Coal geology and coal quality of the Miocene Mugla basin, southwestern Anatolia, Turkey

This work focuses on the relationship between the coal geology and coal quality of the Miocene Mugla basin, Southwestern Anatolia, Turkey. To this end, detailed petrographical, mineralogical and geochemical studies were performed on composite profile samples from the nine coal fields in the Mugla basin (Alatepe, Bagyaka, Bayir, Çakiralan, Ekizköy, Eskihisar, Hüsamlar, Sekköy and Tinaz coal fields). The Mugla lignite is a high ash (from 16 to 56%) and sulphur (from 2.1 to 5.7%) lignite which is petrographically characterised by a high huminite content, mainly gelinite macerals. The mineral matter of the studied lignite samples is made up mainly of clay minerals and quartz, with the exception of the Sekköy and Ekizköy lignites, in which calcite is the dominant mineral phase with minor amounts of quartz, clay minerals, pyrite and gypsum and traces of aragonite. Syngenetic opal is also frequently identified in these samples. The differentiation of these two types of lignite with specific mineralogical patterns is attributed to the contemporaneous development of peatlands with a high detrital input, dominated by the quartz and clay mineral setting, and peatlands with low detrital supply and a dominant carbonate-rich lacustrine environment. The higher water table of the latter allowed the precipitation of micritic carbonates and the development of lakes with abundant mollusc fauna. This differentiation is also evidenced by the geochemical data. Thus, the Sekköy, Ekizköy, Hüsamlar, Bayir and Alatepe lignites are characterised by relatively low Al and Fe contents (<1.4%) and high sulphur contents (4.2 to 5.7%). In addition Sekköy and Ekizköy show relatively high contents of Ca (6.3–7.1% compared to 1.6–3.8% in the other lignites). All the lignite samples studied are characterised by relatively high Mo and U contents when compared with the worldwide averages of trace elements in coal. Relatively high alkaline syngenetic conditions of the peat-forming environment of the Mugla coal are deduced from the following mineralogical, petrographical and geochemical evidence: (a) the precipitation of syngenetic opal (dissolution of quartz and re-precipitation as opal) and calcite; (b) minor and very early syngenetic sulphide precipitation (only framboidal and euhedral pyrite); (c) high bacterial activity, typical of high pH conditions, inferred from low preservation of tissue structures; (d) preservation of aragonite gastropod shells; and (e) the anomalous enrichment of U, Mo and W. A key result of the study of Mugla limnic coals (at least of the Sekköy and Ekizköy coal fields) is that a major influence was exerted on the early diagenetic evolution of the coal by the hydrochemistry of the lacustrine waters. This hydrochemistry was largely linked to the lithology of the surrounding source rock areas although the final evolutionary trend of the solute composition in the lake waters, characterized by very high carbonate and sulphate contents, was largely enhanced by the endorheic river drainage system and the arid–semiarid paleoclimatic situation under which organic matter accumulation took place.     

An experimental approach to the palynology of cave deposits

Surface sediment, speleothems, and bat guano from two adjacent, topographically different cave sites in eastern Spain have been studied palynologically to elucidate the potential of cave sediments for palaeoenvironmental reconstruction. A cave opening with a large entrance and constant width presented far fewer problems of alteration in the pollen assemblages than a sac‐like cave opening with a constricted entrance. Pollen concentration is linked primarily to the amount of pollen input rather than to the result of post‐depositional alteration. Sampling should be undertaken away from parietal and rear areas and avoiding moisture zones. Lateral differences in the pollen spectra indicate that sampling should be on the basis of a multiple‐profile approach and selection of dry rather than wet sediments. If these procedures are followed, within‐cave sediments can realistically reflect not only local but also regional vegetation of the site. Copyright © 2000 John Wiley & Sons, Ltd.     

The palynology and provenance of the coal fragments contained in the late-Pleistocene Lleiniog gravels of Anglesey,North Wales

The numerous coal clasts in the late-Pleistocene fluvioglacial Lleiniog Gravels of eastern Anglesey contain a varied assemblage of Westphalian A (and possibly also early Westphalian B) spores. Directional sedimentary structures indicate that the meltwater currents which deposited the gravels came mainly from the north and east, while glacial striae and erratic trains indicate that the parent (? Devensian) glacier flowed from the northeast. Consideration is given to the possibility that the coal clasts were derived from the breaking-up, fairly locally, of far-travelled rafts of Coal Measures. It is concluded, however, that the most probable explanation is still Greenly's (1919) postulate that the source is a yet-to-be-identified submarine outcrop situated only a few kilometres northeast of Lleiniog.     

