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1.
《Russian Geology and Geophysics》2014,55(11):1306-1315
We present new original data on the geochemistry of scandium in the coals of Asian Russia, Mongolia, and Kazakhstan. In general, the studied coals are enriched in Sc as compared with the average coals worldwide. Coal deposits with abnormally high, up to commercial, Sc contents were detected in different parts of the study area. The factors for the accumulation of Sc in coals have been identified. The Sc contents of the coals depend on the petrologic composition of coal basins (composition of rocks in their framing) and the facies conditions of coal accumulation. We have established the redistribution and partial removal of Sc from a coal seam during coal metamorphism. The distribution of Sc in deposits and coal seams indicates the predominantly hydrogenic mechanism of its anomalous concentration in coals and peats. The accumulation of Sc in the coals and peats is attributed to its leaching out of the coal-bearing rocks and redeposition in a coal (peat) layer with groundwater and underground water enriched in organic acids. The enrichment of coals with Sc requires conditions for the formation of Sc-enriched coal-bearing rocks and conditions for its leaching and transport to the coal seam. Such conditions can be found in the present-day peatland systems of West Siberia and, probably, in ancient basins of peat (coal) accumulation. 相似文献
2.
Factors controlling the vegetation distribution and coal‐forming environments in a strike‐slip basin. The Pennsylvanian Peñarroya‐Belmez‐Espiel Basin,southern Spain 
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下载免费PDF全文 Coal‐forming environments require humid to perhumid conditions. Tectonics governs the size, location and availability of coal seams developed in such environments. While large Pennsylvanian paralic basins generated thick and continuous coal seams, many other small coeval basins, which were tectonically active, developed a puzzling succession, with carbonaceous deposits that varied in size, thickness and the nature of the coal‐forming flora. This study, conducted in the Peñarroya‐Belmez‐Espiel coalfield, a Variscan strike‐slip basin in the south of Spain, provides insights into this subject. The coal seams analysed, generated in different depositional environments, have quantitatively different palynological assemblages. Lacustrine coals are dominated by lycopsids; distal alluvial plain/marginal lacustrine coals are dominated by sphenophytes and tree ferns, and middle alluvial fan coals are dominated by sphenophytes, tree ferns and lycopsids. This means that when conditions were favourable for peat accumulation, peat accumulated regardless of the nature of the available flora. 相似文献
3.
A detailed macro- and micro-petrological investigation of 8 coal seam profiles of Eocene age from the sub-Himalayan zone of Jammu was undertaken in order to characterize them petrographically and to focus on their evolution. The quantitative data suggest that these coals are vitrinite rich, with low concentrations of inertinite and rare occurrences of liptinite. According to microlithotype concentration these coals may be characterized as vitrinite rich, with minor amounts of clarite, vitrinertite and trimacerite. The dominant minerals are clays, siderite and pyrite (occurring mostly as disseminations, cavity filling and in framboidal state). These coals are vitric in type, low volatile bituminous in rank and ashy in grade.The petrographic character and the presence of teleutospores suggest that, similar to other Tertiary coal deposits in the world, the angiosperm flora contributed chiefly to the development of coal facies in the area. The maceral and microlithotype composition shows that these coals originated from the low forest and undisturbed (in situ) peat in foreland basins under limno-telmatic depositional conditions. The water was brackish with regular influxes of fresh water. 相似文献
4.
This paper presents a review of the genetic types and geochemical processes that have formed ‘metalliferous’ coals around the world. Primary attention is given to elements in coal that are currently being extracted from coal as raw material (Ge and U) or have, in our opinion, the best chance for such use (REE, Ag, Au, and PGE). Coals with anomalously high concentrations of other metals having potential for economic by-product recovery (Be, Sc, V, Ga, Sb, Cs, Mo, W, and Re) are briefly considered. Original data and a survey of the literature indicate that metalliferous coals are in many coal basins. Ore formation in coal-bearing structures may occur during peat accumulation, during diagenesis of the organic matter, or by epigenesis. Various metals are supplied to sedimentary basins as minerals that are transported by water and wind or as ionic species in surface water and descending and ascending underground water and may be incorporated into peat or coals. The modes of occurrence of metals in the enriched coals are diverse. The data presented in this review indicates that metalliferous coals should be regarded as promising for economic recovery for by-products in the course of coal mining and combustion. 相似文献
5.
