Analysis of the ore-controlling role of Guojiadian mantle branch structure, Northwest Shandong Peninsula, China

Metallogenesis in the gold ore-concentrated zone of Northwest Shandong Peninsula is closely related to deep processes. The region in the eastern part of North China entered into the stage of mantle plume evolution during the Yanshanian movement, following the long-time stage of stable platform evolution during Paleozoic time. At that time, the ore-concentrated zone of Northwest Shandong Peninsula just entered into the development-evolution stage of the Laiyang sub-mantle plume and the Guojiadian mantle branch structure in its periphery. The core-mantle-source gold was present in the gas-liquid form, and it migrated through mantle plume??sub-mantle plume??mantle branch structure??favorable tectonic expansion zone to the favorable loci of the mantle branch structure, where gold was deposited as ores, thereafter constituting a series of large- to medium-sized gold deposits distributed around the Guojiadian mantle branch structure. This study also dealt with the Jiaojia fault as the main detachment (fault altered rock) belt on the northwestern margin of the mantle branch structure and also presented a basic cognition about the fact that the Sanshandao fault as the listric fault on the hanging wall of the detachment belt. Furthermore, on this basis, this study also pointed out the orientation for further ore prospecting in this region.