40Ar/39Ar dating of ignimbrites and plinian air-fall layers from Cappadocia,Central Turkey: Implications to chronostratigraphic and Eastern Mediterranean palaeoenvironmental record

Magmatism forming the Central Anatolian Volcanic Province of Cappadocia, central Turkey, records the last phase of Neotethyan subduction after ∼11 Ma. Thirteen large calc-alkaline ignimbrite sheets form marker bands within the volcano-sedimentary succession (the Ürgüp Formation) and provide a robust chronostratigraphy for paleoecologic evaluation of the interleaved paleosols. This paper evaluates the chronologic record in the context of the radiometric, magnetostratigraphic and lithostratigraphic controls. Previous inconsistencies relating primarily to K/Ar evidence were reason for the initiation of an integrated study which includes ⁴⁰Ar/³⁹Ar dating, palaeomagnetic and stratigraphic evidence. The newly determined ⁴⁰Ar/³⁹Ar-ages (Lepetit, 2010) are in agreement with Ar/Ar and U/Pb data meanwhile published by Pauquette and Le Pennec (2012) and Aydar et al. (2012). The ⁴⁰Ar/³⁹Ar-ages restrict the end of the Ürgüp Formation to the late Miocene. The paleosol sequence enclosed by the ignimbrites is thus restricted to the late Miocene, the most intense formation of pedogene calcretes correlating with the Messinian Salinity Crisis.     

Sorption of methane on lignite from Polish deposits

Coal samples from Miocene lignite deposits (ortholignite—ECE-UN 2002) in Belchatow, Adamow, Konin and Turow (Poland) were analyzed to determine the relationships between coal properties and gas capacity.Investigations presented here addressed the occurrence of methane sorbet in lignite deposits within Poland's largest penetrated lignite deposits (e.g., Belchatow, Adamow, Turow and Konin).Lignite samples collected from surface mines were detritic coal with variable contents of xylites. The highest level of xylites (up to 25 vol.%) was found in carbon samples taken from the Belchatow deposit. Samples from other mines contained no more than 10 vol.% xylites. Petrographic compositions were dominated by huminite group macerals (73-88 vol.%) with atrinite, densinite and texto-ulminite, a porous form of ulminite; inertinite groups were less important components (4-8 vol.%).Isotherms were determined for methane sorption at 298 K with test pressure ranges below 1.2 MPa. At a pressure of 1.0 MPa, the largest gas capacity of approximately 1.7 [dm³ STP/kg] was found in the sample from Belchatow. This result may have been attributable to differences in the porosity of the samples; the porosity of the sample from Belchatow was twice as high as the porosities of the other coal samples. This variation in porosity resulted from the lithologic and maceral composition of the coal sample that contained substantial quantities of porous textinite and texto-ulminite.The thermal sorption equation was used to determine the limiting values of isosteric enthalpy of sorption, which suggested weak interactions between methane and the lignite matrix. The residual gas capacity of the tested samples was also determined.All samples exhibited a high residual methane-bearing capacity, which may not only cause methane to be released from coal at a pressure of 1 bar but also may pose a gas risk during mining operations.     

Quality and durability assessments of the armourstones for two rubble mound breakwaters (Mersin,Turkey)

Due to economic reasons, natural stones (armourstones) of various sizes and qualities are very frequently used for the constructions of the breakwaters to protect coastal engineering structures from wave actions. Deterioration of the armourstones with time in the form of abrasion and disintegration may end up with the damage of the structures. Therefore, it is necessary to investigate the long-term performance and quality of the armourstones, which should be sound and durable. Mersin and Kumkuyu harbours were constructed using four different limestones obtained from two quarries. The limestones have different characters and site performances. In this study, the material and mass properties of the limestones taken from the quarries with known site performances as armourstones are investigated. The site performances and durability of the limestones are compared with the field measurements and laboratory works. Thus, the information obtained is used to assess long-term durability of the armourstones. The long-term performance of the Degirmencayi and Tirtar upper level limestones are observed to be good whereas it is rather poor for the Tirtar middle and lower level limestones. Comparison between the predicted and observed durabilities of the armourstones indicated that CIRIA/CUR, RDI_d, RERS, and wet to dry strength ratio give better results based on their field performances. However, the prediction of the durability of the limestones is poor in case RDIs, average pore diameter, and saturation coefficient are used.     

