Mesozoic geodynamic evolution and metallogenic series of major metal deposits in Jiaodong Peninsula,China

Abstract

The Jiaodong area is located in the conjunctional site of the Paleotethys and the Pacific metallogenic domains,and experienced strong Mesozoic tectonic-magmatic activities and metallogenisis of major metal deposits. In this paper,based on a comprehensive analyses and identification on tectonic setting of major Mesozoic magmatisms and metallogenic type of typical deposits,combined with the geological and structural features in the Jiaodong area, we conclude that the geodynamic evolution of the metallogenisis is manly controlled by the collisional orogeny of the Yangtze and the North China plates as well as subduction of the Paleopacific plate,and further divide it into six periods of continental collisional orogen in Late Triassic,transformation from passive to active continental margin and crustal accretion in Middle Jurassic,transformation from crust accretion to collapse in Early Cretaceous,large-scale delamination of lithosphere and intense crust-mantle interaction in Early Cretaceous,subduction of the continental margin arc,and intense extension of post-arc lithosphere in Late Cretaceous, corresponding to six phases of gold and polymetallic metallogenisis: ~ 205 Ma,160 ~ 155 Ma,135 ~ 125 Ma,125 ~ 115 Ma,115 ~ 100 Ma and 100 ~ 90 Ma,respectively. The precious and nonferrous deposits which formed in the six periods of metallogenisis show regular spatial and temporal distribution,and roughly include six metallogenic series,nine sub-series and sixteen deposit types,which can be subdivided into seven precious and nonferrous metallogenic zones( belts) from west to east: the western Laizhou,Zhaoyuan-Pingdu,Qixia-Penglai-Fushan,the northeastern margin of the Jiaolai Basin,Muping-Rushan,Wendeng-Weihai,and Rongcheng. In general,in the Jiaodong area,orogenic gold deposits are still prospecting focal targets,and the exploration of the porphyry-type nonferrous deposits are potential to make breakthroughs.Meanwhile,we should also pay enough attention into the meso-epithermal multiple-metal deposits.