Apatite is a characteristic mineral for the iron deposits in the Ningwu region. Apatite shows a range of d13CPDB values from à9.6& to à0.6&,and most of them with the d13CPDB values distributed in a range of mantle carbon (i.e.,à2& to à9&),except for samples T-06-1 and J-06-3. Apatites in the Ningwu porphyry iron deposits yield a narrow variation range of 87Sr/86Sr values from 0.706326 to 0.707577,similar to those of the volcanic and subvolcanic rocks and higher than that of a typical mantle-derived magmatic apatite (i.e.,about 0.7040),indicating that formation of the apatites was involved with crust material contamination. d13CPDB and 87Sr/86Sr values of the apatite indicate a possible contribution of mantle-derived fluid and material to formation of the Ningwu porphyry iron deposits,supported by regional geology,regional gravities and geochemistry of the volcanic and subvolcanic rocks in the Ningwu region.