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  • Conference paper
    Puech A, Canou J, Bernardini C, Pecker A, Jardine RJ, Holeyman Aet al., 2012,

    SOLCYP: a four-year JIP on the behaviour of piles under cyclic loading

    , London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 263-270
  • Conference paper
    Rimoy SP, Jardine RJ, Silva M, Foray PY, Tsuha CHC, Yang ZXet al., 2012,

    Local and global behaviour of cyclically loaded instrumented model displacement piles in sand

    , London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 279-286
  • Journal article
    Schofield N, Heaton L, Holford SP, Archer SG, Jackson CAL, Jolley Det al., 2012,

    Seismic imaging of 'broken-bridges': linking seismic to outcrop-scale investigations of intrusive magma lobes

    , Journal of the Geological Society of London, Vol: 169, Pages: 421-426

    Three-dimensional seismic datasets have provided unrivalled insights into magma flow within sub-volcanic systems. One of the key revelations is that sills appear to be constructed of a series of discrete magma lobes that form during the emplacement of magma into host-rock. We focus on a large sill, within the Faroe–Shetland Basin, North Atlantic, that is well imaged on seismic data, and identify the presence of ‘broken bridges’ within the sill, developed between elongate magma lobes, and reveal for the first time in three dimensions the development of broken bridges. Critically, by relating the imaged structures to key outcrop-scale examples we confirm that bridge and broken-bridge structures are oriented perpendicular to the magma flow direction. This work thus demonstrates a key link that can be made between seismic-scale investigation of intrusions and sub-seismic (outcrop-scale) processes, highlighting the seemingly scale-invariant nature of the magmatic emplacement process.
  • Journal article
    Kovacevic N, Jardine RJ, Potts DM, Clukey E, Brand J, Spikula Det al., 2012,

    A numerical simulation of progressive slope failures generated by salt diaiprism combined with active sedimentation

    , Geotechnique: international journal of soil mechanics, Vol: 62

    This paper describes advanced finite element simulations of a geologically active andperiodically unstable 700m high underwater escarpment located in the Gulf of Mexicothat has been created by uplifting salt diapirs combined with sediment deposition. Thesite's geological history, soil permeability and clay shear strength characteristicsgovern current slope stability and determine the timing of any future failure. Thegeological and geotechnical conditions are reported before presenting fully coupled,large displacement, numerical simulations employing critical state formulations of theslope's evolution over the last 600,000 years. The latter form the basis for strainsoftening analyses of the pore pressure equalisation and progressive failure processesthat control current slope stability. The analyses also address the ground movementpatterns that precede instability, giving useful information for geohazard riskassessment and early warning monitoring system design.
  • Journal article
    Jardine RJ, Standing JR, 2012,

    Field axial cyclic loading experiments on piles driven in sand

    , Soils and Foundations, Vol: 52, Pages: 723-737
  • Journal article
    Mercader J, Gosse JC, Bennett T, Hidy AJ, Rood DHet al., 2012,

    Cosmogenic nuclide age constraints on Middle Stone Age lithics from Niassa, Mozambique

    , Quaternary Science Reviews, Vol: 47, Pages: 116-130, ISSN: 0277-3791

    The late phases of the Middle Stone Age (MSA) in the East African Rift System (EARS) are known for their evolutionary shifts and association with bottlenecks, transcontinental expansion, and climatic fluctuations. The chronology of MSA sites contemporaneous with these eco-demographic upheavals is uncertain because of the scarcity of datable sites and the poor understanding of their depositional and erosional histories. We apply terrestrial cosmogenic nuclide dating in a stratigraphic section with a complex exposure history to the study of the Luchamange Beds, a widespread sedimentological unit underlying MSA sites from the shores of Lake Niassa (Mozambican EARS). We use an innovative approach, which may be applicable elsewhere, to calculate their age using a Monte Carlo-based Bayesian model that links depth profiles of 26Al and 10Be, and uses other geomorphic and cosmogenic nuclide age constraints on episodic erosion and burial. The age of the basal Luchamange Beds is 42 + 77/-15. ka, and the MSA occupation on top is 29 + 3/-11 ka. These dates suggest temporal overlap between MSA and the earliest Later Stone Age and diversity in cultural manifestations at the end of the MSA. © 2012 Elsevier Ltd.
  • Journal article
    Freitas TMB, Potts DM, Zdravkovic L, 2012,

