The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt.The formation of the polymetallic deposits has close genetic relationships with Early Cretaceous intermediate-acid intrusions.In this study,LA-ICP-MS zircon geochronology of two Mesozoic intermediate-acid intrusive rocks(including the Shima porphyritic granodiorite and Gaozi quartz diorite porphyry)in the Ningzhen region were systematically investigated.These new geochronological data demonstrate that the intermediate-acid magmatism in the Ningzhen region dates to approximately between 109 and101 Ma.We present new40Ar-39Ar phlogopite ages for the Cishantou skarn iron deposits that constrain the timing of the mineralisation in the Ningzhen region.The phlogopite in the Cishantou skarn deposits yielded a40Ar-39Ar plateau age of 104±1 Ma.This result coincides with the ages of the Anjishan and Tongshan Cu(Mo)deposits in the Ningzhen region.Our high-precision geochronological data together with recent high-precision geochronological studies(such as zircon LA-ICP-MS U-Pb,zircon SHRIMP U-Pb,molybdenite Re-Os and single-mineral40Ar-39Ar dates)reveal that there were four periods(152-135 Ma,135-127 Ma,127-121 Ma,109-101 Ma)of magmatism and ore formation in the middle-lower Yangtze River metallogenic belt.The Mesozoic intermediate-acid magmatism and mineralisation in the Ningzhen region belong to the latest episode in the middle-lower Yangtze River metallogenic belt. The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt. The formation of the polymetallic deposits has close genetic relationships with Early Cretaceous intermediate-acid intrusions. In this study, LA-ICP-MS zircon geochronology of two Mesozoic intermediate-acid intrusive rocks (including the Shima porphyritic granodiorite and Gaozi quartz diorite porphyry) in the Ningzhen region were systematically investigated. These new geochronological data demonstrate that the intermediate-acid magmatism in the Ningzhen region dates to approximately between 109 and 101 Ma. We present new 40Ar-39Ar phlogopite ages for the Cishantou skarn iron deposits that constrain the timing of the mineralization in the Ningzhen region. Phlogopite in the Cishantou skarn deposits yielded a 40Ar-39Ar plateau age of 104 ± 1 Ma. This result coincides with ages of the Anjishan and Tongshan Cu (Mo) deposits in the Ningzhen region.Our high-precision geochronolo gical data together with recent high-precision geochronological studies (such as zircon LA-ICP-MS U-Pb, zircon SHRIMP U-Pb, molybdenite Re- Os and single-mineral 40Ar- 39Ar dates) 135 Ma, 135-127 Ma, 127-121 Ma, 109-101 Ma) of magmatism and ore formation in the middle-lower Yangtze River metallogenic belt. The Mesozoic intermediate-acid magmatism and mineralization in the Ningzhen region belong to the latest episode in the middle-lower Yangtze River metallogenic belt.