦岭陡岭群变质杂岩Sm-Nd、Rb-Sr、40Ar/39Ar、207Pb/206Pb年龄 |
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| 引用本文：沈洁,张宗清,刘敦一.1997.东秦岭陡岭群变质杂岩Sm-Nd、Rb-Sr、40Ar/39Ar、207Pb/206Pb年龄[J].地球学报,18(3):248-254. |
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| 基金项目:国家自然科学基金 |
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| 中文摘要:本文用单颗粒锆石逐级蒸发２０７Ｐｂ／２０６Ｐｂ、Ｓｍ Ｎｄ、Ｒｂ Ｓｒ、４０Ａｒ／３９Ａｒ年代学方法对东秦岭陡岭群变质杂岩的形成时代、变质时期和构造归属进行了研究。结果表明：陡岭群变质杂岩形成于早元古代，年龄为２０００Ｍａ左右，在其形成后遭受了多期变质作用。片麻岩Ｓｍ Ｎｄ等时年龄１８７８±２５６Ｍａ（εＮｄ（ｔ）＝＋２．８±２．６）代表了Ｓｍ Ｎｄ同位素系统重新发生均一化作用的时间。主期变质作用发生在８３３±１７Ｍａ（角闪石４０Ａｒ／３９Ａｒ高温坪年龄）；另一期变质作用发生于４２２±１６Ｍａ（片麻岩Ｒｂ Ｓｒ等时年龄）；此外，还有一期热事件，为３２３±８Ｍａ（角闪石４０Ａｒ／３９Ａｒ低温坪年龄）。陡岭群变质杂岩的同位素特征与华北陆块秦岭群相似，可能是秦岭群的一部分。 |
| 中文关键词:陡岭群 同位素年龄 秦岭 |
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| Sm Nd、Rb Sr、 40 Ar/ 39 Ar、 207 Pb/ 206 Pb Age of the Douling Metamorphic Complex from Eastern Qinling Orogenic Belt |
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| Abstract:The Douling metamorphic complex (the Douling Group) , situated in Eastern Qinlin gorogenic belt, the joint zone between the North China and the Yangtze plate, consists mainly of gneisses, Di leptites and amphibolites. The ages of the metamorphic rocks of the Douling Group have been measured by single zircon stepwise evaporation deposition for 207 Pb/ 206 Pbage investigations, Sm Nd, Rb Sr and 40 Ar/ 39 Ar methods. The isotopic data show that the Douling Group was formed in early Proterozoic (about 2 000 Ma). After its formation, the Douling Group was subjected to several strong metamorphism and thermal events. The Sm Nd isochron age (1 878±256 Ma, ε Nd (t) =+2.8±2.6) of the gneisses may represent the time of the first strong metamorphism. The main period of metamorphism occurred in Jinningian, 833 ±17 Ma ( 40 Ar/ 39 Ar high temperature plateau age of hornblende). The Rb Sr isochron age of the gneisses, 422±16 Ma, represent a metamorphism of Late Caledonian . In addition, there are a thermal event in Variscan, 323±8 Ma ( 40 Ar/ 39 Ar low temperature plateau age of the hornblende). The isotopic characteristic of the Douling Group is similar to that of the Qingling Group of the North China Plate and probably one part of the Qingling Group. |
| keywords:Douling Group isotopic data Qingling |
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