| Abstract: | On the basis of analysing the plate movements nearby China,activities ofTanlu deep seated fracture zone,and the characteristics of regional and local structuresin Jiaodong region,three tectonic phases have been recognized with respect to Mesozoic Cenozoic regional tectonic evolution. The first one is the period of J_2 K_1 with SE NWcompression,during which the crustd erived granitic rocks and the associated golddeposits were formed.According to the deformation pattern, Jiaodong area can be dividedinto two tectonic subdistricts with Taocun fault zone being the boundary,i.e. the eastand west part of Jiaodong block. To the east part, an anticlockwise rotation took place,leading to the formation of structures resulting from rotation and shearing. In westJiaodong block, brittle-ductile faults with vertical conjugate pattern and steep dippingstrike-slip brittle faults were formed in intermediate and upper crust,respectively. K_2 isthe second tectonic phase when Jiaodong was in a SE-NW extending situation and fourNE-striked extensive structure zones were formed,which controlled the formation anddistribution of Aishan-stage,Laoshan-stage granitic bodies,and thepolymetallic(gold) silver mineralization related to Aishan-stage intrusions. The thirdphase is the one of NEE-SWW compression during N-Q when post-ore faults wereformed. It is also suggested that a rising mantle plume might be the deep condition for theformation of mafic dyke swarm,alkaline basalt,and gold mineralization in the workingarea. |
