煤中惰质组在泥炭沼泽古环境研究中的应用

惰质组是煤中一种常见的显微组分。它不仅能用来鉴别成煤前植物的木炭化程度,而且还是泥炭沼泽古环境恢复的有效途径。近年来,欧洲学者利用惰质组成功推算了地史时期三叠纪—侏罗纪之交(T—J)的古火灾温度及类型,并重建了古植被类型及泥炭沼泽古生态环境变化。与其它方法相比,利用煤中惰质组含量及其反射率进行古环境恢复的工作对于植物种类繁多、沉积岩层中夹杂的煤层或煤炭、尤其对于古气候环境波动较大的地质转折时期最为理想。因此,利用惰质组的部分参数对我国含煤沉积盆地的古生态恢复以及成煤环境的研究有积极的借鉴意义。     

神东矿区富惰质组煤的形成条件研究——惰质组分的真菌交替成因意义

应用煤岩学分析方法,对神东矿区富惰质组煤中惰质组分的种类、含量、形态特征、真菌衍生物特征所反映的泥炭沼泽条件进行研究,揭示了真菌交替作用对惰质组分的成因意义。     

Provincial variation of carbon emissions from bituminous coal: influence of inertinite and other factors

We observe a 1.3 kg C/net GJ variation of carbon emissions due to inertinite abundance in some commercially available bituminous coal. An additional 0.9 kg C/net GJ variation of carbon emissions is expected due to the extent of coalification through the bituminous rank stages. Each percentage of sulfur in bituminous coal reduces carbon emissions by about 0.08 kg C/net GJ. Other factors, such as mineral content, liptinite abundance and individual macerals, also influence carbon emissions, but their quantitative effect is less certain.The large range of carbon emissions within the bituminous rank class suggests that rank-specific carbon emission factors are provincial rather than global. Although carbon emission factors that better account for this provincial variation might be calculated, we show that the data used for this calculation may vary according to the methods used to sample and analyze coal. Provincial variation of carbon emissions and the use of different coal sampling and analytical methods complicate the verification of national greenhouse gas inventories.     

Reactivity of semifusinite and fusinite in the view of micro-Raman spectroscopy examination

The study was performed on inertinite concentrates prepared from 19 samples of bituminous, mostly coking, coal (R_r = 0.87–1.42%) from the Upper Silesian Coal Basin of Poland. In all examined samples, total semifusinite differs from fusinite, in terms of mean values, by higher frequencies of the D1 and D4 band position and lower frequency of the D3 band position, higher G band FWHM, the A_D3/A_ALL and A_D4/A_ALL ratios (where A_ALL means the surface of all the Raman bands), and lower D1 band FWHM, the I_D1/I_G and A_D1/A_ALL ratios. Similar differences exist between reactive and non-reactive semifusinites. The diameter of coherent domains (L_a) increases in the following sequence: reactive semifusinite < non-reactive semifusinite < fusinite. The A_{D3 + D4}/A_ALL ratio reflects inertinite reactivity in bituminous coals, and decreases with the increase of mean reflectance (R_r) of semifusinite and fusinite. Using the A_{D3 + D4}/A_ALL, I_D1/I_G and A_D1/A_ALL ratios or the D3 band position it is possible to interpret thresholds dividing, in terms of mean values, total semifusinite and fusinite, coming from different coals. The results of the study suggest that the term “semifusinite” should only comprise reactive and semi-reactive components. Non-reactive semifusinite should be considered fusinite. Semifusinite from bituminous coals (of R_r ≈ 0.9–1.4%), defined in the proposed way, would be characterized by the A_{D3 + D4}/A_ALL ratio ≥ 0.35, or the I_D1/I_G ratio ≤ 1.03.     

Inertinite-rich Tertiary coals from the Zeya–Bureya Basin, Far Eastern Russia

Selected Tertiary coals from the Zeya–Buryea Basin, Far Eastern Russia, were investigated for aspects of their coal type, rank, depositional environment and post-depositional history. The coals have been examined in outcrop (lithotype logging), microscopically (maceral, reflectance and fluorescence), and geochemically (proximate analysis).Two laterally extensive coal-bearing horizons occur: one of Palaeocene age and the other of early Miocene age. The Palaeocene coals were investigated in active open-cut mines at Raichikhinsk and Yerkovtsi and the early Miocene deposit in an abandoned open-cut mine at Cergeyevka.Palaeocene coals at Raichikhinsk and Yerkovtsi were indistinguishable from each other macroscopically, microscopically, and geochemically. The deposits were sufficiently coalified that brightness logging could be undertaken. Dull coals, with numerous fusainous wisps, were dominant. Four dulling-up sequences, which represent stacked peat deposits, were observed at Raichikhinsk. At Yerkovtsi, only a small section of the middle of the seam, which was mostly dull and muddy coal, was investigated. Petrographically, these coals were dominated by inertinite group macerals, which is unusual in non-Gondwanan coals and rare in the Tertiary. Rank classification was problematic with volatile matter (VM) content of vitrain (daf), macroscopic appearance, and microscopic textures suggesting subbituminous B rank, but carbon content, moisture content and specific energy indicating a lignite rank.Notwithstanding complications of rank, estimates of the maximum-range burial depths were calculated. Taking the VM (daf) content of vitrain as 48%, burial depth estimates range from 900 m for a high geothermal gradient and long heating time to a maximum of 3300 m for a low geothermal gradient and short heating time. These estimates are maxima as the coal rank may be lower than implied by the VM.The Cergeyevka deposit is a soft brown coal. Limited sampling of the upper-most portion indicated a high moisture content (75% daf) and an unusual, hydrogen-rich geochemistry. Lack of identifiable liptinites using either reflected light or fluorescence microscopy suggested a significant bituminite component. Otherwise, the coals appear to be typical for the Tertiary. An estimate of 125 m maximum burial depth was obtained using the bed-moisture content of the coal, which is around the present burial depth.Comparison of present-day thicknesses with inferred burial depths suggests that at least 500 m of section is missing between the Palaeocene coals and the early Miocene coals.Palaeoenvironmental considerations suggest that fire played a significant role in the accumulation of the peats at Raichikhinsk and Yerkovtsi. At Cergeyevka, peat accumulation ended by drowning of the mire.Two tuff beds were recognised within the seam at Raichikhinsk and one in the seam at Yerkovtsi. Correlation of the tuff beds is uncertain but they should prove useful in regional coal seam correlation and interpreting coal depositional environments. Geochemical analysis by XRF was complicated by high loss-on-ignition (LOI) values. Despite extensive alteration, an acid igneous source is implied from the presence of free quartz and TiO₂/Al₂O₃ ratios of 0.02 to 0.05.