Seismic interpretation and generation of key depth structure surfaces within the Devonian and Carboniferous of the Central North Sea, Quadrants 25 – 44 area

This report details the rationale, methodology and results of a regional seismic interpretation of the western margin of the Central North Sea (CNS) area, specifically over the Mid North Sea High area, the offshore extension of the Northumberland Trough and the Forth Approaches area. The aim of the interpretation was to create maps that show the distribution of Palaeozoic basins and highs, and where possible interpret key Devono-Carboniferous surfaces and main structural elements in order to build a tectono-stratigraphic model of the Palaeozoic geology. Some 50,000 line kilometres of predominantly 2D seismic data have been interpreted and tied to key released wells in the study area. The seismic and well data were augmented by donated reports from sponsor companies. A set of 5 depth structure maps of selected Palaeozoic horizons has been produced for the pre-Permian succession. These maps provide a key element to aid assessment of the petroleum prospectivity of the Palaeozoic within the study area. The surfaces, with a grid spacing of 5000 m, give a regional view of the topography of the horizons, and comprise: Upper Permian Base Zechstein Group; Lower Carboniferous near Top Scremerston Formation; Lower Carboniferous near Top Fell Sandstone Formation; Lower Carboniferous near Top Cementstone Formation; and Middle Devonian near Top Kyle Limestone Group. The regional structure map of the area constructed for this report and observations made from the seismic data, have been integrated with peer reviewed published information to describe a tectonostratigraphic model for the region (Leslie et. al., 2015). A new pre-Permian subcrop map is presented here that builds on existing publications (Smith,1985a, b; Kombrink et al., 2010) and incorporates all relevant new well penetrations since the previous map was published. The well dataset has been either validated or re-interpreted before being integrated with the new seismic interpretation (Kearsey et al., 2015). Figure 10 in Section 3.3.1 below summarises the regional structures referred to in the general observations listed below. General observations on the structures defined across Quadrants 29, 30, 31, 37, 38 and 39: The Middle-Upper Devonian basins and highs follow a NW-SE trend across Quadrants 29-30 and 37-38; Lower Carboniferous sequences (Tournaisian and Visean) are interpreted to be present in depocentres across much of the area covered by Quadrants 29 to 38; wells, mainly drilled on the structural highs, constrain the edge of the Lower Carboniferous basins; There is a structurally complicated area in the southernmost part of Quadrant 38 which comprises a folded Visean and probably Namurian succession. The structure can be interpreted either as an anticlinal rollover on a low-angle fault, or as a compressional anticlinal fold (see Figure 17 below). The structure trends broadly NNE-SSW, plunging northwards into Quadrant 38

Tectonic synthesis and contextual setting for the Central North Sea and adjacent onshore areas, 21CXRM Palaeozoic Project

This report is designed simply to provide a summary tectonic outline and contextual setting against which offshore seismic and well data relating to the Devono-Carboniferous evolution of the Central North Sea, Forth Approaches, and adjacent UK onshore region can be considered. This summary is intended to help better frame the questions that will arise during interrogation of that data; the findings that result from that analysis are presented elsewhere in the report series (Arsenikos et al., 2015; Kimbell & Williamson, 2015; Monaghan et al., 2015). Apparently contradictory, wrench- or extension-dominated patterns of Lower Carboniferous basin development are recorded in the Forth Approaches, Quadrant 29, North Dogger and Silverpit basins of the Central North Sea, as well as the Midland Valley of Scotland (MVS) and Northumberland and Solway basins onshore. Partitioning Carboniferous deformation across inherited pre-existing Caledonian or Tornquist structures is likely to be an important control on the tectonic architecture developed in these regions during intervals of the geological record in the Carboniferous. Onshore, spatially separate but contemporaneous domains of extension-dominated tectonics versus wrench-dominated tectonics explain the contrasting tectonic framework of the MVS/Forth Approaches region (wrench-dominated) compared with Northumberland Basin (classic ‘stags head’ structure). NE-SW trending Caledonian inheritance strongly controls the domain boundaries and the patterns of deformation created in each of these domains. Offshore, in the Devono-Carboniferous basins of the Central North Sea, the likelihood that strain is partitioned in a similar way across features inherited from the NW-SE Tornquist trend is proposed and examined. The data currently under consideration suggests that a NW-SE trending wrench-dominated domain is spatially associated with the region underlain by the Dogger Granite pluton; domains affected by extension-dominated tectonics appear to be arranged on either side of that feature, namely the Quadrant 29 and North Dogger basins to the NE, and the Silverpit Basin to the SW. Extension is expressed as a NE-SW directed stretch in both of these domains. Patterns of broadly N-S trending fold axes need to be carefully assessed in terms of their structural setting, as folding cannot implicitly be linked with inversion/compression when partitioned strains are developed. Superficially similar features can develop in the MVS in dextral transpression, in north Northumberland buttressed around the Cheviot Granite in overall dextral wrench, and as superimposed late compressional folds in end-Variscan convergence, for example in the Boldon syncline of County Durham. Offshore, similar inversion effects can be seen in the patterns of transpressive faulting associated with features such as the Murdoch Ridge, and with examples of superimposed NE-SW trending extensional faults active in the latest Carboniferous to early Permian

