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  • Journal article
    Pupim FDN, Bierman PR, Assine ML, Rood DH, Silva A, Merino ERet al., 2015,

    Erosion rates and landscape evolution of the lowlands of the Upper Paraguay river basin (Brazil) from cosmogenic <SUP>10</SUP>Be

    , GEOMORPHOLOGY, Vol: 234, Pages: 151-160, ISSN: 0169-555X
  • Journal article
    Jordan JR, Kimura S, Holland PR, Jenkins A, Piggott MDet al., 2015,

    On the Conditional Frazil Ice Instability in Seawater

    , JOURNAL OF PHYSICAL OCEANOGRAPHY, Vol: 45, Pages: 1121-1138, ISSN: 0022-3670
  • Journal article
    Martin-Short R, Hill J, Kramer SC, Avdis A, Allison PA, Piggott MDet al., 2015,

    .Tidal resource extraction in the Pentland Firth, UK: Potential impacts on flow regime and sediment transport in the Inner Sound of Stroma

    , RENEWABLE ENERGY, Vol: 76, Pages: 596-607, ISSN: 0960-1481
  • Journal article
    Wyshnytzky CE, Ouimet WB, McCarthy J, Dethier DP, Shroba RR, Bierman PR, Rood DHet al., 2015,

    Meteoric <SUP>10</SUP>Be, clay, and extractable iron depth profiles in the Colorado Front Range: Implications for understanding soil mixing and erosion

    , CATENA, Vol: 127, Pages: 32-45, ISSN: 0341-8162
  • Journal article
    D'Arcy M, Boluda DCR, Whittaker AC, Carpineti Aet al., 2015,

    Dating alluvial fan surfaces in Owens Valley, California, using weathering fractures in boulders

    , EARTH SURFACE PROCESSES AND LANDFORMS, Vol: 40, Pages: 487-501, ISSN: 0197-9337
  • Journal article
    Jackson CA-L, Jackson MPA, Hudec MR, 2015,

    Understanding passive margin kinematics: a critical test of competing hypotheses for the origin of the Albian Gap, Santos Basin, offshore Brazil

    , Geological Society of America Bulletin, Vol: 127, Pages: 1730-1751, ISSN: 1943-2674

    Thin-skinned gravitational gliding and spreading drive deformation on salt-bearing passive margins. Such margins typically have an updip extensional domain kinematically linked to a downdip contractional domain. However, calculating magnitudes of extension and shortening in salt-bearing margins is difficult because the initial widths of diapirs are uncertain. Extension and shortening may be cryptic, being hidden in widening or shortening of diapirs. -This uncertainty can lead to controversy in regional analysis. The Santos Basin, offshore Brazil, contains a prime example of this uncertainty in the form of an enigmatic structure known as the "Albian Gap", a zone up to 75 km wide within which the Albian section is missing. The Albian Gap has beenvariably interpreted as the product of post-Albian extensional faulting (the extension model) or as an Albian salt structure evacuated in response to loading by post-Albian sediments (the expulsion model). We evaluate these two models by: (i) structurally restoring a regional seismic reflection profile across the Albian Gap using both models;(ii) quantitatively analyzing the geometry of the Upper Cretaceous rollover overlying the Albian Gap; and (iii) synthesizing and critically evaluating arguments previously advanced in support of extension or expulsion. We propose a revised model for the evolution of the Albian Gap that invokes Albian thin-skinned extension and post-Albiansalt expulsion. Our approach shows that critical analysis of geological observations from borehole-constrained seismic reflection data can be used to assess the relative roles of the key processes in the deformation of salt-bearing passive margins.

