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Penryn, United Kingdom
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Pringle J.K.,Keele University | Ruffell A.,Queen's University of Belfast | Jervis J.R.,Keele University | Donnelly L.,Wardell Armstrong LLP | And 6 more authors.
Earth-Science Reviews | Year: 2012

Geoscience methods are increasingly being utilised in criminal, environmental and humanitarian forensic investigations, and the use of such methods is supported by a growing body of experimental and theoretical research. Geoscience search techniques can complement traditional methodologies in the search for buried objects, including clandestine graves, weapons, explosives, drugs, illegal weapons, hazardous waste and vehicles. This paper details recent advances in search and detection methods, with case studies and reviews. Relevant examples are given, together with a generalised workflow for search and suggested detection technique(s) table. Forensic geoscience techniques are continuing to rapidly evolve to assist search investigators to detect hitherto difficult to locate forensic targets. © 2012 Elsevier B.V..


Ruffell A.,Queen's University of Belfast | Pirrie D.,Helford Geoscience LLP | Power M.R.,4669 West Lawn Drive
Geological Society Special Publication | Year: 2013

Geological trace evidence including, for example, soil, sand and rock dust has been examined using a wide range of analytical techniques. Whilst such materials are common in rural locations, in urban areas, such geological materials are often perceived to be restricted to parks, recreational areas, gardens and waste ground. However, both geological materials and the wide range of analytical methods used to characterize them are much more applicable to the whole urban environment than is generally realized, with the main differences being the types and amounts of sample analysed and the methods adopted. The range of geological applications can be summarized as those deployed at the broad (decimetres-kilometres) to small (millimetres- decimetres) scale. The broad spatial variation in soil, roadway, water, buildings materials, and wind- or water-borne particles can be contrasted with the variation in urban materials from dwellings to streets or gardens and parks, along with the micro-spatial and stratigraphical variation in each. In addition, geological principles and techniques that have not been used before can be applied to urban materials to provide comparisons of material that were not previously achievable, or to add a further proxy to established methods. The latter point is demonstrated with a case study using X-ray diffraction and QEMSCAN® of a criminal case where building plaster with peculiar qualities could be compared between a suspect's vehicle and plaster present along the escape route from a murder scene. © The Geological Society of London 2013.


Pirrie D.,Helford Geoscience LLP | Rollinson G.K.,University of Exeter | Power M.R.,4669 West Lawn Drive | Webb J.,University of Gloucestershire
Geological Society Special Publication | Year: 2013

In the investigation of serious crimes, soil can be, in some cases, a very valuable class of trace evidence. The complexity of soil is part of the reason why it is useful as trace evidence but is also an inherent problem, as there are many different parameters in a soil sample that could potentially be characterized. The inorganic components of soils are dominated by minerals, along with anthropogenic particulate grains; thus, the analysis of soil mineralogy as the main technique for inorganic forensic soil characterization is recommended. Typical methods that allow the bulk mineralogy to be determined, such as X-ray diffraction (XRD), do not allow the texture of the particles to be characterized. However, automated scanning electron microscopy (SEM) provides both modal mineralogy and also allows particle textures to be characterized. A recent advance in this technique has been the ability to report the modal mineralogy of a sample as 'lithotypes', which are defined on the basis of a combination of mineralogy and other parameters, such as grain size and mineral associations. Defined lithotype groups may include monominerallic grains but also, importantly, allow the automated quantification of rock types and other anthropogenic materials. Based on a simulated forensic scenario, the use of lithotyping is evaluated as an aid in the analysis of soil samples. This technique provides additional discrimination when comparing different soil samples. © The Geological Society of London 2013.