Deep geothermal resource assessment of early carboniferous limestones for Central and Southern Great Britain

Early Carboniferous limestones (ECL) host active geothermal systems in Central and Southern Britain. Equivalent rocks have been successfully developed for geothermal energy in Belgium and the Netherlands, but the ECL has yet to be fully assessed as a geothermal resource in Britain. We use established statistical methods to assess the depth, distribution, and geothermal potential of the ECL in Central and Southern Britain. Total heat in place (HIP) resources of 1415 (P10)–1528 (P90) EJ may be present, with a tentative potential recoverable thermal power of 106–222 GW. Further work is needed to understand the resource by identifying areas with sufficient flow rates for successful development such as enhanced permeability zones around faults, fractures or karsts

National geological screening : East Anglia region

This report is the published product of one of a series of studies covering England, Wales and Northern Ireland commissioned by Radioactive Waste Management (RWM) Ltd. The report provides geological information about the East Anglia region to underpin the process of national geological screening set out in the UK’s government White Paper Implementing geological disposal: a framework for the long-term management of higher activity radioactive waste (DECC, 2014). The report describes geological features relevant to the safety requirements of a geological disposal facility (GDF) for radioactive waste emplaced onshore and up to 20 km offshore at depths between 200 and 1000 m from surface. It is written for a technical audience but is intended to inform RWM in its discussions with communities interested in finding out about the potential for their area to host a GDF

National seismic hazard maps for the UK: 2020 update

This report is the published product of a study by the British Geological Survey (BGS) to update the national seismic hazard maps for the UK. This is to take account of advances in seismic hazard methodology since the last seismic hazard maps were developed by Musson and Sargeant (2007) and present the results in a format that will be compatible with the future Eurocode 8 revisions

Chapter 58 Evidence of late Neoproterozoic glaciation in the Caledonides of NW Scandinavia

Abstract: The northwestern part of the Scandinavian Caledonides, formed by SE-to ESE-directed thrusting through the Neoproterozoic W. Baltica continental shelf, contains numerous small and often isolated outcrops of diamictite and associated strata. No precise biostratigraphic or isotopic data are available to constrain the age of these sediments, but, on the basis of their stratigraphic position, most are correlated with the Mortensnes Formation (Fm.) in E. Finnmark and also presumed to be of glaciogenic origin. The Mortensnes Fm. has been correlated with the 580 Ma Gaskiers glacial event on the basis of d 13 C isotope studies. Structurally, the deposits occur in the Autochthon (below the Torneträsk Fm.), within an external imbricate zone (Lower Allochthon), within cover successions lying unconformably on allochthonous basement (Window Allochthon) palaeogeographically derived from below or outboard of the Lower Allochthon and, more rarely, within the Middle Allochthon, derived from outboard of the Window Allochthon. Evidence for a glaciogenic origin is typically poor or lacking. Only in the Komagfjord Antiformal Stack (Window Allochthon), where an up to 40-m-thick succession of three fining upwards cycles has been mapped, are the deposits comparable in thickness and complexity to the Mortensnes Fm. Other sequences are sometimes ,1 m thick and unconformably overlain by post-'glacial' deposits. The Vakkejokk Breccia, a submarine slump in the Torneträsk area of the Autochthon closely underlies the correlative Precambrian -Cambrian lithostratigraphic boundary in E. Finnmark but overlies the first appearance of the boundary marker fossil Treptichnus pedum. Although sometimes interpreted as periglacial, this seems unlikely in view of the 30-508 palaeolatitude during deposition. Calcite nodules (,1 cm size) in the Vakkejokk Breccia have previously been interpreted as glendonite, but the microstructure and palaeolatitude makes this unlikely; they are likely a replacement of gypsum. Diamictites of uncertain origin have also been found in the Ediacaran Lower Siltstone Member of the Torneträsk Fm. and unconformably under the ?Lower Cambrian Lomvatn Fm. in the Komagfjord Antiformal Stack

National geological screening : Central England region

This report is the published product of one of a series of studies covering England, Wales and Northern Ireland commissioned by Radioactive Waste Management (RWM) Ltd. The report provides geological information about the Central England region to underpin the process of national geological screening set out in the UK Government’s White Paper Implementing geological disposal: a framework for the long-term management of higher activity radioactive waste (DECC, 2014). The report describes geological features relevant to the safety requirements of a geological disposal facility (GDF) for radioactive waste emplaced onshore and up to 20 km offshore at depths between 200 and 1000 m from surface. It is written for a technical audience but is intended to inform RWM in its discussions with communities interested in finding out about the potential for their area to host a GDF