  • Journal article
    Portenga EW, Bierman PR, Duncan C, Corbett LB, Kehrwald NM, Rood DHet al., 2015,

    Erosion rates of the Bhutanese Himalaya determined using <i>in situ</i>-produced <SUP>10</SUP>Be

    , GEOMORPHOLOGY, Vol: 233, Pages: 112-126, ISSN: 0169-555X
  • Journal article
    Patruno S, Hampson GJ, Jackson CA-L, 2015,

    Quantitative characterisation of deltaic and subaqueous clinoforms

    , Earth-Science Reviews, Vol: 142, Pages: 79-119, ISSN: 1872-6828

    Clinoforms are ubiquitous deltaic, shallow-marine and continental-margin depositional morphologies, occurring over a range of spatial scales (1-104 m in height). Up to four types of progressively larger-scale clinoforms may prograde synchronously along shoreline-to-abyssal plain transects, albeit at very different rates. Paired subaerial and subaqueous delta clinoforms (or ‘delta-scale compound clinoforms’), in particular, constitute a hitherto overlooked depositional model for ancient shallow-marine sandbodies. The topset-to-foreset rollovers of subaqueous deltas are developed at up to 60 m water depths, such that ancient delta-scale clinoforms should not be assumed to record the position of ancient shorelines, even if they are sandstone-rich. This study analyses a large dataset of modern and ancient delta-scale, shelf-prism- and continental-margin-scale clinoforms, in order to characterise diagnostic features of different clinoform systems, and particularly of delta-scale subaqueous clinoforms. Such diagnostic criteria allow different clinoform types and their dominant grain-size characteristics to be interpreted in seismic reflection and/or sedimentological data, and prove that all clinoforms are subject to similar physical laws. The examined dataset demonstrates that progressively larger scale clinoforms are deposited in increasingly deeper waters, over progressively larger time spans. Consequently, depositional flux, sedimentation and progradation rates of continental-margin clinoforms are up to 4-6 orders of magnitude lower than those of deltas. For all clinoform types, due to strong statistical correlations between these parameters, it is now possible to calculate clinoform paleobathymetries once clinoform heights, age spans or progradation rates have been constrained. Muddy and sandy delta-scale subaqueous clinoforms show many different features, but all share four characteristics. (1) They are formed during relative sea-level stillstands (e.g.

  • Journal article
    Freitas TMB, Potts DM, Zdravkovic L, 2015,

    Numerical study on the response of two footings at Bothkennar research site

    , Geotechnique, Vol: 65, Pages: 155-168, ISSN: 1021-8637

    This paper presents a numerical study of the performance of two instrumented surface footings at the Bothkennar Clay research site in the UK. Footing A was loaded to failure over 4 days, reaching a net bearing capacity of qr = 138 kPa; footing B was loaded to 89 kPa, at an identical loading rate, and left to consolidate under maintained load for about 11 years. The preloaded footing was then loaded to failure over 3 days, reaching qr = 204 kPa. The increase in bearing capacity was significantly larger than that expected due to consolidation effects alone, and it is anticipated that the occurrence of creep and other ageing processes may have played a major role in the observed response. The complete loading history of the two footings is simulated by means of coupled axi-symmetric finite-element analyses in which the foundation soil is described using an elastic–viscoplastic model that mimics isotach viscosity. The ground profile and the model parameters are derived based on the extensive laboratory and field test data available in the literature. The numerical analyses are able to describe accurately the footings behaviour during first loading, the development of delayed settlement under maintained load and the increase in bearing capacity due to preloading. The paper emphasises various issues regarding the application of elastic–viscoplastic models to model boundary value problems in conditions close to failure.

  • Journal article
    Maes J, Muggeridge AH, Jackson MD, Quintard M, Lapene Aet al., 2015,

    Scaling heat and mass flow through porous media during pyrolysis

    , HEAT AND MASS TRANSFER, Vol: 51, Pages: 313-334, ISSN: 0947-7411
  • Journal article
    Yang ZX, Jardine RJ, Zhu BT, Rimoy Set al., 2015,

    Closure to "Stresses Developed around Displacement Piles Penetration in Sand" by Z. X. Yang, R. J. Jardine, B. T. Zhu, and S. Rimoy

  • Conference paper
    Singh A, Gupta S, Sinha R, Carter A, Kristina KJ, Mark DF, Buylaert J-P, Mason PJ, Murray AS, Jain M, Paul Det al., 2015,

    Large–scale avulsion of the late Quaternary Sutlej river in the NW Indo–Gangetic foreland basin

