Zircon SHRIMP U-Pb geochronology of the granitoid intrusions from Jinchanggouliang-Erdaogou gold orefield and its significance.
金厂沟梁—二道沟金矿田内花岗岩类侵入体锆石的离子探针U—Pb年代及意义

The SHRIMP U-Pb dating results on zircons from granitoid intrusions in Jinchanggouliang- Erdaogou gold orefield suggest that this region experienced at least three phases of magmatism during Mesozoic, which are represented by the emplacements of the Xitaizi monogranite, the Loushan pyroxene-bearing quartz diorite, and the Xiduomiangou granodiorite as well as dioritic dike at 218 ?4 Ma (Indosinian), 161 ?1 Ma (early Yanshanian) and 126 ?1 Ma (late Yanshanian), respectively. The geochemical characteristics of these intrusions indicate that they were related to orogenesis, formed at intracontinental extensional periods of late- or post-orogenesis. The age of 126 ?1 Ma of the pre- or syn-gold mineralization dioritic dike from Erdaogou mine district constrains the maximum age of the gold mineralization in the area, which, in combination with previous geochronology data, indicates that gold mineralization in the area took place at between 126-118 Ma. This shows that the gold deposits in the district are essentially coeval with those of other gold-concentrating provinces in North China Craton, such as Jiaodong, Xiaoqinling and Liaodong, and further confirms that the late Yanshanian is the most important and extensive period of gold mineralization in north China. In addition, the similarities of the late timing of gold mineralization with respect to the latest felsic magmatism in these major gold-concentrating areas are probably indicative of that gold mineralization is likely a latest stage product of orogeneses or regional tectono-magmatism.