从神木煤田2~（－2）煤层煤岩特征看泥炭沼泽演化     

周春光  杨起  康西栋 《煤田地质与勘探》1996,(6)

在研究神木煤田２－２煤层煤岩特征的基础上，划分了三种泥炭沼泽类型，即开阔水体草本沼泽、陆地森林沼泽和潮湿森林沼泽。泥炭沼泽由三角洲平原上的浅水湖泊演化而来并经历了三个演化阶段。成煤植物早期以草本为主，中期和后期以木本为主。森林火灾和洪泛事件在中期最为频繁。  相似文献   

从"译文"想到龙潭多金属钨矿的重新评价     

薛步高 《矿产与地质》2003,17(2):145-149

通过与美国Fort knox等7个大型金矿床[1]及广东莲花山斑岩型含金钨矿床的对比,认为龙潭现存铁帽状钨矿相当于含钨(锡)氧化物的硫化物带的中上部,其中下部主体硫化物带应是今后找金评价的重点.  相似文献   

The geology, petrology, palynology and geochemistry of Permian coal basins in Tanzania: 2. Songwe-Kiwira Coalfield     

P. Semkiwa  W. Kalkreuth  J. Utting  F. Mpanju  H. Hagemann 《International Journal of Coal Geology》2003,55(2-4):157-186

This study provides coal quality, petrological, palynological and geochemical (Rock Eval) data on Permian coal seams and associated shales and mudstones of the Karoo Supergroup of the Songwe-Kiwira Coalfield, Tanzania. The coal seams, which have a cumulative thickness of 6.80 m, occur in the shale–coal–sandstone facies of the Mchuchuma Formation of Artinskian to Kungurian(?) age.Coal quality data (calorific values, volatile matter contents) and vitrinite reflectances indicate high volatile C bituminous to high volatile A bituminous coals, having relatively high ash yields (22–49 wt.%) and highly variable sulphur contents (0.17–9.2 wt.%). They could be used to fuel small-scale power generation units thereby providing electricity to nearby towns and villages. Also, the coals could be used as a substitute for wood, which is becoming increasingly scarce. In rural Tanzania, charcoal is still the main energy source for cooking, and wood is used extensively in brick kilns and for making roofing tiles.Petrological analysis indicated that the coals are dominated by dull to banded dull lithotypes, with seams at the base of the Mchuchuma Formation enriched in inertinite macerals (up to 83 vol.%), whereas up-section vitrinite contents increase. Palynological analyses indicated that the assemblage in the lower Mchuchuma Formation (Scheuringipollenites assemblage) is dominated by trilete spores, whereas in the remainder of the section, non-taeniate disaccates dominate (Scheuringipollenites–Protohaploxypinus assemblage). Facies critical macerals suggest for most seams a marsh/wet forest swamp depositional setting, which is consistent with the palynological data.Rock Eval analyses indicate type II/III kerogen, with Tmax (°C) values ranging from 426 to 440, corresponding to the early stage of hydrocarbon generation. Thermal Alteration Indices (2 to 2+) and vitrinite reflectance levels (0.60–0.83 Ro (%) support the Rock Eval maturity assessment, and despite the predominance of terrestrial-derived organic matter, there is evidence of oil generation and expulsion in the form of cavity and fracture filling exsudatinite.  相似文献   

Petrologic and geochemical characteristics of Seam 9-3 and Seam 2, Xingtai Coalfield, Northern China     

Yuzhuang Sun  W. Püttmann  W. Kalkreuth  B. Horsfield 《International Journal of Coal Geology》2002,49(4)