    Implications of the definition of the Φ function in elastic-viscoplastic models

    , GEOTECHNIQUE, Vol: 62, Pages: 643-648, ISSN: 0016-8505
  • Journal article
    Elsheikh AH, Jackson MD, Laforce TC, 2012,

    Bayesian Reservoir History Matching Considering Model and Parameter Uncertainties

    , MATHEMATICAL GEOSCIENCES, Vol: 44, Pages: 515-543, ISSN: 1874-8961
  • Conference paper
    Yan H, Liu J-G, Morgan G, 2012,

    High Quality DEM Generation from PCIAS

    , 2012 IEEE International Geoscience & Remote Sensing Symposium (IGARSS2012), Pages: 4950-4953
  • Conference paper
    Wu M-C, Liu J-G, Yan H, Mason Pet al., 2012,

    Three-Dimensional Surface Displacement Map of The 2008 Wenchuan Earthquake Derived From Phase Correlation Sub-pixel Offset Method and Adaptive Local Kriging DInSAR Data

    , 2012 IEEE International Geoscience & Remote Sensing Symposium, Pages: 3899-3902
  • Conference paper
    Spinneken J, Heller V, Kramer S, Piggott M, Vire Aet al., 2012,

    Assessment of an Advanced Finite Element Tool for the Simulation of Fully-nonlinear Gravity Water Waves

    , The 22nd International Ocean and Polar Engineering Conference

    The aim of the present study is to provide a rigorous analysis of the water wave modelling capabilities of the advanced multipurpose CFD code Fluidity. This code has been developed atImperial College London over a large number of years and benefits from an open source GNU license. In contrast to similar studies adopting closed-source in-house or commercial solutions,the results presented herein may be verified by any computer literate reader. The investigation focuses on the simulation of gravity water waves; their detailed understanding being fundamental to the design of many offshore (marine) solutions, including the emerging fields of wave energy conversion and floatingoffshore wind applications. Both small amplitude (linear hydrodynamics) and finite amplitude (nonlinear hydrodynamics) regular waves are simulated in a 2D Numerical Wave Tank (NWT). First, and assessment of the NWT’s capabilities in accurately modelling wave propagation and wave energy conservation of linear waves is undertaken. Subsequently, the simulated wave field is directly compared with results obtained from linear wavemaker theory. For the purpose of the nonlinear wave investigation, two wave generation techniques are adopted, and comparisons with a high-order potential flow theory are made. The overall agreement between the simulation results and theory was found to be very good.
  • Journal article
    Gourbet L, Shuster DL, Balco G, Cassata WS, Renne PR, Rood Det al., 2012,

    Neon diffusion kinetics in olivine, pyroxene and feldspar: Retentivity of cosmogenic and nucleogenic neon

    , Geochimica et Cosmochimica Acta, Vol: 86, Pages: 21-36, ISSN: 0016-7037

    We performed stepwise degassing experiments by heating single crystals of neutron- or proton-irradiated olivine, pyroxene and feldspar to study diffusion kinetics of neon. This is important in evaluating the utility of these minerals for cosmogenic 21Ne measurements and, potentially, for Ne thermochronometry. Degassing patterns are only partially explained by simple Arrhenius relationships; most samples do not exhibit a precisely-determined activation energy in an individual diffusion domain. Regardless, we find clear differences in diffusion kinetics among these minerals. Based on sub-selected data, our estimates for neon diffusion kinetics (activation energy E a and pre-exponential factor D o, assuming the analyzed fragments approximate the diffusion domain) in each mineral are as follows: for the feldspars, E a ranges from ~65 to 115kJ/mol and D o from 3.9×10 -3 to 7.1×10 2cm 2s -1; for the pyroxenes, E a ranges from ~292 to 480kJ/mol and D o from 1.6×10 2 to 2.9×10 11cm 2s -1; for the olivines, E a ranges from ~360 to 370kJ/mol and D o from 1.5×10 6 to 5.0×10 6cm 2s -1. Differences in these parameters are broadly consistent with the expected effect of structural differences between feldspar, and olivine and pyroxene. These results indicate that cosmogenic 21Ne will be quantitatively retained within olivine and pyroxene at Earth surface temperatures over geological timescales. The diffusion kinetics for feldspars, on the other hand, predicts that 21Ne retention at Earth surface temperatures will vary significantly with domain size, crystal microtexture, surface temperature, and exposure duration. Quantitative retention is expected only in favorable conditions. This conclusion is reinforced by additional measurements of cosmogenic 21Ne in coexisting quartz and feldspar from naturally irradiated surface samples; sanidine from a variety of rhyolitic ignimbrites exhibits quantitative retention, whereas alkali-feldspar from several
  • Journal article
    Balco G, Purvance MD, Rood DH, 2012,

