Geological Characters and Genesis Analysis of Greenstone-type BIF Iron Deposits in Dharwar Craton, India

India takes up about 7% of iron ore reserves in the world, which is dominated by Precambrian BIF iron. In which, the BIF iron ores occurred within greenstone belt or green schist serve as the most important type of iron deposits in India. The greenstone belts were well developed in Dharwar Craton and South India Shield, where a lots of BIF iron deposits were developed in different strata sequences and rock association.The geochemical characters of BIF deposits in Chitradurga and Kushtagi greenstone belts have been analyzed and discussed in this paper. The results show that these BIFs can be classified into shaleand quartz BIFs by using the limit of 2% Al₂O₃ content. And these BIFs show three lithofacies, such as quartzoxide, carbonate or sulfides phases. The major and trace elements geochemistry show that these BIFs were formed by the joint action of terrigenous clastic and volcanic clastic sedimentary. The rare earth elements geochemistry shows that these BIFs have negative Ceanomalies and positive Eu anomalies.The dating data of Dharwarcraton suggest that two major volcanisms occurred in 2.7~2.65 Ga and 2.58~2.54 Ga, and two stages continental accretions happened in 2.7~2.6 Ga and 2.58~2.52 Ga, which caused the formation of Dharwarcraton and related greenstone belts. As for the ore-forming materials source of these BIFs deposits, the Feand SiO₂ were came from the high-temperature hydrothermal of AMOR, the O₂ was sourced from marine biological photosynthesis, and these BIF deposits were formed by the combined action of chemical and clastic sediments under this environment.