冲绳海槽南部流纹岩中角闪石的化学特征及其对岩石成因的指示
发布时间：2018-08-30 09:18
【摘要】：为了揭示冲绳海槽西南端流纹岩成因,利用电子探针和LA-ICP-MS对该流纹岩中角闪石进行了主量和微量元素测定。所有角闪石主量元素成分变化范围小,晶体化学特征主要表现为:CaB1.60,CaA=0,(Na+K)A0.33,NaB介于0.23~0.39之间,均为钙质镁闪石。微量元素以富集Sc、V、Cr、Co、Ni和REE,亏损Rb、Sr、Ba、Zr、Th、U和Pb为特征,这些元素的富集与亏损与复杂的类质同象作用有关。由角闪石温压计得出其结晶时的温度范围为775~839℃,压力为0.12GPa,大致相当于4km的深度。角闪石的成因矿物学研究显示该流纹岩中角闪石为壳-幔混合成因,进一步表明冲绳海槽南部流纹岩由幔源玄武质岩浆与壳源长英质岩浆混合形成的中基性岩浆在浅层岩浆房中结晶分异而形成,且壳幔混合源很可能是冲绳海槽西南端火山岩岩浆的主要来源。
[Abstract]:In order to reveal the origin of rhyolite at the southwest end of Okinawa trough, the major and trace elements of amphibole in the rhyolite were determined by electron probe and LA-ICP-MS. The major element composition of all amphibole varies in a small range. The main crystal chemical characteristics of the amphibole are as follows: 1: CaB1.60 (CaA0) and (Na K) A0.33 (NaB) between 0.23 and 0.39, all of which are calcareous magnesite. The enrichment of trace elements is characterized by enrichment of Sc,V,Cr,Co,Ni and REE, depleted Rb,Sr,Ba,Zr,Th,U and Pb. The enrichment of these elements is related to the deficiency and complex isomorphism. The crystallization temperature range of amphibole temperature and pressure is 775 ~ 839 鈩，
本文编号：2212648
[Abstract]:In order to reveal the origin of rhyolite at the southwest end of Okinawa trough, the major and trace elements of amphibole in the rhyolite were determined by electron probe and LA-ICP-MS. The major element composition of all amphibole varies in a small range. The main crystal chemical characteristics of the amphibole are as follows: 1: CaB1.60 (CaA0) and (Na K) A0.33 (NaB) between 0.23 and 0.39, all of which are calcareous magnesite. The enrichment of trace elements is characterized by enrichment of Sc,V,Cr,Co,Ni and REE, depleted Rb,Sr,Ba,Zr,Th,U and Pb. The enrichment of these elements is related to the deficiency and complex isomorphism. The crystallization temperature range of amphibole temperature and pressure is 775 ~ 839 鈩，
本文编号：2212648
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