The effects of groundwater level and vegetation on creep of the Mam Tor landslip

The creeping Mam Tor landslide (North Derbyshire, UK) is sliding slowly downhill at up to 0.5 m per year. Annual measurements using conventional surveying techniques have shown that creep is exacerbated by periods of heavy rainfall, but to establish a detailed correlation between creep and groundwater levels requires spatially and temporally higher resolution monitoring. We have acquired three years of such data from wire creep meters, borehole piezometers and rainfall monitoring. These measurements showed that creep is strongly focused into the winter months and that it correlates well with groundwater levels. Summer grass and fern growth exerts a strong influence on rainfall infiltration, recycling much of the summer rainfall back to the atmosphere, and explaining the seasonal variability of creep motion.     

Do mature hydrocarbons have an influence on acid rock drainage generation?

The generation of acid rock drainage (ARD) is a biogeochemical process that causes severe ecological impacts, threatening human health worldwide. Microbes involved in acid drainage reactions are generally considered autotrophic but heterotrophic and mixotrophic microorganisms have often been identified at ARD sites. This raises questions about the role of organic matter naturally present at these sites, such as mature hydrocarbons, in promoting the microbial processes underpinning ARD generation. To investigate this, aerobic microcosm experiments were carried out using ARD samples collected at a well-characterised site in northern England (Mam Tor, Derbyshire). Organic analyses indicated the presence of substantial amounts of mature, petroleum-derived hydrocarbons and microbial analyses indicated that the sediment hosts acidophilic bacteria with the capability of degrading petroleum-derived compounds. However, the aerobic microcosm experiments indicated that these petroleum-derived hydrocarbons were not used by the bacterial community and, therefore, are not involved in the reactions that ultimately lead to ARD generation. These observations support a primary role for autotrophs in ARD generation.     

Impact of predicted climate change on landslide reactivation: case study of Mam Tor, UK

Global change is expected to result in worldwide increases in temperature and alteration of rainfall patterns. Such changes have the potential to modify stability of slopes, both natural and constructed. This paper discusses the potential effect of global climate change on reactivation of landslides through examination of predicted changes in rainfall pattern on the active landslide at Mam Tor, Derbyshire, UK. This landslide is of Pleistocene origin and is crossed by a road that is now abandoned. Damaging winter movement is known to occur when precipitation reaches both 1-month triggering and 6-month antecedent thresholds. Return periods for threshold exceedence is modelled statistically, and the climate change data from the UKCIP 2002 report (Hulme et al. 2002) is applied to this model. For the predicted changes in precipitation, it is shown that the instability threshold could decrease from 4 to 3.5 years by the 2080s for the medium–high climate change scenario. However, predicted temperature changes could influence the response of the landslide through increased evapotranspiration leading to a change in the triggering precipitation thresholds, and this will help counter the impact of changes in precipitation. Analysis of sources of uncertainty in the model has been used to establish the factors that contribute to the predicted changes in stability. Assessment of these factors can provide an indication of the potential impact of climate change on landslides in other areas of the UK.     

Summary of project TOR: delineation of a stepwise, sharp, deep lithosphere transition across Germany–Denmark–Sweden

