Regional coal seam gas distribution and burial history of the Hunter Coalfield,Sydney Basin     

K. L. Pinetown 《Australian Journal of Earth Sciences》2014,61(3):409-426

Basin modelling has been used to improve understanding of the origin and temporal evolution of coal seam gas in the Hunter Coalfield of the Sydney Basin. Burial history models were produced based on data from seven boreholes located in the southern, eastern, central and western areas of the coalfield. Mean random vitrinite reflectance (R_v,r) data, derived from measurements of mean maximum reflectance (R_v,max), were used for calibration of the models. A qualitative sensitivity analysis of one model shows that varying the paleoheat flow has a greater influence on calculated R_v,r than varying the eroded overburden thickness.

The differences between the constructed models are significant enough to provide plausible explanations for regional gas distribution in the Hunter Coalfield. Coals in the south of the coalfield appear to have the greatest potential for thermogenic gas generation. Modelling has shown that areas that have low gas contents and decreased permeability have been uplifted more, and buried less, compared with areas that have high gas contents. Burial history modelling shows noticeable variations in the extent of burial and uplift, and, consequently, in thermal maturities and potential for thermogenic gas generation; together with the assessment of other coal and gas property data, it appears that present-day gas contents may partially reflect coal ranks and adsorption capacities, with late-stage biogenic gas generation replenishing CH₄ volumes that were lost following uplift during the Late Cretaceous.  相似文献   

The Somerset Dam Layered basic intrusion,Southeastern Queensland     

C. I. Mathison 《Australian Journal of Earth Sciences》2013,60(1):57-86

The Somerset Dam Layered Basic Intrusion is probably a sub‐volcanic magma chamber, and it consists of 20 saucer‐shaped layers composed of troctolites, olivine gabbros, ferrigabbros, and leucogabbros. The layered sequence is 1650 ft (500 m) thick, and comprises several repetitions of a standard pattern termed a zone. Each zone is generally composed of four layers, and successive mineral assemblages from the base upwards are: plagioclase‐olivine, plagioclase‐augite‐olivine, plagioclase‐augite‐magnetite‐ilmenite, and plagioclase‐uralite. Pronounced modal and textural changes define the boundaries between these layers. Within a zone, systematic variation in the proportions and compositions of minerals is thought to be the result of a slight decrease in temperature, and an increase in the partial pressures of water vapour and oxygen from the base to the top.

Repetition of zones is explained by a mechanism involving periodic renewals of magma. Lack of progressive changes in mineral compositions and proportions from the base to the top of the layered sequence is also a consequence of the magma composition, the control of water vapour pressure, and the limited range of crystallisation temperatures. Gravitational settling of early minerals does not explain the variation within a zone, or the small‐scale rhythmic layering that is locally developed, and it is concluded that diffusion has been an important control.  相似文献   

Lithostratigraphy of the late Early Permian (Kungurian) Wandrawandian Siltstone,New South Wales: record of glaciation?     

S. G. Thomas  C. R. Fielding  T. D. Frank 《Australian Journal of Earth Sciences》2013,60(8):1057-1071

The late Early Permian (273 – 271 Ma) Wandrawandian Siltstone in the southern Sydney Basin of New South Wales represents a marine highstand that can be correlated over 2000 km. A mainly fine-grained terrigenous clastic succession, the Wandrawandian Siltstone contains evidence for cold, possibly glacial conditions based on the presence of outsized clasts and glendonites, mineral pseudomorphs after ikaite, a mineral that forms in cold (0 – 7°C) marine sediments. A lithostratigraphic and facies analysis of the unit was conducted, based on extensive coastal outcrops and continuous drillcores. Eight facies associations were identified: (i) siltstone; (ii) siltstone with minor interbedded sandstone; (iii) interbedded tabular sandstone and siltstone; (iv) admixed sandstone and siltstone to medium-grained sandstone; (v) discrete, discontinuous sandstone intervals; (vi) chaotic conglomerate and sandstone in large channel forms; (vii) chaotically bedded and pervasively soft-sediment-deformed intervals; and (viii) tuffaceous siltstone and claystone. Using lithology and ichnology, relative water depths were ascribed to each facies association. Based on these associations, the unit was divided into five informal members that reveal a history of significant relative sea-level fluctuations throughout the formation: member I, interbedded/admixed sandstone and siltstone; member II, siltstone; member III, slumped masses of members I and II; member IV, siltstone and erosionally based lensoid sandstone beds and channel bodies; and member V, interbedded/admixed sandstone and siltstone with abundant tuffs. Member I marks an initial marine transgression from shoreface to offshore depths. Member II records the maximum water depth of the shelf. Member III is interpreted to be a slump sheet; plausible mechanisms for its emplacement include seismicity produced by tectonism or glacio-isostatic rebound, changes in pore-water pressures due to sea-level fluctuations, or an increase in sedimentation rates. Members IV and V record minor fluctuations in depositional environments from offshore to shoreface water depths. Member IV includes regionally extensive, large channel bodies, with composite fills that are interpreted as storm-influenced mass-flow deposits. Member V includes a greater abundance of volcanic ash. Glacial controls (isostasy, eustasy) and tectonic affects may have worked in concert to produce the changes in depositional environments observed in the Wandrawandian Siltstone.  相似文献   

