Dating of coal fires in Xinjiang, north-west China

Coal fires in China consume vast amounts of fuel and cause serious environmental problems. Most of these coal fires are related to mining activity. However, naturally produced palaeo coal fires in Xinjiang, north‐west China, have been recognized via burnt rocks. The burnt rocks in the study area are found at different river terraces underlying unburnt alluvial and river terrace deposits. Several age groups of coal fires have been identified based on the positions of burnt rocks at river terraces and the relationship between the burnt rocks and the terrace deposits. These palaeo coal fires are: (1) Pliocene – Early Quaternary in age at 200 m above present river terrace deposits; (2) Middle Pleistocene in age, at > 90 m; (3) Late Pleistocene, at 90–70 m; (4) Holocene; (5) burnt rocks relating to active coal fires. Palaeomagnetic data of the burnt rocks from different terraces give normal remanent magnetization and help further to constrain the ages of the coal fires.     

The Metamorphism of Fe-rich Pelites from Connemara, Ireland

Connemara pelites show progressive metamorphism from stauroliteto upper sillimanite zones and possess low Mg/(Fe + Mg) values,typically 0.30 to 0.35 from about 100 analyses. As a consequenceof their composition, many sillimanite zone pelites lack bothmuscovite and K-feldspar. Staurolite, garnet, biotite, muscovite,feldspars and iron ores have been microprobe analysed in 48samples. Assemblages, textures and mineral compositions indicatethat metamorphism followed a sequence of continuous and discontinuousreactions with systematic variations in mineral Mg/(Mg + Fe)as predicted by theory. Contrary to some common assumptions,most reaction takes place along divariant equilibria; univariantreactions are seldom reached because reactants such as chloriteor muscovite are first consumed along divariant curves. Pelitepetrogenetic grids showing univariant curves can only indicatelimits to natural assemblages; they typically do not show whichreactions have actually taken place. Physical conditions of metamorphism have been calculated bya variety of means; temperatures range from 550° for thestaurolite zone to 650° for the upper silimanite zone, withthe first appearance of sillimanite near 580°. An earlykyanite-staurolite metamorphism at pressures above about 5 kbwas followed by a steepening of the thermal gradient leadingto regional cordierite and andalusite. This was probably accompaniedby uplift with pressures of around 4 kb for roeks near the sillimanite-inisograd.     

Thermal alteration of coal in the Khasyn coalfield, Magadan region, Russia

The Early Cretaceous coal deposits of the Khasyn coalfield are intruded by Palaeogene diabase dikes. The coal has vitrinite reflectance values of 2.0–2.5% R_o, and characteristics of normal anthracite at some distance from the dikes, but at direct contact with the dike two morphological coal varieties occur: coal inclusions in the diabase dike and dispersed carbonaceous matter within the dike rock. Both types of coaly matter have properties typical of anthracites: strong anisotropy, altered internal structure and high vitrinite reflectance values ranging from 3.8 to 5.5% R_o. The X-ray diffraction measurements of the interplanar spacing d(002) and the crystallite sizes Lc and La show rather similar values for coal inclusions in the dike and dispersed carbonaceous matter. The additional reflection at 3.37 Å, corresponding to semi-graphite admixture, occurs in the coal and carbonaceous matter inside the dike and is absent in the natural coal outside the dike.     

接近于铁橄榄石端员组份的铁橄榄石集合体的发现及其初步研究

铁橄榄石集合体为无根岩石。外观呈铁黑色,风化面呈亮栗褐色。本文对铁橄榄石集合体的形态特征、物理性质和化学成分进行了研究。通过化学式的计算,其化学式为:(Mg_(0.0168)Fe_(0.9802)Mn_(0.003))_2[SiO_4],证明其为铁橄榄石的端员组份。此外,还对其进行了穆斯堡尔谱分析、X射线粉晶衍射分析和红外光谱分析。其穆斯斑堡尔谱分析结果与人工合成的铁橄榄石数据相近,它的衍射数据及计算的晶胞参数也与JCPDS所提供的标准数据非常接近,这些进一步证明了铁橄榄石集合体的成分接近于铁橄榄石端员组份。     

