河北省牛圈银(金)矿床成因初探

Study on the Genesis of the Niujuan Silver(Gold) Deposit in Hebei Province

通过对牛圈银(金)矿床的细粒花岗岩、隐爆角砾岩、同位素特征等方面研究,笔者认为与矿床关系密切的隐爆角砾岩(次火山岩)由基底岩石的部分重熔形成,而成矿物质来源于下地壳-上地幔重熔岩浆;成矿热液为重熔岩浆分异演化形成的富气相流体。这些热液与次火山岩浆相伴或滞后上升,经多次隐爆作用在破碎带中形成矿床。银矿体呈脉状产出于粗粒花岗岩之破碎带中,含矿岩石为隐爆角砾岩。熔浆物质既成角砾又呈胶结物,成矿带发育中低温热液蚀变。矿床为含矿凝灰岩(英安质)熔浆经隐爆作用形成的浅成中低温热液矿床。

Through the study on the fine granite,the underground-explosive breccia and the isotope feature of the Niujuan silver（gold） deposit,this article suggests that the underground-explosive breccia（sub-lava） is formed by the partial remelting of basal rocks.The metallogenic material is from the remelting magma of the lower crust-upper mantle.The metallogenic hydrotherm is gas-rich liquid formed by differentiation of remelting magma.Ascending with or after the sub-lava,the liquid forms deposit in crushed zone after many times of underground exploding.As a vein,the silver orebody occurred in the crushed zone of coarse-grained granite.The ore-bearing rock is underground explosive breccias.The magma material forms both gravel and cement.The alteration is epithermal and mesothermal.The deposit should be epithermal and mesothermal deposit formed by underground exploding of ore-bearing tuff.