Fluvial stratigraphy and palaeoenvironments in the Pasinler Basin, eastern Turkey

Valley floor sediments from the Pasinler Basin, eastern Turkey, provide evidence for Pleistocene and Holocene floodplain conditions. Three terrace surfaces are present. Evidence for tectonic processes active during the Late Neogene are widespread within the basin but do not appear to have substantially influenced the detail of the Holocene palaeoenvironmental record. Significant changes in hydrology are recorded, with more stable floodplain conditions occurring at around 9,000, 5,500 and 4,000 cal. yr. BP. Incision occurred sometime after approximately 4,000 BP, probably as a response to dual climatic and human controls. Comparisons with key sites in the Anatolian region and beyond suggest these changes are part of a regional climatic pattern, perhaps influenced by changes in the East African Monsoon. Differences in the details of the records across the region reflect the characteristics of the local environment, which, increasingly in the latter Holocene, includes human activity

Floodplain environmental change during the younger dryas and holocene: Evidence from the lower kennet valley, south central England

Many lowland rivers across northwest Europe exhibit broadly similar behavioural responses to glacial-interglacial transitions and landscape development. Difficulties exist in assessing these, largely because the evidence from many rivers remains limited and fragmentary. Here we address this issue in the context of the river Kennet, a tributary of the Thames, since c. 13,000 cal. BP). Some similarities with other rivers are present, suggesting that regional climatic shifts are important controls. The Kennet differs from the regional pattern in a number of ways. The rate of response to sudden climatic change, particularly at the start of the Holocene and also mid-Holocene forest clearance, appears very high. This may reflect abrupt shifts between two catchment scale hydrological states arising from contemporary climates, land use change and geology. Stadial hydrology is dominated by nival regimes, with limited winter infiltration and high spring and summer runoff. Under an interglacial climate, infiltration is more significant. The probable absence of permafrost in the catchment means that a lag between the two states due to its gradual decay is unlikely. Palaeoecology, supported by radiocarbon dates, suggests that, at the very start of the Holocene, a dramatic episode of fine sediment deposition across most of the valley floor occurred, lasting 500-1000 years. A phase of peat accumulation followed as mineral sediment supply declined. A further shift led to tufa deposition, initially in small pools, then across the whole floodplain area, with the river flowing through channels cut in tufa and experiencing repeated avulsion. Major floods, leaving large gravel bars that still form positive relief features on the floodplain, followed mid-Holocene floodplain stability. Prehistoric deforestation is likely to be the cause of this flooding, inducing a major environmental shift with significantly increased surface runoff. Since the Bronze Age, predominantly fine sediments were deposited along the valley with apparently stable channels and vertical floodplain accretion associated with soil erosion and less catastrophic flooding. The Kennet demonstrates that, while a general pattern of river behaviour over time, within a region, may be identifiable, individual rivers are likely to diverge from this. Consequently, it is essential to understand catchment controls, particularly the relative significance of surface and subsurface hydrology

Out-of-hospital cardiac arrest and survival in a patient with Noonan syndrome and multiple lentigines: a case report

BACKGROUND: A 9-year-old Arabic boy attending middle school presented with an out-of-hospital cardiac arrest due to ventricular fibrillation recorded by Holter electrocardiographic monitoring. He had a background history of Noonan syndrome with multiple lentigines (also known as LEOPARD syndrome), a rare condition of autosomal dominant inheritance with approximately 200 cases reported worldwide. CASE PRESENTATION: Apart from characteristic features, the boy was known to have asymmetric septal hypertrophy with a maximum wall thickness of 24 mm measured by cardiovascular magnetic resonance imaging. A day prior to the event, he attended cardiology follow-up at our institution, and Holter monitoring was commenced. Following cardiopulmonary resuscitation by bystanders and paramedics, he reverted back into sinus rhythm after a total downtime of 24 min. He was initially treated in the intensive care unit and underwent implantable cardioverter defibrillator implantation. He has made a full recovery and remains at the top of his class. CONCLUSION: This case demonstrates that sudden cardiac arrest in patients with secondary forms of hypertrophic cardiomyopathy is not necessarily protected by apparently favorable phenotypes and that events may be preceded by non-sustained ventricular tachycardia observed by Holter monitoring. Implantable cardioverter defibrillator implantation plays a critical role in both primary and secondary prevention in patients at high risk of out-of-hospital cardiac arrest

