%0 Journal Article
%T Geochemistry of the Nb-enriched basalt and its significances in Zaheba ophiolite melange<br>扎河坝蛇绿混杂岩内富铌玄武(安山)岩的地球化学特征及其地质意义
%A NIU HeCai
%A SHAN Qiang
%A YU XueYuan
%A ZHANG Bing
%A LUO Yong
%A YANG WuBin
%A <br>牛贺才
%A 单强
%A 于学元
%A 张兵
%A 罗勇
%A 杨武斌
%J 岩石学报
%D 2009
%I 
%X Nb-enriched basaltic rocks are identified within the Zaheba ophiolite melange in the eastern Junggar, northern Xinjiang. They show high Nb contents of 7.22×10-6 to 21.91×10-6, SiO2 contents of 46.71% to 57.65% and TiO2 contents of 1.00% to 1.76%, similar to Nb-enriched basalts from Archaean greenstone belt. The REE patterns are of LREE enrichment with weak Eu anomalies, suggesting obvious fractionation. Moreover, they are characterized by obviously negative Nb anomalies and negative Ti anomalies, suggesting that the Nb-enriched basalts were probably derived from partial melting of mantle peridotite that interacted with slab melt under high geothermal gradient in the intra-ocean arc setting of the Paleo-Asian Ocean. Moreover, Nb-enriched basalts occurred in the Zaheba ophilite as a fore-arc accretionary prism.The association of the Nb-enriched basalts with ultra-high pressure metamorphic rocks found previously by the authors implies that more than two times of the Paleo-Asian oceanic crust subduction with different characteristics were recorded in the ophiolite. Therefore, multiple partial melting of the subducting oceanic crust and ocean sediments, and the succedent interactions between the slab melt and peridotite in the mantle wedge was probably responsible for the crust growth and the formation of central Asian orogenic belts.
%K Nb-enriched basalt
%K Zaheba ophiolite melange
%K Oceanic crust subduction
%K Oceanic sediment<br>富铌玄武(安山)岩
%K 扎河坝蛇绿混杂岩体
%K 洋壳俯冲
%K 大洋沉积物
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=2013B5467E3054B1614CEC199353FCED&aid=926432D02485841CC2CC084860BA5500&yid=DE12191FBD62783C&vid=C5154311167311FE&iid=E158A972A605785F&sid=DE4E739E935BD9A7&eid=9C6D270E246D943F&journal_id=1000-0569&journal_name=岩石学报&referenced_num=0&reference_num=58