Natural heavy mineral anomaly characteristics in the northern segment of Ning-Wu area, Jiangsu Province, and their response to copper-gold deposits

The Ning-Wu volcanic basin is one of the important iron-sulfur-copper-gold ore concentration areas in the middle-lower Yangtze River metallogenic belt. The study is based on the database of natural heavy mineral survey in the northern segment of the Ning-Wu basin. Based on ZSAPS2.0 software and GIS platform, the authors selected characteristic minerals related to volcanic hydrothermal filling type copper-gold deposits and delineated natural heavy mineral combinatorial anomalies. It is found that heavy mineral assemblages composed of such minerals as copper minerals (chalcopyrite, bornite, azurite, chalcocite, malachite), native gold, pyrite, barite respond obviously to volcanic hydrothermal filling type copper-gold deposits. Moreover, the authors delineated composite anomalies of natural heavy minerals according to anomaly combination. The composite anomalies were evaluated by ore-forming geological conditions, the corresponding relations of the known deposits, anomaly intensity, anomaly dimensions, and conformity extent of natural anomalies. The results achieved by the authors provide some evidence for dividing copper-gold prospecting areas in the northern segment of the Ning-Wu volcanic basin.