苏丹东部地区BIF型铁矿和CID型铁矿的发现及其找矿意义

在苏丹东部地区新元古代地层中，新发现的BIF铁矿是与火山岩密切相关的Algoma型铁矿，矿石品位TFe 37.78%，对进一步研究努比亚地盾的形成时代和古地理环境有一定的参考意义。苏丹79区块发现的含铁石英砂岩，呈北东向带状分布， 角度不整合于努比亚地盾之上，通过与西澳CID型铁矿对比，存在交错层理和底砾岩等明显的再生沉积特征，矿石品位TFe 31.91%～39.33%;通过对BIF型铁矿、CID型铁矿和努比亚杂砂岩三者部分元素及氧化物含量的分析对比，以及控矿地质因素分析， CID型铁矿是由BIF铁矿风化剥蚀后搬运沉积于附近古河道内;苏丹努比亚地盾区CID型铁矿的发现，为今后找矿工作提供了新目标，具有十分重要的找矿意义。

Discovery of BIF Iron Ores and CID Iron Oresin Eastern Sudan and Its Prospecting Significance

A BIF iron deposit newly discovered in the Neoproterozoic stratum of Eastern Sudan is an Algoma type iron deposit having close connection with volcanic rocks. The ore grade is TFe37.78%. This is referential for further studies into the forming age and paleogeographic setting of the Nubian Shield. The ferriferous quartz sandstone found in Block 79 occurs NE in a zonal matrix andoverlies the Nubian Shield with an angular unconformity. Comparison with the CID iron deposits in Western Australia,there is obvious characteristics of redeposition like cross-bedding and basal conglomerateand the ore grade is TFe31.91%~39.33%. Comparative analysis of partial element and oxide contents in BIF iron ores, CID iron ores and the Nubian greywacke and investigation of the ore-controlling factors discovered that the CID iron ores are products of weathered or denudated BIF iron ores that were transported to and then deposited in the nearby paleochannels. The discovery of CID iron ores in the Nubian Shield area of Sudan offers a new target for future prospecting efforts and has very important prospecting significance.