松辽盆地北部绥棱背斜带演化特征及对铀成矿的控制作用

Tectonic evolution of Suiling anticline belt in the northern Songliao Basin and its control effect on uranium mineralization

绥棱背斜带的形成主要受两个构造期次的影响,一次是白垩纪嫩江组沉积末期的构造运动,形成了背斜带的雏型;另一次是晚白垩明水组沉积晚期的构造运动,使背斜带发育完善成现今的构造形态。这两次构造运动使该背斜带具备了以下有利铀成矿条件,一是背斜顶部遭受剥蚀形成的构造天窗,有利于含铀含氧水渗入地下岩层;二是背斜带及其周边产生一些断裂破碎带,使烃类还原物质有了向上渗入的通道;三是沉积岩层发生了破碎,裂隙发育,增强了岩层的渗水性,提高了岩石的容矿能力;四是背斜带的翼部形成了补-径-排体系中的径流区,是铀成矿的有利部位。

The Suiling anticline belt is mainly formed by two tectonic periods. The first is the tectonic movement in the late depositional period of the Cretaceous Nenjiang Formation, forming the prototype of the anticline belt. The other is the late tectonic movement of the Late Cretaceous at the end stage of Mingshui Formation, which makes the development of the anticline belt into the present tectonic form. These two tectonic movements make the anticline belt possess the following favorable uranium metallogenic conditions： one is the structural skylight that is formed by the erosion of the top of the anticline, which is favorable for the infiltration of oxygen-bearing water containing uranium into the underground rock formation; Secondly, there axe some fractured fractures in the anticline belt and its periphery, which make the hydrocarbon-reducing substances penetrate upwards; Thirdly, the sedimentary rock layers axe broken and the fractures develop, which enhance the water seepage of the rock formation and improve the capacity of the rock; Fourthly, a runoff area that belongs to the recharge-runoff- discharge system is formed in the wings of the anticline, which is a favorable site for uranium mineralization.