815℃灰化前后淮北煤中矿物质变化特征     

郑刘根  陈园平  刘桂建  CHOU Chen-lin 《岩石矿物学杂志》2013,32(1):106-112

以淮北煤田二叠纪5、4煤层15个煤样品为研究对象,对样品在815℃下进行灰化,并采用等离子体原子发射光谱(ICP-AES)对煤灰中成分进行测定,采用X射线衍射(XRD)对原煤以及灰化后的样品中矿物质成分进行了分析.在此基础上,探讨了煤中矿物质种类及影响煤中矿物质的主要因素,分析了煤中矿物质在815℃灰化前后的变化特征.结果表明,煤中矿物质种类受多种因素影响,灰化过程中矿物质的种类、含量会发生改变,且部分矿物在高温作用下发生变化,重新组合,形成相对较稳定的新矿物,从而为今后煤灰的综合利用提供科学论据.  相似文献   

Seeds for Change? Attaining the benefits of community gardens through council policies in Sydney,Australia     

Gregory Mintz 《The Australian geographer》2014,45(4):541-558

Modern industrial systems of food production cause a wide range of detrimental impacts to the environment, human health and society. Integrating community gardens into local food systems is one way to counteract some of those impacts. This research looks at the elements that community garden policies should contain in order to best promote community gardens and attain their benefits. Focusing on Sydney, the research evaluates and compares the quality of the community garden policies with the distribution of community gardens in local councils and across broader geographic regions. Councils or regions that might benefit from greater access to community gardens are identified and ways in which councils, and the Sydney Region as a whole, might improve their community garden policies are discussed.  相似文献   

Fitting refugees into the normative narrative of Australian multiculturalism     

Charishma Ratnam 《Urban geography》2013,34(8):1198-1209

Australia publicly espouses its multiculturalism as a key component of its national identity. In this paper, I argue that despite the importance of multiculturalism to Australia’s identity, political decisions and discourse has muddied its remit with respect to humanitarian migrant intake programs and outcomes. Australia’s history of selective migrant intake and restrictive refugee policy continues the Othering of past policies into contemporary settings. Refugee policy has become a political football. During the most recent national election campaign (May 2019), the plight of sick and ill refugees, currently housed offshore in detention centers, was used as a political pawn. Lost amid this political rhetoric were the traumatic narratives of forced migrants resettling in Australia’s cities. Without possibility for a loud voice in public discourse, there is little opportunity for more Australians to understand how refugees experience detention centers, struggle to attain residency visas, and make “home” in multicultural Australia. I draw on research with Sri Lankan refugees in Sydney to give voice to these micro-level, place-based experiences of vulnerable arrivals. These stories, I think, can (re)shape and enrich Australia’s multicultural identity because they challenge us to not only accept difference but recognize the circumstances through which Australia’s diversity seeds its narrative.  相似文献   

The Particularity of Global Places: Placemaking Practices in Los Angeles and Sydney     