Nelson Eby G.,University of Massachusetts Lowell | Charnley N.,University of Oxford | Pirrie D.,Helford Geoscience LLP | Hermes R.,1 Kiowa Lane | And 2 more authors.
American Mineralogist | Year: 2015

Trinitite is the glass formed during the first atomic bomb test near Socorro, New Mexico, on July 16, 1945. The protolith for the glass is arkosic sand. The majority of the glass is bottle green in color, but a red variety is found in the northern quadrant of the test site. Glass beads and dumbbells, similar in morphology to micro-tektites, are also found at the Trinity site. The original description of this material, which appeared in American Mineralogist in 1948, noted the presence of two glasses with distinctly different indices of refraction (n = 1.46 and 1.51-1.54). Scanning electron microscopy (SEM) and Quantitative Evaluation of Minerals by SCANning electron microscopy (QEMSCAN) analysis is used to investigate the chemical composition and fine-scale structure of the glass. The glass is heterogeneous at the tens of micrometer scale with discrete layers of glass showing flow-like structures. The low index of refraction glass is essentially SiO2 (high-Si glass), but the higher index of refraction glass (low-Si glass) shows a range of chemical compositions. Embedded in the glass are partially melted quartz (α-quartz as determined by X-ray diffraction) and feldspar grains. The red trinitite consists of the same two glass components along with additional Cu-rich, Fe-rich, and Pb-rich silicate glasses. Metallic globules are common in the red trinitite. In terms of viscosity, the high-Si and low-Si glasses differ by several orders of magnitude, and there is minimal mixing between the two glasses. QEMSCAN analysis reveals that there are several chemical subgroups (that can be characterized as simple mixtures of melted mineral components) within the low-Si glasses, and there is limited mixing between these glass subgroups. The red trinitite contains regions of Fe-rich glass, which show sharp contact with surrounding Fe-poor glass. Both the textural and chemical data suggest that these two glasses existed as immiscible liquids. The metallic droplets in the red trinitite, which consist of variable amounts of Cu, Pb, and Fe, show textural evidence of unmixing. These metals are largely derived from anthropogenic sources-Cu wire, Pb bricks, and the steel tower and bomb casing. The combination of mineralogical and chemical data indicate that temperatures on the order of 1600 °C and pressures of at least 8 GPa were reached during the atomic detonation and that there was a reducing environment during cooling, as evidenced by the presence of native metals, metal sulfides, and a low-Fe3+/Fe2+ ratio. Independent estimates of maximum temperature during the detonation are on the order of 8000 K, far higher than suggested by the mineral data. This discrepancy is probably due to the very short duration of the event. In all respects, the trinitite glasses are similar to tektites and fulgurites, and by analogy one conclusion is that temperature estimates based on mineralogical observations for these materials also underestimate the maximum temperatures. © 2015 by Walter de Gruyter Berlin/Boston 2015.


Little C.T.S.,University of Leeds | Birgel D.,University of Vienna | Boyce A.J.,Scottish Enterprise | Crame J.A.,British Antarctic Survey | And 6 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2015

Fossil hydrocarbon seeps are present in latest Cretaceous (Maastrichtian) volcaniclastic shallow shelf sediments exposed on Snow Hill and Seymour Islands, James Ross Basin, Antarctica. The seeps occur in the Snow Hill Island Formation on Snow Hill Island and are manifest as large-sized, cement-rich carbonate bodies, containing abundant thyasirid bivalves and rarer ammonites and solemyid bivalves. These bodies have typical seep cement phases, with δ13C values between -20.4 and -10.7‰ and contain molecular fossils indicative of terrigenous organic material and the micro-organisms involved in the anaerobic oxidation of methane, including methanotrophic archaea and sulphate-reducing bacteria. On Seymour Island the seeps occur as micrite-cemented burrow systems in the López de Bertodano Formation and are associated with thyasirid, solemyid and lucinid bivalves, and background molluscan taxa. The cemented burrows also have typical seep cement phases, with δ13C values between -58.0 and -24.6‰. There is evidence from other data that hydrocarbon seepage was a common feature in the James Ross Basin throughout the Maastrichtian and into the Eocene. The Snow Hill and Seymour Island examples comprise the third known area of Maastrichtian hydrocarbon seepage. But compared to most other ancient and modern seep communities, the James Ross Basin seep fauna is of very low diversity, being dominated by infaunal bivalves, all of which probably had thiotrophic chemosymbionts, but which were unlikely to have been seep obligates. Absent from the James Ross Basin seep fauna are 'typical' obligate seep taxa from the Cretaceous and the Cenozoic. Reasons for this may have been temporal, palaeolatitudinal, palaeobathymetric, or palaeoecological. © 2014 Elsevier B.V.


