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在印度三个时代不同的地洼区中,出现重要的赋存于沉积岩中的铀矿化作用。这些地洼区是:a)印度南部的元古代库达帕洼地;b)印度东北部梅加拉亚的白垩纪Madadek盆地;c)印度北部的晚第三纪喜马拉雅前渊。库达帕洼地呈新月形,沿南印度克拉通东缘沉积,紧邻东加茨活动带,面积达44,500km~2。该洼地由数个上升、下落断块组成。在这些断块内,浅水砂质(库达帕亚组)和钙质(库尔努尔组)沉积物厚度超过12km,同时从2,000—600Ma,至少有四期粒玄岩墙侵入。铀矿化作用主要呈沥青铀矿(含硫化物)和次生铀矿物形式,沿库达帕洼地面南缘出现于磷质碳酸盐岩和共生物的帕帕格尼组砂质岩、砾岩中。如Tummalapalli、Ammasripall,在梅加拉亚,约200米厚的河流相、海相砂质、泥质沉积物分布于1.5km高的西隆高原南缘的Mahadek盆地。该盆地的铀矿化限于河流相、边缘海相早白垩世“石英粗砂碎屑岩/亚长石砂岩”型Mehadek砾岩中,如Comasahat,Pdensashakap、Domiasiat,并呈沥青铀矿、水硅铀矿、钛钠矿形式。这些矿物与还原剂(如碳、生物成因黄铁矿)紧密共生。在喜马拉雅前渊,铀矿化赋存于河流相锡瓦利克砂岩中,并主要产于锡瓦利克砂岩的下-中或中-上接触面上,如Thein、Morni、Hamirpur,Naugajiarao等地。矿化主要呈沥青铀矿、水硅铀矿(与硫化物共生)和大量次生铀矿物形式——这主要是由于持续至现在的反复的活化作用和沉淀作用。这三个地洼区铀成矿作用的共同特点是河流相沉积物围岩(主要为砂岩,并来源于丰富的酸性源区)、远成热液成矿作用和原始成矿作用时的强烈还原环境。这特征可作为在地洼区寻找赋存于沉积岩中的铀矿化的标志。
In the three different Indian depression areas, important uranium mineralization occurred in sedimentary rocks. These depressions are: a) the Proterozoic Kudapa depression in southern India; b) the Cretaceous Madadek Basin in Meghalaya in northeastern India; and c) the late Tertiary Himalayan foreland in northern India. The cudapar depression was crescent-shaped and deposited along the eastern edge of the southern Indian craton, with an area of 44,500 km2, close to the Donatz zone. The depression consists of several rising and falling blocks. Within these blocks, the sediments of the shallow water sandy kudapa group and the calcareous krunur group exceed 12 km in thickness and invade at least four episodic dykes from 2,000-600 Ma. Uranium mineralization is mainly in the form of bitumen uranium (including sulfide) and secondary uranium minerals, occurring along the Pagagni group sandstones of phosphoric carbonate and symbiotic along the southern margin of the Kudaapa surface, Conglomerate. Such as Tummalapalli, Ammasripall, about 200 meters thick in the Meghalaya. Marine sandy and muddy sediments are distributed in the Mahadek basin on the southern margin of the 1.5-km high Shillong Plateau. The basin’s uranium mineralization is limited to the river facies, marginal marine Early Cretaceous “quartz coarse sand clastic / metamorphic sandstone” Mehadek conglomerate, such as Comasahat, Pdensashakap, Domiasiat, and asphaltic uranium ore, water silicon Uranium, titanium and titanium ore form. These minerals coexist closely with reducing agents such as carbon and biogenic pyrite. In the Himalayan foreland, uranium mineralization occurs in fluvial-phase Sivalik sandstones and mainly occurs on the lower-middle or mid-upper contact surfaces of the Sivalik sandstones such as Thein, Morni, Hamirpur and Naugajiarao. The mineralization is mainly in the form of bitumen uranium, hydrous silicon uranium (symbiotic with sulphide) and a large number of secondary uranium mineral forms - mainly due to repeated activation and sedimentation up to now. The common features of uranium mineralization in these three depression areas are that the fluvial facies sedimentary rocks (mainly sandstones, which are derived from rich acid source areas), the strong hydrothermal mineralization and intense mineralization Restore the environment. This feature can be used as a marker for finding uranium mineralization in sedimentary rocks in Diwa area.