Abstract: In order to identify the magma source of the Bolong metallogenic granodiorite porphyry,the Sr-Nd-Pb isotopes of the metallogenic granodiorite porphyry are tested systematically.The test results show that,the values of δ⁸⁷Rb/δ⁸⁶Sr and δ⁸⁷Sr/δ⁸⁶Sr are from 1.265 to 10.151 2 and from 0.711 041 to 0.725 101，and the value of (87Sr/86Sr)i is from 0.707 59 to 0.709 83.The value of (¹⁴³Nd/¹⁴⁴Nd)i and ε_Nd(t) are from 0.512 09 to 0.512 30 and from -7.714 774 to -3.572 778 respectively.And the ranges of δ²⁰⁶Pb/δ²⁰⁴Pb,δ²⁰⁷Pb/δ²⁰⁴Pb and δ²⁰⁸Pb/δ²⁰⁴Pb are from 17.068 to 17.820,from 15.485 to 15.556,and from 36.861 to 37.804 correspondingly.The characteristics of Sr-Nd-Pb isotope shows that,the magma source of the Bolong copper mine area owns the property of EMⅠ and EMⅡ type enriched mantle and it may have originated from the mantle fluid metasomatism wedge area formed by the oceanic curst subduction dehydration,and been contaminated by the lower crust mass in the process of invasion.The Bolong porphyry copper deposit is formed in the magmatism process induced with the northward subduction of the Bangong Lake Neo-Tethyan Ocean.

Key words: Sr-Nd-Pb isotope, Granodiorite porphyry, Geochemistry