Natural coal fires in the Kuznetsk Coal Basin: Geologic causes,climate, and age

The paper summarizes data on the Pleistocene combustion metamorphic complexes of the Kuznetsk Coal Basin. Paralava and clinker samples are dated by 40Ar/39Ar incremental heating. The 40Ar/39Ar ages of the combustion metamorphic rocks permit reconstructions of the succession of renewed activity of ancient faults in the Salair zone and age estimates for the evolution of the present-day drainage network. Cross sections of burned rocks from the western margin and center of the Kuznetsk Basin are compared. The geologic factors of coal ignition risks are analyzed. On the western margin of the Kuznetsk Basin, paleofires occurred in steeply dipping thick seams with predominant crushed vitrain–clarain coal, which has a high oxygen and methane adsorption capacity. Highly denuded high-temperature combustion metamorphic complexes are most often localized in the arches of slightly broken anticlines. Oxygen was supplied to the coals during the Late Cenozoic renewed fault activity and the subsequent erosion of the sediments. The natural fires in the area were a result of external rather than spontaneous ignition. The depths of the paleofires (up to 200 m) indicate that they occurred in a warm and dry climate. In the center of the Kuznetsk Basin, dispersed fire foci appeared in seams of self-igniting coals with the erosion propagation of the current drainage network. The combustion metamorphic complexes here are partly eroded and consist mostly of clinkers with a low degree of alteration. The 40Ar/39Ar ages and geological data indicate that the earliest large-scale combustion events on the western periphery of the basin occurred in the Eopleistocene (1.3–0.9 Ma).The oldest 40Ar/39Ar age of a coal fire episode (1.7 ± 0.3 Ma) might be the upper age boundary of the altitude differentiation of topography, which corresponds to the renewed activity of the Tyrgan and Afonino–Kiselevsk faults. The later synchronous combustion events on the western margin (0.2 ± 0.1 Ma) and in the center of the basin (0.13–0.02 Ma), most probably, occurred during the Kazantsevian interglacial, which gave rise to the present-day drainage network.     

Multi-sensor data fusion for the detection of underground coal fires

The spontaneous combustion of coal causes widespread underground coal fires in several countries, amongst which is China. These coal fires cause serious environmental, economic and safety problems. In northern China, the coal fires occur within a wide region stretching 5000 km east-west and 750 km north-south. Remote sensing therefore provides an ideal tool for monitoring this environmental hazard over such a large and remote area. As part of a research project to detect, measure, monitor and extinguish these coal fires, this paper describes a remote-sensing-based multi-sensor data-fusion methodology for detecting the underground fires. The methodology is based on fusing a variety of satellite-based image types (optical, thermal, microwave) together with airborne data (optical and thermal infrared) and ancillary data sources such as geological and topographic maps. The results of the remote-sensing data fusion are presented, using pixel-based, feature-based and decision-based fusion approaches.     

Emission of carbon-bearing gases and aerosols from natural fires on the territory of Russia based on space monitoring

The results of the space monitoring of natural fires during the period 2010–2014 to estimate the areas destroyed by fire, volumes of the emissions of greenhouse gases, and fine particulate aerosols over the entire territory of Russia and its individual regions are presented. The methods of research, the regularities of the seasonal recurrence of fires distinguished in different regions, as well as the peculiarities of emissions of small gas components and aerosols in different months are described.     

Estimating the depth of underground coal fires using data integration techniques

Underground coal fires in China cause serious environmental problems, in addition to the loss of valuable coal resources. The present study aims at developing a quick and practical method to estimate the depth of coal fires using data integration techniques.
  In coal fields which have underground coal fires, the subsurface fires are associated with surface thermal anomalies. Airborne thermal infrared scanner data and colour infrared photographs were used in this study to depict the coal fire front and the outcrop of coal seams, respectively. A Digital Elevation Model (DEM) of the study area was produced from topographic maps at 1:25 000 scale. Finally, taking into account the spreading direction of the coal fires and the relationships between thermal anomalies, relief factors and the occurrence of coal seams, the depths of the coal fires were obtained automatically by means of integration of remote sensing data and GIS techniques. This helped to target the fire fighting operations and made them more cost effective.     

