云南主要双峰式火山岩及相关矿产资源

Major Bimodal Volcanic Rocks and Associated Mineral Resources in Yunnan Province,Southwest China

云南双峰式火山岩时空分布较为广泛,贯穿云南及整个西南"三江"地区的地质发展演化过程,并伴有各具特色的矿产。本文基于前人的研究资料,总结了云南主要的双峰式火山岩的时空分布和相关矿产资源的情况,并讨论与双峰式火山岩有关的地质构造背景。总结出在地质历史演化过程中,云南主要分布有:(1)元古宙:滇中地区中元古代大红山群、河口群、东川群、昆阳群中的碱性火山岩及细碧-角斑岩类火山岩组合,新元古代与苏雄组同期的双峰式火山岩;(2)早寒武世梅树村期:扬子地台西缘玄武岩和凝灰岩等火山喷发记录;(3)中—晚志留世:滇西普洱大平掌铜多金属矿区大凹子组(S2+3d)细碧岩-石英角斑岩建造;(4)中—晚泥盆世:滇西北德钦羊拉里农组(D2+3l)碎屑岩夹双峰式火山岩+碳酸盐岩;(5)早三叠世:金沙江造山带攀天阁组(T1p)流纹岩+崔依比组(T1c)玄武岩(细碧岩或蚀变玄武岩)组成的"双峰式"火山岩,滇西洱源岩群双峰式火山岩;(6)中—晚三叠世:澜沧江造山带中南段忙怀组(T2m)流纹岩、流纹英安岩、流纹质火山碎屑岩、少量玄武岩和小定西组(T3x)玄武质火山碎屑岩以及芒汇河组(T3mh)玄武岩、流纹质火山碎屑岩组成的双峰式火山岩;(7)古近纪:剑川组(E2j)碱性玄武岩-粗面质火山角砾岩组合等7个阶段的双峰式火山岩,其地质构造背景各异,并伴有各具特色的矿产。这些双峰式火山岩可以作为制约云南及整个西南"三江"地区关键地质演化和成矿事件的标志性地质现象,是研究其地质构造背景和成矿作用的重要依据。

Bimodal volcanic rocks are widely distributed in Yunnan Province.They occurred throughout the whole process of geological development and evolution in Yunnan Province and the Sangjiang area in southwestern China,forming a variety of special minerals resources.Based on previous research results,this paper summarized the temporal and spatial distribution of bimodal volcanic rocks and associated minerals resources,and discussed the geotectonic setting about the bimodal volcanic rocks in Yunnan.The process of geologic evolution history in Yunnan can be summarized below：（1）Proterozoic：the Mesoproterozoic alkaline volcanic rocks series and spilite-keratophyre association of Dahongshan Group,Hekou Group,Dongchuan Group,Kunyang Group,etc.in central Yunnan,and also the Neoproterozoic bimodal volcanic rocks,which is equivalent to the Suxiong Formation;（2）Meishucunian stage of early Cambrian：basalt and tuff in the western margin of the Yangtze Block;（3）Middle-Late Silurian：spilitequartz keratophyre assemblage of the Da＇aozi Formation（S2＋3 d）in the Dapingzhang copper-polymetallic ore district in Pu＇er,western Yunnan;（4）Middle-Late Devonian：clasolite of Linong Formation（D2＋3 l）,intercalated with bimodal volcanic rocks and carbonate rocks,in Yangla,Deqin,northwest Yunnan;（5）Early Triassic：Pantiange Formation（T1 p）rhyolite and Cuiyibi Formation（T1 c）basalt（spilite or altered basalt）in the Jinshajiang orogen,and Eryuan Group bimodal volcanic rocks in western Yunnan;（6）Middle-Late Triassic：Manghuai Formation（T2 m）rhyolite,rhyolitic dacite,rhyolitic pyroclastic rock,minor basalt,and Xiaodingxi Formation（T3 x）basaltic pyroclastic rock and Manghuihe（T3 mh）basalt rhyolitic pyroclastic rock;and（7）Paleogene：Jianchuan Formation（E2 j）alkali basalt and potassic volcanic breccia constitute seven episodes of bimodal volcanic rocks,characteristic of various geotectonic settings and related special minerals.These bimodal volcanic rocks can be used as an iconic geological phenomenon of key geological evolution and metallogenic events in Yunnan and the whole Sanjiang area of southwestern China,which is important evidence for studying the geotectonic setting and mineralization.