Application of passive seismic to the detection of buried hollows

Pilot studies involving the use of passive seismic techniques in a range of geological settings and applications, e.g., mapping bedrock, studies of soil erosion and Quaternary mapping have shown that it is a versatile, non-invasive and economic technique. This paper presents the findings of three case studies that trialled the use of passive seismic techniques for the detection and characterisation of buried hollows in carbonate rocks, comprising: i) a buried hollow in the Cretaceous Chalk at Ashford Hill in the Kennet Valley, a tributary of the River Thames, UK; ii) buried karst in the foundation excavations for wind turbines in Carboniferous Limestone at Brassington, Wirksworth, Derbyshire, UK, and iii) defining the extent of solution hollows that host terrestrial Miocene deposits, near Friden, Newhaven, Derbyshire, UK. Whilst case studies ii) and iii) are focused on areas of buried dolines, the geological context of the Ashford Hill site is more complex; comprising a deformation hollow with an uplifted “pinnacle” of chalk bedrock at the centre. The data were collected using a (Tromino), a three-component, broadband seismometer to measure background ambient noise (microtremors induced by wind, ocean waves, industrial machinery, road and rail traffic, etc.). The Tromino is small, portable with an operating range of 0.1 Hz to 1,024 Hz and interpreted using proprietary software (Grilla), which subjects the data to Fourier transformation and smoothing. Where possible, estimated shear wave velocities used in the Grilla Software modelling, based on peaks identified on the H/V spectrum, have been calibrated using borehole data or parallel geophysical techniques. In each case, the karst features were defined by Nakamura’s horizontal to vertical (H/V) spectral ratio technique, where microtremors are converted to show impedance contrasts (velocity x density), or a pseudo layered seismic stratigraphy of the near surface along each profile. An additional benefit of the use of this technique is its depth of penetration and potential for defining the structural and lithological context of the hollows, thereby contributing to the process understanding associated with their formation. To this end the technique has helped define discontinuity (fault, joint or bedding) guidance of the hollows.S. Castellaro, Mrs J. Renwick, West Coast Energy Ltd (GDF Suez), Mr Roger Durrant (Raymond Brown Construction Ltd

Geomorphological insight into changing tectonic regime, Pasinler Basin, Turkey

The Pasinler Basin, in the East Anatolian Contractional Province, features a suite of geomorphological zones, visible in the field, air photographs and Landsat and SRTM DEM imagery. These zones reflect past and current tectonically influenced processes. Collins et al: Geomorphological insight into changing tectonic regime, Pasinler Basin, Turkey. 2 of 26 Remnants of the Erzurum-Kars plateau representing Mio-Pliocene volcanism, associated with transtensional tectonics, have been modified by two stages of drainage development: an earlier, shallow valley network, which was modified following uplift and tilting to form the present system characterised by deep narrow valleys that supply alluvial fan complexes. These fans discharge onto the present, aggradation-dominated basin floor. Initial normal faulting induced massive slope failures on the basin’s northern margin. This extensional phase within the basin was reversed by the Late Pleistocene, with thrust faults modifying and producing landforms, and affecting sediment sequences, along both the north and south basin margins. The shift from a transtensional regime and associated volcanism to normal faulting in the Pliocene-Early Pleistocene, and then to the present compression-dominated regime appears to correspond with regional tectonic changes resulting from collision of the Arabian microplate and the subsequent westward movement of the Anatolian microplate

Modelling the brittle rock failure by the quaternion-based bonded-particle model in DEM