Six samples of Carboniferous (Mississippian–Pennsylvanian) coal (Seam 9-3) and 11 samples of Permian coal (Seam 2) from the Xingtai Coalfield were studied by petrological and organic geochemical methods. Both seams show different petrological and geochemical compositions. In Seam 9-3 of the Carboniferous age, the predominant maceral is vitrinite (83%) whereas in Seam 2 of Permian age, inertinite predominates (45%). “Barkinite” was found with an average content 1% only in Seam 2. Sixty-four different aromatic compounds were identified by gas chromatography (GC)/mass spectrometry (MS) analysis of solvent extracts (Extr) of both seams. Abundant polyaromatic sulfur hydrocarbons (PASH) were determined in coal samples from Seam 9-3, while they are very low in samples from Seam 2. 1,2,5-Trimethylnaphthalene and 1,2,5,6-tetramethylnaphthalene contents are much higher in Seam 2, while 2-methylfluorene contents are higher in Seam 9-3. Cadalene was found in Seam 2 with a high content of 94 mg/kg coal but was not detected in samples from Seam 9-3. This might indicate a different floral contribution to the sedimentary organic matter. All petrologic and geochemical results indicate that Seam 2 formed in a more oxidized environment compared with Seam 9-3.  相似文献   

浅析贵州二叠系上统龙潭组27号煤层的聚煤规律   总被引：1，自引：0，他引：1  

郑建军 《中国煤田地质》2007,19(6):3-4,13

通过对27号煤层沉积背景、环境演化过程、分布特点、赋存状态、结构特点和煤厚变化特征进行分析，认为27号煤层主要沉积于海陆交互相环境，赋存在龙潭组中下部，厚0．1～4．8m，为薄-中厚煤层。该煤层在威宁-毕节以东、兴仁-贵阳-遵义以西范嗣内都有分布，夹石0～5层，～般为3层，向两南方向夹层增多。煤层厚度有北薄南厚、由西向东为薄-厚-薄的变化规律，六盘水煤田、织纳煤田为聚煤中心地带，  相似文献   

Geochemistry and mineralogy of the Late Permian coals from the Songzao Coalfield, Chongqing, southwestern China   总被引：4，自引：0，他引：4  

DAI ShiFeng  ZHOU YiPing  REN DeYi  WANG XiBo  LI Dan  ZHAO Lei 《中国科学D辑(英文版)》2007,50(5):678-688

Mineralogy and geochemistry of the four main workable coal seams (No.6, No.7, No.8, and No.11) of Late Permian age from the Songzao Coalfield, Chongqing, Southwest China, were examined using in- ductively coupled plasma-mass spectrometry (ICP-MS), X-ray fluorescence spectrometry (XRF), cold-vapor absorption spectrometry (CV-AAS), ion-selective electrode (ISE), scanning electron mi- croscopy equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), and X-ray diffraction analysis (XRD). The results showed that the main workable No.8 Coal that accounts for about 60% of the total coal reserves in the Songzao Coalfield was not enriched in hazardous trace elements. The No.11 Coal has high concentrations of alkaline elements, Be (9.14 μg/g), Sc (12.9 μg/g), Ti (9508 μg/g), Mn (397 μg/g), Co (23.7 μg/g), Cu (108 μg/g), Zn (123 μg/g), Ga (32 μg/g), Zr (1304 μg/g), Nb (169 μg/g), Hf (32.7 μg/g), Ta (11.4 μg/g), W (24.8 μg/g), Hg (0.28 μg/g), Pb (28.1 μg/g), Th (24.1 μg/g), and rare earth elements (509.62 μg/g). The concentration of Nb and Ta in the No. 11 Coal is higher than the industrial grade, and their potential utilization should be further studied. Besides pyrite, quartz, calcite, and clay minerals, trace minerals including chalcopyrite, marcasite, siderite, albite, mixed-layer clay minerals of illite and smectite, monazite, apatite, anatase, chlorite, and gypsum were found in the No.11 Coal. It should be noted that alabandite of hydrothermal origin and anatase occurring as cement were identi- fied in coal. In addition, the clayey microbands derived from alkaline volcanic ashes were identified in the coal. The dominant compositions of these clayey microbands were mixed-layer clay minerals of illite and smectite, which were interlayered with organic bands. The modes of occurrence of alkaline volcanic ash bands indicate that the volcanic activities were characterized by the multiple eruptions, short time interval and small scale for each eruption during peat accumulation. The alkaline volcanic ashes were the dominant factors for the enrichment of alkaline elements, Nb, Ta, Zr, Hf, and rare earth elements, and the sulfide minerals are the main carriers of Ga, Cu, and Hg in the No. 11 Coal.  相似文献   

