THE GEOCHEMICAL BOUNDARY BETWEEN SOUTH CHINA AND YANGTZE BLOCKS AND ITS CONSTRAINT ON THE FORMATION OF SUPER LARGE DEPOSITS

It is indicated based on the isotope mapping in the South China that t here existed an abrupt changing zone of Pb isotopes (ACZ) between the South China and Yangtze Blocks, which marks their boundary. This bound ary controled the genesis of all of the super large deposits related w ith deep source mineralization, whose occurrence positions were tightl y associated with contract and turning of ACZ along with forming conto ur line trap at both sides of the boundary. ACZ was usually consistent with the positive anomaly of gravity and approximately corresponding to the geological boundary currently recognized, but did not well matc h the major tectonic lines occurring on the surface.