    , European Geosciences Union General Assembly 2015

    River avulsions are important processes in the spatial evolution of river systems in tectonically active sedimentary basins as they govern large–scale patterns of sediment routing. However, the pattern and timing of avulsions in large river systems are poorly documented and not well understood. Here we document late Quaternary paleo– river channel changes in the Indo–Gangetic basin of northwest India. Using a combination of satellite remote sensing and detailed sediment coring, we analyse the large–scale planform geometry, and detailed sedimentary andstratigraphic nature of a major fluvial sedimentary deposit in the shallow subsurface. This sediment body records aggradation of multiple fluvial channel fills. Satellite remote sensing analysis indicates the trace of the buried channel complex and demonstrates that it exists in region of the Himalayan foreland where no major rivers are currently present. Thus it records the former drainage pathway of a major river, which has since been diverted. We use optically stimulated luminescence dating techniques to develop an age model for the stratigraphic succession and hence constrain the timing of river channel existence and diversion. Provenance analysis based on U–Pb dating of detrital zircons and detrital mica Ar–Ar ages indicate sediment sources in the Higher Himalayan Crystalline andLesser Himalayan Crystalline Series indicating that this paleo–river channel system formed a major perennial river derived from the main body of the Himalaya. Specifically we are able to fingerprint bedrock sources in thecatchment of the present–day Sutlej river indicating that the paleo–fluvial system represents the former course of the Sutlej river prior to a major nodal avulsion to its present day course. Our results indicate that on geologically relatively short time–scales, we observe dramatic along strike shifts in the location of major Himalayan rivers. Our sediment records

  • Journal article
    Yang ZX, Guo WB, Zha FS, Jardine RJ, Xu CJ, Cai YQet al., 2015,

    Field Behavior of Driven Prestressed High-Strength Concrete Piles in Sandy Soils

    , Journal of Geotechnical and Geoenvironmental Engineering, Vol: 141, ISSN: 1943-5606

    Driven piles are used widely both offshore and onshore. However, accurate axial capacity and load-displacement prediction is difficult at sand-dominated sites, and offshore practice is moving towards cone penetration test (CPT) based design methods developed from instrumented pile research and database studies. However, onshore use of these methods remains limited; there is a paucity of high quality case histories to assess their potential benefits clearly, and application in layered profiles may be uncertain. This paper presents new tests on prestressed concrete (PHC) pipe piles driven in sands for a major new Yangtze River bridge project in China, assessing the performance of the ‘new CPT’ and conventional capacity approaches, considering the influence of weak sublayers on base resistance and noting the marked changes in shaft capacity that apply over time.

  • Journal article
    Su K, Latham J-P, Pavlidis D, Xiang J, Fang F, Mostaghimi P, Percival JR, Pain CC, Jackson MDet al., 2015,

    Multiphase flow simulation through porous media with explicitly resolved fractures

    , Geofluids, Vol: 15, Pages: 592-607, ISSN: 1468-8123

    Accurate simulation of multiphase flow in fractured porous media remains a challenge. An important problem is the representation of the discontinuous or near discontinuous behaviour of saturation in real geological formations. In the classical continuum approach, a refined mesh is required at the interface between fracture and porous media to capture the steep gradients in saturation and saturation-dependent transport properties. This dramatically increases the computational load when large numbers of fractures are present in the numerical model. A discontinuous finite element method is reported here to model flow in fractured porous media. The governing multiphase porous media flow equations are solved in the adaptive mesh computational fluid dynamics code IC-FERST on unstructured meshes. The method is based on a mixed control volume – discontinuous finite element formulation. This is combined with the PN+1DG-PNDG element pair, which has discontinuous (order N+1) representation for velocity and discontinuous (order N) representation for pressure. A number of test cases are used to evaluate the method's ability to model fracture flow. The first is used to verify the performance of the element pair on structured and unstructured meshes of different resolution. Multiphase flow is then modelled in a range of idealised and simple fracture patterns. Solutions with sharp saturation fronts and computational economy in terms of mesh size are illustrated.

