喀雅克登塔格地区两期基性岩墙的岩石化学特征及意义

Kayakedengtage Area Two Basic Dike Rocks Geochemistry and Significance

卡雅克登塔格地区发育2期基性岩墙(脉),分别为华力西期和燕山期,获得同位素年龄分别为380.3±1.5Ma(U-Pb)和176.2±3.5Ma(K-Ar)。反映了泥盆纪晚期(华力西期)和侏罗纪早期(燕山期)在研究区地壳曾发生过2期显著的陆内伸展构造运动。华力西期基性岩脉的侵入代表了陆内伸展由稳定转向活动,基性岩墙(脉)以北西向展布在晚泥盆纪以前的地质体中为特点;燕山期基性岩脉的侵入代表了陆内伸展由活动转向稳定拆沉,基性岩墙(脉)以近南北向或近东西向展布在侏罗纪及以前的地质体中为特点。

The two periods of basic dyke developed in Kyakedengtage area are Variscan Period and Yanshan Period, with isotopic age of 380.3±1. 5 Ma （U-Pb） and 176.2±3.5 Ma （K-At） respectively. As indicated, in late Devonian （Variscan） and early Jurassic （Yanshanian）, the studied area had two significant crusts of intracontinental extension tectonic movements. The basic dyke intrusion in Variscan Period represents that the intracontinental extension changes from stable to active, with a northwest distribution of basic dyke in the geological body before late Devonian; In contrast, the basic dyke intrusion in Yansanian Period represents that the movable intracontinental extension turns to stable delamination. The basic dyke runs nearly north-south or east-west in geological body before Jurassic Period.