云南省临沧市勐托新近系褐煤的微量元素地球化学特征

为研究云南临沧勐托新近系褐煤的微量元素地球化学特征,共采集了11个褐煤样品,采用ICP MS和ICP CCT MS(As和Se)对煤中微量元素进行了测试。结果表明：与中国煤相比,勐托褐煤中Rb(96.1 mg/kg)、Sb(15.3 mg/kg)和Cs(25.9 mg/kg)显著富集,W(10.6 mg/kg)和U(20.2 mg/kg)富集,Be(7.84 mg/kg)、Ga(16.1 mg/kg)、As(11.6 mg/kg)、Cd(0.67 mg/kg)、Sn(6.66 mg/kg)、Pb(34.6 mg/kg)、Bi(3.86 mg/kg)和Th(28.2 mg/kg)稍富集,微量元素组成与大寨富锗煤不同,与酸性花岗岩物源供应有关。勐托褐煤中REY含量范围为121~420 mg/kg,平均251 mg/kg,均较大寨富锗褐煤高,且以Ce显著正异常和Eu显著负异常为特征,明显区别于大寨褐煤,Eu负异常和上陆壳标准化的REY分配模式均表明勐托褐煤中稀土元素受盆地周边花岗岩风化陆源碎屑供应影响。     

Palaeovegetational and palaeoenvironmental trends in the summit of the Guaiquinima massif (Venezuelan Guayana) during the Holocene

The summits of the table mountains (tepuis) from the Neotropical Guayana region are remote environments suitable for palaeoecological studies with evolutionary, biogeographical and palaeoclimatic implications. Here, using palynological analyses of two radiocarbon‐dated peat bogs from a tepui summit, the Holocene palaeovegetational trends are reconstructed, and related to possible forcing factors. Because of the pristine character of the Guaiquinima summit, the recorded palaeoenvironmental changes are probably due to natural causes, which makes them valuable archives of the natural component of climatic change at a millennial time scale. The sequence begins with pioneer communities or meadows similar to present‐day ones, between about 8.4 and 4.5 ky BP. After this date, and until about 2 kyr BP the expansion of gallery forests suggests an increase in precipitation, documented also at regional (Neotropical) level. Between ca. 2 kyr BP and the last century, gallery forests are replaced by forests characteristic of the upper Guaiquinima altitudes, coinciding with a regional phase of reduced moisture. The present‐day meadows, established relatively quickly during the last century, substituted the former upland forests. In the locality studied, the main controlling factor of the vegetation during the Holocene seems to have been the moisture balance. In contrast to other tepui summits, there is no clear evidence for changes linked to temperature oscillations. This could be due to the elevation of the site, far from any characteristic ecological boundary, that makes it insensitive to this parameter. Copyright © 2005 John Wiley & Sons, Ltd.     

Capacity and mechanism of phenol adsorption on lignite

A raw lignitic coal from Soma, Turkey was investigated to determine its potential as an adsorbent for phenol removal from wastewaters. Kinetic batch tests demonstrated that phenol could be completely removed from solution given sufficient solids loading and reaction time. The adsorption capacity of 10 mg/g obtained with the lignite is low compared to those achievable with activated carbons (around 300 mg/g). However, when normalized for the surface area, the adsorption capacity was much larger for the lignite (1.3 mg/m²) than that generally observed with activated carbons (0.05–0.3 mg/m²). Hydrogen-bonding of the phenolic –OH with the oxygen sites on the lignite surface is the most likely mechanism for adsorption. Though water molecules also have affinity for the same oxygen sites, lateral benzene ring interactions make phenol adsorption energetically more favorable. Since phenol molecules adsorbed in this fashion would project their benzene rings into solution, formation of a second layer through the action of the dispersive π–π interactions between the benzene rings is very likely. Residual water quality with respect to major elements and heavy metals was within acceptable limits defined by the ASTM standards. Dissolution of organic matter from the lignite was also observed to be negligible.     

Magnetotelluric images of the crust and mantle in the southwestern Taurides, Turkey

Inversion of the magnetotelluric data across the southwestern Taurides reveals two subzones of crust with varying thicknesses: conductive lower crust (<75 Ω m), overlain by resistive (>350 Ω m) upper crust, with four resistive cores (>2000 Ω m) separated by three relatively conductive vertical zones. The first and second vertical zones coincide with surface faults interpreted in Anatolia, such as Fethiye Burdur Fault Zone. The third one is the most conductive and lies in continuity with the Strabo Fault Zone in the Mediterranean Sea. A hypocentral cross section of earthquakes along the profile shows more dense seismic activity in the second resistive core where the conductive crust is not present beneath it. The depth of the crust/upper mantle boundary varies between 30 and 50 km and has an undulating character. The resistivity of the upper mantle reaches 500–1000 Ω m.     

