Concentrations and origins of platinum group elements in Late Paleozoic coals of China

摘要

The platinum group elements (PGEs) in 63 samples collected from the Late Paleozoic coal-bearing strata in western Guizhou Province and North China were determined using high-resolution inductively coupled plasma-mass spectrometry (HR ICP-MS). The study shows that PGEs in coal have five different sources: magmatic hydrothermal inputs, low-temperature hydrothermal fluids, synsedimentary volcanic ash, detrital minerals of terrigenous origin, and seawater. This study indicates that the first three sources can lead to enrichment of PGEs in these Chinese coals. The typical low contents of PGEs in most of the studied coals, defined as background contents in this work, mainly originate from detrital minerals. The background content of Pd (150 ng/g) is higher than that of Pt (30 ng/g), and much higher than that of Ru (5 ng/g), Rh (14 ng/g), and Ir (1 ng/g). The Pd content is nearly 15-fold higher than the crustal abundance. In contrast, Pt content is lower than its crustal abundance. The relatively good correlation between Pd, Pt, and ash contents suggests that the PGEs are associated with minerals.