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塔吉里霞隆花岗闪长岩体位于冈底斯构造岩浆岩带西段,拉萨地块中西部。岩石w(SiO_2)=63.38%~72.56%;w(Al_2O_3)=13.85%~15.73%;Alk(K_2O+Na_2O)=5.12%~6.79%;w(K_2O)/w(Na_2O)=0.67~1.32;A/CNK=0.90~1.02,属Ⅰ型弱过铝质高钾钙碱性系列。稀土总量∑REE=128.34×10~(-6)~167.25×10~(-6),LREE/HREE=6.94~10.73,轻稀土富集重稀土亏损,配分曲线呈右倾型;δEu=0.69~0.86,弱负铕异常。岩石具有富集Rb、Th、K等大离子亲石元素,而亏损Ba、U、Nb、P等高场强元素的特征,岩石显示出岛弧火山岩亲缘性。锆石U@b定年结果表明,塔吉里霞隆岩体主要侵位于126.3±1.1Ma,属早白垩世晚期。塔吉里霞隆花岗闪长岩显示出壳幔混合源特征,班公湖-怒江洋壳岩石圈的南向俯冲和随后发生的板片回转可以较好的解释岩体成因。
Tarim jialian granodiorite body is located in the western section of the Gangdise tectonic magmatic belt, central and western Lhasa block. (K 2 O) / w (Na 2 O) = 0.67 ~ 1.32 for rock (SiO 2) = 63.38% ~ 72.56%; w Al 2 O 3 = 13.85% ~ 15.73%; Alk K 2 O + Na 2 O = A / CNK = 0.90 ~ 1.02, is a type of weak permanganate high potassium calcium alkaline series. LREE / HREE = 6.94 ~ 10.73, the REE depleted heavy rare earth, the distribution curve showed a right-inclined type; δEu = 0.69 ~ 0.86, weak negative Eu anomaly. The rocks are enriched with large ion lithophile elements such as Rb, Th and K and depleted in high field strength elements such as Ba, U, Nb and P. The rocks show the affinity of island arc volcanics. The results of zircon U b dating show that the major intrusions of the Tarijalian-Xiaolong granite are located at 126.3 ± 1.1Ma, belonging to the late Early Cretaceous. The Xiajili Xialong granodiorite shows the features of crust-mantle mixing source. The southward subduction of the Bangong-Nujiang oceanic lithosphere and subsequent plate rotation can well explain the genesis of the rock mass.