Pirrie D.,Helford Geoscience LLP | Jonkers H.A.,Dommerswijk 10 | Smellie J.L.,University of Leicester | Crame J.A.,British Antarctic Survey | McArthur J.M.,University College London
Antarctic Science | Year: 2011

We report on the discovery of a new outcrop of fossiliferous Neogene sediments on northern James Ross Island, northern Antarctic Peninsula. Approximately 100 specimens of the pectinid bivalve Austrochlamys anderssoni (Hennig, 1911) were collected from the permafrost active layer. This bivalve species has a late Miocene to late Pliocene range and has previously been reported from both the glaciomarine Hobbs Glacier Formation and the interglacial Cockburn Island Formation in the James Ross Island area. The localized presence of abundant A. anderssoni within the permafrost suggests that the fossils have been frost heaved from an outcrop of either the Cockburn Island or the Hobbs Glacier formations, originally deposited on northern James Ross Island. The overall shell form, general absence of associated Antarctic Peninsula-derived clasts in the host sediment, and the measured 87Sr/86Sr isotope ratio of the shells (0.709050) which is indistinguishable from that for pectinid bivalves from the Cockburn Island Formation on Cockburn Island (0.709047) suggest that the shells were derived from a unit similar in age to the Cockburn Island Formation. This suggests that the Cockburn Island Formation was originally more laterally extensive than was previously known. © 2011 Antarctic Science Ltd.


Pirrie D.,Helford Geoscience LLP | Rollinson G.K.,University of Exeter
Geology Today | Year: 2011

Identifying and quantifying the relative abundance of minerals is a fundamental part of many aspects of both pure and applied geology. Historically, quantitative mineralogy could be achieved using optical microscopy and point counting. This is a slow and operator dependent process, and practically impossible to achieve in, for example, very fine grained samples. Over the last decade a range of automated mineralogy technologies have arisen from the global mining industry and are being increasingly used in other branches of geology. These technologies, based on scanning electron microscopy with linked energy dispersive spectrometers, have the potential to revolutionise how we quantify mineralogy. In addition, during measurement, the sample textures are also captured, providing a wealth of valuable data for the geologist. In this article we review the current state of automated mineralogy and highlight the many areas of application for this technology. © 2011 Blackwell Publishing Ltd, The Geologists' Association & The Geological Society of London.


Marshall J.D.,University of Liverpool | Pirrie D.,Helford Geoscience LLP
Geology Today | Year: 2013

Carbonate concretions are common features of sedimentary rocks of all geological ages. They are most obvious in sandstones and mudstones as ovoid bodies of rock that protrude from natural outcrops: clearly harder or better cemented than their host rocks. Many people are excited by finding fossils in the centre of mudstone-hosted concretions (Fig. 1) but spend little time wondering why the fossils are so well preserved. While the study of concretions has benefitted from the use of advanced analytical equipment, simple observations in the field can also help to answer many questions. For example, in cliff sections, original sedimentary beds and sedimentary structures can be traced right through concretions (Fig. 2): so it can be deduced that the concretion clearly formed after these depositional structures were laid down. In this article we explain how and where concretions form and discuss the evidence, ranging from outcrop data to sophisticated laboratory analyses, which can be used to determine their origins. The roles of microbes, decaying carcasses, compaction and groundwaters are highlighted. Concretions not only preserve fossils but can also subdivide oil, gas and water reservoirs into separate compartments. 1 An early diagenetic carbonate concretion split in half to reveal an ammonite retaining its original aragonite shell, from the Maastrichtian of Antarctica. Image courtesy of Alistair Crame (British Antarctic Survey, NERC). Lens cap is 6 cm. 2 Calcite cemented concretion standing proud from the otherwise poorly cemented sandstones. Large spherical concretions commonly occur in sandstones, where the porosity and permeability are equal in all directions. Jurassic, Bencliffe Grit, Osmington Mills, Dorset. Vertical thickness is 80 cm. © 2013 Blackwell Publishing Ltd, The Geologists' Association & The Geological Society of London.


