伊犁盆地南缘洪海沟矿床富大矿体地质特征与成因机制研究

洪海沟矿床是近年来伊犁盆地南缘发现的大型铀矿床,既有砂岩型工业铀矿体也有煤岩型工业铀矿体。本文从洪海沟矿床地质特征研究入手,分析该地区铀成矿的主控因素,从构造和沉积的角度探讨其对氧化带发育和铀空间定位的约束。研究认为,构造斜坡带中次级隆起为成矿体提供流体的补给与氧化流体运移的动力,构造坡度的变异部位是成矿物质卸载的有利部位。主砂体是氧化流体运移的通道,制约并引导氧化流体的运移方向,砂体变异造成氧化带尖灭并控制着铀矿体的空间定位。氧化流体分带的多样性造成矿体类型和形态的多样,层间氧化带的平面分带性控制着砂岩型铀矿体的产出,氧化流体的垂向分带性控制煤岩型铀矿体的空间产出。

Geological Characteristics and Genetic Mechanism of the Honghaigou Uranium Deposit in the Southern Margin of Yili Basin

Honghaigou deposit is one of the large uranium deposits discovered in the southern margin of the Yili basin in recent years, which hosts not only sandstone type U bearing orebodies but also coal type uranium orebodies. In this paper, we firstly studied the geological characteristics of the Honghaigou deposit, analyzed main controlling factors and then discussed the constraint of structure and sedimentation on the oxidation zone development and uranium spatial orientation. The study suggests that secondary uplifting along structural slope provides driving force for recharge and migration of fluid, with change sites of the slope being favorable for unloading of ore forming minerals. The main sandbody is channel for migration of oxidation fluid, which restricts the direction of the migration of the oxidation fluid. The change of sandbody resulted in pitching out of oxidation zone and spatial distribution of uranium orebodies. The diversity of the oxidized fluid zonation resulted in the diversity of orebody types and morphology, with the planes of interlayer oxidation zone controlling the occurrence of sandstone type uranium orebodies and the vertical zonation of oxidized fluid controlling the spatial location of the coal type uranium orebodies.