Abstract: A series of amygdalaes with asphalt, chlorite, quartz, native copper, occur in the Puge basalt, Southern Sichuan, China. The petrological and mineralogical features of different amygdalae were systematically studied by modern analytical techniques. The results show that chlorite in the amygdalae belongs to diabantite, formed in a medium-high temperature, organic-rich hydrothermal environment. Asphalt belongs to petroleum asphalt and was derived from bioclastic
limestone of the Middle Permian Yangxin Formation (P2 y). Chlorite, asphalt, quartz and native copper crystallized in the organic hydrothermal fluid, which are derived from late basic volcanic activity under the tectonic stress after the formation of basalt. A commonly recognized sequence of the processes for the formation of these amygd alaes can be summarized as follows: the later magma stage of Puge basalt → Cu-rich volcanic hydrothermal fluid→tectonic stress→organic ore-fluid →chlorite →the first generation of asphalt →white quartz → smoke-gray quartz, the second generation of asphalt, and native copper →chalcocite→prehnite. The asphaltene amygdalae, crystal cavities and tectonic fracture zone in the basalt can be regarded as important prospecting indicators for Cu mine ralization in the Emeishan Large Igneous Province.

Key words: asphalt, chlorite, basalt, amygdala, Puge, Souhtern Sichuan