    Corrigendum to " Exposure dating of precariously balanced rocks" [Quaternary Geochronology 6 (2011) 295-303]

    , Quaternary Geochronology, Vol: 9, ISSN: 1871-1014
  • Journal article
    Bodas Freitas TM, Potts DM, Zdravkovic L, 2012,

    The effect of creep on the short-term bearing capacity of pre-loaded footings

    , COMPUTERS AND GEOTECHNICS, Vol: 42, Pages: 99-108, ISSN: 0266-352X
  • Journal article
    Davis M, Matmon A, Rood DH, Avnaim-Katav Set al., 2012,

    Constant cosmogenic nuclide concentrations in sand supplied from the Nile River over the past 2.5 m.y.

    , Geology, Vol: 40, Pages: 359-362, ISSN: 0091-7613

    Quartz sand in the eastern Mediterranean coastal plain is supplied through an extended transport system, which includes the Nile River, east Mediterranean longshore currents, and inland eolian transport. While the concentrations of cosmogenic nuclides (26Al and 10Be), and their ratio, in modern sand deposited along the coast of the eastern Mediterranean reflect the combined effect of exposure and burial during transport, the concentrations of these nuclides in buried sands are the result of decay of this initial dosing. Samples of modern exposed sand (n = 3) collected from the coastal plain of Israel yield an average 26Al/10Be ratio of 4.8 ± 0.2, significantly lower than the expected ratio of 6.8 for exposed quartz grains at the surface. A similar ratio of 4.5 ± 0.3 was measured in a late Pleistocene sand sample, indicating similar exposure-burial histories during transport in spite of the difference in climatic conditions. The results imply a steady, preburial cosmogenic nuclide ratio related to the Nile River's ability, through storage and recycling, to buffer the effects of climatic and tectonic perturbations on cosmogenic nuclide concentrations in the transported quartz. All ancient and buried sand samples (n = 11) fall on a decay path that originates from the concentrations and ratio of 26Al and 10Be in modern sand, suggesting steady preburial concentrations of cosmogenic nuclides in quartz sand over the past 2.5 m.y. © 2012 Geological Society of America.
  • Journal article
    Smith A, Crawford IA, Gowen RA, Ambrosi R, Anand M, Banerdt B, Bannister N, Bowles N, Braithwaite C, Brown P, Chela-Flores J, Cholinser T, Church P, Coates AJ, Colaprete T, Collins G, Collinson G, Cook T, Elphic R, Fraser G, Gao Y, Gibson E, Glotch T, Grande M, Griffiths A, Grygorczuk J, Gudipati M, Hagermann A, Heldmann J, Hood LL, Jones AP, Joy KH, Khavroshkin OB, Klingelhoefer G, Knapmeyer M, Kramer G, Lawrence D, Marczewski W, McKenna-Lawlor S, Miljkovic K, Narendranath S, Palomba E, Phipps A, Pike WT, Pullan D, Rask J, Richard DT, Seweryn K, Sheridan S, Sims M, Sweeting M, Swindle T, Talboys D, Taylor L, Teanby N, Tong V, Ulamec S, Wawrzaszek R, Wieczorek M, Wilson L, Wright Iet al., 2012,

    Lunar Net-a proposal in response to an ESA M3 call in 2010 for a medium sized mission

    , EXPERIMENTAL ASTRONOMY, Vol: 33, Pages: 587-644, ISSN: 0922-6435
  • Journal article
    Jackson CAL, 2012,

    The initiation of submarine slope failure and the emplacement of mass-transport deposits in salt-related minibasins: a 3D seismic reflection case study from the Santos Basin, offshore Brazil

