Platinum and Palladium in Coal Rock and Geochemical Anomaly in Eastern Yunnan Province, Southwest China

A series of geochemical anomalies of Pt and Pd were found in 1 358 recombined samples from a geochemical stream sediment survey in eastern Yunnan Province, China. Chemical optical emission spectroscopy, X-ray fluorescence analysis, and inductively coupled plasmas atomic emission spectrometry analyses of 22 elements and chemical compositions of 21 samples from coal-bearing strata from the Late Paleozoic, Mesozoic, and Cenozoic show Pt and Pd concentrated to some extent in coal rocks, with Pd/Pt<1. As, Pt, B, Au, Pd, V, Sb, U, Pb, and W are enriched in the Lower Carboniferous coal-bearing strata of the Wanshoushan Formation; B, Mo, As, Pt, U, W, Pb, Pd, and V are enriched in the Lower Permian coal-bearing strata of the Liangshan Formation; Pt, Cu, Mo, Pd, As, V, and Ag are enriched in the Upper Permian coal-bearing strata of the Xuanwei Formation; As, B, Pb, Pt, Pd, U, W, Sb, Mo, Zn, and Ag are enriched in the Upper Triassic coal-bearing strata of the Xujiahe Formation; and Pt, As, and Pb are enriched in the lignite of the Pliocene Ciying Formation. Combining analyses of the sedimentary environment and local volcanic activity reveal that the coal- bearing strata in the Xuanwei Formation are possibly related to the Permian Emeishan basalt.