Project Tor (Teleseismic Tomography across the Tornquist Zone in Germany–Denmark–Sweden) is now producing results. We are able to detect very significant deep lithosphere differences, and we can now discuss the sharpness laterally. In 1996–1997, our 120 seismographs constituted the largest seismic antenna ever in Europe. The Tor area was chosen along a well-studied crustal profile of an earlier project, and the inversion efforts are concentrated on the deep lithosphere and asthenosphere differences to depths around 300 km. The Tor investigation can be called two-and-a-half-dimensional, as it has a 900-km profile length with 100 km width plus a few seismographs off the profile. The Tor data have been subjected to P-wave travel time tomography, surface wave and receiver function analysis as well as anisotropy and scattering measurements. Through ray tracing in a compiled crustal model and subtraction of the modelled travel time anomalies, the influence of the lower lithosphere/asthenosphere on the seismic rays from distant earthquakes is being established. Travel time tomography results confirm very large lateral lithosphere differences of 4–6% in P-wave velocity. For several events of the large data base, it is demonstrated that the observed P-wave travel time anomalies of 1–2 s can be divided almost equally between known crustal effects and lower lithosphere/asthenosphere differences, which then must account for about 1 s of the travel time differences. The transition is interpreted to be sharp and steep in two places. It goes all the way through the lithosphere at the northern rim of the Tornquist Zone near the border between Sweden and Denmark, and here the lithosphere difference is large. A smaller lithosphere difference is found near the southern edge of the Ringkøbing-Fyn High just north of the border between Denmark and Germany. Also, this transition is sharp and steep, and goes all through the lithosphere. These two sharp transitions divide the Tor region into three different lithosphere structures distinguishable in P-wave travel time tomography, surface wave dispersion, P- and S-wave anisotropy, and partly in P-wave scattering.     

国外海相油气田勘探实例(之一)挪威埃科菲斯克油田

介绍了挪威埃科菲斯克油田的基本概况及油田勘探历史,描述了该盆地的演化、油气系统、区域地层及沉积相。该油田的构造类型为盐丘构造,主要的储集层为麦斯特里希特统(K2)—下古新统(丹麦阶)托尔组和埃科菲斯克组。埃科菲斯克组以构造裂隙为主,托尔组主要发育与缝合线有关的裂隙。白垩地层主要为生物成因,其成分为分解的贝壳或浮游的Cocccophorid藻颗石、浮游类和海底有孔虫类。     

Book reviews

Book review in this article
Bibliography of Alluvial-fan Deposits, by Tor H. Nilsen and Thomas E. Moore
Coastal Oceanography, ed. by H. G. Gade, A. Edwards and H. Svendsen.
Siliciclastic Shelf Sediments, ed. by R. W. Tillman and C. T. Siemers
Glacial Lake Agassiz, edited by J. T. Teller and Lee Clayton     

Building the ‘competitive city’: labour and Toronto’s bid to host the Olympic games

Toronto’s quest to host the Summer Olympic Games has dominated both contemporary planning discourse and practice. For some, the pursuit of the games embodies Toronto’s transformation into a ‘competitive’ global city. Relatively unexplored in this discourse are the contradictory roles that labour plays in contemporary urban development. I argue that the new labour geography can provide some interesting insights into such processes. Specifically, labour geographers have given workers with divergent interests greater agency in shaping economic landscapes and have noted the multi-scalar organisation of labour. The paper looks at the contradictory and conflicting positions held by different labour unions in Toronto toward the city’s bid to host the 2008 Olympics. The case study suggests that labour is an active agent in processes shaping contemporary Toronto and support the bid for complex reasons ranging from the promise of jobs to potential future organising opportunities.     

Enacting geographies

We conclude the editorial by glancing ahead to the individual papers. This overview seeks only to highlight motifs, themes, arcs and trajectories (since the papers will obviously exceed anything we might say about them).John Wylie's paper, An essay on ascending Glastonbury Tor, draws upon the work of Merleau Ponty and Heidegger to illustrate how the act of visualizing itself is always a making of seer and seen. The paper thus seeks to speak of a subjectivity produced and performed via practices of ascension and elevation, and, in doing so, to move towards a new understanding of visible landscape in terms of sensuous practices. Cataloguing his own ascent of Glastonbury Tor, Wylie seeks to enact the Tor for the reader, engendering its visibility, its cultural histories, and thus its sensuous reality through his narrative.Motifs of landscape and practice recur in Mitch Rose's paper, Landscape and Labyrinths, which seeks to sketch out a conceptual and methodological approach to cultural landscape beyond the structuralism of cultural geography, which, Rose argues, skewers landscape through stabilisations of meaning. An ontology of overdetermination and surplus, as elaborated by Althusser and Bataille, is offered by Rose as a possible means of becoming attentive to the excessiveness of landscape.Derek McCormack's A paper with an interest in rhythm moves from the false problematic of representing movement to become an exposition of movement within the folds of writing. In a virtuosic exploration of rhythm McCormack produces an animated space that moves, folds and achieves consistency via both non-subjectifying and subjectifying forces. Theoretical considerations are not side-stepped by this performance; rather, the particular rhythms of Deleuze, Guattari and Lefebvre are engaged and enfolded by the paper.Paul Harrison's paper The Caesura: Remarks on Wittgenstein's interruption of theory, or, why practices elude explanation, presents a precise and exacting philosophical exposition of the work of Ludwig Wittgenstein. Harrison uses the work of Wittgenstein to offer a diagnosis of idealism within much contemporary social analysis. Linking up with the special issue's concerns, Harrison suggests that it is the performative which occupies the space vacated by Idealism; a replacement of the Cartesian Ideals of certainty for 'infinitive', and distinctly geographic, understandings––taking -place, making -sense––which speak of the time of the present, not of all Time.     

