Re-Os DATING OF POLYMETALLIC Ni-Mo-PGE-Au MINERALIZATION IN LOWER CAMBRIAN BLACK SHALES OF SOUTH CHINA AND ITS GEOLOGICAL SIGNIFICANCE--A DISCUSSION

摘要

Sir: Thirty years ago, Fan et al. (1973) reported an entirely new type of ore from Cambrian black shales of south China containing percent values for Ni, Mo, As and, in some cases, Zn, together with substantial amounts of Pt, Pd, and Au (>100-1,000 ppb). Subsequently Chen et al. (1982) and Fan (1983) described additional Ni-Mo ore bed occurrences in a 1,600-km belt between Kunming and Hangzhou. Mao et al. (2002, p.1057) describe the deposits as a thin layer having a wide lateral extent "over hundreds of kilometers in southern China [that] contrasts with the lenticular shape of exhalative deposits, which are usually located near hydrothermal vents and are continuous over only a few kilometers, at most."