Extensive methane-derived authigenic carbonates in the Irish Sea

Extensive areas of methane-derived authigenic carbonate (MDAC) have been mapped in the Irish Sea. In the Irish Sector, 23 seabed mounds associated with the Codling Fault Zone were identified by multi-beam echo sounder mapping. Inspection by ROV-mounted video showed that these mounds are rocky features rising 5–10 m above the normal seabed; sampling showed that they are comprised of quartz grains bound together by carbonate cement, probably MDAC. Two separate locations have been mapped in the UK Sector. At Texel 11, seabed mounds and a 6–8 m high cliff were mapped geophysically (MBES, SSS and seismic profiler surveys). Video surveys showed that both the mounds and the cliff are rocky reefs colonised by a prolific fauna. Samples proved to be carbonate-cemented sediments, and carbon isotope analysis (δ¹³C −41 to −46% PDB) showed that the cement was MDAC. Similar surveys of the Holden’s Reefs area proved the presence of similar rocky reefs which are also cemented by MDAC. The total area covered by these two MDAC occurrences is estimated to be >500,000 m². These MDAC occurrences are comparable in nature and formation to the ‘bubbling reefs’ of the Kattegat. As the bubbling reefs are “seabed features formed by leaking gas”, one of the marine habitats identified by the European Commission’s Habitats Directive as being sensitive and worthy of protection, it is suggested that the Irish Sea carbonate reefs should also be considered as special habitats.     

Line profiles in symbiotic stars

High resolution profiles of permitted and forbidden lines in symbiotic stars are described, with particular reference to the broad wings. An interpretation of the data in terms of an optically thin accretion disc around a hot subdwarf is presented.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Interdisciplinary research: framing and reframing

Framing encompasses the processes of identifying and bounding the area of research and based on our own experiences as academics we have found significant differences in the ways that researchers establish and frame a disciplinary, compared to an interdisciplinary, research project. In this paper we have attempted to contribute to the development of the conceptual framework underpinning interdisciplinary research through analysis of interviews with a number of academics already working in an interdisciplinary manner. Successful projects are able to identify and support the processes that allow the communication and negotiation that is necessary, not just for the initial framing of a research funding proposal but to be able to maintain negotiation. Self awareness and continual reflexivity and a willingness to be questioned by others are essential to this process.     

The role of innovation in advancing understanding of hydrological processes

Innovation and understanding hydrological processes are intimately linked. Existing research has demonstrated the role of technological, societal, and political drivers in shaping and delivering new understandings in hydrological processes. In this paper we pose three research questions to explore how innovation can further our understanding of hydrological processes, if working towards the sustainable development goals (SDGs) provides a helpful focus, and whether specific mechanisms can be used to facilitate innovation and research into hydrological processes. First, we examine key aspects of innovation and explore innovation in the context of water security. We then present a series of innovation projects to determine their effectiveness in delivering innovation in managing hydrological processes, but also their contribution to scientific understanding. Our research suggests that product and process innovation were more closely related to increasing scientific understanding of hydrological processes than other forms of innovation. The NE Water Hub demonstrated that the design of the innovation ecosystem was crucial to its success and provides a model to integrate innovation and research more widely to further scientific understanding and deliver behaviour change to address the SDGs.     

An integrated model of clastic injectites and basin floor lobe complexes: implications for stratigraphic trap plays

Injectites sourced from base‐of‐slope and basin‐floor parent sandbodies are rarely reported in comparison to submarine slope channel systems. This study utilizes the well‐constrained palaeogeographic and stratigraphic context of three outcrop examples exposed in the Karoo Basin, South Africa, to examine the relationship between abrupt stratigraphic pinchouts in basin‐floor lobe complexes, and the presence, controls, and character of injectite architecture. Injectites in this palaeogeographic setting occur where there is: (i) sealing mudstone both above and below the parent sand to create initial overpressure; (ii) an abrupt pinchout of a basin‐floor lobe complex through steep confinement to promote compaction drive; (iii) clean, proximal sand beds aiding fluidization; and (iv) a sharp contact between parent sand and host lithology generating a source point for hydraulic fracture and resultant injection of sand. In all outcrop cases, dykes are orientated perpendicular to palaeoslope, and the injected sand propagated laterally beneath the parent sand, paralleling the base to extend beyond its pinchout. Understanding the mechanisms that determine and drive injection is important in improving the prediction of the location and character of clastic injectites in the subsurface. Here, we highlight the close association of basin‐floor stratigraphic traps and sub‐seismic clastic injectites, and present a model to explain the presence and morphology of injectites in these locations.     

