Concentration and mode of occurrence of trace elements in marine oil shale from the Bilong Co area, northern Tibet, China
Concentration and mode of occurrence of trace elements in marine oil shale from the Bilong Co area, northern Tibet, China
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DOI：
10.1016/j.coal.2010.10.004
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发表时间：
2011
影响因子：
5.6
通讯作者：
X. Fu;Jian Wang;Y. Zeng;F. Tan;Xinglei Feng
中科院分区：
文献类型：
--
作者：
X. Fu;Jian Wang;Y. Zeng;F. Tan;Xinglei Feng
碧龙错油页岩带位于南羌塘坳陷。该带与藏北北方羌塘坳陷的胜利河-长蛇山油页岩带一起，代表了中国潜在的大型海相油页岩资源。为了更好地了解海相油页岩的地球化学特征，对碧龙错地区18个油页岩样品进行了研究，测定了其中56种元素。Mo、Se、Cd、Cs、As、Bi、U、Rb、Pb、Th、Li、Sr和Zn的含量是地壳平均浓度（Clarke值）的1.3 ~ 35.0倍，而其他元素的含量略高于/低于各自的Clarke值。与澳大利亚油页岩相比，澳大利亚碧龙错油页岩样品中Ce、Co、Cs、F、Ga、Hf、Nb、Nd、Pb、Pr、Rb、Sc、Sn、Th、Zr等元素含量相对较高，而As、Br、Cd、Cr、Cu、Dy、Er、Eu、Ho、Lu、Mo、Ni、Se、Tb、Tm、U、V、Y、Yb、Zn等元素含量相对较低。然而，微量元素的分布模式是非常相似的，这表明油页岩中的微量元素形态是由一般的过程，而不是由一个特定的样品中的个别地球化学机制。碧龙错油页岩中的元素按其赋存状态可分为A、B、C三组组合。A组（Si-Al-K-Na-Ti-Zr-Sc-Th-Sn-Nb-Ga-Ta-Be-Hf-Cs-Li-Rb-ash-REEs）与灰分产率密切相关，主要具有无机亲合性。B组（Cr-W-Mg-Mn-Br-F-Sr-Ba）与灰分产率呈弱或负相关（F除外）。C组（Zn-Bi-Cd-Ca-Fe-Pb-Hg-Co-Cu-Ni-P-Mo-Se-U-As-V）与灰分产率呈负相关系数（Bi除外），可能具有有机亲和力。
The Bilong Co oil shale zone is located in the South Qiangtang depression. This zone, together with the Shengli River-Changshe Mountain oil shale zone in the North Qiangtang depression, northern Tibet plateau, represents a potentially large marine oil shale resource in China. With the aim of better understanding geochemistry of marine oil shale, 18 samples from the Bilong Co area are studied and 56 elements in them are determined. The contents of Mo, Se, Cd, Cs, As, Bi, U Rb, Pb, Th, Li, Sr, and Zn are enriched from 1.3 to 35.0 times as compared with the average concentration in the crust (Clarke values), whereas the other elements are slightly higher/lower than the respective Clarke values. Compared to common Australian oil shales, the contents of Ce, Co, Cs, F, Ga, Hf, Nb, Nd, Pb, Pr, Rb, Sc, Sn, Th, and Zr in the Bilong Co oil shale samples exhibit relatively high levels, whereas As, Br, Cd, Cr, Cu, Dy, Er, Eu, Ho, Lu, Mo, Ni, Se, Tb, Tm, U, V, Y, Yb, and Zn are relatively depleted. However, the distribution patterns of trace elements are quite similar indicating that trace-element speciation in oil shale is governed by general processes rather than by individual geochemical mechanisms within one particular sample. The elements in the Bilong Co oil shale may be classified into three groups of association according to their modes of occurrence, i.e. Groups A, B, and C. Group A (Si–Al–K–Na–Ti–Zr–Sc–Th–Sn–Nb–Ga–Ta–Be–Hf–Cs–Li–Rb–ash–REEs) is strongly correlated with ash yield and mainly has an inorganic affinity. Group B (Cr–W–Mg–Mn–Br–F–Sr–Ba) has weakly or negatively positive correlation coefficients (with an exception of F) with ash yield. Group C (Zn–Bi–Cd–Ca–Fe–Pb–Hg–Co–Cu–Ni–P–Mo–Se–U–As–V) shows negative correlation coefficients with ash yield (with an exception of Bi) and possibly has an organic affinity.