GEOLOGICAL CONDITIONS OF GOLD DEPOSITS IN XIAOTIAN MESOZOIC VOLCANIC BASIN, ANHUI PROVINCE

Studies of geological characteristics, mineralization and volcanism, fluid inclusion show that:1. the basement of metamorphic rocks is the "Primary source rocks" and the "secondary source rocks" are derived from partly melted "primary source rocks" with Mesozoic magma; 2. Mesozoic Maotanchang-stage volcanic activity, as the important factor of the gold mineralization, activated gold to be migrated in volcanic hydrothermal solution and to be concentrated in favorable places forming gold deposits; 3. basement structures control certainly gold minerogenesis, volcanic structures control directly mineralization zonation and mineralization positions, e.g. gold deposits of subvolcanic hydrothermal type occurring around the crater of central type volcano and ones of volcanic hydrothermal type in one side of the crater of fissure-type volcano, and type of fault controls the kind, fineness, and zone of ores in a gold deposit; 4. the ore-forming hydrothermal solution consisting of mainly meteoric water and somefew magmatic water.Studing the controlling conditions of gold minerogenesis of various genie types, the author proposes a minerogenetic series and minerogenetic model of gold and ore-reaching direction in this area.