HAN Tao^{1, 2} , ZHU Xiao-qing¹ , CHEN Nan-sheng¹

1.State Key Laboratory of Ore Deposit Geochemistry , Institute of Geochemistry , Chinese Academy of Sciences, Guiy ang 550002, China;
2. Graduate University of Chinese Academy of Sciences , Beijing 100049, China

Abstract: This paper studied the occurrence of platinum group elements (PGE) in the polymetallic layer of black shales, Zunyi, Guizhou using sequential chemical extraction(SCE) , heavy liquid separation and inductively coupled plasma mass spectrometry ( ICP-MS) , and discussed the evolution of PGE in black shales. The results of SCE indicated that PGE mainly concentrates in sulfide minerals. The occurrences of Pt and Pd in the layer are diff erent : a part of Pt is adsorbed in clay minerals while Pd is likely to form independent minerals in addition to adsorption portion in clay minerals. Combined with previous research result s, we proposed that PGE transported in the hydro-thermal fluid as different complexes, such as chlorine, bisulfide and ammonia complexes. The clay minerals, organic matter and sulfide served as geochemical barriers in the mineralization of PGE.