| الوصف: |
冀东晚古生代东湾子岩体由角闪石岩、少量辉石岩和辉长岩组成。典型的堆晶结构、全岩和镁铁质矿物(透辉石、角闪石)的上凸型稀土分布模式、相容元素含量低且变化范围大(如:角闪石岩中V=296×10~(-6)～673×10~(-6))的特征表明了岩体的堆晶成因。计算得到的与辉石岩中的透辉石相平衡的熔体具有很高的稀土含量,轻重稀土分馏较为明显,富集大离子亲石元素(如:Sr,Ba,K),亏损高场强元素(如:Nb,Zr,Ti),具有典型的弧岩浆特征。透辉石和角闪石的矿物成分也具有弧岩浆的特征。高钙透辉石、大量的角闪石与黑云母的存在说明母岩浆富水。透辉石在高P_(H_2O)的状态下与熔体反应,生成角闪石的结构特. ; The Late Paleozoic Dongwanzi pluton is made up of hornblendite, pyroxenite and gabbro. Cumulate origin of these rocks is suggested by the cumulative textures, the convex-upward BEE patterns of whole rock and mafic minerals (diopside and hornblende), and the low and large variation of compatible elements such as V in hornblendites. Calculated BEE patterns of the parental magma in equilibrium with the pyroxenite show strong fractionation between LREE and HREE. The enrichment in LILE (e. g. Sr, Ba, K) and depletion in HFSE (e. g. Nb, Ta, Ti), along with the compositiong of diopside and hornblende, suggest their arc magmatic affinity. High Ca-diopside, magmatic hornblende and the reactions between diopside and melt to form amphibole all call be attributed to the high content of water in the parental magma. It seems that the parental magma with H(2)O content >3%, was originated from partial melting of a metasomatized mantle wedge which was dominated by amphibole-bearing spinel peridotite. The metasomatism by fluids released from the down-going Palco-Asian oceanic slab led to the formation of the enriched mantle. Based on these data, we believe that the Dongwanzi mafic pluton was formed as a consequence of subduction of the Paleo-Asian Ocean beneath the northern margin of the North China craton. ; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000269813000021&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; SCI(E) ; 中文核心期刊要目总览(PKU) ; 中国科技核心期刊(ISTIC) ; 中国科学引文数据库(CSCD) ; 7 ; 08 ; 1975-1988 ; 25 |