阿尔金奇克山斜长角闪岩同位素年龄及其地球化学特征
发布时间：2019-08-14 15:14
【摘要】：阿尔金奇克山地区侵入于地层中的斜长角闪岩原岩为辉长岩,岩石地球化学组成显示斜长角闪岩的SiO_2和Al_2O_3含量较高为49.29%~51.03%和12.27%~14.49%,Na_2O+K_2O含量低为2.35%~4.37%,MgO和Mg~#值为6.48%~10.12%和48.7~59.6,具Eu负异常,样品的MgO对SiO_2、Al_2O_3、TiO_2及Cr-Rb和Rb/Nb-Rb/Zr关系图显示明显相关性,表明其为地幔岩浆经分异演化形成。岩石富集Rb、Th和U,亏损Nb、Sr和P,且Th/Ta为1.05~2.771,Nb/La为0.88~1.02,多小于1,显示岩石在演化过程中受到了地壳轻微混染,推断岩石形成于板内伸展环境。利用LA-ICP-MS微区原位定年获得斜长角闪岩~(206)Pb/~(238)U-~(207)Pb/~(235)U谐和年龄503±5 Ma和~(206)Pb/~(238)U加权平均年龄为479±6 Ma,该年龄段为阿尔金峰期变质阶段,指示岩石形成于479 Ma以前。
[Abstract]:The plagioclase protolith invaded into the strata in Aljinqikeshan area is gabbro. The geochemistry composition shows that the SiO_2 and Al_2O_3 contents of plagioclase hornblende are 49.29% 5.03% and 12.27% 14.49%, while the Na 2O K 2O content is 2.35% 4.37%, and the Eu and Mg~# values are 6.48% 10.12% and 48.7% 5.96, respectively. The MgO of the sample has negative anomalies of SiO_2, and the rock geochemistry composition shows that the plagioclase content of plagioclase hornblende is 49.29% 5.03% and 12.27% 14.49%, while that of Na 2O K 2O is 2.35% 4.37%. The relationship between Al_2O_3,TiO_2 and Cr-Rb and Rb/Nb-Rb/Zr shows obvious correlation, indicating that it is formed by differentiation and evolution of mantle magma. The rocks are enriched in Rb,Th and U, deficient in Nb,Sr and P, and Th/Ta is 1.05 鈮，
本文编号：2526641
[Abstract]:The plagioclase protolith invaded into the strata in Aljinqikeshan area is gabbro. The geochemistry composition shows that the SiO_2 and Al_2O_3 contents of plagioclase hornblende are 49.29% 5.03% and 12.27% 14.49%, while the Na 2O K 2O content is 2.35% 4.37%, and the Eu and Mg~# values are 6.48% 10.12% and 48.7% 5.96, respectively. The MgO of the sample has negative anomalies of SiO_2, and the rock geochemistry composition shows that the plagioclase content of plagioclase hornblende is 49.29% 5.03% and 12.27% 14.49%, while that of Na 2O K 2O is 2.35% 4.37%. The relationship between Al_2O_3,TiO_2 and Cr-Rb and Rb/Nb-Rb/Zr shows obvious correlation, indicating that it is formed by differentiation and evolution of mantle magma. The rocks are enriched in Rb,Th and U, deficient in Nb,Sr and P, and Th/Ta is 1.05 鈮，
本文编号：2526641
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