Relict sand wedges in soliflucted London Clay at Wimbledon, London, UK

Exposures on Wimbledon Hill, SW London, in the Palaeogene London Clay Formation, are described. The 3° slopes are mantled by clayey solifluction (head) deposits, comprising two superimposed sheets, each around 1.2 m thick. The lower sheet exhibits relict sand wedges forming polygons 1.0-1.5 m across, up to 50 mm wide and 1.25 m deep. These have no surface expression. The wedges are sand-filled and modify significantly the hydrogeology and properties of the solifluction mantle. There are no sand wedges in the upper solifluction sheet.The mechanics of emplacement of the lower solifluction sheet are explored and the high initial water content estimated. Subsequent desiccation and consolidation have reduced the thickness of this sheet by at least 35%, thus distorting contained features such as the wedges. An active layer about 0.4 m thick is inferred to have formed in the top of the lower solifluction sheet. No direct dating was undertaken but, by analogy with relevant dated sites in southern Britain and the Netherlands it is inferred that the lower solifluction sheet was emplaced during the first part of the Loch Lomond Stadial and frost-cracked during a subsequent, colder and more arid part. On this basis, following filling of the cracks by sand, emplacement of the upper solifluction sheet would have occurred in the later part of the Loch Lomond Stadial.     

Millennium-long recession of limestone facades in London

Historical data on the temperature and precipitation data for London has been combined with output from the Hadley Model to estimate the climate of London for the period 1100–2100 CE. This has been converted to other parameters such as freeze–thaw frequency and snowfall relevant to the weathering of stone facades. The pollutant concentrations have been estimated for the same period, with the historical values taken from single box modelling and future values from changes likely given current policy within the metropolis. These values are used in the Lipfert model to show that the recession from karst weathering dominates across the period, while the contributions of sulphur deposition seem notable only across a shorter period 1700–2000 CE. Observations of the late seventeenth century suggest London architects witnessed a notable increase in the recession rate and attributed “fretting quality” to “smoaks of the sea-coal”. The recession rates measured in the late twentieth century lend some support to the estimates from the Lipfert model. The recession looks to increase only slightly, and frost shattering will decrease while salt weathering is likely to increase.     

Consuming transnational fashion in London and Mumbai

Drawing on focus group research in London and Mumbai, this paper charts the changing social and cultural contours of transnational fashion consumption. Transnationality is approached as a complex social field, participation in which is not restricted to the members of specific ethnically-defined transnational communities. Following a discussion of the nature of transnational fashion, the paper explores the discursive practices of a wide range of consumers with different degrees of investment in this transnational field encompassing differences of gender and generation, education and occupation. We highlight the existence of multiple forms of modernity (rather than a simple gradient from Western modernity to Eastern tradition), with social and cultural change taking place at an uneven pace and subject to periodic disruption and temporary reversals. In contrast to more linear notions of globalization, defined in terms of the relentless erosion of local difference, our research demonstrates the persistence of locally-specific cultures of consumption in both London and Mumbai. Drawing from Appadurai’s work on the social life of things and Bourdieu’s analysis of the sociology of taste, we attempt to characterise these locally specific consumption cultures. We argue against conventional accounts of ‘authenticity’ as an innate property of particular social groups or particular goods, suggesting that the meaning of goods is defined by their active appropriation in specific contexts of use.     

Sedimentary characteristics of suspensions in London Stormwater

The paper reports the results of an investigation into the size and compositional variations of suspended solids during storm-runoff events in an urban catchment. Particle-size analysis indicates that the mass-size distribution for suspended sediments is typically bimodal, although the relative size, breadth and location of the peaks varies through the cycle and from one storm to another. The importance of particle aggregation on the size distributions is discussed and the role of organic particulates in this relation examined. The elemental composition is dominated by silicon and aluminium with the mineralogy being dominated by impure mixtures of quartzo-feldspathic material.The observed textural, compositional and mineralogical variations have been used as diagnostic properties in the identification of source materials and their transport history through the catchment.     

Geology and the London Underground

Geology as a whole is the main influence on determining the feasibility of tunnelling for underground railways, and at what cost. Favourable conditions encouraged the early development of a network, significantly alter the methods used for construction, and are what form the tunnels, in terms of horizontal and vertical alignment. Local geology is shown, by means of two cross-sections following the tunnels, to be more important than the overall regional geology, where the underlying strata exhibit pronounced variations in permeability, and so mechanical properties. Geological complexities specific to the area of tunnelling generate problems during construction, but lead to technological innovation in the long term and a better understanding of local stratigraphy. As the result of this, and the increase in the quality of preliminary surveys, we are increasingly able to tunnel in areas previously considered treacherous.     

Geology of London,UK

The population of London is around 7 million. The infrastructure to support this makes London one of the most intensively investigated areas of upper crust. However construction work in London continues to reveal the presence of unexpected ground conditions. These have been discovered in isolation and often recorded with no further work to explain them. There is a scientific, industrial and commercial need to refine the geological framework for London and its surrounding area. This paper reviews the geological setting of London as it is understood at present, and outlines the issues that current research is attempting to resolve.     

Geological traces of Saxon churches in the London Basin

A comprehensive examination of the building materials of London Basin churches suggests that many more may reveal evidence of an Anglo-Saxon origin than has previously been accepted.     

A case history of a deep basement in London Clay

The case history of the deep excavation for the National Gallery extension in London is presented in this paper. Comparisons with data from other sites show that it is typical for that of similar projects in Central London. Class 1 predictions of the retaining wall behaviour (prior to construction) using the Model London Clay constitutive relationship considerably over-estimated wall and ground movements. Retaining wall and ground movements are also considerably over-predicted by analyses using a simple linear elastic/perfectly plastic soil model, despite optimistic parameters being assumed for the soils. Predictions made using the constitutive model BRICK are closer to the measured deflected shape, but are also higher than measured values. Parametric studies of the effect of various parameters suggest that a “best estimate” of the wall movements are still well in excess of those measured. It is concluded that these differences are due to three-dimensional effects and deficiencies in the model. The “beam-spring” computer software for retaining walls FREW gives similar results to the analyses using the simple model. Analyses of the same problem carried out by a different operator using another finite element code, but with the same constitutive model, yielded somewhat different results and highlight the need for careful interpretation of finite element analyses.     

Hazard transformation and hazard management issues in the London megacity

Megacities are likely to present the greatest future challenges for hazard management. In them increasingly complex societies are continually modifying responses to dynamic sets of external risks. Although most have proven resilient to past disasters, new types of threat are emerging. London — which is both the world's oldest megacity and one of its most resilient — has long experience of the transformation of hazards in time and space. Although not as hazard-prone as some megacities, this one is increasingly exposed to a wide range of interactive hazards. Here trends of flooding, air pollution and terrorism are discussed together with policy responses. London demonstrates that robust action can be successful in reducing high-intensity hazards but it also shows that contemporary management is characterised by top-down technological fixes whose long-term effectiveness is questionable. In general, anticipatory responses have been limited and present-day London has not capitalised on its rich legacy of successful experience in coping with hazard.