Metallogenic regularity and metallogenic model of the Middle-Lower Yangtze River Valley Metallogenic Belt

The Middle-Lower Yangtze River Valley Metallogenic Belt (MLYB) is one of the most important metallogenic belts in China. There are extensive studies on ore-forming geologic conditions, metallogenic regularity as well as metallogenic models in the past decades, a series of theories on the formation of ore deposits in MLYB have been proposed and recognized. In this paper the new advances on ore-forming geological conditions, metallogenic regularity of the MLYB have been reviewed, and a new model for the mineralization in the MLYB has been constructed. Based on compound structural system, the range and sub-metallogenic domains of the MLYB have been redesigned. Through collecting and analysis of the newly published isotopic age dating data, the spatial-temporal of ore deposits in MLYB has been set up. After analysis the geological, geophysical and geochemical information, the re-worked complex net fault structural system that controll the intrusions and ore deposits are outlined. Finally, a compensate model for the MLYB, the fault-uplifted areas and fault-depressions are constructed accordingly. We propose that the overall processes of the metallogeny underwent three stages: the strike-slip compressional stage (146 similar to 135Ma), the strike-slip tensile stage (135 similar to 126Ma), and the stretching extensional stage (126 similar to 123Ma). The mantle-crust interaction stimulated by the far stress field of the Paleo-Pacific plate subduction led to the reworking of the Neoproterozoic subduced arc magmatic material stored in the the lower crust or lithospheric mantle and the reactivation of the fault system that formed during the collision between the North China Block and the South China Block in Mesozoic. This "source reworking plus structure reworking (double rework)" is the major mechanism that governed the evolution and formation of the MLYB.