    , Geological Society of America Bulletin, Vol: 124, Pages: 746-761

    3D seismic reflection data are used to characterise the seismic expression and investigate the origin of two mass transport complexes, which are contained in two salt-related minibasins on the São Paulo Plateau, offshore SE Brazil. The mass transport complex contains numerous slide blocks, which are expressed on seismic data as broadly tabular packages of weakly-deformed reflections. Individual slides blocks are up to 50 m thick and up to 1 km2 in plan-view. The slide blocks are flanked by laterally continuous reflections, which are interpreted as the seismic expression of either a thin mudstone-dominated debrite deposit or a thin interval of hemipelagic mudstones. The surface that bounds the base of the mass transport complex is planar and this suggests that the associated gravity flow event was associated with only limited erosion of the seafloor. The upper surface of the mass transport complex is very rugose and onlapped by overlying strata, indicating that the slide blocks formed seabed relief of up to 20 m. The mass transport complex occurs at the base of a unit that thins towards the margins of the studied minibasins, and the slide blocks in the mass transport complex decrease in size and density away from the salt-cored structural high that separates the two minibasins. Based on its seismic-stratigraphic context and the spatial distribution of the slide blocks which is contains, the mass transport complex is interpreted to have been derived from the failure of material of the margins of the salt-cored high in response a period of relatively rapid minibasin subsidence. The results of this study indicate that large volumes of sedimentary material may be derived from the margins of salt-related minibasins in relatively distal submarine settings. From a geohazard perspective this observation is important, as it is typically thought that the risk associated with submarine slope failure, and the transport and emplacement of large blocks, is low in relatively
  • Journal article
    Collins GS, 2012,

    Moonstruck magnetism

    , Science, Vol: 335, Pages: 1176-1177
  • Journal article
    Glover PWJ, Walker E, Jackson MD, 2012,

    Streaming-potential coefficient of reservoir rock: A theoretical model

    , Geophysics, Vol: 77, Pages: D17-D43, ISSN: 1942-2156

    The streaming potential is that electrical potential whichdevelops when an ionic fluid flows through the pores of a rock.It is an old concept that is recently being applied in many fieldsfrom monitoring water fronts in oil reservoirs to understandingthe mechanisms behind synthetic earthquakes. We have carriedout fundamental theoretical modeling of the streaming-potentialcoefficient as a function of pore fluid salinity, pH, and temperatureby modifying the HS equation for use with porous rocksand using input parameters from established fundamental theory(the Debye screening length, the Stern-plane potential, the zetapotential, and the surface conductance). The model also requiresthe density, electrical conductivity, relative electric permittivityand dynamic viscosity of the bulk fluid, for which empiricalmodels are used so that the temperature of the model may bevaried. These parameters are then combined with parametersthat describe the rock microstructure. The resulting theoreticalvalues have been compared with a compilation of data for siliceousmaterials comprising 290 streaming-potential coefficientmeasurements and 269 zeta-potential measurements obtainedexperimentally for 17 matrix-fluid combinations (e.g., sandstonesaturated with KCl), using data from 29 publications.The theoretical model was found to ably describe the main featuresof the data, whether taken together or on a sample by samplebasis. The low-salinity regime was found to be controlled bysurface conduction and rock microstructure, and was sensitiveto changes in porosity, cementation exponent, formation factor,grain size, pore size and pore throat size as well as specific surfaceconductivity. The high-salinity regime was found to be subjectto a zeta-potential offset that allows the streaming-potentialcoefficient to remain significant even as the saturation limit isapproached
  • Journal article
    Johnson JS, Everest JD, Leat PT, Golledge NR, Rood DH, Stuart FMet al., 2012,

    The deglacial history of NW Alexander Island, Antarctica, from surface exposure dating

    , Quaternary Research, Vol: 77, Pages: 273-280, ISSN: 0033-5894

    Recent changes along the margins of the Antarctic Peninsula, such as the collapse of the Wilkins Ice Shelf, have highlighted the effects of climatic warming on the Antarctic Peninsula Ice Sheet (APIS). However, such changes must be viewed in a long-term (millennial-scale) context if we are to understand their significance for future stability of the Antarctic ice sheets. To address this, we present nine new cosmogenic 10Be exposure ages from sites on NW Alexander Island and Rothschild Island (adjacent to the Wilkins Ice Shelf) that provide constraints on the timing of thinning of the Alexander Island ice cap since the last glacial maximum. All but one of the 10Be ages are in the range 10.2-21.7ka, showing a general trend of progressive ice-sheet thinning since at least 22ka until 10ka. The data also provide a minimum estimate (490m) for ice-cap thickness on NW Alexander Island at the last glacial maximum. Cosmogenic 3He ages from a rare occurrence of mantle xenoliths on Rothschild Island yield variable ages up to 46ka, probably reflecting exhumation by periglacial processes. © 2011 University of Washington.

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