Abstract:

To investigate the geochemical characteristics of trace elements in the Mengtuo Neogene lignite of Lincang in western Yunnan, a total of 11 lignite samples were collected, and the trace elements were determined by ICPMS and ICPCCTMS(As and Se). Results indicated that the enriched trace elements were different from the Dazhai Gerich coals, i.e., significant enrichment of Rb(96.1 mg/kg), Sb(15.3 mg/kg) and Cs(25.9 mg/kg), enrichment of W(10.6 mg/kg) and U(20.2 mg/kg), and slight enrichment of Be(7.84 mg/kg), Ga(16.1 mg/kg), As(11.6 mg/kg), Cd(0.67 mg/kg), Sn(6.66 mg/kg), Pb(34.6 mg/kg), Bi(3.86 mg/kg) and Th(28.2 mg/kg) when compared to common Chinese coals, which might be inherited from the weathered granite around coalaccumulating basin. The REY concentrations in Mengtuo lignite range from 121 mg/kg to 420 mg/kg, with an average of 251 mg/kg, higher than that of Chinese coals. The UCCnormalized REY distribution patterns of Mengtuo lignite are characterized by the significant positive Ce anomaly and negative Eu anomaly, obviously differentiating from that of Dazhai coals, suggesting a terrigenous input of REY from weathered granite.

Key words: trace elements, geochemistry, lignite, Mengtuo, Lincang