National geological screening : Eastern England region

This report is the published product of one of a series of studies covering England, Wales and Northern Ireland commissioned by Radioactive Waste Management (RWM) Ltd. The report provides geological information about the Eastern England region to underpin the process of national geological screening set out in the UK’s government White Paper Implementing geological disposal: a framework for the long-term management of higher activity radioactive waste (DECC, 2014). The report describes geological features relevant to the safety requirements of a geological disposal facility (GDF) for radioactive waste emplaced onshore and up to 20 km offshore at depths between 200 m and 1000 m from surface. It is written for a technical audience but is intended to inform RWM in its discussions with communities interested in finding out about the potential for their area to host a GDF

Palaeozoic petroleum systems of the central North Sea/Mid North Sea High

This report synthesises the results of the 21CXRM Palaeozoic project to describe the Carboniferous and Devonian petroleum systems of the Central North Sea/Mid North Sea High area (Quadrants 25–44). Focusing on frontier areas to the north of the Southern North Sea gas fields and west of the Auk-Flora ridge, integration of a large volume of seismic, well, geophysical, organic geochemistry, maturity and reservoir property data at regional scale has established: Extensional to strike-slip Devonian and Carboniferous basins cutting across the Mid North Sea High on orientations strongly controlled by basement inheritance, granites and a complex Palaeozoic stress field. Varsican orogenic transpression and inversion was superimposed resulting in a variety of structural trapping styles and burial/uplift histories, and a complicated pre-Permian subcrop map. A widespread spatial and temporal extent of oil and gas mature source rock intervals within the Carboniferous succession particularly; o lower Carboniferous (Visean) coals and mudstones of the Scremerston Formation, dominantly fluvio-deltaic and lacustrine with some marine influence, dominantly gas prone. Gas mature in Quadrant 41 and central-southern Quadrants 42-44 and oil mature in the Forth Approaches and North Dogger Basin o lower-mid Carboniferous (Visean-Namurian) coals and mudstones of the Yoredale and Millstone Grit formations in fluvio-deltaic to marine cycles, gas prone with oil prone intervals. Gas mature in central Quadrant 41 and southern Quadrants 42-43, oil mature across northern Quadrants 41-44, Quadrant 36, 38 and 39. o Lower-mid Carboniferous (Visean-Namurian) mudstones and siltstones of the Cleveland Group, over 1 km thick, deposited in dominantly marine environments. Gas mature to overmature in southern Quadrants 41-44 and modelled as having generated oil and gas. Potentially widespread reservoir intervals of varying reservoir quality. Favourable intervals include the Upper Devonian sandstone of the Buchan Formation expecially where fractured, channels within the fluvio-deltaic lower-mid Carboniferous (Visean-Namurian) Scremerston, Yoredale and Millstone Grit formations, the laterally extensive, high net:gross Fell Sandstone Formation, and possibly turbidites or shoreface sands within marine mudstones/siltstones in southern Quadrants 41-44 (likely tight gas unless early hydrocarbon charged) Widespread opportunities for structural (fault/fold/dip) traps utilising a Silverpit mudstone, or Zechstein evaporite seal as in the Breagh Field. Intraformational Carboniferous seals are documented widely in onshore Carboniferous fields and in some offshore fields and should be further investigated, particularly in mudstone/siltstone-dominated basinal successions with modelled Carboniferous and recent hydrocarbon generation, along with possibilities for stratigraphic traps. Basin modelling predicts oil and gas generation at a variety of times (Carboniferous, Mesozoic and Cenozoic dependent on the well) from lower-mid Carbonferous (Visean-Namurian) strata in Quadrants 41-44. In the Forth Approaches, Quadrant 29/North Dogger basins and on the poorly constrained Devonian-Carboniferous Mid North Sea High, oil window maturity levels are modelled at selected wells in a largely gas-prone sequence, though basinwards gas maturity may be achieved. It is recommended that the contribution and volumetrics of relatively thin oil-prone intervals within the Carboniferous succession be further investigated

The history of AIDS exceptionalism

In the history of public health, HIV/AIDS is unique; it has widespread and long-lasting demographic, social, economic and political impacts. The global response has been unprecedented. AIDS exceptionalism - the idea that the disease requires a response above and beyond "normal" health interventions - began as a Western response to the originally terrifying and lethal nature of the virus. More recently, AIDS exceptionalism came to refer to the disease-specific global response and the resources dedicated to addressing the epidemic. There has been a backlash against this exceptionalism, with critics claiming that HIV/AIDS receives a disproportionate amount of international aid and health funding