A CC BY or equivalent licence is applied to that at least the Author Accepted Manuscript (AAM) arising from this submission, in accordance with the grant's open access conditions. The research data are publicly available online at: https://doi.org/10.17633/rd.brunel.25117811.This paper presents an investigation of brittle rock failure by the quaternion-based bonded-particle model in discrete element method (DEM). Unlike traditional approaches that utilize Euler angles or rotation matrices, this model employs unit quaternions to represent the spatial rotations of particles. This method simplifies the representation of 3D rotations, providing a more intuitive framework for modelling complex interactions in granular materials. The numerical model was validated by the uniaxial compression tests on rock, with good agreement with well-documented experimental data in terms of the rock uniaxial compression strength (UCS) and failure mode. During loading, the rock sample demonstrated a linear-elastic response at an axial strain of smaller than 0.45%. However, as internal bond breakage accumulated, this linear relationship weakened, and the stress-strain curve began to deviate from its initial linear trajectory. The bond breakage and the overall deformation of the rock were primarily controlled by the shear bonding force. The UCS was achieved at an axial strain of 0.625%, at which point the internal shear bonding force chains were predominantly aligned vertically. The brittle failure occurred when the internal damage of solids nucleated to form an interconnected failure plane, accompanied by a sharp rise in the internal damage ratio. The area of failure plane increased with the loading strain rate, gradually transforming the failure pattern from the local damage to a complete fragmentation.This research was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) New Investigator Award (Grant No. EP/V028723/1) and the Royal Society, Sino-British Fellowship Trust International Exchanges Award (No. IES∖R2∖202023)

Assumptions and reality in ground models - the case of drift-filled hollows and associated subsurface features in London, United Kingdom

Copyright © 2023 The Author(s), The subsurface of London is often assumed to be relatively simple, with Late Cretaceous and Palaeogene strata sitting within and forming a synclinal structure (the London Basin). The surface has been modified by mostly fluvial processes during the Quaternary. More recently, a picture of more complex conditions has begun to be developed, largely driven by the need for deeper foundations, groundwater control and tunnelling. One group of significant features are referred to as ‘drift-filled hollows’ (DFH). These are commonly closed depressions in the surface of the bedrock (typically the London Clay Formation), that are infilled by later deposits. Adjacent and underlying strata is sometimes disturbed A new database shows that DFH are more widespread than previously thought, but also highlights issues in how they are classified. It also raises questions about the validity of the ‘simple’ geological model of London and highlights the danger of using assumptions when planning development, and for reconstructing past events

Evaluation of frost heave and moisture/chemical migration mechanisms in highway subsoil using a laboratory simulation method

Seasonal processes in cold countries significantly affect the engineering characteristics of highway subsoil over time. Cyclical freeze-thaw leads to changes in thermal and moisture conditions. As a result, road bearing capacity can progressively change from the initial design. In this work, a modified laboratory method was developed, with cyclical freeze-thaw of soil samples and simultaneous supply of deionised water and a de-icing agent (sodium chloride) to the base. The benefits of the test procedure included slow freezing, simulating the conditions that can be experienced by highway soils in cold environments, extended soil column heights and a larger number of identical soil samples, which allowed experimental variability to be assessed. The method included the monitoring of moisture and chemical mass transfer in the soils. Samples supplied with deionised water experienced ice segregation in their upper parts, and significant heave. While soils supplied with NaCl solution behaved in a similar fashion during their first freeze-thaw cycle, the second cycle saw a reduction in the rate of migration of the freezing front within the soils and also less ice segregation and less heave due to increased salinity. Salt was preferentially transferred upwards in the soil columns as a result of the thermal gradient, including negative pressure associated with cryosuction, and osmotic pressure. The new method provides a more realistic laboratory approach to assessing potential freeze-thaw impacts, and the effects of de-icing agents on soils beneath roads, and in different settings.JSC Center (International program “Bolashak”)

Novel Methodology for Scaling and Simulating Structural Behaviour for Soil–Structure Systems Subjected to Extreme Loading Conditions

Data Availability Statement: The study did not report any data.Copyright © 2023 by the authors. This paper is concerned with the calibration and validation of a numerical procedure for the analysis of pile performance in soft clays during seismic soil–pile–superstructure interaction (SSPSI) scenarios. Currently, there are no widely accepted methods or guidelines. Centrifuge and shaking table model tests are often used to supplement the available field case histories with the data obtained under controlled conditions. This paper presents a new calibration method for establishing a reliable and accurate relationship between full-scale numerical analysis and scaled laboratory tests in a 1g environment. A sophisticated approach to scaling and validating full-scale seismic soil–structure interaction problems is proposed that considers the scaling concept of implied prototypes as well as “modelling of models” techniques that can ensure an excellent level of accuracy. In this study, a new methodology was developed that can provide an accurate, practical, and scientific calibration for the relationship between full-scale numerical analysis and scaled laboratory tests in the 1g environment. The framework can be followed by researchers who intend to validate their seismic soil–structure interaction findings