Water quality and relationship between superficial and ground water in Rome (Aniene River basin,central Italy)

Chemical, physical, and biological features of streams and ground water of the North-Eastern area of Rome are jointly analyzed in order to assess the status of water resources. Ground water was investigated with classical survey methods (pH, temperature, and electric conductivity). Microbiological pollution, faunal composition, and stream surrounding area conditions of surface waters were studied, in order to quantify the residual value of these ecosystems from both a human and an environmental point of view. Results show a general impairment of the system and the comparison between superficial waters and shallow ground waters makes it possible to detect the presence of a connection between the two levels. This relationship occurs as an exchange from superficial waters (streams and rivers) to the shallow aquifers. Where superficial waters are contaminated, as in the Tor Sapienza stream, pollutants move to the shallow aquifers too, due to the decreased pressure of the over-exploited aquifer. Moreover, uncontrolled drilling activity, diffused in urban areas, makes it possible the connection between shallow and deep ground water. Notwithstanding this, the mixing between superficial and deep ground water system in Rome is not very widespread and, apparently, limited to restricted areas.     

Stylolite-controlled layering in an homogeneous limestone: pseudo-bedding produced by burial diagenesis

It is often assumed that layering in many shelf and platform limestones at weathered outcrop is always bedding: the layers always beds, and the surfaces always bedding planes. Recognition of bedding is fundamental to facies and basin analysis. Examination of part of the Lower Carboniferous High Tor Limestone of the Gower, South Wales, shows that a totally diagenetic layering (pseudo-bedding) resembling, and parallel to primary depositional layering (true bedding), has been produced by the generation of parallel, more or less evenly-spaced stylolite surfaces during burial diagenesis. These stylolite surfaces are picked out by weathering at outcrop and resemble bedding planes. Evidence that the stylolite surfaces do not mark original bedding planes includes: a cross-cutting relationship of a stylolite surface to a primary bedding surface; lack of lithological change across, or sedimentary structures associated with, a stylolite surface; original bedding that is not coincident with stylolite surfaces and has not suffered pressure-dissolution; and lack of sedimentological evidence that the layers defined by the stylolite surfaces are true primary depositional beds. The generation of parallel and more or less evenly-spaced stylolite surfaces could be explained by a mathematical-kinetic model based on the relationship between pressure-dissolution, diffusion, and reprecipitation. Recognition of true bedding depends upon presence of lithological changes and/or sedimentary structures. It is suggested that pseudo-bedding could be confused with true bedding in some open platform/shelf lagoon facies where lithological changes or sedimentary structures are scarce or absent.     