郝启勇 《中国地质灾害与防治学报》2021,32(1):65-69
为了研究黄河北矿区土壤盐渍化现状及特征,采用野外调查、钻探、现场采样和室内分析测试等手段获取了土壤盐分含量和地下水特征数据,分析了区内土壤盐分含量、空间分布、垂向变化及与浅层地下水的相互关系。结果显示,研究区土壤主要以潜在盐渍土和轻度盐渍土为主,土壤盐分中阴离子以重碳酸根和硫酸根离子为主,阳离子以钠和钙离子为主。土壤垂向上显示表聚性（0～20 cm）,表层盐渍化严重,深部盐渍化程度有所降低。研究区土壤盐渍土与浅层地下水存在内在的自然的直接关系,土壤全盐量与地下水中溶解性总固体(TDS)含量呈明显正相关关系,而与浅层地下水位埋深呈负相关关系。研究区煤炭的开发利用,将加剧和恶化土壤盐渍化程度,煤炭的开采需要合理确定地表塌陷的程度,以此来倒逼煤炭的开采开发模式,从而减缓土壤盐渍化程度。 相似文献
6.
The No. 1 and No. 2 coal seams from the Permian Vryheid Formation in the east Witbank Coalfield, South Africa are described with respect to their distribution, thickness and quality. These two coal seams accumulated in a postglacial climatic environment and peat accumulation was closely associated with and influenced by deposition in a braided river system. The fluvial channels that were syndepositional with peat accumulation have resulted in thinning of coal below and above channel axes and pinch-out of coal adjacent to channel margins. Low-ash coal originated from peat which accumulated in areas away from the influence of clastic sedimentation. In contrast, higher-ash coals are situated adjacent and parallel to channel margins where interbedded channel sand and silt contaminated the peat.The lower No. 1 seam peat originated under near-optimum conditions in a lacustrine swamp which blanketed an underlying platform of glaciofluvial braided river sediment. This peat swamp was not subjected to syndepositional clastic contamination and as a result is of superior quality (lower ash/higher calorific value and volatile matter) than the overlying No. 2 coal seam. The No. 2 seam is split by a clastic parting produced by a braided fluvial channel which transected the swamp midway through peat accumulation. This fluvial clastic parting deleteriously affected coal thickness and quality.A comparison of the Gondwanan Permian peat-forming conditions with those from Carboniferous northern hemisphere counterparts suggests that the differences in coal characteristics between these two regions are probably related to different palaeoclimatic conditions and basin tectonics. Cool-temperate climatic conditions which prevailed over the Permian peat swamps resulted in less species diversification of vegetation at these high-latitude settings than the diverse floral assemblages of the Carboniferous swamps. A stable intracronic basin platform caused lateral dispersion of sedimentary facies rather than the stacking of vertical facies which occurred in rapidly subsiding depositories. Partial exposure of the Permian peat swamps during peat accumulation may account for the relatively higher inertinite content of the coals. 相似文献
7.
华北晚古生代陆表海盆地海侵事件微观沉积特征及成煤探讨 总被引：3，自引：0，他引：3
采用沉积学、煤地质学、古生物学、地层学及地球化学等多技术手段,结合比较分析法的思路,分析了事件型海侵的特点和海侵事件沉积组合特征,研究发现:海侵事件沉积组合为区域对比性强、具沉积时间连续性与相序间断性的暴露沉积-煤层-灰岩组合,其关键沉积学特征是煤层底板的暴露沉积.海侵事件组合灰岩的古生化石个体小、破碎强烈等特征表现为高能量水体运动等环境,孢粉表现为低含量的单缝孢和裸子植物及高含量的三缝孢.地球化学分析表明暴露沉积为陆相环境,煤层中的微量元素表现为海相主要原因是由于泥炭沼泽覆于深水后受海水影响所致.海侵事件成煤与海侵过程成煤差异体现在两个方面:第一,盆地属性差异,即海侵事件成煤形成于陆表海盆地之中,而海侵过程成煤则形成于具有缓坡的边缘海盆地,第二,成煤原理存在着差异,海侵事件成煤强调的是成煤前海侵未发生前的碎屑体系废弃而发育大量泥炭沼泽且被后期突发性海侵终止,而海侵过程成煤则强调的是泥炭沼泽发育于滨海的活动碎屑体系并终止于后期的缓慢海平面上升. 相似文献
8.
