滇西户撒盆地新近系褐煤微量元素地球化学特征

为探讨滇西户撒盆地新近系褐煤的微量元素地球化学特征及指示意义,采集了5口验证钻孔内15层褐煤的新鲜样品,利用ICP-MS对微量元素含量进行测试。结果表明,与中国煤微量元素背景值进行比较,户撒盆地褐煤Rb、Cs、Th富集,Be、Sc、Cr、Cu、Ga、In、W、Pb、U稍富集。户撒褐煤富集的潜在有害微量元素有Be(5.32mg/kg)、Cr(39.8mg/kg)、Cu(39.7 mg/kg)、Pb(32.8 mg/kg)、Th(39.3 mg/kg)和U(7.39 mg/kg)。褐煤的REE总量为196.03~550.42 mg/kg,平均为306.71 mg/kg,远高于中国煤的REE总量均值(136 mg/kg),表现出LREE明显富集,HREE相对亏损特征。δCe值负异常与微量元素比值特征均表明户撒泥炭的沉积期主要为酸性还原环境。δE负异常与球粒陨石标准化分配模式表明户撒新近系褐煤稀土元素与盆缘酸性花岗岩的陆源供给有关。

Geochemical signatures of the trace elements in the Neogene lignites in the Husa Basin,western Yunnan

In order to investigate geochemical signatures of the trace elements in the Neogene lignites in the Husa Basin, western Yunnan, a total of 15 layers of fresh lignite samples were collected in 5 boreholes, and the trace elements were determined by using ICP-MS. The Neogene lignites in the Husa Basin display significant enrichment of the elements Rb, Cs, Th, and slight enrichment of the elements Be, Sc, Cr, Cu, Ga, In, W, Pb and U when compared to the common Chinese coals. The potentially hazardous trace elements in the lignites in the Husa Basin include the elements Be (5.32mg/kg), Cr (39.8 mg/kg), Cu (39.7 mg/kg), Pb (32.8 mg/kg), Th (39.3 mg/kg) and U (7.39 mg/kg). The REE concentrations in the lignites in the Husa Basin range from 196.03 to 550.42mg/kg, with an average of 306.71 mg/kg, much higher than that of the common Chinese coals. The right-leaning REE distribution patterns suggest the significant LREE enrichment and relative HREE depletion, and are in general agreement with those of the upper crust. The negative Ce anomaly and trace elelment ratios indicate that the peats in the Husa Basin were once deposited in the acidic reducing sedimentary environments. The negative Eu anomaly and chondrite-normalized REE distribution patterns indicate that the origins of the Neogene lignites in the Husa Basin have something to do with the terrigenous supply of acidic granites along the margins of the Husa Basin.