Hydrogeochemical and isotopic investigation of the Kolan geothermal field, southeastern Turkey

The Kolan geothermal field is located 24 km northwest of the Karakoçan area of Elaz city in southeastern Turkey. The Keban crystallized limestone of Permo-Carboniferous age is the oldest unit in the area. This unit is overlain by the middle-upper Eocene Krkgeçit formation consisting of conglomerate, sandstone, limestone and marl alternations. The youngest unit in the area is the Upper Miocene-Lower Pliocene Karabakr formation consisting of basalt, andesite and tuffs. Thermal Springs in the Kolan field issue along two major fault zones. The temperature of the hot springs is between 38°C and 45°C. Thermal waters in the area are heated by the geothermal gradient. The waters are classified as hot or very hot and as brackish waters. On the basis of International Association of Hydrogeologists Classification (IAH), waters are grouped as Ca–Na-HCO₃–CO₂-bearing thermal and mineral waters. Chemical analyses indicate a chemical composition of Ca>(Na+K)>Mg - HCO₃>SO₄>Cl. Saturation calculations reveal that the waters are oversaturated with respect to calcite, dolomite and aragonite while undersaturated with respect to gypsum, anhydrite and halite minerals. On the basis of ¹⁸O, ²H and ³H isotope data, Kolan waters are of meteoric origin, recharged from high elevations and then circulated deeply.     

The Investigation of Mass Transfer in the Karasu Karstic Aquifer, Konya, Turkey

In this study, the changes in the chemical composition of the groundwater along a flow path were examined by using the water samples collected from unconfined, semi-confined and confined parts of the Karasu karstic aquifer. It was determined that transport of bicarbonate, calcium, and magnesium was dominant in unconfined and semi-confined parts of the aquifer, whereas calcite and dolomite precipitate in the confined parts. On the other hand, gypsum dissolution is present in all parts of the aquifer. In addition, the computed saturation indices explain the occurrences and precipitation of travertines in the Goksu Valley, which is the discharge area for the aquifer. Electronic Publication     

褐煤煤层气储集特征及气含量确定方法

褐煤基质中的孔隙以中孔、大孔为主。实验表明,褐煤对甲烷的吸附能力很低;褐煤基质中的游离气含量通常占总气含量的50%以上。因此,传统的煤层气含量确定方法不适用于褐煤。本文建立了褐煤煤层气含量的确定方法,将吸附气含量与相应储层压力及温度条件下的游离气含量相加,即得到褐煤总的气含量等温线。利用这条等温线,即可获得该温度下不同储层压力时的气含量值。     

Petrogenesis of lawsonite and epidote eclogite and blueschist, Sivrihisar Massif, Turkey

The Sivrihisar Massif, Turkey, is comprised of blueschist and eclogite facies metasedimentary and metabasaltic rocks. Abundant metre‐ to centimetre‐scale eclogite pods occur in blueschist facies metabasalt, marble and quartz‐rich rocks. Sivrihisar eclogite contains omphacite + garnet + phengite + rutile ± glaucophane ± quartz + lawsonite and/or epidote. Blueschists contain sodic amphibole + garnet + phengite + lawsonite and/or epidote ± omphacite ± quartz. Sivrihisar eclogite and blueschist have similar bulk composition, equivalent to NMORB, but record different P–T conditions: ～26 kbar, 500 °C (lawsonite eclogite); 18 kbar, 600 °C (epidote eclogite); 12 kbar, 380 °C (lawsonite blueschist); and 15–16 kbar, 480–500 °C (lawsonite‐epidote blueschist). Pressures for the Sivrihisar lawsonite eclogite are among the highest reported for this rock type, which is rarely exposed at the Earth's surface. The distribution and textures of lawsonite ± epidote define P–T conditions and paths. For example, in some lawsonite‐bearing rocks, epidote inclusions in garnet and partial replacement of matrix epidote by lawsonite suggest an anticlockwise P–T path. Other rocks contain no epidote as inclusions or as a matrix phase, and were metamorphosed entirely within the lawsonite stability field. Results of the P–T study and mapping of the distribution of blueschists and eclogites in the massif suggest that rocks recording different maximum P–T conditions were tectonically juxtaposed as kilometre‐scale slices and associated high‐P pods, although all shared the same exhumation path from ～9–11 kbar, 300–400 °C. Within the tectonic slices, alternating millimetre–centimetre‐scale layers of eclogite and blueschist formed together at the same P–T conditions but represent different extents of prograde reaction controlled by strain partitioning or local variations in fO₂ or other chemical factors.     