内蒙古胜利煤田共生锗矿品位纵向变化规律研究   总被引：4，自引：0，他引：4  

杜刚  汤达祯  武文  孙培城  白云来  杨文彬  玄艳琴  张立成 《煤田地质与勘探》2004,32(1):1-4

通过对29个钻孔的 200件煤样锗含量分析,发现20个钻孔锗含量沿煤层纵向有 6种变化形式。特别值得注意的是,大多数钻孔显示锗含量在煤层中部出现高峰值,而有别于以往所报道的锗只在煤层顶、底部相对富集的研究结论。笔者认为,胜利煤田锗的富集主要发生在泥炭化阶段,主要作用机制是有机质的吸附作用;此外,锗的聚集强度还随着原始沉积环境和锗源供给条件而变化。   相似文献   

黄陇煤田应用金刚石钻进的问题     

张晓宏 《煤田地质与勘探》2003,31(6):60-62

分析了黄陇煤田大佛寺井田金刚石单管和双管取心及绳索取心钻井技术应用效果;指出了存在的问题;展望了黄陇煤田发展金刚石绳索取心工艺技术。   相似文献   

Petrographic and geochemical effects of sill intrusions on coal and their implications for gas outbursts in the Wolonghu Mine, Huaibei Coalfield, China   总被引：3，自引：0，他引：3  

Jing-Yu Jiang Yuan-Ping Cheng  Lei WangWei Li  Liang Wang 《International Journal of Coal Geology》2011,88(1):55-66

Since the early 1980s, fifteen outbursts have occurred in the Huaibei Coalfield of China. These outbursts were reported to be associated with sills. To study the effect of sill intrusions on coal seam and their relationship to methane outbursts, eleven samples from the No. 10 coal seam were taken from the Wolonghu Mine at various distances from a diorite sill. Comparisons were made between unaltered and heat-affected coals using petrographic and chemical data, micropore characteristics, adsorption properties of coal, and gas outburst indexes from field. Approaching the intrusion, vitrinite reflectance levels increased from 2.74% to 5.03%, and the thermal aureole of the sill ~ 60 m (from the sill boundary to sample 9). Three zones along this gradient were identified as corresponding to (1) thermal evolution zone No. 1 (0-5 m from sill), (2) thermal evolution zone No. 2 (5-60 m from sill), and (3) unaltered zone. The methane adsorption capacity of coal samples in the thermal evolution zone No. 2 was generally higher than in the two other zones, and the unaltered zone higher than the thermal evolution zone No. 1. It is concluded that the contact-metamorphism decreased the adsorption capacity of coal and the thermal evolution of sill increased it. The trap effect of sill, combined with the mudstone and siltstone roof and floor of the No. 10 coal seam, provided a seal for the formation of a gas pocket. Abnormally high formation pressures at the No. 10 coal seam led to two outbursts.  相似文献   

基于偏最小二乘法的土壤汞含量高光谱反演   总被引：1，自引：0，他引：1  

宋玉  塔西甫拉提·特依拜  李崇博  侯艳军  陶兰花  张飞 《地理与地理信息科学》2015,31(3):44-47,53

采集新疆准东煤田典型土壤样品44个,在实验室测定风干后的土样汞含量和光谱反射率,经预处理后分析两者的相关性,运用偏最小二乘法(PLSR)建立土壤汞含量高光谱估算模型,由均方根误差RMSE和决定系数R2检验模型的预测能力和稳定性,并比较不同预处理方法的适用性。结果表明:反射率一阶微分光谱是估算土壤汞含量较好的指标,估算R2为0.77、RMSE为0.032。通过各种光谱预处理方法可提高土壤汞含量的估算精度,为研究区生态环境的恢复和评价提供依据。  相似文献