青海三江成矿带然者涌铅锌银矿床地质特征及找矿方向

针对青海三江成矿带然者涌铅锌银矿区找矿潜力巨大(铅锌银矿石资源量668.03万t)但勘探程度较低的现状,本文从查明矿床地质特征、矿体特征和控矿构造等角度入手开展了该典型矿床地质、矿床成因的研究。结果表明,矿体受构造控制,具有成层呈带分布特点,连续性较差,厚度变化较大。矿(化)体赋存于构造破碎带中,赋矿围岩为中-下二叠统诺日巴尕日保组构造角砾岩、碎裂状砂岩夹板岩等,受构造控制特征十分明显。该区岩浆活动微弱,矿床的形成与岩浆活动无明显成因联系,矿质多在层间破碎带等空间充填交代形成,其成矿机理与沉积地层的地下热(卤)水有明显关系。断裂构造控制矿体总体产出形态及赋存部位,为成矿热(卤)水提供了运移通道和赋存空间。顶部的大量挥发分及热液携带部分有用组分沿东西断裂带运移上升,在运移过程中与围岩发生接触交代、溶离促使金属矿物更进一步富集成矿。初步认为,然者涌矿床成因为热液充填-叠加改造铅锌银多金属矿床。

Geological characteristics and prospecting direction of the Ranzheyong lead-zinc-silver deposit in Sanjiang metallogenic belt,Qinghai Province

Base on this phenomenon of great prospecting potential and low exploration level, the Ranzheyong Lead-zinc-silver ore deposits is studied with application of metallogeny. It shows that the orebody is controlled by the structure and has the characteristics of stratification and zonation. layered, layered-like, lenticular and irregular sac-like ore deposits with variable size are distributed along the east-west direction. The continuity of the orebody is poor and the thickness varies greatly. It is formed in structural fracture belt and the host rock is tectonic breccia and fractured feldspar-quartz sandstone interbedded with silty slate. the ore deposit has a weak magmatic activity and occurs in tectonic fracture zone of Nuoribagaribao formation in the middle and lower Permian. It is obviously controlled by the structure and has no obvious connection with magmatic activity. Metallogenic material was formed by the process of filling and replacement in interlayer and fracture zone, the metallogenic process is obviously driving by underground hot water (brine) in sedimentary strata. Fault structure is controlling morphology and the occurrence location, and that provides migration channel and occurrence space for metallogenic hot (brine) water. A large number of volatiles and some useful components carried by hydrothermal fluids at the top migrate upward along the east-west fracture zone, In the process of migration, contact metasomatism occurred with the surrounding rock and that the liquation promotes further enrichment of metallic minerals. It is preliminarily believed that the deposit of Lead-zinc-silver polymetallic deposits was formed by hydrothermal filling-superposition transformation process.