Microfacies and depositional environment of Tertiary Tanjung Enim low rank coal, South Sumatra Basin, Indonesia 总被引：2，自引：2，他引：2
The South Sumatra basin is among the most important coal producing basins in Indonesia. Results of an organic petrography study on coals from Tanjung Enim, South Sumatra Basin are reported. The studied low rank coals have a mean random huminite reflectance between 0.35% and 0.46% and are dominated by huminite (34.6–94.6 vol.%). Less abundant are liptinite (4.0–61.4 vol.%) and inertinite (0.2–43.9 vol.%). Minerals are found only in small amounts (0–2 vol.%); mostly as iron sulfide.Based on maceral assemblages, the coals can be grouped into five classes: (1) humotelinite-rich group, (2) humodetrinite-rich group, (3) humocollinite-rich group, (4) inertinite-rich group and (5) humodetrinite–liptinite-rich group. Comparing the distribution of maceral assemblages to the maceral or pre-maceral assemblages in modern tropical domed peat in Indonesia reveals many similarities. The basal section of the studied coal seams is represented typically by the humodetrinite–liptinite-rich group. This section might be derived from sapric or fine hemic peat often occurring at the base of modern peats. The middle section of the seams is characterized by humotelinite-rich and humocollinite-rich groups. The precursors of these groups were hemic and fine hemic peats. The top section of the coal seams is typically represented by the humodetrinite-rich or inertinite-rich group. These groups are the counterparts of fibric peat at the top of the modern peats. The sequence of maceral assemblages thus represents the change of topogenous to ombrogenous peat and the development of a raised peat bog.A comparison between the result of detailed maceral assemblage analysis and the paleodepositional environment as established from coal maceral ratio calculation indicates that the use of coal maceral ratio diagrams developed for other coal deposits fails to deduce paleo-peat development for these young tropical coals. In particular, mineral distribution and composition should not be neglected in coal facies interpretations. 相似文献
9.
10.
中国含煤岩系层序地层学研究进展 总被引：16，自引：3，他引：13
层序地层学理论为人们理解聚煤作用模式提供了新的思路,通过近二十年的研究,人们认识到含煤岩系旋回性与不同级别的全球海平面变化规律密切相关,认识到有工业价值的煤层形成于基准面(海平面)抬升过程,相继提出幕式聚煤作用、海侵过程成煤、事件成煤作用、海相层滞后阶段聚煤等基于层序地层分析的聚煤作用理论。同时概括出层序地层格架下基于可容空间增加速率与泥炭堆积速率的关系的厚煤层聚集模式。今后的研究将会进一步对不同构造背景下的含煤岩系层序地层格架样式、层序地层格架下的优质煤炭资源聚集模式、煤层在地球演化的长周期过程中的地质意义等方面进行探索,此外,针对中国五大聚煤区的成煤时期及盆地构造背景的特殊性,中国学者还会进一步总结其层序地层格架样式以及聚煤模式,并将其用于指导中国优质煤炭资源预测 相似文献
11.
The Ruhuhu Basin in SW Tanzania contains several small coal basins (i.e. Mchuchuma, Ngaka North, Mbalawala, Lumecha), consisting of fault controlled half-grabens submitted to several stages of tectonic activation. All basins underwent fragmentation in the ? middle Jurassic and late Miocene to Pliocene. Palaeotopography of pre-Karoo basement was partly responsible for the development of coal seam thickness distribution. Facies characteristics of the lower/middle and upper Mchuchuma Formation and the »Scarp sandstone« of the overlying Ketewaka formation exhibit synsedimentary basin subsidence. Vitrinite reflectance data suggest similar temperature gradients and burial history for the Mchuchuma and Ngaka subbasins. The application of a computer simulation program revealed the considerable effect of post-sedimentary tilting of depositional surfaces. In the Mchuchuma basin the back rotation of the base of the economic coal seam was calculated at -2°, the Ngaka basin showed an even higher degree of back rotation of -6°. Cyclicity was determined by Markov chain analysis for both basins. Mainly fining upward cycles prevail being characteristic for a fluvial environment. The depositional model for the Mchuchuma basin represents a meandering river system with a lower basal channel fill and an upper suspension load dominated cycle with accompanying overbank and flood plain sediments. The Ngaka basin shows an environment tentatively attributed to a braided river system. Thinning of coal seams and increased ash values in upper stratigraphic units depict deteriorating peat forming and preserving conditions. Swamp water chemistry was responsible for peat preservation, channel configuration and to some degree differential compaction governed the coal seam geometry. A slightly warmer climate than usually described for the Gondwana coals is proposed for the Lower Permian Tanzania coals. The diversity of microfloral evolution, eustatic sea level rises in the Sakmarian of Australia and available palaeotemperature curves demonstrate a probable mean annual temperature of 10–12 °C for a palaeolatitude of 60° S for the Tanzania coal fields. 相似文献
12.
