甘肃西成铅—锌矿田干酪根的特征

本文对西成矿田中泥盆统内含有机碳岩石中干酪根分析，认为该区内的干酪根主要由镜质体，壳质体，藻质体，惰质体，惰质组和矿物质组成，属于腐植型干酪根，颜色从淡黄到黑色，从西向东颜色加深，Ｒ０值也有同样的趋势，说明在矿区内成熟度不一致，热解分析发现Ｓ２峰有分叉现象，经过氯仿抽提后分叉消失，从可溶有机质的色谱分析中发现有大量氮硫氧化合物，证明分叉现象可能是由氮硫氧化合物引起。Ｒ０值越大，反映出干酪根的再改造

THE CHARACTER OF KEROGEN IN THE XICHENG Pb-Zn OREFIELD,GANSU PROVINCE

The Xicheng Pb-Zn Orefield, which belongs to the Hercynian Kunlun-Qiling accretionary fold belt, is located in Xihe county, Gansu province. Pb-Zn ore beds are confined to the Devonian sediments of this fold belt. There is a lot of organic carbon in the sediments, and these ore bodies are mainly distributed in the organic-rich strata.Kerogen in carbon-bearing rocks is discussed in this paper. The components of kerogen in this area are mainly vitrinite, exinite, alginite and inertinite, so the kerogen belongs to sopropel-humus type kerogen. The maturity of kerogen differs from place to place in the orefield. By py-rolysis, samples, especially shale samples, studied showed a double S2 signal; in these cases the first of the two peaks can be eliminated by a preliminary chloroform extraction. NSO-compounds were found by the chromatogram analysis; therefore the first peak of S2 may be due to NSO-compounds. It is concluded from the maturity and R0 value of kerogen that several episodes of hydrothermal activities occurred in this area. The ore deposits in the Xicheng Orefield were found by hydrothermal activities.