冈底斯西段萨果花岗岩地球化学和年代学特征及其地质意义
发布时间：2019-03-25 09:16
【摘要】：萨果花岗岩位于冈底斯西段中、南亚带交界位置,主要岩石类型有二长花岗岩和花岗闪长斑岩,岩石总体上富Si,K,贫Mg,Ca,w(Si O2)=64.84%~70.1%,w(K2O)/w(Na2O)=1.21~1.75,A/CNK=0.99~1.2,w(Al2O3)介于14.48%~15.52%,属过铝质岩石,稀土总量(ΣREE)变化范围为256.1×10~(-6)~428.8×10~(-6),LREE/HREE10,轻稀土富集,δEu=0.77~0.85,弱的铕负异常。Rb、Th和K等大离子亲石元素富集,而Ba、U和Ta等高场强元素亏损。岩石学特征表明岩石总体上具岛弧花岗岩特征,仅少数岩石显示碰撞花岗岩的特点,结合区域花岗岩浆演化和构造环境等地质背景,推断萨果花岗岩体可能形成于俯冲向同碰撞的过渡环境。二长花岗岩的LA-ICP-MS锆石U-Pb年龄为(88.6±1.5)Ma。萨果花岗岩是新特提斯洋向北俯冲的产物,表明印亚大陆碰撞起始时间晚于88.6 Ma。
[Abstract]:The Sago granite is located at the junction of the south Asian zone in the west part of Gangdise. The main rock types are monzogranite and granodiorite porphyry. The rocks are generally rich in Si,K, and poor Mg,Ca,w (Si O2) = 64.84% / 70.1%. W (K2O) / w (Na2O) = 1.211.75, ACNK = 0.991.2, w (Al2O3) = 14.48% / 15.52%, belongs to peraluminous rock, and 危 REE varies from 256.1 脳 10 ~ (- 6) to 428.8 脳 10 ~ (- 6), LREE/HREE10, The lithophile elements of large ions such as RB, Th and K are enriched, while the high field strength elements such as Ba,U and Ta are deficient in the enrichment of light rare earths and the negative anomaly of europium with weak 未 Eu=0.77~0.85,. The petrological characteristics show that the rocks have the characteristics of island arc granite in general, only a few rocks show the characteristics of collisional granite, combined with the geological background such as regional granitic magma evolution and tectonic environment. It is concluded that the Sago granitic body may be formed in the transitional environment of subduction to syncollision. The LA-ICP-MS zircon U-Pb age of monzogranite is (88.6 卤1. 5) Ma.. The Sago granite is a product of the northward subduction of the New Tethys Ocean, indicating that the Indo-Asian collision started later than 88.6 Ma..
【作者单位】： 成都理工大学;达州市安全生产监督管理局;广西壮族自治区遥感中心;四川省地矿局攀西地质队;
【基金】：西藏1，
本文编号：2446839
[Abstract]:The Sago granite is located at the junction of the south Asian zone in the west part of Gangdise. The main rock types are monzogranite and granodiorite porphyry. The rocks are generally rich in Si,K, and poor Mg,Ca,w (Si O2) = 64.84% / 70.1%. W (K2O) / w (Na2O) = 1.211.75, ACNK = 0.991.2, w (Al2O3) = 14.48% / 15.52%, belongs to peraluminous rock, and 危 REE varies from 256.1 脳 10 ~ (- 6) to 428.8 脳 10 ~ (- 6), LREE/HREE10, The lithophile elements of large ions such as RB, Th and K are enriched, while the high field strength elements such as Ba,U and Ta are deficient in the enrichment of light rare earths and the negative anomaly of europium with weak 未 Eu=0.77~0.85,. The petrological characteristics show that the rocks have the characteristics of island arc granite in general, only a few rocks show the characteristics of collisional granite, combined with the geological background such as regional granitic magma evolution and tectonic environment. It is concluded that the Sago granitic body may be formed in the transitional environment of subduction to syncollision. The LA-ICP-MS zircon U-Pb age of monzogranite is (88.6 卤1. 5) Ma.. The Sago granite is a product of the northward subduction of the New Tethys Ocean, indicating that the Indo-Asian collision started later than 88.6 Ma..
【作者单位】： 成都理工大学;达州市安全生产监督管理局;广西壮族自治区遥感中心;四川省地矿局攀西地质队;
【基金】：西藏1，
本文编号：2446839
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