The presence of Holocene cryptotephra in Wales and southern England

There have been few detailed studies into the tephrostratigraphy of southern Britain. We report the tephrostratigraphy of two sites, one in southern England (Rough Tor, Cornwall) and one in Wales (Cors Fochno, west Wales). Our study extends the known southernmost reach of Icelandic cryptotephra in northern Europe. Given the large distance between sites in southern England and eruptive sources (e.g. Iceland 1500–1700 km distant), most of the cryptotephra layers consist of sparse numbers of shards, even by the standards of distal tephrostratigraphy (as low as 3 shards cm⁻¹), each layer spanning only 1 or 2 cm in depth. We identify multiple cryptotephra layers in both sites, extending the known distribution of several tephra layers including the MOR‐T4 tephra (∼AD 1000) most probably of Icelandic origin, and the AD 860 B tephra correlated to an eruption of Mount Churchill, Alaska. The two sites record contrasting tephrostratigraphies, illustrating the need for the inclusion of multiple sites in the construction of a regional tephrostratigraphic framework. The tephra layers we describe may provide important isochrons for the dating and correlation of palaeoenvironmental sequences in the south of Britain. 2017 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd.

     

作为赋存于花岗岩中钨锡矿化勘探指南的流体包裹体异常——前景展望

Studies of the distribution and abundance of fluid inclusions in granitic quartz associated with granite-hosted Sn-W mineralization of the British Isles reveal local and regional scale anomalies.At a sampling interval of c.5～50m,inclusion abundances increase towards zones of vein and stockwork mineralization exemplified by case history examples from exploration prospects in the Mourne Mountains of Northern Ireland and the Carrock Fell mining district of northwestern England.These steam aureoles provide a greater exploration target than the zone of visible alteration and mineralization and the lithogeochemical halo.But it is important to link them to geochemical data on fluid inclusion compositions,such as the semi-quantitative data from decrepitation-linked,ICP-AES (D-ICP)analysis,to optimize their exploration potential.Regional scale fluid inclusion anomalies,based on sampling intervals of c. 2km from the Sn-W mineralized granites of southwest England also broadly correlate with zones of intense mineralization in some areas. Regional-scale D-ICP analyses of quartz from SW England granites did not provide any convincing regional scale anomalies linked to mineralization except for positive boron anomalies around the centrally-mineralized Birch Tor area of the Dartmoor granite.Follow-up D-ICP analysis of quartz from stream sediments from this area,however,could be used to discriminate between samples related to mineralization from those draining unmineralized areas,using multivariate statistical analysis.At the present stage of development, the main contribution of fluid inclusion studies to mineral exploration is mostly limited to the conceptual stage where they continue to contribute to ore genetic theory and models.Costs and lack of knowledge transfer between research scientists and mineral explorationists limit their direct use during regional and target selection stages of exploration.Analysis of steam sediment quartz,using the more sensitive ICP-MS technique as a variant of the D-ICP method,appears to offer the greatest potential for future development as an exploration tool.     

Das Holozän im Binnenland — die geologische Gegenwart

With regards to exogenic proceedings the postglacial time was characterized till now as a geologically stable time, and by this as “the geological present time”. This view may be correct if, e. g., the pedogenesis is considered with continuous processes, but only apparently. But there are differences which are explicable genetically only partly up to the presence, if in Middle Europe holocene rock bildings are considered with, as cave sediments, calc-tufa, peat layers, fluviatile sediments, and others. Finally the man as a further modifying factor is added to, since about the last 5.000 years. Since about the last 20 years a more extensive data material was gained by working for the fluviatile proceedings in the holocene. Therefore at the Lower Rhine, but also at the Danube (“Eisernes Tor”) and on the border of the Alps there is perceptible a trend in diminuation of fluviatile effectivness in approach to the present time. Phases of activities with an interval of about 1.000 years, at least in the youngest holocene, are settled on this principal process. By this, parts of the valley soil are reworked and deposited again downwards the valley. The reason for these proceedings, trends and the shorter activities is unknown, although there are first reference points for connections with oscillations of the glaciers in the Alps and of the sea level in the North Sea. Apparently slight climatic impulses in the border zone of oceanic and continental climate, which are not even perceptible on the vegetation history, might be the reason, at least partly. Next to that it is thinkable that continuously proceeding evolutions can lead to abrupt alterations at swell value. Beyond it, the quantitative effects of human activities are largely unknown. A geoscientific research, oriented into the future, only can come to results reach in meaning if it is able to value the factor of time, and by this the youngest of all earth history.     

