滇西南翁孔坝铜多金属矿床火山岩系地质特征及其与铜的成矿关系

Geological characteristics of volcanic series and their relationships with copper mineralization at Wengkongba copper polymetallic deposit,Southwest Yunnan Province

翁孔坝铜多金属矿床是近年来在澜沧江构造带南段的云县-景洪火山弧上新发现的铜多金属矿床,与中三叠世陆相火山岩系密切相关,且具有较大的找矿潜力。文章在野外详细调查的基础上,结合赋矿火山岩岩石学特征,对矿区内火山岩系进行了系统研究,将其细分为5个喷发旋回,9个岩性段(T_(2)s^(3-1)~T_(2)s^(3-9)),认为该矿床具有火山沉积-成岩成矿期和改造成矿期两期成矿作用,为陆相火山沉积-改造型铜多金属矿床。其中,火山岩成矿作用为成矿提供了物质来源,具有明显的岩性/岩相组合控矿特征,笔者综合认为该套火山岩系是矿床主要的控矿因素之一,进而初步建立了其与铜成矿的“时-空-成因”关系图。

The Wengkongba copper deposit is a newly discovered copper polymetallic deposit in the Yunxian-Jinghong volcanic arc of the southern section of the Lancang River tectonic belt.It is closely related to Middle Triassic continental volcanic series and has great prospecting potential.Based on detailed field investigation and petrological characteristics of the ore-bearing volcanic rocks,this paper makes a systematic study on the volcanic rock series of the deposit and recognizes that the host rocks can be subdivided into 5 eruptive cycles and 9 lithologic sections(T_(2)s^(3-1)~T_(2)s^(3-9)).It is considered that the deposit has two stages of mineralization,namely volcanic depositiondiagenetic mineralization period and reformed mineralization period.It is a continental volcanic sedimentarymodified copper polymetallic deposit.Among them,volcanic mineralization provides material source for minera lization and has obvious lithology/lithofacies combination ore-controlling characteristics.The author comprehensively considers that the volcanic series is one of the main ore-controlling factors of the deposit,and then preliminarily establishes the"time-space-genesis"relationship between the volcanic series and copper mineralization.