安徽歙县蛇绿岩地球化学特征及形成构造环境  

Geochemical Characteristics and Tectonic Setting of Ophiolites in Shexian County,Anhui Province

作　　者：杨建明[1] 王希斌[2] 鲍佩声[2] 

机构地区：[1]衡阳工学院采矿工程系,衡阳421001 [2]中国地质科学院地质研究所

出　　处：《岩石矿物学杂志》1993年第3期232-242,共11页Acta Petrologica et Mineralogica

摘　　要：岩石化学、微量元素及稀土元素地球化研究表明:歙县蛇绿岩内地幔橄榄岩稀土元素配分为LREE富集型,不同于我国其他造山带地幔橄揽岩。歙县蛇绿岩壳层组合属于钙碱性和拉斑玄武岩间过渡系列,具类似的微量及稀土元素比值和稀土元素配分模型,且大离子亲石元素(LIL)和LREE高度富集。在Zr—Ti—Y和Hf—Ta—Th图解内,蛇绿岩基性熔岩成分点均落入钙碱性玄武岩区。结合岩石及区域地质资料,歙县蛇绿岩应形成于弧后(弧间)盆地环境。Studies on chemical composition and trace elements and REE geochemistryof mantle peridotite in opholites of Shexian County show that its chondrite-normalized patterns are of LREE--enriched type, quite different from mantleperidotite from other orogenic belts of China. The crustal sequence of Shexianophiolites belongs to the transitional series behaeen calc--alkaline basaltand tholeiite and all through has similar trace elements and REE ratios andchondrite--normalized REE patterns, with high enrichment of large--ion lithophileelements and LREE. In Zr--Ti--Y and Hf--Ta--Th diagrams, compositionalponits of basic lava of Shexian ophiolites all fall into the area of calc--alkalinebasalt. This, combined with petrological and regional geological data, has hed theauthors to believe that Shexian ophiolites were formed in a back--arc (interarc)basin environment.

关 键 词：蛇绿岩 稀土族 构造环境 地球化学 

分 类 号：P588.323[天文地球—岩石学]