宋彪, 李锦轶, 张进, 朱志新, 王煜, 徐新. 西准噶尔托里地区塔尔根二长花岗岩锆石U-Pb年龄——托里断裂左行走滑运动开始的时间约束[J]. 地质通报, 2011, 30(1): 19-25.
    引用本文: 宋彪, 李锦轶, 张进, 朱志新, 王煜, 徐新. 西准噶尔托里地区塔尔根二长花岗岩锆石U-Pb年龄——托里断裂左行走滑运动开始的时间约束[J]. 地质通报, 2011, 30(1): 19-25.
    SONG Biao, LI Jin-yi, ZHANG Jin, ZHU Zhi-xin, WANG Yu, XU Xin. Zircon SHRIMP U-Pb age of Targen monzogranite in western Junggar, Xinjiang, China: Initial time of left-lateral slip of the Tuoli fault[J]. Geological Bulletin of China, 2011, 30(1): 19-25.
    Citation: SONG Biao, LI Jin-yi, ZHANG Jin, ZHU Zhi-xin, WANG Yu, XU Xin. Zircon SHRIMP U-Pb age of Targen monzogranite in western Junggar, Xinjiang, China: Initial time of left-lateral slip of the Tuoli fault[J]. Geological Bulletin of China, 2011, 30(1): 19-25.

    西准噶尔托里地区塔尔根二长花岗岩锆石U-Pb年龄——托里断裂左行走滑运动开始的时间约束

    Zircon SHRIMP U-Pb age of Targen monzogranite in western Junggar, Xinjiang, China: Initial time of left-lateral slip of the Tuoli fault

    • 摘要: 西准噶尔中部的托里断裂切错了塔尔根岩体,如果确定了该岩体的时代,就可以限定托里断裂左行走滑运动开始的最大时限。所研究的样品为浅肉红色二长花岗岩,采样位置位于托里县城以南、托里断裂南东,距离该断裂面约50m。用SHRIMP 对岩石中的锆石进行了U-Th-Pb同位素测定,共测得29个颗粒的31个数据。这31个数据中,206Pb/238U年龄最小值为279.5Ma±2.7Ma,最大值为337.3Ma±2.7Ma,相差达58Ma,差异大于17%。Th/U比为0.31~0.88,U含量为65×10-6~384×10-6,Th含量为23×10-6~142×10-6。根据CL图像,将其中13个点的206Pb/238U年龄进行加权平均计算,将加权平均值295.8Ma±2.5Ma作为岩体的侵位年龄。塔尔根岩体被托里断裂左行错开这一地质现象,以及该岩体的锆石定年结果,清楚地表明托里断裂的左行走滑运动一定是发生在295Ma以后,即其左行走滑运动不是发生在石炭纪期间。

       

      Abstract: The Targen monzogranite was sheared by the Tuoli fault in the middle of west Junggar and the maximum initial time of left-lateral slip of the Tuoli fault will be limited by the emplacement time of the monzogranite. The sample, light fleshred monzogranite, was collected at N45°45.911′, E83°32.584′, located at the south of the Tuoli City, 50 meter southeast to the fault plane. The U-Th-Pb isotope data of 29 grains, i.e. 31 spots, of zircons in the sample were obtained by using the SHRIMP Ⅱ in Beijing SHRIMP Center. In all of the data,the 206Pb/238U ages of the zircons are between (279.5±2.7)Ma~(337.3±2.7)Ma, with the Th/U ratios of 0.31~0.88, U contents of 65×10-6~384×10-6 and Th contents of 23×10-6~142×10-6. According to the observation of the very similar CL images of the zircons, the weighted average value of 206Pb/238U age of (295.8±2.5) Ma was obtained by the calculation using 13 among the 31 data, which is interpreted as the emplacement time of the Targen monzogranite. Based on the fact of left-lateral slip sheared and the emplacement time of the Targen monzogranite,it is clearly indicated that the initiation of left-lateral slip of the Tuoli fault took place after 295 Ma.

       

    /

    返回文章
    返回