中国前寒武纪铁矿床时空分布和演化特征

Temporal-Spatial Distribution and Evolutional Characters of Precambrian Iron Deposits in China

前寒武纪是中国铁矿重要成矿期,该时期的铁矿资源/储量占全国的65.6%。前寒武纪铁矿床类型可分(火山)沉积变质型铁矿床、与火山侵入活动有关的铁矿床、沉积型铁矿床、复合成矿作用型铁矿床和岩浆型铁矿床五类,再细分为条带状铁建造铁矿床、与细碧角斑质火山侵入活动有关的中浅变质铁矿床、沉积变质热液改造型铁矿床等8个亚类。(火山)沉积变质型铁矿床是前寒武纪铁矿床的主要类型,其储量、矿产地和开采量均占全国首位,其中最主要的是条带状铁建造铁矿床亚类,是前寒武纪的特征类型,是仅发育在前寒武纪时期的铁矿床。中国最古老的铁矿床形成于古太古代,新太古代是中国铁矿最重要的形成时期,此期间形成铁矿的储量约占全国铁矿总储量50%,矿床类型是与绿岩带有关的阿尔戈马型条带状铁建造铁矿床。中国前寒武纪铁矿床主要分布在中国东部、陆块区和陆块边缘和内部的裂谷中,其成矿规模、成矿区域、成矿类型和成矿演化特点明显。

Precambrian is very important period for iron deposit generation. The proved iron ore resource/reserve occupies 65.6% of the total in China. The Precambrian iron deposits can be divided into 5 types： （volcanic）meta-sedimentary type, volcanic type, sedimentary type, complex type and magmatic type. And it can be further divided into 8 subtypes： such as BIF subtype,mid-light meta-deposit about spilite-keratophyre subtype, sedimentary-meta hydrothermal solution reworked subtypes etc. The（volcano）meta-sedimentary iron deposit, especially the BIF iron deposit is the most important type. Its reserve,mineral occurrence and mining measure are the national first in China. And the BIF deposit is characteristic type, which formation belongs to the Algoma BIF related to the green rock belt and develops only in the Precambrian period. The oldest iron deposit in China formed in Paleoarchean. The Neoarchean is the most important period of the iron deposit formation in China. The iron ore reserve in this period is about 50% of the total in China. The Chinese iron ore deposits are distributed in the eastern region of China, mainly in paleocontinental margins and rifts within paleocontinents.