Timing and thermochemical constraints on multi-element mineralisation at the Nori/RA Cu–Mo–U prospect, Great Bear magmatic zone, Northwest Territories, Canada

The timing of Cu–Mo–U mineralisation at the Nori/RA prospect in the Paleoproterozoic Great Bear magmatic zone has been investigated using Re–Os molybdenite and ⁴⁰Ar–³⁹Ar biotite geochronology. The Re–Os molybdenite ages presented are the first robust sulphide mineralisation ages derived from the Great Bear magmatic zone. Cu–Mo–U mineralisation is hosted in early to syn-deformational hydrothermal veins consisting of quartz and K-feldspar or more commonly tourmaline-biotite-quartz-K-feldspar, with associated wall-rock alteration assemblages being predominantly biotite. Sulphide and oxide minerals consist of chalcopyrite, molybdenite and uraninite with lesser pyrite and magnetite. Elevated light rare earth elements and tungsten concentrations associated with the Cu–Mo–U mineralisation have also been reported at the prospect by previous workers. Molybdenite and uraninite occur intimately in dravitic tourmaline growth zones and at grain margins, attesting to their syngenetic nature (with respect to hydrothermal veining). Two molybdenite separates yield Re–Os model ages of 1,874.4 ± 8.7 (2σ) and 1,872.4 ± 8.8 Ma (2σ) with a weighted average model age of 1,873.4 ± 6.1 Ma (2σ). Laser step heating of biotite from the marginal alteration of the wall-rock adjacent to the veins yields a ⁴⁰Ar–³⁹Ar maximum cooling age of 1,875 ± 8 Ma (MSWD = 3.8; 2σ), indistinguishable from the Re–Os molybdenite model age and a previously dated ‘syn-tectonic’ aplitic dyke in the region. Dravitic tourmaline hosts abundant primary liquid–vapour–solid-bearing fluid inclusions. Analytical results indicate liquid–vapour homogenisation at >260°C constraining the minimum temperature of mineralisation. The solids, which are possibly trapped, did not homogenise with the liquid–vapour by 400°C. Salinities in the inclusions are variable. Raman spectra identify that at least some of the solids are calcite and anhydrite. Raman spectra also confirm the vapour phases contain some CO₂; whereas clathrates or CH₄ was not observed or detected. Quartz grains only host secondary fluid inclusions, which fluoresce under ultraviolet light, indicating trapped hydrocarbons. We speculate that these resulted from Phanerozoic fluid circulation through the Proterozoic basement. The collective interpretation of the age, hydrothermal character and associated metals, high temperature and variable salinity suggests that the Nori/RA Cu–Mo–U mineralisation can be linked with the earliest stages of plutonism in the Great Bear magmatic zone. From a regional perspective, the mineralisation may pre-date the extensive multi-element mineralisation now recognised as part of the iron oxide copper–gold (IOCG) spectrum of deposits. As IOCG provinces generally contain a variety of mineralisation styles, we interpret this as the earliest phase of the extensive mineralising system.     

Fossil oribatid mites (Acari, Oribatida) from the Florisbad Quaternary deposits, South Africa

In a pioneer application of acarology to Quaternary fossil-bearing sediments in southern Africa, the oribatid composition in the Florisbad Quaternary sediments was determined and compared to the currently known distribution of those species. Nine species of oribatid mites were recorded in the Holocene aeolian deposits of the third test pit, three species from the Middle Stone Age (MSA) horizon sediments of the third test pit, and thirteen species from the Holocene spring sediments. The Florisbad results indicate a better agreement between the oribatid fauna of the last interglacial MSA horizon of the third test pit and the organic-rich mid-Holocene deposits near the spring than between either of these and early- and late-Holocene aeolian sediments of the third test pit, suggesting some similarity in microsedimentary environments. The majority of the species recorded in the sediments are parthenogenetic and can be regarded as pioneer species.     

Attribution of precipitation changes on ground–air temperature offset: Granger causality analysis

International Journal of Earth Sciences - This work examines the causal relationship between the value of the ground–air temperature offset and the precipitation changes for monitored 5-min...