《Urban geography》2013,34(2):92-119

What makes places different from one another in the context of globalization? An analysis of 17 emblematic practices in two global cities, Los Angeles and Sydney, provides the empirical basis for answering this question. Evidence from the built environment, the social geography, and the patterns of disorder in the inner cities of these two global places shows that these cities were more alike in the late 1960s than they are today. The differentiation of the two places has increased as the effects of globalization have become more pervasive. The evidence presented in this paper suggests that there is nothing inherent in contemporary globalization that requires global cities to have inner city slums, ghettoes, massive homelessness, residential disinvestment, White flight, relict or suboptimally-utilized brownfields, illegal prostitution, a war on drugs, public spaces awash with guns, and so forth. Places are viewed here as constellations of distinctive practices configured in particular geographical settings at the intersection of specific conjunctures of historical change. Places matter in the epoch of globalization as differentially embedded, bounded particularities consisting of a mixed assortment of human practices forming causally consequential fields of effects.  相似文献   

Religious Belief across ‘Post-secular’ Sydney: the multiple trends in (de)secularisation     

Deborah Stevenson  Adam Possamai  Awais Piracha 《The Australian geographer》2010,41(3):323-350

Cities were once thought to be crucibles of secularisation, where the retreat from religion and its expression would be most pronounced. This decline in faith was linked to the heightened levels of heterogeneity and cosmopolitanism within cities. However, there is recent evidence of both the continuation and of the recession of the secularisation process in contemporary Western societies, with the mix and pace of these trends being quite unique to different countries. Significantly, this combination of processes has been argued to be part of a ‘post-secularist’ paradigm. Drawing on census data, this paper examines the spatial patterns of religious affiliation and non-belief in the Australian city of Sydney. Sydney has divergent geographies of faith and non-faith indicating the spatial multiplicities of religious belief. The decrease in Christianity in some areas of the city has been matched by an increase in non-Christian faiths, while in other areas there has been little change. Some parts of the city—especially those areas with a strong mix of affluence, diversity and cosmopolitanism—betray the strongest levels of secularisation and the retreat of faith. At least five geographies of faith and non-belief are recognisable within Sydney. While post-secularisation has been recognised as internationally uneven, this research demonstrates that it is also uneven across a world city like Sydney. The Sydney variations in (de)secularisation reflect city-based effects, including the historic and contemporary patterns of immigrant settlement, established and emerging religious communities, the segmented geographies of class and affluence, and the development of zones of cosmopolitanism. The findings point to the need for further research on the micro-geographies of religious belief and non-belief and community relations, and the on links between religious communities and civil society.  相似文献   

Petrographic properties of major coal seams in Turkey and their formation     

Selami Toprak   《International Journal of Coal Geology》2009,78(4):263-275

Most types of coal in Turkey are generally low in rank: lignite, and subbituminous. Most of the coal was formed during the Miocene, Eocene, and Pliocene ages. There are only a few thin Jurassic-age coal occurrences in Turkey. Pennsylvanian age bituminous coal is found on the Black Sea coast. General implications of the petrographic properties of Turkey's coal seams and coal deposits have not yet been taken into consideration comparatively or as a whole.For this study, about 190 channel samples were collected from different locales. The composite profile samples of the seams were taken into considerations. The content and depositional properties as well as some chemical and physical properties of the main coal seams are compared. All coal samples tend to have similar coal petrographic properties and were deposited in intermontane lacustrine basins. Later, they were affected by faulting and post-depositional volcanic activity. As a result, there are variations in the properties and rank of the coal samples. The most abundant coal maceral group is huminite and the most abundant maceral is gelinite. The liptinite and inertinite contents of the coal are low and the maceral contents of the coals show great similarity. The depositional environments of the all coals are lacustrine dominated.  相似文献   

中国煤成油研究进展和展望   总被引：2，自引：1，他引：2  

胡社荣  潘响亮 《地球科学进展》1996,11(3):265-269

中国煤和含煤岩系内石油的发现是在５０￣６０年代，而提出应在我国进行煤和含煤岩成油问题的研究是８０年代初，自提出煤成油问题以来短短的十余年时间里，不仅在有机岩石学，煤成油地球化学，热模拟实验和煤成油综合研究等煤和含煤岩系成油理论上取得了进展，而且在油勘探的实践上，在吐鲁番和彩南取得了重要的进展。  相似文献