Abstract:

Compared with the abundance of Pt and Pd in mafic and ultramafic rocks in China, the Emeishan flood basalts have higher geochemical backgrounds. These results suggest that the recognization of the Pt-Pd geochemical anomalies related mafic intrusive bodies with Pt-Pd minerlization is key technology from the Permian Emeishan flood basalt for exploration. Results from a stream sediment geochemical survey at a sampling density of 4-6 samples per square kilometer show that contrast values, computed Pt and Pd concentrations in stream sediment to those in different rocks, can effectively delineate Pt and Pd geochemical anomalies related mafic intrusive bodies from high geochemical background area. An extensive local geochemical anomalous belt of Pt, Pd, As, Sb, Hg, Cr, Ni and Pb was delineated over the contact area among limestone, basalt and fault of NE direction around Hongyan village using the stream sediment survey at a scale of 1∶50,000. A new concealed maficultramafic intrusive body containing PGE mineralization was predicted.

Key words: geochemical anomaly of Pt-Pd, Emeishan flood basalt rock, mafic and ultramafic rock