热液成矿流体中的有机物质

热液流体中的主要有机质包括腐殖物质（t＜50℃）、有机羧酸（t＝80～140℃）、原油（120～180℃）和水溶性甲烷气（180～300℃）。腐殖物质在初始矿源层形成中起重要作用，在腐殖酸缩合成干酪根过程中通过去氧而导致还原的成岩环境，从而有效地防止金属元素在初始矿源石化过程中的分散。有机羧酸是干酪很早期演化的必然产物，富含有机羧酸的油田卤水可以成为MVT铅锌矿的成矿流体。在一定成熟度范围内原油可能成为汞金热液流体的重要有机组分。水溶性甲烷气是铜、铀、金等中低温热液流体的重要有机组分。有机质演化的阶段性决定了相应热液流体中有机质的类型；此外沉积建造的类型、金属元素在油／卤之间分配系数差异和构造条件差异导致了金属矿化分异。

ORGANIC MATTER IN HYDROTHERMAL ORE-FORMING FLUID

The predominant organic matter in hydrothermal ore-forming fluid varies with temperature from humic substance (t < 50℃), carboxylic acids (t = 80 ~ 140℃), crude oil (t = 120 ~ 180℃), to water-soluble mehane (t = 180 ~300℃). Humic substance plays an important role in the formation of prime ore source. Humic substance may be responsible for reducing the diagenetic environment due to its deoxidization when condensating into kerogen, and this environmnt is favorable to protecting metal elements from being dispersed during the diagenesis of ore source.Carboxylic acids are derived from kerogen at the early stage of evolution. Oilfield brines which are rich in such organic acids may be oreforming fluid responsible for the MVT Ph-Zn deposits. When reaching a certain degree of maturation,crude oil may be an important organic composition of hydrothermal ore-forming fluids of gold and mercury. And for low-middle temperature ore-forming fiuids of meals such as Cu, U, and Au, water-soluble methane tnay be a main organic constituent: The evolution stage of organic matter in sedimentary rocks results in the type of organic componerits in fluids, and the mineralizing differentiation of metals may be attributed to sedimentary formation type, partitioning coefficients of metals between oil and water, and tectonic background.