Mineralizing types geological characteristics and geodynamic background of molybdenum deposits in Xilamulun molybdenum polymetal metallogenic belt on northern margin of North China Craton

Recently, a new molybdenum metallogenic belt was discovered along Xilamulun geosuture zone on northern margin of North China Craton. It spans 400km in length and 300km in width. More than 10 Mo deposits of large-middle scale were discovered during the last 4 years. The Mo deposits of this belt are controlled jointly by EW-, NE- and NW-trending faults, and are associated with acid granites in time and space. The Mo deposits are usually distributed in granite body, along the endo- or exo-contact zones of the granite porphyry, or nearby. The Mo deposits can be classified into four types; porphyry, quartz vein, volcanic hydrothermal and greisen type. The relationship between the Mo deposits and intrusives shows that the Mo deposits are associated with Si- and K-rich intrusive. Based on the metallogenic chronology, the authors suggested that there existed three main stages of Mo mineralization (245Ma, 150Ma and 138Ma respectively) in the Xilamulun metallogenic belt. The corresponding geodynamic background covers the post-collisional extension of the newly-amalgamated North China-Siberian plates during Indo-Chinese epoch , to the transition of tectonic regimes and lithospherie thinning in eastern China.