Petrogenesis and structural petrology of high-pressure metabasalt pods,Sivrihisar, Turkey

Lawsonite eclogite pods ranging in size from 3 cm to 6 m occur in lawsonite blueschist and eclogite facies metasedimentary and metabasaltic rocks in the Sivrihisar Massif, Turkey. Some pods have a core of lawsonite eclogite surrounded by alternating, centimeter-scale layers of lawsonite blueschist, eclogite, and transitional eclogite–blueschist, all with similar basaltic bulk composition. These pods also contain texturally late lawsonite-rich veins and layers. Most eclogites and blueschists within the pods lack reaction textures, but some blueschists near pod margins contain texturally complex garnet as well as glaucophane rims on omphacite, suggesting retrogression of eclogite to blueschist. Phase diagrams (pseudosections) calculated for the lawsonite eclogite core of a meter-scale pod indicate that the eclogite equilibrated at ∼22–24 kbar, ∼520°C. Lawsonite eclogite and blueschist at the tectonized margin of the same pod equilibrated at similar temperatures and slightly lower pressures. The composite eclogite–blueschist pod is foliated, lineated, and folded. An earlier generation of lineated omphacite in the pod core has a different spatial orientation than the lineation at the pod margin, although electron backscattered diffraction data show that core and rim omphacite have similar lattice preferred orientation patterns. Petrologic and structural data are consistent with mechanical formation of pods by folding and dissection of eclogite layers at high-P, and localized retrogression at pod margins during initial stages of exhumation at P–T conditions >425°C, 16 kbar.     

Monazite ages and the evolution of the Menderes Massif, western Turkey

The Menderes Massif experienced polyphase deformation, but distinguishing Pan-African events from Alpine tectono-metamorphic evolution, and discriminating Eocene–Oligocene shortening from recent extension remain controversial. To address this, monazite in garnet-bearing rocks from the massifs Gordes, Central, and Cine sections were dated in thin section (in situ) using the Th–Pb ion microprobe method. Cambro–Ordovician monazite inclusions in Cine and Central Menderes Massif garnets are ~450 m.y. older than matrix grains. Monazites in reaction with allanite from the Kuzey Detachment, which bounds the northern edge of the Central Menderes Massif, are 17±5 Ma and 4.5±1.0 Ma. The Pliocene result shows that dating of monazite can record the time of extension. The Kuzey Detachment might have exhumed rocks a lateral distance of ~53 km at a rapid rate of ~12 mm/year assuming the present ~20° ramp dip, Pliocene monazite crystallization at ~450°C, and a geothermal gradient of ~25°C/km. Assuming an angle of 60°, the rate decreases to ~5 mm/year, with the detachment surface at ~21 km depth in the Pliocene. Two Gordes Massif monazites show a similar allanite–monazite reaction relationship and are 29.6±1.1 Ma and 27.9±1.0 Ma, suggesting that the Cenozoic extension in the Gordes Massif, and possibly the entire Menderes Massif, might have begun in the Late Oligocene.     

Depositional setting and geometric structure of the Beypazari lignite deposits, Central Anatolia, Turkey

The Neogene Beypazari basin is one of the important coal districts of Central Anatolia with approximately 600 million short tons lignite reserves. The coal-bearing Neogene sediments occurring in the Beypazari basin are divided into seven formations, in ascending order; Çoraklar, Hirka, Akpinar, Çayirhan, Bozbelen and Kirmir Formations with Sariyar Limestone and Teke volcanics.The Çoraklar Formation consists of cross-bedded sandstones, channel-fill conglomerates, mudstones, carbonaceous shales and volcanoclastic pebblestones, which are fluvial in origin. The lower lignite seam occurs in the lower part of the Çoraklar Formation.The upper lignite seam occurs in the uppermost part of the Çoraklar Formation and is overlain by the Hirka Formation with a sharp contact. The Hirka Formation consists mainly of alternating shale, mudstone, bituminous shale, claystone, tuffite and silicified limestone, and they all are apparently of lacustrine origin.The lignite deposite occur in the Çayirhan and Koyunaǧili parts of the Beypazari Neogene basin. The Çayirhan coal field consists of lower and upper lignite seams, but the Koyunaǧili field contains only an upper lignite seam.The lower lignite seam, which does not crop out at the surface, indicates a fluvial origin of the lignite deposits, based on the lateral discontinuity and the lower sulphur content of the lower lignite seam, and the sedimentologic and stratigraphic features of the associated sediments. But the uniform stratigraphic and sedimentologic features, high sulphur content and wide-spread distribution of the upper lignite seam indicate that the upper lignites were deposited probably in a mud-flat facies of playa-lake environment. The lower and upper lignites are completely different in relation to the depositional environment, the geometry and degree of rank in lateral directions.The lateral spreading and geometry of the lower lignite deposits were controlled by channel, floodplain and well-drained marshes of a fluvial system. On the basis of recent drillings and field investigations, the lower lignite deposit has been demonstrated to be a linear spreading parallel to the axis of the channel fills and throughcross beds in clastic sediments of fluvial facies. Therefore, the lower lignite deposits trend along a northeastern direction and is not expected to be as widely spread as the upper lignites.     

