煌斑岩与某些热液矿床关系新探──兼论幔源C－H－O流体的分异演化

THE RELATIONSHIP BETWEEN LAMPROPHYRES AND SOME HYDROTHERMAL DEPOSITS:IMPLICATIONS FOR A DIFFERENTIATION MODEL OF MANTLE-DERIVED C-H-O FLUIDS

本文指出了煌斑岩与某些热液矿床之间在大的时、空尺度上密切相关，而在小尺度上则具有明显的独立性。提出并论证了煌斑岩及某些热液矿床形成过程中的幔源Ｃ－Ｈ－Ｏ流体的分异演化模式，即溶解了大量常量及微量元素的高温幔源Ｃ－Ｈ－Ｏ流体上升进入地壳后，因压力降低及挥发分组成的变化发生分异作用，形成相对富含铁镁质的硅酸盐流体及相对富含硅碱质的Ｃ－Ｈ－Ｏ流体，前者在地壳浅部定位形成钙碱性煌斑岩，而后者则引发并参与了地壳中的某些热液成矿作用。

In regional scale, calc-alkaline lamprophyres are related to hydrothermal deposits temporaly and spatialy while they are independent in small scale. On the basis of analysing the geological features of lamprophyres and hydrothermal deposits and the activity of mantle-derived C-H-O fluids, the authors have proposed the differentiation model of the mantle-derived C-H-O fluids with respect to the formation of lamprophyres and mineral deposits. When the high-temperature dense mantle-derived C-H-O fluids that contain a large amount of major and minor elements move upwardly into the lower crust, differentiation takes place, due to pressure drop or other changes,forming a Mg-and Fe-rich valotile-saturated silicate liquid phase and a Si-and alkalis-rich C-H-O fluid phase. The former migrates upwardly and emplaces in the upper crust to form lamprophyre dykes. And the latter takes part in some hydrothermal mineralization.