Compacted clay soils are used as barriers in geoenvironmental engineering applications and are likely to be exposed to salinization and desalinization cycles during life of the facility. Changes in pore fluid composition from salinization and desalinization cycles induce osmotic suction gradients between soil–water and reservoir (example, landfill/brine pond) solution. Dissipation of osmotic suction gradients may induce osmotic swelling and consolidation strains. This paper examines the osmotic swelling and consolidation behaviour of compacted clays exposed to salinization and desalinization cycles at consolidation pressure of 200 kPa in oedometer assemblies. During salinization cycle, sodium ions of reservoir fluid replaced the divalent exchangeable cations. The osmotic swelling strain developed during first desalinization cycle was 29-fold higher than matric suction induced swelling strain of the compacted specimen. Further, the diffusion controlled osmotic swelling strain was 100-fold slower than matric suction-driven swelling process. After establishment of ion-exchange equilibrium, saturated saline specimens develop reversible osmotic swelling strains on exposure to desalinization cycles. Likewise the saturated desalinated specimen develops reversible osmotic consolidation strains on exposure to cycles of salinization. Variations in compaction dry density has a bearing on the osmotic swelling and consolidation strains, while, compaction water content had no bearing on the osmotic volumetric strains. 相似文献
13.
Stephen F. Greb Cortland F. Eble Donald R. Chesnut Jr. 《International Journal of Coal Geology》2002,50(1-4)
More than 130 Mt of Pennsylvanian coal is produced annually from two coal fields in Kentucky. The Western Kentucky Coal Field occurs in part of the Illinois Basin, an intercratonic basin, and the Eastern Kentucky Coal Field occurs in the Central Appalachian Basin, a foreland basin. The basins are only separated by 140 km, but mined western Kentucky coal beds exhibit significantly higher sulfur values than eastern Kentucky coals. Higher-sulfur coal beds in western Kentucky have generally been inferred to be caused by more marine influences than for eastern Kentucky coals.Comparison of strata in the two coal fields shows that more strata and more coal beds accumulated in the Eastern than Western Kentucky Coal Field in the Early and Middle Pennsylvanian, inferred to represent greater generation of tectonic accommodation in the foreland basin. Eastern Kentucky coal beds exhibit a greater tendency toward splitting and occurring in zones than time-equivalent western Kentucky coal beds, which is also inferred to represent foreland accommodation influences, overprinted by autogenic sedimentation effects. Western Kentucky coal beds exhibit higher sulfur values than their eastern counterparts, but western Kentucky coals occurring in Langsettian through Bolsovian strata can be low in sulfur content. Eastern Kentucky coal beds may increase in sulfur content beneath marine zones, but generally are still lower in sulfur than mined Western Kentucky coal beds, indicating that controls other than purely marine influences must have influenced coal quality.The bulk of production in the Eastern Kentucky Coal Field is from Duckmantian and Bolsovian coal beds, whereas production in the Western Kentucky Coal Field is from Westphalian D coals. Langsettian through Bolsovian paleoclimates in eastern Kentucky were favorable for peat doming, so numerous low-sulfur coals accumulated. These coals tend to occur in zones and are prone to lateral splitting because of foreland tectonic and sedimentation influences. In contrast, Westphalian D coal beds of western Kentucky accumulated during low differential tectonic accommodation, and therefore tend to be widespread and uniform in characteristics, but exhibit higher sulfur values because they accumulated in seasonally drier paleoclimates that were unfavorable for peat doming. Hence, basin analyses indicate that many differences between the mined coals of Kentucky's two coal fields are related to temporal changes in paleoclimate and tectonic accommodation, rather than solely being a function of marine influences. 相似文献
14.
生油煤形成的环境制约 总被引：4，自引：1，他引：4
通过对不同沉积环境下形成煤系源岩生烃潜力的对比研究，揭示出成煤古环境对煤成烃生成具有控制作用，并根据煤系源岩中赋存大分子有机质裂解产物分子的组成特征，提出了识别有利成烃煤相的分子有机地球化学方法——氢指数-苯酚/辛烷图解判识法。结果表明，沼泽环境覆水越深，煤中有机质富氢程度越高，生油气性能越好，裂解产物表现为正构烷烃和正构烯烃相对含量增加，以低本酚/辛烷值和高氢指数为特征；反之，沼泽环境覆水越浅，煤中有机质氢含量越低，裂解产物以高含量酚类化合物和芳香烃为特征，生油气性能关。由此表明，覆水型沼泽应是煤在烃，特别是煤成油生成的有利相带。 相似文献
15.