Earthquake disaster risk assessment and evaluation for Turkey

Turkey is the one country in which 90% of the buildings are subject to the risk of earthquake disaster. Recent earthquakes revealed that Turkey’s present residential reinforced-concrete constructions are insufficient in earthquake resistance. Many of the buildings which collapsed or were severely damaged have been rehabilitated by applying simple methods, whose adequacy is questionable. As in Japan and the United States, Turkey’s earthquake assessment studies have increased, especially after earthquakes in 1999, In US, several methodologies and standards, such as Hazard-US (HAZUS) and Applied Technology Council (ATC) 13-20-21 and 156, provide comprehensive earthquake loss estimation methodology for post-earthquake assessment. This paper provides post-earthquake assessment and disaster management for Turkey. The main aim of the post-earthquake assessment discussed is to evaluate loss and estimate damage through disaster management approach. Classification criteria for damage are essential to determine the situation after an earthquake in both the short and long terms. The methodology includes probabilistic-based analysis, which considers the magnitude of Ms ≥ 5.0 earthquakes between 1900 and 2005, for determining the probabilistic seismic hazard for Turkey.     

褐煤孔隙结构及比表面积特征

为揭示褐煤孔隙结构及比表面特征,选取全国主要褐煤产地样品,进行煤岩显微组分含量测定和低温氮吸附实验,从吸附曲线形态、比表面积、孔径结构分布刻画煤储层微孔隙特征,探讨孔径结构与比表面积的关系,分析BET比表面积与煤岩显微组分的相关性。结果表明：褐煤低温液氮曲线形态大致可以分为无吸附回线、有拐点的吸附回线和无拐点的吸附回线3类;BET比表面积随BJH总孔体积的增加呈线性增加趋势,在2~10 nm范围内的孔径和比表面积关系可以分为正相关、负相关和复合相关3种;显微组分组和比表面积的相关性较弱,但比表面积与细屑体含量具有较好的线性关系。     

褐煤生物产气规律及其液相体系中阳离子变化特征

为研究褐煤生物产气规律及其液相体系中常见阳离子变化特征,以内蒙古胜利褐煤为产气底物,寺河矿区煤层气井排采水中微生物作为发酵菌群,利用5 L厌氧发酵罐进行模拟生物产气实验,采用离子色谱仪对发酵液中的NH₄⁺、K⁺、Ca²⁺、Mg²⁺和Na⁺5种阳离子浓度进行动态监测。结果表明：煤模拟生物产气周期为33 d,分为缓慢增长期、快速增长期和平缓期3个阶段,33 d单位质量煤净产甲烷量最高达23 μmol/g;产气体系中NH₄⁺（741.5 mg/L）和K⁺（994.5 mg/L）离子质量浓度变化最为明显,Ca²⁺（26 mg/L）、Mg²⁺（10.7 mg/L）和Na⁺（72 mg/L）次之,表明发酵液中5种阳离子均参与了褐煤生物产气过程,且被不同程度地释放和利用;褐煤生物产气量与阳离子浓度有一定相关性,单位质量煤产气量与NH₄⁺和K⁺浓度呈正相关,与Ca²⁺、Mg²⁺浓度呈负相关。此外,NH₄⁺和K⁺以及Ca²⁺和Mg²⁺之间浓度呈显著正相关。由实验结果可知：褐煤生物产气液相体系中4⁺、K⁺、Ca²⁺、Mg²⁺和Na⁺5种阳离子会随着煤中有机组分的厌氧降解而缓慢释放、再吸附,同时可被微生物利用参与细胞内的生物化学反应。