Gas geochemistry of natural analogues for the studies of geological CO2 sequestration

Geological sequestration of anthropogenic CO₂ appears to be a promising method for reducing the amount of greenhouse gases released to the atmosphere. Geochemical modelling of the storage capacity for CO₂ in saline aquifers, sandstones and/or carbonates should be based on natural analogues both in situ and in the laboratory. The main focus of this paper has been to study natural gas emissions representing extremely attractive surrogates for the study and prediction of the possible consequences of leakage from geological sequestration sites of anthropogenic CO₂ (i.e., the return to surface, potentially causing localised environmental problems). These include a comparison among three different Italian case histories: (i) the Solfatara crater (Phlegraean Fields caldera, southern Italy) is an ancient Roman spa. The area is characterised by intense and diffuse hydrothermal activity, testified by hot acidic mud pools, thermal springs and a large fumarolic field. Soil gas flux measurements show that the entire area discharges between 1200 and 1500 tons of CO₂ per day; (ii) the Panarea Island (Aeolian Islands, southern Italy) where a huge submarine volcanic-hydrothermal gas burst occurred in November, 2002. The submarine gas emissions chemically modified seawater causing a strong modification of the marine ecosystem. All of the collected gases are CO₂-dominant (maximum value: 98.43 vol.%); (iii) the Tor Caldara area (Central Italy), located in a peripheral sector of the quiescent Alban Hills volcano, along the faults of the Ardea Basin transfer structure. The area is characterised by huge CO₂ degassing both from water and soil. Although the above mentioned areas do not represent a storage scenario, these sites do provide many opportunities to study near-surface processes and to test monitoring methodologies.     

Short- and long-term gas hazard: the release of toxic gases in the Alban Hills volcanic area (central Italy)

In the Alban Hills area, strong areally diffuse and localised spot degassing processes occur (Tivoli, Cava dei Selci, Solforata, Tor Caldara). The gas comprises a large proportion of CO₂, with minor CH₄, H₂S and Rn. These advective features are generated by fluid leakage from buried reservoirs hosted in the structural highs of the Mesozoic carbonate basement. Gas migration towards the surface is controlled by fault and fracture systems bordering the structural highs of the carbonate formations (e.g. Ciampino high). His release is triggered when the total pressure of the fluid phase exceeds the hydrostatic pressure, thus forming a free gas phase. Furthermore, both the sudden and catastrophic, and slow and continuous gas release at surface, of naturally occurring toxic species (CO₂, H₂S and Rn) poses a serious health risk to people living in this geologically active area.This paper presents data obtained from soil gas and gas flux surveys, as well as gas isotopes analyses, which suggest the presence of a deep origin gas flux enriched in carbon dioxide and minor species (CH₄ and H₂S), as well as a channelled migration of geogas mixtures having a Rn component which is not produced in situ.In regards to the health risk to local inhabitants, it was found that some anomalous areas had been zoned as parkland while others had been heavily developed for residential purposes. For example, many new houses were found to have been built on ground which has soil gas CO₂ concentrations of over 70% and a CO₂ flux of about 0.7 kg m⁻² day⁻¹, as well as radon values of more than 250 kBq/m³. In addition, an indoor radon survey has been conducted in selected houses in the town of Cava dei Selci to search for a possible correlation between the local geology and the radon concentration in indoor air. Preliminary results indicate high indoor values at ground floor levels (up to 1000 Bq/m³) and very high values in the cellars (up to 250.000 Bq/m³). It is recommended that land-use planners incorporate soil gas and/or gas flux measurements in the environmental assessment of areas of possible risk (i.e. volcanic or structurally active areas).     

