伊犁盆地南缘某矿床构造与铀成矿关系

THE RELATIONSHIP BETWEEN THE STRUCTURE AND URANIUM MINERALIZATION IN THE NORTH OF IYLI BASIN

某矿床是伊犁盆地南缘地浸砂岩型铀矿田重要组成部分,矿床地质构造及成矿模式有别于铀矿田内其它矿床.通过构造单元划分,矿床定位于盆地南缘构造活动区.新构造运动以来,频繁的多期次构造活动造就褶皱、断裂发育.盆缘适度抬升为层间氧化带发育提供势能的同时,主控矿断裂产出部位及性质决定了地下水补径排体系、层间氧化带发育空间和铀矿化的赋存部位.据区域地质构造活动事件和断层泥石英碎砾微观特征分析划分出控矿断裂的6个活动期次与利用矿石U-Pb同位素年龄划分出的4个成矿期次在时间上具对应关系,构造运动的间歇期是铀主成矿期,多期次构造活动导致铀成矿具多期和多阶段性.

The deposit is an important part of sandstone type uranium deposits in the north of Iyli basin;the characteristics of geologic structure and the uranium mineralization model are different from other deposits. By dividing the construction units, these deposits can be located on the area of tectonic activity in the north of Iyli basin. Since the latest tectonic activity, the characteristics of the fold and fractures are developed, because of the frequent multiple periods of tectonic activity. The uplift in the edge of Iyli basin provided the potential energy to the development of interlayer oxidation zone, at the same time, the position and characteristics of the major fractures determined groundwater recharge-runoff-discharge system,the developed space of the interlayer oxidation zone and the position in which uranium ore developed.According to the event of the geologic structure and microcosmic shape of gouge quart pieces, we divide the major fractures into six periods, which were corresponded with four mineralization periods dividing by the age of the ore U-Pb isotope. The intermittent tectonic movement is the major mineralization time.The multiple periods of structure led to the multiple periods and multiple phases of uranium mineralization, then richen and finally formed to a deposit.