【摘要】：薩果花崗巖位于岡底斯西段中、南亞帶交界位置,主要巖石類型有二長花崗巖和花崗閃長斑巖,巖石總體上富Si,K,貧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%,屬過鋁質(zhì)巖石,稀土總量(ΣREE)變化范圍為256.1×10~(-6)~428.8×10~(-6),LREE/HREE10,輕稀土富集,δEu=0.77~0.85,弱的銪負(fù)異常。Rb、Th和K等大離子親石元素富集,而Ba、U和Ta等高場強元素虧損。巖石學(xué)特征表明巖石總體上具島弧花崗巖特征,僅少數(shù)巖石顯示碰撞花崗巖的特點,結(jié)合區(qū)域花崗巖漿演化和構(gòu)造環(huán)境等地質(zhì)背景,推斷薩果花崗巖體可能形成于俯沖向同碰撞的過渡環(huán)境。二長花崗巖的LA-ICP-MS鋯石U-Pb年齡為(88.6±1.5)Ma。薩果花崗巖是新特提斯洋向北俯沖的產(chǎn)物,表明印亞大陸碰撞起始時間晚于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 鹵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..
【作者單位】： 成都理工大學(xué);達(dá)州市安全生產(chǎn)監(jiān)督管理局;廣西壯族自治區(qū)遙感中心;四川省地礦局攀西地質(zhì)隊;
【基金】：西藏1，

本文編號：2446839