全球铬铁矿床成因类型、地质特征及时空分布规律初探

全球铬铁矿资源丰富,但分布极不均衡.铬铁矿的成因类型主要有层状和豆荚状2种,这2种类型的铬铁矿床地质特征、成因模式差异显著.在全球范围内铬铁矿矿床的成矿时代和空间分布具有明显的时空规律性,古元古代是铬铁矿最重要成矿期,该期形成的铬铁矿占总资源量的58.5％,以形成大型-超大型层状铬铁矿为主,中-新生代是全球铬铁矿床形成数量最多、分布范围最广的重要成矿期,该期形成的铬铁矿占总资源量的24.9％,以形成中小型豆荚状铬铁矿为主.铬铁矿在全球的分布可划分为5个重要层状铬铁矿矿田(南非布什维尔德-津巴布韦大岩墙、北美斯蒂尔沃特、南美坎坡福莫索、印度苏金达、芬兰凯米-俄罗斯普拉科夫斯科)和7个豆荚状铬铁矿带(津巴布韦舒鲁圭、东北非、乌拉尔、特提斯、西太平洋岛弧、加勒比岛弧和马达加斯加),并对各重要成矿区带的资源潜力进行了探讨.通过对全球铬铁矿成因类型、地质特征和时空分布规律的探讨,对深入了解地幔的物质组成、物理化学环境、地幔物质的运移、深部地质作用及板块运动的动力学机制、深俯冲和地球深部再循环轨迹有重要的理论意义.

A review on genetic types, geological characteristics and temporal and spatial distribution of chromite deposits in world

There are abundant chromite resources in the world, but their distribution is extremely uneven. Chromite deposits can be classified into two genetic types, namely stratiform and podiform deposits. The two types of chromite deposits have significant differences in geological characteristics and genetic models. Worldwide, the mineralization age and spatial distribution of chromite deposits have obvious temporal and spatial regularities. Paleoproterozoic is the most important metallogenic period of chromite, which accounts for more than 58.5% of the total resources, mainly forming large or super-large stratiform chromite; The Mesozoic-Cenozoic is an important metallogenic period with the largest number and widest distribution of chromite deposits in the world, which accounts for more than 24.9% of the total resources,mainly forming small and medium-sized podiform chromite.The distribution of chromite in the world can be divided into 5 important stratiform chromite ore fields(Bushveld in South Africa-Great Dyke in Zimbabwe, Stillwater in North America, Campo Formoso in South America, Sukinda in India, Kemi in Finland-Burakovsky in Russia) and 7 podiform chromite belts(Shurugwi in Zimbabwe,northeast Africa, Urals, Tethys, western Pacific Island Arc, Caribbean Island Arc, and Madagascar), and the resource potential of each important metallogenic ore field/belt was discussed. A study on genetic types, geological characteristics and temporal and spatial distribution of chromite deposits in the world was carried out, which has important theoretical significance to understand the material composition of the mantle, the physical and chemical environment, the migration of mantle material, the dynamic mechanism of deep geological processes and plate movement, deep subduction and the recirculation path of the deep earth.