辽宁青城子铅锌银金矿田控矿构造与找矿方向

Ore-control Structures and Ore Prospecting in the Qingchengzi Ph-Zn-Ag-Au Orefield, Liaoning Province

辽宁青城子铅锌银金矿田为一处集铅锌银金多个大型矿床于一区的重要成矿集中区。青城子中深构造层次的片麻岩穹隆（或变质核杂岩）构成了该区构造的主体。矿区中由片麻岩穹隆所构成的构造组合控制了矿体的定位、形态以及矿床的规模。青城子片麻岩隆起西南侧的卷曲褶皱翼内北东、北西走向的陡倾斜断裂发育，矿床主要为沿断裂交代充填的脉状铅锌矿，矿床规模较小；片麻岩隆起滑脱伸展翼多层顺层滑脱断裂带，为后期成矿提供了较大的容矿空间，有利于形成规模较大的矿床。

The Qingchengzi Ph-Zn-Ag-Au ore field is an ore cluster area where several large deposits occur. The tectonic pattern of the Qingchenzi Ph-Zn-Ag-Au ore field is dominated by a crustal extensional gneiss dome (or metamorphic core complex) at a medium depth. The structural assemblage of the extensional gneiss dome governs the deposition and the shapes of orebodies as well as the sizes of the ore deposits. In the southwest folded limb of the gneiss dome, NE- or NW-striking steep faults are widely distributed and cut the bedding of the metamorphic stratiform formation. The steep faults strictly control the orebodies which are generally of small size. Ore deposits are characterized by filling-replacement lead-zinc veins with high-grade lead and zinc ores occurring within the steep faults. On the basis of the features of the structures which control the ore-forming activity and shapes of the orebodies, the orebodies are divided into Nanshan-style and Benshan-style. The leadzinc deposits such as Beilazi, Xiquigou, Mapao, Benshan, Erdaogou, Dadonggou and Nanshan are dominated by filling-replacement vein-like orebodies. In the extensional slipping limb of the gneiss dome, there are abundant metallogenic elements in Gaixian Group and Dashiqiao Group in the upper part of the tnetamorphic strait form formation, thus favorable for preliminary enrichment. Several interlayer detachment fault zones are well developed in the extensional slipping limb and extend persistently. The faults are normally of large size and likely to provide space for the formation of ore deposits, even large deposits. The ore-forming process was dominated by hydrothermal alteration instead of filling, resulting in the formation of low grade lead-zinc deposits. The major deposits, such as the Zhenzigou lead--zinc deposit, the Gaojiapuzi silver deposit and the Xiaotongjiapuzi gold deposit, are of stratiform or stratoid style in the extensional slipping limb.