排序方式: 共有35条查询结果,搜索用时 15 毫秒
31.
Geochemical significance of pyrrolic nitrogen compounds in various kinds of crude oils from the Tarim Basin 总被引:1,自引:0,他引:1
This is a report of the differences in abundances of pyrrolic nitrogen compounds and distribution of alkylated carbazoles
among various oils from the Tarim Basin. At the same time, their geochemical significance is discussed. 相似文献
32.
Baiguoyuan silver-vanadium deposit is generally thought to be of sedimentary-diagenetic origin. Based on the characteristics
of barites, it is suggested that hydrothermal transformation has been involved in mineralization. The barites in black shale
can be grouped into irregular ones which were formed during early diagenesis and tabular ones which were formed during late
diagenesis. The tabular barites are replaced by pyrite and have formed a regular girdle around them. PlXE analysis states
that Ag is greatly concentrated in pyrite replacement girdle. The girdle is the product of hydrothermal transformation. The
transformation is one of the main mineralization stages of Baiguoyuan deposit. 相似文献
33.
Organic lipids with different occurrence modes in a sedimentary core in a subtropical freshwater lake, Gucheng Lake, were
sequentially extracted, separated and analyzed. The down-core variations of OEP index of alkanes, C18:2/C18:0 ratios of fatty acids, ratios of bound, fatty acids to free fatty acids, thermo-maturity indices of hopanoid hydrocarbons
and rerative concentrations of sedimentary minerals revealed an evident increasing in allochthonous input from rock detritus
below 12.28 m in the sedimentary profile. The distribution pattern of tightlybound β-hydroxy fatty acids indicated a difference
in bacterial communities above and below the boundary, as well as the gammacerane index may assign a significant change in
lake water salinity. The evidence, in general, suggested that a significant paleoenvironmental change had taken place in ca.
9.6 kaBP on the regional basis. 相似文献
34.
High performance liquid chromatography (HPLC) has the advantages of rapid analysis and high sensitivity. In the present study a suitable analytical condition has been established for HPLC, and the LAS in modern sediments from core Zhu-9 at the Pearl River mouth has been determined by HPLC. The concentrations of C12-LAS homologues are the highest. The sedimentation flux of C12-LAS was correlated with the average flow of the Xijiang and Beijiangrivers: the higher the flow rate, the larger the C12-LAS sedimentation flux. This shows that the more rapidly the river flows, the shorter the LAS will stay in freshwater, the less the extent of biodegradation, the larger the C12-LAS sedimentation flux in the core Zhu-9. 相似文献
35.
Sun Yongge Wang Zhiyong Sheng Guoying Zhang Shihuan Peng Ping’an Fu Jiamo Wang Wuhe Yuan Mingshen 《科学通报(英文版)》2001,46(20):1737-1740
To date, questions remain as to how to differentiate between coaland interbedded shale-sourced oils in coal measures. Based
on the hypothesis that δ13C value of sedimentary organic matter is controlled by the depositional environment and productivities of biota grown in such
depositional setting, this note examines compound specific carbon isotopic profiles from coal and interbedded shale extracts
using the gas chromatography-isotope ratio mass spectrometry technique (GC/IRMS). The results show that compound specific
carbon isotope values from coal extracts are enriched in13C relative to that of interbedded shale extracts, and provide useful information in characterizing coal- and interbedded shale-sourced
oils in coal measures. An example for its successful application from the Turpan Basin, Northwestern China is presented. 相似文献