Paragenesis of unusual Fe-cordierite (sekaninaite)-bearing paralava and clinker from the Kuznetsk coal basin,Siberia, Russia

Sekaninaite (X_Fe > 0.5)-bearing paralava and clinker are the products of ancient combustion metamorphism in the western part of the Kuznetsk coal basin, Siberia. The combustion metamorphic rocks typically occur as clinker beds and breccias consisting of vitrified sandstone–siltstone clinker fragments cemented by paralava, resulting from hanging-wall collapse above burning coal seams and quenching. Sekaninaite–Fe-cordierite (X_Fe = 95–45) is associated with tridymite, fayalite, magnetite, ± clinoferrosilite and ±mullite in paralava and with tridymite and mullite in clinker. Unmelted grains of detrital quartz occur in both rocks (<3 vol% in paralavas and up to 30 vol% in some clinkers). Compositionally variable siliceous, K-rich peraluminous glass is <30% in paralavas and up to 85% in clinkers. The paralavas resulted from extensive fusion of sandstone–siltstone (clinker), and sideritic/Fe-hydroxide material contained within them, with the proportion of clastic sediments ≫ ferruginous component. Calculated dry liquidus temperatures of the paralavas are 1,120–1,050°C and 920–1,050°C for clinkers, with calculated viscosities at liquidus temperatures of 10^1.6–7.0 and 10^7.0–9.8 Pa s, respectively. Dry liquidus temperatures of glass compositions range between 920 and 1,120°C (paralava) and 920–960°C (clinker), and viscosities at these temperatures are 10^9.7–5.5 and 10^8.8–9.7 Pa s, respectively. Compared with worldwide occurrences of cordierite–sekaninaite in pyrometamorphic rocks, sekaninaite occurs in rocks with X_Fe (mol% FeO/(FeO + MgO)) > 0.8; sekaninaite and Fe-cordierite occur in rocks with X_Fe 0.6–0.8, and cordierite (X_Fe < 0.5) is restricted to rocks with X_Fe < 0.6. The crystal-chemical formula of an anhydrous sekaninaite based on the refined structure is | \textK_0.02 |(\textFe_1.54^{2 +} \textMg_0.40 \textMn_0.06 )_{\Upsigma 2.00}^M [(\textAl_1.98 \textFe_0.02^{2 +} \textSi_1.00 )_{\Upsigma 3.00}^T1 (\textSi_3.94 \textAl_2.04 \textFe_0.02^{2 +} )_{\Upsigma 6.00}^T2 \textO₁₈ ]. \left| {{\text{K}}_{0.02} } \right|({\text{Fe}}_{1.54}^{2 + } {\text{Mg}}_{0.40} {\text{Mn}}_{0.06} )_{\Upsigma 2.00}^{M} [({\text{Al}}_{1.98} {\text{Fe}}_{0.02}^{2 + } {\text{Si}}_{1.00} )_{\Upsigma 3.00}^{T1} ({\text{Si}}_{3.94} {\text{Al}}_{2.04} {\text{Fe}}_{0.02}^{2 + } )_{\Upsigma 6.00}^{T2} {\text{O}}_{18} ].     

Disequilibrium in co-existing clinopyroxene and garnet from blueschist-facies Fe-rich eclogites, Voltri Group, Italy

Abstract Clinopyroxenes and garnets from 11 blueschist-facies Fe-rich eclogite samples from the Voltri Group show a wide range of chemical compositions. Detailed analyses of single pyroxene and garnet grains show wide and scattered chemical inhomogeneity, the K_D(K_D= (Fe₂₊/Mg)^Gt/(Fe²⁺/Mg)^Cpx) ranges from 20 to 87 based on rim analyses only. The data obtained indicate that the mineral pairs never attained equilibrium under uniform P-T conditions and that the compositions of the metamorphic minerals were influenced mainly by the composition of the pre-metamorphic minerals and by topotactical reactions.     

Controlling coal fires using the three-phase foam and water mist techniques in the Anjialing Open Pit Mine,China

Natural Hazards - Coal fires are a serious environment, health, and safety hazard throughout the world. They damage the environment, threaten the health of people living nearby, burn away...     