16.
Jane C. Shearer Timothy A. Moore Thomas D. Demchuk 《International Journal of Coal Geology》1995,28(2-4)
Floral character in mires has changed progressively through time. In the Carboniferous, pteridophytes, sphenophytes and lycophytes were dominant but by the Permian gymnosperms were an important component of mire flora. During the early Mesozoic gymnosperms remained the characteristic mire vegetation, together with pteridophytes, and conifers became dominant during the Jurassic. Cretaceous and Paleocene vegetation are similar, with taxodiaceous flora being important in mire vegetation. From the Eocene onwards, however, angiosperms were increasingly dominant in mire communities and in the Miocene herbaceous vegetation began to play a significant role. Together with these changes in floral character at least three aspects of coal character also appear to vary sequentially with time and are distinctive in the Tertiary: (1) proportions and thickness of vitrain banding, (2) coal bed thickness and (3) proportions of carbonised material. A compilation has been made of data from the coal literature comparing older coals with those of the Tertiary, in order to give a perspective in which to examine Tertiary coals. It was found that only Tertiary coals contain significant proportions of coal devoid of vitrain bands. In addition, Tertiary coals are the thickest recorded coal beds and generally contain low percentages of carbonised material (many less than 5%) as compared to older coals. It is interesting to note that Paleocene coal beds are similar to Cretaceous coals in that they tend to be thinner and contain higher proportions of carbonised material than do younger Tertiary coals.The absence of vitrain bands in some Tertiary coal beds is thought to result from the floras dominated by angiosperms, which are relatively easily degraded as compared to gymnosperms. The thickness of Tertiary coals may be related to an increase in biomass production from the Carboniferous through to the Tertiary, as plants made less investment in producing lignin, an energy-intensive process. In addition, with less lignin in plants, easier degradation of biomass may have facilitated nutrient recycling which, in turn, led to greater biomass production. Increased biomass production may have also ‘diluted’ the carbonised material present in some Tertiary peats, leading to lower proportions in the coal. Another possible cause of decreased carbonised components in Tertiary coal is that decreasing lignin content resulted in decreased charring during fires, as lignin is particularly prone to charring. A third possibility is that the carbonised component of peat may be concentrated during coalification so that Tertiary coals, generally of lower rank than Mesozoic or Paleozoic coals, contain a smaller fraction of carbonised plant material. It is not at present clear which of these mechanisms may have affected carbonised material in peat and coal but it is clear that lignin type and content has had an important role in determining peat and coal character since the Paleozoic. 相似文献
17.
S.I. Arbuzov L.P. Rikhvanov S.G. Maslov V.S. Arhipov A.M. Belyaeva 《International Journal of Coal Geology》2006,68(3-4):127-134
One hundred twenty-two samples of Jurassic and Paleogene brown coals and 1254 peat samples from the south-eastern region of the Western-Siberian platform were analyzed for gold by the neutron-activation method. Mean content of Au in Jurassic coals is 30 ± 8 ppb, in Paleogene coals is 10.6 ± 4.8 ppb, and in peat is 6 ± 1.4 ppb. Concentrations of gold as high as 4.4 ppm were found in coal ash and 0.48 ppm in the peat ash. Coal beds with anomalous gold contents were found at Western-Siberian platform for the first time.Negative correlation between gold and ash yield in coals and peat and highest gold concentrations were found in low-ash and ultra-low-ash coals and peat. Primarily this is due to gold's association with organic matter.For the investigation of mode of occurrence of Au in peat the bitumen, water-soluble and high-hydrolyzed substances, humic acids, cellulose and lignin were extracted from it. It was determined that in peat about 95% of gold is combined with organic matter. Forty to sixty percent of Au is contained in humic acids and the same content is in lignin. Bitumens, water-soluble and high-hydrolyzed substances contain no more than 1% of general gold quantity in peat.The conditions of accumulation of high gold concentrations were considered. The authors suggest that Au accumulation in peat and brown coals and the connection between anomalous gold concentrations and organic matter in low-ash coals and peat can explain a biogenic–sorption mechanism of Au accumulation. The sources of formation of Au high concentration were various Au–Sb, Au–Ag Au–As–Sb deposits that are abundant in the Southern and South-Eastern peripheries of the coal basin. 相似文献
18.
