摘要
The late Triassic to early Jurassic granites are widely distributed in the Yichun area,Heilongjiang Province,which are dominated by porphyaceous monzonitic granite,monzonitic granite porphyry,syenogranite,alkali-feldspar granite and alkali granite.And the discovered iron-plolymetallic deposits and gold deposits related to these rocks are mainly of porphyry,skarn,skarn-hydrothermal,magmatic hydrothermal and epithermal hydrothermal types.The major rock-forming and ore-forming ages are late Triassic to early Jurassic(U-Pb zircon LA-ICPMS age of 191~225Ma),and the ore-forming age is slightly later than the metallogenic epoch.This paper studies the major rock types,geologic ages,tectono-magmatic evolution,genetic types of the early Mesozoic granites and mineralization characteristics of different continental-collision stages.We divide the metallogenic series into two metallogenic subseries:the Mo-Pb-Zn-Fe-W-Au(Ag) metallogenic subseries of porphyaceous monzonitic granite-monzonitic granite porphyry of continental collisional-postcollisional structural transposition and the Fe-Mo-Pb-Zn-NbTa metallogenic subseries of syenogranite-alkali-feldspar granite-alkali granite of postcollisional collapse episode.These two metallogenic subseries differ in metallogenic features,i.e.,ore-forming elements,mineralization intensity and types.And these differences are related with granite source areas,the degree of crust-mantle mixture,mixture ratio,granite emplacement depth and metallogenic tectonic background.