Nuclear magnetic resonance studies of ancient buried wood—II. Observations on the origin of coal from lignite to bituminous coal

Coalified logs ranging in age from Late Pennsylvania to Miocene and in rank from lignite B to bituminous coal were analyzed by ¹³C nuclear magnetic resonance (NMR) utilizing the cross-polarization, magic-angle spinning technique, as well as by infrared spectroscopy. The results of this study indicate that at least three major stages of coalification can be observed as wood gradually undergoes transformation to bituminous coal. The first stage involves hydrolysis and loss of cellulose from wood with retention and differential concentration of the resistant lignin. The second stage involves conversion of the lignin residues directly to coalified wood of lignitic rank, during which the oxygen content of intermediate diagenetic products remains constant as the hydrogen content and the carbon content increases. These changes are thought to involve loss of methoxyl groups, water, and C₃ side chains from the lignin. In the third major stage of coalification, the coalified wood increases in rank to subbituminous and bituminous coal; during this stage the oxygen content decreases, hydrogen remains constant, and the carbon content increases. These changes are thought to result from loss of soluble humic acids that are rich in oxygen and that are mobilized during compaction and dewatering. Relatively resistant resinous substances are differentially concentrated in the coal during this stage. The hypothesis that humic acids are formed as mobile by-products of the coalification of lignin and function only as vehicles for removal of oxygen represents a dramatic departure from commonly accepted views that they are relatively low-molecular-weight intermediates formed during the degradation of lignin that then condense to form high-molecular-weight coal structures.     

煤层受古河流冲刷的预测及探讨

古河流冲刷是影响煤矿规划、设计、开采方式不同的常见原因之一,并直接影响煤炭回收率、原煤质量。本文系统地分析其产生的原因及其危害,并结合生产实践,提出三种比较合理的预测方法。三种不同方法预测的综合利用,使之能更好的为生产服务。     

Inclusions in Aquamarine from the Suprunovskoye Pegmatite Deposit, Russia

Please refer to the attachment(s) for more details.     

Eclogites from the Obnazhennaya Kimberlite Pipe,Yakutia, Russia

Mineralogy and petrography of six eelogite xenoliths from the Obnazhennaya kimberlite pipe ar e described. Based upon modal and mineral compositions, these eclogites can be divided into Group A (five samples) and Group B (one sample), as per Coleman et al. (1965) and Shervais et al. (1988). Group-A eclogites are orthopyroxene-bearing, and their constituent minerals have high Mg# and Cr₂O₃ content. The clinopyroxenes in this type of eelogite have low jadeite component. The geochemical features of Group-A eclogites are similar to garnet pyroxenite, and e believed to be the product of high-pressure fractionates from an alkaline basaltic melt in thear upper mantle. Group-B eelogite (0-82/91) contains higher Al₂O₃ and FeO and lower MgO and Cr₂O₃; its composition is similar to a high-aluminum basalt or gabbro. This eelogite could have crystallized under high pressure in the upper mantle from a basaltic melt, without significant fractionation. Alternatively, it also could be the relict of subducted oceanic crust. However, no evidence exists at present that definitively indicates a crustal origin for this Group-B eelogite xenolith.     

Fe-rich cordierites from acid volcanic rocks,an optical and x-ray single-crystal structure study

Low-cordierites from volcanic rocks of Tuscany (Italy), Lipari (Italy), and of the Cerberean Cauldron (Australia) were investigated. Both single crystal structure refinements and optical data indicate that the Italian samples contain only low concentrations of volatiles (<0.3 wt.%), whereas in the crystals from the Cerberean Cauldron more than 50% of the structural channels are occupied, preferentially by H₂O (1.6–1.9 wt.%). This high volatile concentration is in qualitative agreement with the estimated p,T-conditions (4–4.5 kbar at 750–780° C) of the magma prior to eruption. In contrast, the Italian cordierites have formed at temperatures above 950° C and pressures below 2 kbars. Low-cordierites of volcanic origin reveal the same high degree of Si, Al-ordering as observed for low-cordierites from metamorphic rocks and pegmatites. The crystals studied possess F(mol)=(Fe+Mn)/(Fe+Mn+Mg)>0.4 and provide additional information about the crystal structure of Fe-rich cordierites. With increasing FeMg substitution the mean T₁1(Al)-O distance decreases slightly, which is probably not caused by substitution of smaller cations on t₁1 but by angular distortion of the tetrahedron.     

Geochemical classification of hydrocarbon gases of the coal basins of East Russia

A geochemical and genetic classification has been developed for the hydrocarbon gases of the coal and coal-and-oil-and-gas-bearing basins of East Russia. Diverse forms of the natural gas transfer were identified. The principle quantitative gas-geochemical coefficients were distinguished for the purpose of the genetic classification of the hydrocarbon gases in the studied region.