Occurrence and morphology of pyrite in Bulgarian coals 总被引：2，自引：0，他引：2
Coals with different degrees of coalification (ranging from lignite to anthracite) from seven Bulgarian coal basins have been investigated. The forms of pyrite and their distribution have been established. The types found are: massive pyrite, represented by the homogeneous, cluster-like and microconcretionary varieties; framboidal pyrite, appearing in inorganic and bacterial forms; euhedral pyrite, which is either isolated or clustered; anhedral pyrite, in its infilling and replacement varieties; and infiltrational pyrite, as a replacement or infilling mineral.Most of the forms of the euhedral, framboidal and massive pyrite developed during peat deposition. The anhedral replacement pyrite formed in the peat bed during early diagenesis. Infiltrational pyrite filled fractures and cleats formed during the diagenesis, catagenesis and metagenesis.Both similarities and differences with respect to the distribution of the pyrite types have been determined between coals of different ranks from Bulgarian coal basins. These differences are due to: the presence of Fe and S in the rocks adjacent to ancient peat bogs; the activities of ground and surface waters which brought Fe and S into the peat bogs; the geochemical character (pH and Eh) of the peat bogs and the sulphur bacteria development; and the tectonic situation during diagenesis, catagenesis and metagenesis. 相似文献
19.
A review of coal properties pertinent to carbon dioxide sequestration in coal seams: with special reference to Victorian brown coals 总被引：2，自引：1，他引：1
M. S. A. Perera P. G. Ranjith S. K. Choi A. Bouazza J. Kodikara D. Airey 《Environmental Earth Sciences》2011,64(1):223-235
This paper presents reviews of studies on properties of coal pertinent to carbon dioxide (CO2) sequestration in coal with specific reference to Victorian brown coals. The coal basins in Victoria, Australia have been
identified as one of the largest brown coal resources in the world and so far few studies have been conducted on CO2 sequestration in this particular type of coals. The feasibility of CO2 sequestration depends on three main factors: (1) coal mass properties (chemical, physical and microscopic properties), (2)
seam permeability, and (3) gas sorption properties of the coal. Firstly, the coal mass properties of Victorian brown coal
are presented, and then the general variations of the coal mass properties with rank, for all types of coal, are discussed.
Subsequently, coal gas permeability and gas sorption are considered, and the physical factors which affect them are examined.
In addition, existing models for coal gas permeability and gas sorption in coal are reviewed and the possibilities of further
development of these models are discussed. According to the previous studies, coal mass properties and permeability and gas
sorption characteristics of coals are different for different ranks: lignite to medium volatile bituminous coals and medium
volatile bituminous to anthracite coals. This is important for the development of mathematical models for gas permeability
and sorption behavior. Furthermore, the models have to take into account volume effect which can be significant under high
pressure and temperature conditions. Also, the viscosity and density of supercritical CO2 close to the critical point can undergo large and rapid changes. To date, few studies have been conducted on CO2 sequestration in Victorian brown coal, and for all types of coal, very few studies have been conducted on CO2 sequestration under high pressure and temperature conditions. 相似文献
20.
Four bogs in New Zealand were investigated in order to understand the relationship between peat type and depositional environment. This relationship is important because peat type translates into coal type, and coal types can ultimately be used to infer how and under what conditions the original peat bog formed. In our study, no correlation was found between peat type and depositional environment in the four bogs examined. Moreover, no correlation was found between peat type and either tectonic setting or climate. Water table level and degree of fluctuation are the only parameters which seem to have a good causative relationship on peat type.The bogs, Whangamarino, Moanatuatua and Kopouatai in the North Island and Sponge Swamp in the South Island, all have different depositional settings ranging from coastal plain, to fluvial-meandering and fluvial-braided river floodplain. We found no diagnostic peat types that would allow those different environments to be distinguished from studies of the peat. Data from other tropical and temperate climate peat bogs also support our contention that no diagnostic peat types can distinguish particular depositional settings. However, the level and variability of water table does have a correlation, one that is also seen in bogs elsewhere.From our observations, we infer that the validity of using maceral ratios (directly related to coal type) to indicate depositional environment should be questioned. At best, coal type only represents to what degree the original plant components were degraded, but not how they were degraded. To infer other parameters such as depositional environment, tectonic setting or climate, other data (e.g. distribution of surrounding sediment types, palynology, etc.) must be collected and assessed. 相似文献