Multi-sensor core logging (MSCL) and X-ray computed tomography imaging of borehole core to aid 3D geological modelling of poorly exposed unconsolidated superficial sediments underlying complex industrial sites: an example from Sellafield nuclear site, UK

The 3D characterisation of geology underlying complex industrial sites such as nuclear plants is problematic due to the presence of the built infrastructure that restricts or in some cases completely prevents access for geologists to the subsurface environment. Outcrops are rare, geophysics surveys are often impossible (particularly at nuclear plants where activities such as vibroseis are frowned upon due to their effect on the infrastructure itself), and boreholes are often the only way to obtain subsurface data. Yet, with sedimentary deposits in particular, geotechnical logging undertaken to specific standards sometimes misses key information that could have been used to directly inform the creation of geological 3D models. Multi-sensor core logging (MSCL) and X-ray computed tomography (XCT) undertaken on core obtained from a borehole within the Sellafield nuclear plant, is used to illustrate the potential for the techniques to contribute significantly to the creation of 3D subsurface geological models, particularly where access is restricted, such as within nuclear industry locations. Geophysical characteristics are recorded and used to reassess and enhance geotechnical descriptions, leading to the modification of existing unit boundaries or the creation of new ones. A new sedimentary log was created and this was used in a comparison with existing logs and nearby historic exposures, and as the basis for an illustration of industrial site to regional correlation

Automated characterisation of glaciomarine sediments using X-ray computed laminography

This study investigates the potential of a new high-resolution, non-destructive, X-ray imaging technique for the Quaternary Sciences – computed laminography (CL). Greyscale properties are systematically extracted from digital X-radiographic CL images of cored glaciomarine sediments to analyse and characterise sediments at pixel-scale resolution (< 0.1 mm). We show how this can be achieved manually, and also with an easy-to-use, automated statistical tool which we have devised specifically for use in glaciomarine sediments. This Sediment Characteristics tool, in the form of a plugin for the freely available FIJI/ImageJ programme, extracts mean or median X-ray grey values (GV) – a proxy for sediment density; and associated standard deviation (SD) – a proxy for sediment heterogeneity – at sub-mm resolution, across the width of sediment core CL images. We demonstrate how these properties (GV and SD) can be directly used to characterise sediment properties and in particular to quantify the abundance of gravel clasts, or ice-rafted debris, in cored glaciomarine sediments. The tool’s effectiveness is compared with other, more traditional, X-radiographic methods for counting ice-rafted gravel clasts in glaciomarine sediment. We propose that the CL output and Sediment Characteristics tool also have the potential to quantitatively analyse other 3-dimensional structures, such as cyclic lamination (varve) geometry; deformation structures; bioturbation and void space (porosity). Finally, we present the raw code, allowing open-access, transparency and reproducibility in other formats

Lithological constraints on borehole wall failure: a study on the Pennine Coal Measures of the United Kingdom

Stress-related borehole deformation features have been documented across the United Kingdom, most commonly as borehole breakouts and drilling induced tensile fractures (DIFs). Recent studies using borehole imaging have allowed more detailed investigation of these features and the processes that control their formation. Within the Pennsylvanian Pennine Coal Measures Group (PCM) of the United Kingdom borehole imaging has highlighted a disproportionately high number of breakouts occurring within paleosols located immediately below coal seams. To understand the processes controlling breakout formation, a 10.5 m section of core from the Melbourne 1 borehole, incorporating a typical coal seam / paleosol sequence, was analyzed using multiple techniques including: scanning electron and optical microscopy, X-Ray Fluorescence (XRF), X-ray radiography, Point Load testing, wireline petrophysics and track-based core scanning for physical properties. Strength measurements highlight that breakouts form preferentially in poorly consolidated sediments, with low tensile strength, cross-cut by listric surfaces. The formation and termination of breakouts also corresponds to zones of diagenetic iron mineral growth with a lower propensity to fail. These coincide with greater preservation of sedimentary structures and an increase in the rock’s tensile strength; this intra-unit variation in tensile strength constrains breakout length. This demonstrates that secondary diagenetic processes, including the growth of iron minerals impose, lithological controls on the formation and length of borehole breakouts within the United Kingdom PCM

