山东夏甸金矿烃类组分特征与幔源流体成矿作用探讨

烃类是成矿流体中的重要气相组分之一,与其他气态组分相比烃类则具有组分多元化和性质稳定的特点,同时烃类各组分间的相关特征和配分规律是成矿流体演化过程(氧化-还原条件、温度、压力等环境因素)的重要参数,因此烃类组分宏观和微观特征可以作为成矿物质来源、成矿流体演化以及流体间混合叠加规律的研究工具和手段.宏观上烃类组分在夏甸金矿不同类型地质体中的含量值差异明显:滦家河型花岗岩和硅质岩烃类含量很高,而胶东群变质岩、脉岩、金矿体及矿化蚀变带烃类含量明显偏低;通过烃类组分相关性、配分及比值特征等微观规律研究,可以推测夏句金矿的成矿作用与滦家河型花岗岩不存在直接关系,而与胶东群变质岩和深源的中.基性脉岩具有密切联系,表现出不同类型流体之间的叠加、改造特征,反映了夏甸金矿床乃至整个胶东矿集区具有地幔流体参与并和壳源流体发生不同程度混合,促进成矿物质运移并在合适的条件和构造空间沉淀富集的成矿特点.

Characteristics of hydrocarbon components in the Xiadian gold deposit, Shandong, and mantle-derived fluid mineralization

Hydrocarbon is one of the important gaseous components in ore fluids.Compared with other gaseous components, hydrocarbons are characterized by the diversity of their components and stable properties,and meanwhile the correlation characteristics and partitioning regularity between various hydrocarbon components are important parameters in the geological evolution of the fluids (environmental factors such as oxidation-reduction conditions,temperatures and pressures).Therefore the macro-and microcosmic characteristics of hydrocarbon components can be used as the tool and means of studying the source of ore materials,ore fluid evolution and regularity of mixing and superimposition fluids.Macrocosmically,there is appreciable difference in hydrocarbon contents in different types of geological body in the Xiadian gold deposit:the contents of hydrocarbons in the Luanjiabe-type granite and siliceous rock are very high,while their contents in metamorphic rocks,dike rocks,gold orebodies and mineralization and alteration in the Jiaedong Group are notably lower.By studying the microcosmic characteristics such as the correlation,partitioning and ratios of different hydrocarbon components,it may be deduced that the mineralization of the Xiadian gold deposit is not directly associated with Luanjiahe-type granite but closely associated with metamorphic rocks and plutonic intermediate-basic dike rocks of the Jiaedong Group, as shown by the characteristics of mixing,superimposition and modification of different types of fluid,which demonstrates that the mantle-derived fluids were involved in the Xiadian gold deposit and even in the entire Jiaodong ore deposit concentration area and mixed with crust-derived fluids to different extents,thus facilitating the transport of ore materials and their precipitation and concentration in favorable structural spaces under appropriate conditions to form ore deposits.