Rieuwerts J.S.,University of Plymouth | Mighanetara K.,University of Plymouth | Braungardt C.B.,University of Plymouth | Rollinson G.K.,University of Exeter | And 2 more authors.
Science of the Total Environment | Year: 2014

Mining generates large amounts of waste which may contain potentially toxic elements (PTE), which, if released into the wider environment, can cause air, water and soil pollution long after mining operations have ceased. The fate and toxicological impact of PTEs are determined by their partitioning and speciation and in this study, the concentrations and mineralogy of arsenic in mine wastes and stream sediments in a former metal mining area of the UK are investigated. Pseudo-total (aqua-regia extractable) arsenic concentrations in all samples from the mining area exceeded background and guideline values by 1-5 orders of magnitude, with a maximum concentration in mine wastes of 1.8×105mgkg-1 As and concentrations in stream sediments of up to 2.5×104mgkg-1 As, raising concerns over potential environmental impacts. Mineralogical analysis of the wastes and sediments was undertaken by scanning electron microscopy (SEM) and automated SEM-EDS based quantitative evaluation (QEMSCAN®). The main arsenic mineral in the mine waste was scorodite and this was significantly correlated with pseudo-total As concentrations and significantly inversely correlated with potentially mobile arsenic, as estimated from the sum of exchangeable, reducible and oxidisable arsenic fractions obtained from a sequential extraction procedure; these findings correspond with the low solubility of scorodite in acidic mine wastes. The work presented shows that the study area remains grossly polluted by historical mining and processing and illustrates the value of combining mineralogical data with acid and sequential extractions to increase our understanding of potential environmental threats. © 2013 Elsevier B.V.


PubMed | University of Exeter, University of Plymouth and Helford Geoscience LLP
Type: | Journal: The Science of the total environment | Year: 2014

Mining generates large amounts of waste which may contain potentially toxic elements (PTE), which, if released into the wider environment, can cause air, water and soil pollution long after mining operations have ceased. The fate and toxicological impact of PTEs are determined by their partitioning and speciation and in this study, the concentrations and mineralogy of arsenic in mine wastes and stream sediments in a former metal mining area of the UK are investigated. Pseudo-total (aqua-regia extractable) arsenic concentrations in all samples from the mining area exceeded background and guideline values by 1-5 orders of magnitude, with a maximum concentration in mine wastes of 1.810(5)mgkg(-1) As and concentrations in stream sediments of up to 2.510(4)mgkg(-1) As, raising concerns over potential environmental impacts. Mineralogical analysis of the wastes and sediments was undertaken by scanning electron microscopy (SEM) and automated SEM-EDS based quantitative evaluation (QEMSCAN). The main arsenic mineral in the mine waste was scorodite and this was significantly correlated with pseudo-total As concentrations and significantly inversely correlated with potentially mobile arsenic, as estimated from the sum of exchangeable, reducible and oxidisable arsenic fractions obtained from a sequential extraction procedure; these findings correspond with the low solubility of scorodite in acidic mine wastes. The work presented shows that the study area remains grossly polluted by historical mining and processing and illustrates the value of combining mineralogical data with acid and sequential extractions to increase our understanding of potential environmental threats.

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