中国新生代成矿作用的惰性气体同位素研究与动力学背景

Inert Gas Isotopic Studies and Dynamic Background of Cenozoic Ore-forming Process in China

通过对中国不同类型的、与新生代成矿作用有关的地质样品的惰性气体同位素组成研究 ,揭示出在不同地区新生代地幔流体广泛地参与了不同类型的成矿作用的规律。壳幔相互作用在宏观上控制了成矿作用的发生 ,但在早第三纪和晚第三纪刚开始时 ,地幔脱气作用表现得更为显著 ,2 5Ma可能是一个重要的转折点。虽然不同部位或地段中记录的惰性气体同位素组成有时相对均一 ,有时变化很大 ,但无疑深大断裂带是幔源气体逸出的重要通道 ,也是控制新生代成矿作用的重要构造部位。

Based on studies of isotopic composition of inert gases in geological samples related to different types of Cenozoic ore_forming processes in China, the authors have revealed that Cenozoic mantle fluids must have extensively taken part in different types of ore_forming processes. The interaction between the crust and the mantle controlled the ore_forming process on the whole; nevertheless, at the beginning of Paleogene and that of Neogene, the gas_releasing action of the mantle was especially remarkable, and 25 Ma seems to have been an important turning point. Although isotopic compositions of inert gases recorded in different positions and different sections could either be relatively uniform or vary considerably, the great deep fault belt was undoubtedly an important channelway for the release of gases and also served as an important tectonic position controlling the Cenozoic ore_forming process.