  • Journal article
    Corbett LB, Bierman PR, Lasher GE, Rood DHet al., 2015,

    Landscape chronology and glacial history in Thule, northwest Greenland

    , QUATERNARY SCIENCE REVIEWS, Vol: 109, Pages: 57-67, ISSN: 0277-3791
  • Journal article
    Reusser L, Bierman P, Rood D, 2015,

    Quantifying human impacts on rates of erosion and sediment transport at a landscape scale

    , Geology (Boulder), Vol: 43, Pages: 171-174, ISSN: 0091-7613

    Establishing background (geologic) rates of erosion is prerequisite to quantifying the impact of human activities on Earth’s surface. Here, we present 10Be estimates of background erosion rates for ten large (10,000–100,000 km2) river basins in the southeastern United States, an area that was cleared of native forest and used intensively for agriculture. These 10Be-based rates are indicative of the pace at which the North American passive-margin landscape eroded before European settlement (∼8 m/m.y.). Comparing these background rates to both rates of post-settlement hillslope erosion and to river sediment yields for the same basins, we find that following peak disturbance (late 1800s and early 1900s), rates of hillslope erosion (∼950 m/m.y.) exceeded 10Be-determined background rates more than one-hundred fold. Although large-basin sediment yields during peak disturbance increased 5–10× above pre-settlement norms, rivers at the time were transporting only ∼6% of the eroded material; work by others suggests that the bulk of historically eroded material remained and still remains as legacy sediment stored at the base of hillslopes and along valley bottoms. Because background erosion rates, such as we present here, reflect the rate at which soil is generated over millennial time scales, they can inform and enhance landscape-management strategies.

  • Journal article
    Ouimet W, Dethier D, Bierman P, Wyshnytzky C, Shea N, Rood DHet al., 2015,

    Spatial and temporal variations in meteoric <SUP>10</SUP>Be inventories and long-term deposition rates, Colorado Front Range

    , QUATERNARY SCIENCE REVIEWS, Vol: 109, Pages: 1-12, ISSN: 0277-3791
  • Journal article
    Davies DR, Goes S, Sambridge M, 2015,

    On the relationship between volcanic hotspot locations, the reconstructed eruption sites of large igneous provinces and deep mantle seismic structure

    , Earth and Planetary Science Letters, Vol: 411, Pages: 121-130, ISSN: 0012-821X

    It has been proposed that volcanic hotspots and the reconstructed eruption sites of large igneous provinces (LIPs) are preferentially located above the margins of two deep mantle large low shear-wave velocity provinces (LLSVPs), beneath the African continent and the Pacific Ocean. This spatial correlation has been interpreted to imply that LLSVPs represent long-lived, dense, stable thermo-chemical piles, which preferentially trigger mantle plumes at their edges and exert a strong influence on lower-mantle dynamics. Here, we re-analyse this spatial correlation, demonstrating that it is not global: it is strong for the African LLSVP, but weak for the Pacific. Moreover, Monte Carlo based statistical analyses indicate that the observed distribution of African and Pacific hotspots/reconstructed LIPs is consistent with the hypothesis that they are drawn from a sample that is uniformly distributed across the entire areal extent of each LLSVP: the stronger spatial correlation with the margin of the African LLSVP is expected as a simple consequence of its elongated geometry, where more than 75% of the LLSVP interior lies within 10° of its margin. Our results imply that the geographical distribution of hotspots and reconstructed LIPs does not indicate the extent to which chemical heterogeneity influences lower-mantle dynamics.

  • Journal article
    Stewart JP, Douglas J, Javanbarg M, Bozorgnia Y, Abrahamson NA, Boore DM, Campbell KW, Delavaud E, Erdik M, Stafford PJet al., 2015,

    Selection of Ground Motion Prediction Equations for the Global Earthquake Model

    , EARTHQUAKE SPECTRA, Vol: 31, Pages: 19-45, ISSN: 8755-2930
  • Journal article
    Dilib FA, Jackson MD, Zadeh AM, Aasheim R, Arland K, Gyllensten AJ, Erlandsen SMet al., 2015,

    Closed-Loop Feedback Control in Intelligent Wells: Application to a Heterogeneous, Thin Oil-Rim Reservoir in the North Sea

    , SPE RESERVOIR EVALUATION & ENGINEERING, Vol: 18, Pages: 69-83, ISSN: 1094-6470

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