| 南岭东段燕山期镁铁质岩石Nd-Sr同位素研究及意义 |
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| 引用本文：张树明,巫建华,周维勋.2004.南岭东段燕山期镁铁质岩石Nd-Sr同位素研究及意义[J].地球学报,25(2):248-254. |
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| 基金项目:核工业科学基金项目(编号:Y11218960401) |
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| 中文摘要:南岭东段燕山期镁铁质岩浆活动可划分为4个阶段(中侏罗世、晚侏罗世、早白垩世和晚白垩世)，分别对应4次重要的伸展拉张作用时期。镁铁质岩石具有基本类似的Nd—Sr同位素特征，ISr较高(一般介于0．705～0．710之间)，εNd值变化范围较大(介于-7．90～5．16之间)，表明其岩浆源为壳-幔混合源性质。镁铁质岩石具有板内拉斑玄武岩特征，系形成于板内拉张环境，表明该区在燕山早期的中侏罗世即已进入后造山演化阶段。岩石的成因模式为地幔镁铁质岩浆在上升至地壳底部过程中，受到地壳组分的混染，在岩石圈伸展的深部背景和浅部拉张状态下形成。 |
| 中文关键词:镁铁质岩石 Nd-Sr同位素 燕山期 南岭东段 |
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| Nd-Sr Isotopic Studies Of Yanshanian Mafic Rock in Eastern Nanling Region and Their Implications |
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| Abstract:The East Nanling′s Yanshanian mafic magma activity can be divided into four phase,namely Middle Jurassic,Late Jurassic,Early Cretaceous and Late Cretaceous,which are also four important episodes of extensional activities. The four phases mafic rocks have similar compositions,all characterised by high I _ Sr (commonly from 0.705 to 0.710) and wide variation range of ε_ Nd values ( from -7.90 to 5.16). This implies an origin of crust-mantle mixture.The mafic rock possess features of intraplate basalts,indicating that they are intraplate products and that in East Nanling region there existed a post-orogenic phase in the Middle Jurassic. The rock-forming model is as follows: When mafic magma rose to the crust bottom,it was contaminate by crustal materials,and rocks were formed in the setting of lithosphere extension and crustal extension. |
| keywords:Mafic rocks Nd-Sr isotopes Yanshanian East Nanling region |
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