S.J. Price

Humans as major geological and geomorphological agents in the Anthropocene: the significance of artificial ground in Great Britain

Since the first prehistoric people started to dig for stone to make implements, rather than pick up loose material, humans have modified the landscape through excavation of rock and soil, generation of waste and creation of artificial ground. In Great Britain over the past 200 years, people have excavated, moved and built up the equivalent of at least six times the volume of Ben Nevis. It is estimated that the worldwide deliberate annual shift of sediment by human activity is 57 000 Mt (million tonnes) and exceeds that of transport by rivers to the oceans (22 000 Mt) almost by a factor of three. Humans sculpt and transform the landscape through the physical modification of the shape and properties of the ground. As such, humans are geological and geomorphological agents and the dominant factor in landscape evolution through settlement and widespread industrialization and urbanization. The most significant impact of this has been since the onset of the Industrial Revolution in the eighteenth century, coincident with increased release of greenhouse gases to the atmosphere. The anthropogenic sedimentological record, therefore, provides a marker on which to characterize the Anthropocene.

Diachronous beginnings of the Anthropocene: The lower bounding surface of anthropogenic deposits

Across a large proportion of Earth’s ice-free land surfaces, a solid-phase stratigraphic boundary marks the division between humanly modified ground and natural geological deposits. At its clearest, the division takes the form of an abrupt surface at the base of deposits variously called ‘artificial ground’, ‘anthropogenic ground’ or ‘archaeological stratigraphy’ – which together comprise a distinctive part of the geosphere called the ‘archaeosphere’. In other cases the bounding surface is more diffuse, gradational or mixed, due to action of non-human agencies and anthropedogenic forcings. It is alternately conformable and unconformable. Layers above typically contain artificial features, structures, artifacts and other material traces of human activity, in contrast to their relative absence in layers below. A fundamental characteristic of the boundary is that it is diachronous, still being formed and renewed today. In examining the boundary, this paper asks – does it reflect the diachronous onset and development of the Anthropocene itself?

An assessment of lithostratigraphy for anthropogenic deposits

Abstract The deliberate anthropogenic movement of reworked natural and novel manufactured materials represents a novel sedimentary environment associated with mining, waste disposal, construction and urbanization. Anthropogenic deposits display distinctive engineering and environmental properties, and can be of archaeological importance. This paper shows that temporal changes in the scale and lithological character of anthropogenic deposits may be indicative of the Anthropocene. However, the stratigraphy of such deposits is not readily described by existing classification schemes, which do not differentiate separate phases or lithologically distinct deposits beyond a local scale. Lithostratigraphy is a scalable, hierarchical classification used to distinguish successive and lithologically distinct natural deposits. Many natural and anthropogenic deposits exhibit common characteristics; they typically conform to the Law (or Principle) of Superposition and exhibit lithological distinction. The lithostratigraphical classification of surficial anthropogenic deposits may be effective, although defined units may be significantly thinner and far less continuous than those defined for natural deposits. Further challenges include the designation of stratotypes, accommodating the highly diachronous nature of anthropogenic deposits and the common presence of disconformities. International lithostratigraphical guidelines would require significant modification before being effective for the classification of anthropogenic deposits. A practical alternative may be to establish an ‘anthrostratigraphical’ approach, or ‘anthrostratigraphy’.

The application of 3D geological modelling to aquifer recharge assessments in an urban environment

The development of an attributed 3D model of the Quaternary deposits across 75 km2 of central Manchester and Salford is providing a basis for new types of applied (thematic) outputs. Proprietary software designed specifically for use in Quaternary sequences has been used to construct a model of the glacial and post-glacial sequences in an area now undergoing rapid regeneration. The potential of the model to deliver information relevant to a range of practical applications is illustrated by an urban groundwater case study centred on the industrial area of Trafford Park. The sensitivity of the Permo-Triassic sandstone bedrock aquifer to pollution and the extent to which recharge may occur have been analysed through detailed characterization of the underlying superficial deposits. Potential hydrogeological pathways from ground surface to the sandstone are identified, and thematic outputs show the importance of the Manchester Ship Canal and related waterways as potential sources of recharge and pollution of the bedrock aquifer. The move towards 3D modelling of the shallow subsurface provides flexibility in meeting user needs that is not available from conventional 2D geological sources. It is suggested that modelling of this type should be used by site developers and remediators to design more targeted and cost-effective site investigations and risk assessments.

Scale and diversity of the physical technosphere: A geological perspective

We assess the scale and extent of the physical technosphere, defined here as the summed material output of the contemporary human enterprise. It includes active urban, agricultural and marine components, used to sustain energy and material flow for current human life, and a growing residue layer, currently only in small part recycled back into the active component. Preliminary estimates suggest a technosphere mass of approximately 30 trillion tonnes (Tt), which helps support a human biomass that, despite recent growth, is ~5 orders of magnitude smaller. The physical technosphere includes a large, rapidly growing diversity of complex objects that are potential trace fossils or ‘technofossils’. If assessed on palaeontological criteria, technofossil diversity already exceeds known estimates of biological diversity as measured by richness, far exceeds recognized fossil diversity, and may exceed total biological diversity through Earth’s history. The rapid transformation of much of Earth’s surface mass into the technosphere and its myriad components underscores the novelty of the current planetary transformation.

