地幔流体的前缘研究

地幔流体是与地幔环境处于平衡的气体和挥发分。其主要化学组分为碳、氢、氧、氮、硫（ＣＨＯＮＳ）。它以富于地球内部原始组分为特征，但也包含部分再循环组分。地幔挥发分在弱还原条件下主要为ＣＯ２－Ｈ２Ｏ，强还原环境则以ＣＨ４－Ｈ２Ｏ－Ｈ２为主。地幔流体地球化学的重要性质为：（１）易溶于硅酸盐熔体；（２）净化作用；（３）再沉淀作用。近年来，有关地幔流体中稀有气体和挥发分的起源、分布及同位素组成等前缘领域的研究已取得重要进展。当前拟优先探索的问题包括气体裂化与金刚石成因，非生物成因地幔烃，地幔流体与成矿作用，以及地幔挥发分注入与地壳重熔等。

FRONTIERS OF RESEARCH ON THE MANTLE FLUID

Mantle fluid is a mixture of gases and volatiles at equilibrium with its host mantle ambience and it is mainly composed of carbon, hydrogen, oxygen, nitrogen and sulphur (CHONS). The major fraction of mantle fluid is derived from Earth′s primordial components, however, some recycled materials are also involved. The principal volatile species of the mantle fluid are CO 2 H 2O under mildly reduced conditions, whereas it may be chiefly constituted of CH 4 H 2O H 2 at vary reduced environment. It is considered that high solubility in silicate melts, scavenging impurity and reprecipitation of trace elements are the essential geochemical properties of the mantle fluid. In recent years, some advances on the origin, distribution and isotopic composition of mantle noble gases and volatiles have been made. New priorities in the study of mantle fluid should be given to the following problems: the gaseous cracking and diamond origin, non biogenic mantle hydrocarbons, mantle fluid and metallogeny, as well as crustal remelting during the influx of mantle volatiles.