河南箕山登封岩群变质中基性火山岩的地球化学及年代学研究  

Geochemistry and geochronology of metamorphic medium-basic volcanic rocks of Dengfeng Group in Jishan,Henan Province

作　　者：薛良伟[1] 原振雷[2] 赵太平[3] 陶自强[1] 

机构地区：[1]河南省国土资源科学研究院,河南郑州450053 [2]中国地质大学地球科学与资源学院,北京100083 [3]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地球化学》2005年第1期57-65,共9页Geochimica

基　　金：国家自然科学基金(40272041)~~

摘　　要：对登封岩群TTG杂岩区内的斜长角闪质表壳岩包体以及绿岩区的变质中基性火山岩对比研究表明,其主元素、微量元素、稀土元素和同位素地球化学特征等指示该区的变质中基性火山岩同时同源,具有由拉斑玄武岩向钙碱性玄武岩演变的趋势。登封岩群上下部2件Sm-Nd等时线年龄极为一致,可以合并为一条等时线,年龄为(2512±19)Ma,εNd(t)=2.40±0.16。综合分析认为,箕山地区的登封岩群稍晚于嵩山地区,是在新太古代末期一个非常短暂的时间内形成的,形成于类似现代岛弧的构造环境。The comparisons of major elements, trace elements, the rare earth el ements and the isotopic geochemical characteristics of amphibole supracrustal ro ck inclusions in TTG complex area of Dengfeng Group and metamorphic medium-basi c volcanic rocks in greenstone area have shown that both metamorphic medium-bas ic volcanic rocks and amphibole supracrustal rock inclusions are contemporaneous and isogenous, they have the evolutional trend of tholeiite to calc-alkaline b asalt. The two Sm-Nd isochron curves measured at upper and lower parts of Dengf eng Group are so consistent with each other that they can be considered as one i sochron curve. Their age dated is (2 512±19) Ma, 錘d(t)=2.40at the formation age of Dengfeng Group in Jishan are a was later than that in Songshan area. The former was seemingly formed in the s tructural environment of the contemporary arc in the very short period during th e end of Neoarchean.

关 键 词：地球化学 SM-ND年龄 构造环境 登封岩群 华北克拉通 

分 类 号：P594[天文地球—地球化学] P597[天文地球—地质学]