用扫描电镜-图象分析方法研究某区稀土、铌矿石的元素赋存状态

某区西部矿区稀土,铌矿物是该区有意义的工业矿物。该类矿物的定量准确程度,将直接影响将来的工艺流程。该区稀土、铌矿物具有含量低、种类多、颗粒细,且某些矿物的光性近似、难于鉴定、矿石又遭受表生氧化等特点,故用传统的在显     

新疆尼勒克县喀英迪地区铅锌矿地质特征及成因

喀英迪铅锌矿主要产于早石炭世阿克沙克组及其与晚奥陶世呼独克达坂组的接触带上。通过普查工作共圈定15个铅锌矿体。其中主要矿体4个,Ⅰ-4矿体处于晚奥陶世呼独克达坂组灰岩与早石炭世阿克沙克组的不整合接触面上及其两侧,工程控制总长度为523m,最大斜深100m。倾向70°～100°,倾角一般20°～50°,连续性较好。该矿体铅单工程厚0.86～5.64m,平均2.86m,厚度变化系数为70.57%;锌单工程厚0.80～5.64m,平均1.81m,厚度变化系数为93.97%,属于变化较稳定型矿体。铅单工程品位0.62%～16.47%,平均4.53%,品位变化系数114.34%;锌单工程品位0.53%～12.37%,平均3.78%,品位变化系数57.47%。属于有用组分分布较均匀型矿体。通过对矿床地质特征的研究,认为该矿床属沉积岩容矿的、层控的、构造控制非岩浆型低温热液矿床。     

盾构施工引起地表固结沉降问题的研究

将隧道周围土体视为均质连续各向同性的饱和弹性介质,采用保角变换的方法将含有隧道的半无限平面映射为同心圆环计算域。根据Terzaghi-Rendulic二维固结理论,建立隧道在不透水的情况下周围土体超孔隙水压力分布的控制方程。然后,采用分离变量法计算得到土体超孔隙水压力分布的解析解,最后,根据弹性理论计算得出隧道中线上方地表固结沉降的计算公式。结合算例,分析盾构施工扰动程度、土体渗透系数、土体弹性模量及隧道埋深等因素对隧道中心上方地表处固结沉降的影响。研究结果表明,地表固结沉降的增加值与隧道外侧初始超孔隙水压力值C0的变化量成正比例关系,施工扰动程度越大所引起的固结沉降越大;土体的渗透系数越大固结沉降速度越快,但土体的渗透系数与最终的地表固结沉降量无关;土体的弹性模量越大,最终的地表固结沉降量越小;隧道埋深越深,地表固结沉降所需时间越长,最终的地表固结沉降量也越大。     

基于Hyperion数据的江西德兴矿区粘土矿物信息提取及其找矿意义

江西德兴矿区为我国重要的矿产资源基地, 目前面临资源枯竭的困境, 寻找替代的新矿产迫在眉睫.根据研究区野外土壤实测样品分析, 利用连续统去除的方法提取土壤实测光谱的特征吸收位置, 从而建立粘土矿物含量为因变量的预测方程.检验得知, 高岭石相关系数R为0.811, 拟合系数R2达到0.658, F值为5.275, Sig值为0.047 7, 其小于0.05;绿泥石相关系数R为0.893, 拟合系数R2达到0.797, F值为1.602, Sig值为0.016 6, 其小于0.05;伊利石相关系数R为0.783, 拟合系数R2达到0.619, F值为5.57, 对应的Sig值是0.075 4, 其大于0.05, 说明自变量与因变量之间具有高度相关性, 反演精度较好.从反演结果可知, 研究区的高岭石整体含量较高, 整体上粘土矿物高岭石、绿泥石和伊利石在1号坝、2号坝、4号坝和铜矿区含量较低.由于粘土矿物不断地经过地球化学变化、累积, 产生黄铁矿、黄铜矿及赤铁矿, 所以挑选粘土矿物富集并且地质构造活跃的区域为铁矿石及铜矿石预测区.结合研究区地质解译图与粘土矿物反演结果, 在采矿场与IV号尾矿坝向NE方向沿线上圈定两个遥感找矿有利区.