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克拉玛依西蚊子沟早侏罗世玄武岩的发现为解决新疆北部中生代岩浆活动问题提供了依据.该岩体由灰绿色玄武岩和深灰色橄榄玄武岩组成,具有高TiO2、FeO、P2O5,富K2O、Na2O的特点,属典型的大陆玄武岩;εNd(t)值为4.4～4.9.87Sr/86Sr初始比值为0.70541～0.70543,钕、锶同位素组成表明属幔源火山岩;稀土元素La/Yb变化于1.21～6.65,平均值为3.04,;微量元素丰度值比一般比玄武岩高3～20倍,橄榄玄武岩与玄武岩样品的稀土和微量元素特征有着较大差异,表明原始玄武岩浆发生过分异过程.40Ar/39Ar法测定获(192.7±1.3)Ma(2σ)坪年龄,表明火山岩的喷发形成时代为早侏罗世.准噶尔盆地西北缘早侏罗世早期的基性岩浆喷溢是准噶尔盆地由挤压向伸展转化的标志性地质事件,表明从古生代末期开始至中生代初期形成的大规模的向盆地推覆运动已结束,准噶尔西北缘由前陆盆地向陆内坳陷盆地转化,这对准噶尔盆地油气形成、运移和聚集有重要影响.
The discovery of the Early Jurassic basalts in the Karamay West mosquito ditch provided the basis for solving the Mesozoic magmatic activity in northern Xinjiang, which is composed of gray-green basalt and dark-gray olivine basalt with high contents of TiO2, FeO, P2O5, K2O and Na2O rich It is typical of continental basalts. The εNd (t) value is 4.4 ~ 4.9.87Sr / 86Sr and the initial ratio is 0.70541 ~ 0.70543. The neodymium and strontium isotope compositions are mantle-derived volcanic rocks. The REE changes from 1.21 to 6.65, The average value is 3.04, the abundance of trace elements is 3 ~ 20 times higher than that of basalt, and the characteristics of rare earth and trace elements in olivine basalt and basalt samples are quite different, which indicates that the original basalt magma is over-differentiated.40Ar / 39Ar method The (192.7 ± 1.3) Ma (2σ) plateau was measured to indicate that the volcanic eruption occurred in the Early Jurassic, and the Early Jurassic mafic magma spurt in the northwestern part of Junggar Basin was converted from compression to stretch in the Junggar Basin Indicating that the massive nappe movement to the basin formed from the end of Paleozoic to the early Mesozoic has ended. The northwestern margin of Junggar consists of foreland basin and intracontinental depression basin Of which the formation of oil and gas basin, migration and accumulation have a major impact.