Digital Programmable Timing Device

PatentA digital programmable timing device to control the acquisition of data by a computer from high response probes in periodic flows. Synchronized sampling of probe measurements uses a phase-locked-loop and counting circuits so that the moment of AID conversion always corresponds to a programmable displacement of a stationary probe with respect to moving rotor blades independent of RPM. The rotor speed also is measured digitally in one revolution of the rotor shaft

Predictive Value of Clinical and Laboratory Indices at First Assessment in Women Referred with Suspected Gestational Hypertension

Infiltration of shallow soils by naturally occurring hydrocarbons has been documented in several deepwater environments worldwide. The potential for significant soil modification, such as the development of authigenic carbonates and alteration of the generally expected background geotechnical properties may provide constraints to flowline routing, foundation installation and engineering lifetime performance. This paper presents a review of the current state of knowledge of the authors with special reference to recent investigations in deepwater offshore Angola, and a suggested method for identification, characterization and prediction.Interpretation of 3D exploration seismic, enhanced by AUV (Chirp) data facilitates an initial identification of areas prone to hydrocarbon infiltration and the vertical and spatial extent of potential soil modification. A first pass geotechnical characterisation is developed by targeted seabed CPTs and soil sampling. The generation of an integrated predictive model requires a multidisciplinary advanced testing programme, including geophysical, geotechnical, geochemical and geological analyses.Once the extent, nature, and formative processes of hydrocarbon-related soil modification are understood, an assessment can be made of the challenges posed to a field development. This provides the necessary input to foundation and /or routing feasibility and determines if there is requirement to mitigate, through avoidance or design.<br/

Origin of spectacular fields of submarine sediment waves around volcanic islands: distinguishing eruption-fed supercritical flow bedforms from slope failures

Understanding how large eruptions and landslides are recorded by seafloor morphology and deposits on volcanic island flanks is important for reconstruction of volcanic island history and geohazard assessment. Spectacular fields of bedforms have been recognised recently on submerged flanks of volcanic islands at multiple locations worldwide. These fields of bedforms can extend over 50 km, and individual bedforms can be 3 km in length and 150 m in height. The origin of these bedform fields, however, is poorly understood. Here, we show that bedforms result from eruption-fed supercritical density flows (turbidity currents) in some locations, but most likely rotational landslides at other locations. General criteria are provided for distinguishing between submarine bedforms formed by eruptions and landslides, and emphasise a need for high resolution seismic datasets to prevent ambiguity. Bedforms associated with rotational landslides have a narrower source, with a distinct headscarp, they are more laterally confined, and internal bedform structure does not suggest upslope migration of each bedform. Eruption-fed density currents produce wide fields of bedforms, which extend radially from the caldera. Internal layers imaged by detailed seismic data show that these bedforms migrated up-slope, indicating that the flows that produced them were Froude supercritical. Due to the low density contrast between interstitial fluid and sediment, the extent and dimensions of submarine eruption-fed bedforms is much greater than those produced by pyroclastic density currents on land

The CD94/NKG2A inhibitory receptor educates uterine NK cells to optimize pregnancy outcomes in humans and mice.

The conserved CD94/NKG2A inhibitory receptor is expressed by nearly all human and ∼50% of mouse uterine natural killer (uNK) cells. Binding human HLA-E and mouse Qa-1, NKG2A drives NK cell education, a process of unknown physiological importance influenced by HLA-B alleles. Here, we show that NKG2A genetic ablation in dams mated with wild-type males caused suboptimal maternal vascular responses in pregnancy, accompanied by perturbed placental gene expression, reduced fetal weight, greater rates of smaller fetuses with asymmetric growth, and abnormal brain development. These are features of the human syndrome pre-eclampsia. In a genome-wide association study of 7,219 pre-eclampsia cases, we found a 7% greater relative risk associated with the maternal HLA-B allele that does not favor NKG2A education. These results show that the maternal HLA-B→HLA-E→NKG2A pathway contributes to healthy pregnancy and may have repercussions on offspring health, thus establishing the physiological relevance for NK cell education. VIDEO ABSTRACT.This project was funded by the Wellcome Trust (awards 200841/Z/16/Z to FC and AM and RG86992 to NS and FC), the Medical Research Council (Grant MR/P001092/1 to AS, FC and AM). JAT received funding from the European Research Council under the European Union's Horizon 2020 research and innovation program (Grant Agreement 695551). OH was supported by a MedImmune-Cambridge PhD fellowship. JJ was supported by a Centre for Trophoblast Research PhD fellowship