A proposed decision‐making framework for a national infiltration SuDS map

Purpose – The purpose of this paper is to describe the decision‐making framework and datasets behind a national geographical information system (GIS) map that assesses the suitability of the subsurface for infiltration sustainable drainage systems (SuDS). In combination they provide geoenvironmental information on the necessary geological and hydrogeological considerations to facilitate preliminary site assessment.Design/methodology/approach – The national suitability map comprises four parts, each of which considers a geoenvironmental factor essential to SuDS planning, installation and performance. The first three comprise: drainage; ground stability; and pollutant attenuation potential. The final map highlights those areas where infiltration may result in negative consequences such as the initiation or exacerbation of flooding or ground instability.Findings – The application of the suitability map is demonstrated for an urban setting, showing its relevance to both planning for wide spatial‐assessment an...

Urban Futures: the sustainable management of the ground beneath cities

Abstract Over half of the worlds population now live in cities. In 2011 it was estimated that the global population exceeded 7 billion. Pressures on the environment including land use are increasing. The ground beneath cities and the interaction between physical, biological and chemical processes provides natural capital on which society depends. These benefits and the ground properties and processes that support and deliver them can be considered ecosystem services. Characterizing the ground properties on which ecosystem services depend involves a qualitative assessment of positive and negative impacts of proposed urban sustainability solutions, including use of the ground. The sustainability of a proposed solution depends on how the future might unfold. Future scenario analysis allows consideration of the social, technological, economic, environmental and political changes that may determine the ability of a proposed solution to deliver its benefits now and in the future. Analysis of the positive and negative impacts of a proposed use of the ground on ecosystem function, measured against future scenarios of change, can be integrated to deliver strategies for the future management of the ground and the wider environment beneath cities.

Geophysical anatomy of the Hollin Hill landslide, North Yorkshire, UK.

Geophysical methods are playing an increasingly important role in the investigation and monitoring of landslides; such methods are proving to be particularly effective for revealing the 3D structure, failures surfaces, and the hydrogeological regimes associated with rock and earth slides. In this paper we present the results of a geoelectrical reconnaissance survey of the Hollin Hill landslide, UK. This work was undertaken in advance of the installation of a permanent geophysical and geotechnical monitoring system, and was designed to assess the suitability of resistivity (resistivity mapping and 2D/3D ERT) and self-potential methods (profiling and mapping) for investigating and monitoring this site. In particular, we were concerned to assess the electrical property contrasts and the magnitude of SP response across the study area. The surveys revealed that there was a good resistivity contrast between the slipped material and sandstone bedrock, which allowed us to use resistivity mapping data and ERT models to define the geometry of the landslide. An SP signature consistent with the movement of groundwater through the landslide was observed at the site, and was used to identify seepage patterns associated with the slipped material.

The use of NEXTMap Britain for geological surveying in the Vale of York

Abstract The NEXTMap Britain digital elevation model (DEM) has opened many new opportunities that considerably help and enhance the way we undertake our geological mapping of bedrock, structure, and superficial and artificial deposits. The dataset has been successfully integrated into the digital and conventional mapping workflows of the Vale of York mapping team. A variety of visualization and analysis techniques have been applied throughout the mapping process. These techniques include an initial appraisal of NEXTMap with a comparison to existing geological mapping to define the field mapping strategy and site-specific manipulation using Tablet PCs. NEXTMap interpretation has made an important contribution to the understanding of the extensive glacial and proglacial deposits found in the Vale of York; such as sand bodies resting on lake deposits, and identifying details within morainic and alluvial complexes. For bedrock mapping, NEXTMap has been used to identify landform features that relate to the underlying geology, such as breaks in slope, the extent of escarpments, hillcrests and dip slopes, to provide an overview of the landscape and to save time in mapping out features in the field. Techniques have also been developed to automatically generate these landform features. The dataset has also been used to identify areas where landsliding has occurred, for the accurate mapping of artificial ground and as a key surface for three-dimensional (3D) geological modelling.

URBAN GEOLOGY: INTEGRATING SURFACE AND SUB-SURFACE GEOSCIENTIFIC INFORMATION FOR DEVELOPMENT NEEDS

The British Geological Survey (BGS) operates an urban geoscience programme that aims to provide up-to-date information on ground-related issues for the towns and cities of the UK. Research in the major conurbations of Manchester, Swansea and Glasgow is demonstrating the value of integrating surface geological mapping with sub-surface geoscientific information through the use of three-dimensional models. This approach provides a more holistic view of the near-surface environment and provides a means of identifying potential problems and opportunities at an early stage in any proposed development. If implemented over a wider area, it could assist in designing site investigation strategies and reduce costs by ensuring a more focused approach to strategic planning.