白岗岩型铀矿床:构造和岩浆作用耦合的产物

以罗辛矿床为代表的白岗岩型铀矿是纳米比亚主要的铀矿床类型。白岗岩型铀矿集中产出在元古界达玛拉造山带中,含矿白岗岩是造山期后岩浆作用的产物。白岗岩易于侵入Nosib群罗辛组和可汗组地层中,但对地层没有绝对选择性,在整个Nosib群中都有发现矿化的可能。根据野外特征可将白岗岩分为6种,其中D型、E型是主要的含矿白岗岩,白岗岩具有成矿专属性。区域千岁兰(Welwitschia)断裂控制了白岗岩浆的侵位,其次级断裂以及片理、片麻理构造等为岩浆就位提供了有利张性空间。穹窿的转折部位是有利的成矿位置。构造和岩浆岩是重要的控矿因素,成矿是构造和岩浆作用耦合的结果,是一次构造-岩浆热事件。

The Alaskite-type Uranium Deposit: A Product of Coupling of Tectonism with Magmatism

The alaskite-type uranium deposit is an important uranium deposit type in Namibia. The deposits mainly occurred in the Proterozoic Damaran orogene belt, and the ore-bearing alaskite is the product of the post-orogeny magmatism. The Rossing and Khan Formations are the preferable strata for the emplacement of alaskite. However, they are not the only wall rock for the ore bodies. Ore bodies can be found throughout all the strata in the Nosib group. The alaskites can be classified into 6 types based on their apparent features. The uranium minerals mostly occurred in the D-and E- types of alaskite. The regional Welwitschia fault controlled the emplacement of the magma, the sub-branch of which and schistosity and gneissosity provided extensional space for the locating of magma. The turning areas of domes are the favorable ore-forming locations. Structure and igneous rocks are major controlling factors of ores. The ore-forming process is the product of coupling of structure with magmatism, which is a structure-magmatic thermal event.