关键词: 地质特征, 矿物组合, 成矿期次, 沉积-改造型

Abstract: A copper deposit in Dongchuan，Yunnan is a typical sedimentary-metamorphic reformed copper deposit in the Dongchuan ore concentration area of central Yunnan. The mineralized bodies are lay⁃ ered and stratoid. Its mineral characteristics and metallogenic regularity have important guiding signifi⁃ cance for the mining design of the deposit. Based on the systematic collection of previous geological explo⁃ ration data，combined with field geological survey，drilling core sampling and microscopic thin section identification，the characteristics of ore minerals and mineralization are studied. The results show that the ore-bearing lithology of the deposit is carbonaceous siliceous slate and silty slate in the second member of Dayingpan Formation. Metal minerals are mainly pyrite（36.32%）and chalcopyrite（10.46%）. Gangue minerals are mainly quartz（52.88%）. Chalcopyrite is mostly associated with pyrite and quartz. The ore is dominated by fine-grained metamorphic structure and metasomatic residual structure，and the structure presents the characteristics of patchy，disseminated and scattered. The deposit has undergone three stages of mineralization which are sedimentary diagenesis（mineralization），hydrothermal transformation and su⁃ pergene oxidation. The early sedimentary ore bodies are enriched by weathering and denudation and tecton⁃ ic activities. Later，the structure-metamorphic hydrothermal fluid drives the formation of veinlet ore bodies along the bedding or fissure filling. Malachite and chalcopyrite are direct prospecting indicators for finding similar ore bodies.

Key words: geological characteristics, mineral association, metallogenic stages, sedimentary transfor? mation type