阿尔金奇克山东斜长角闪岩岩石地球化学分析显示：岩石 SiO2和 Al2 O3含量较高，分别为46．99％～51．01％和13．85％～15．82％，MgO 和 FeOT 值为7．00％～7．71％和12．4％～13．5％，属拉斑系列岩石；主量元素 MgO 对 SiO2、Al2 O3、CaO、FeOT 关系图及微量元素 Cr-Rb 和 Rb／Nb-Rb／Zr 关系图，显示岩石演化过程中曾发生部分熔融和分离结晶作用；轻稀土元素微富集指示岩浆可能经历了10％～20％部分熔融和低程度分离结晶的演化。锆石 Lu-Hf 同位素特征表明原岩是由较球粒陨石稍分异的地幔岩浆形成，岩浆的液相线温度为1175～1251℃。微区定年揭示其岩石原岩年龄为718±22Ma，变质年龄为502±14Ma。综合分析认为岩石非新太古代产物，而是形成于新元古代 Rodinia 超大陆汇聚作用之后的伸展期，早古生代经历了阿尔金南缘峰期变质作用，表明此时阿尔金原古特提斯洋已经闭合。%The geochemical analysis of the amphibolite in the east of Qikeshan indicates it belongs to tholeiitic series with high SiO2 and Al2 O3 contents of 46.99%~51.01% and 13.85% ~15.82%,MgO and FeOT contents of 7.00%~7.71% and 12.4%~13.5%.Diagrams of MgO vs.SiO2 ,Al2 O3 ,CaO and FeOT,Cr vs.Rb and Rb/Nb vs.Rb/Zr exhibit that partial melting and fractional crystallization has occurred in the magma evolution.And the slightly enrichment of light rare earth element (LREE)implies the magma has experienced a 10% to 20% of partial melting and low fractional crystallization.Zircon Lu-Hf isotopic data reveal that the protolith was from the mantle-derived magma which was slightly differentiated from the chondrite,and the liquid temperature of the magma was 1175 ~1251℃.Microanalytical dating shows the protolith has an age of 718 ±22Ma with a metamorphic age of 502 ±14Ma.The new data and previous studies indicate that the protolith was not the product of the Neoarchean Era,but formed in the expansion period after the assembly of the Neoproterozoic Rodinia supercontinent, and experienced the peak metamorphism of early Paleozoic South Altyn,revealing that the original ancient Tethys was closed in 502 ±14 Ma.
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