Multi-wavelength observations of the 2014 June 11 M3.9 flare: temporal and spatial characteristics

We present multi-wavelength observations of an M-class flare(M3.9) that occurred on 2014 June 11. Our observations were conducted with the Dunn Solar Telescope(DST), employing adaptive optics, the multi-camera system Rapid Oscillations in Solar Atmosphere(ROSA), the new Hydrogen-Alpha Rapid Dynamics camera(HARDcam) in various wavelengths, such as Ca II K, Mg I b_2(at 5172.7 ?A), and Hα narrow band and G-band continuum filters. Images were re-constructed using the Kiepenheuer-Institut Speckle Interferometry Package(KISIP) code, to improve our image resolution. We observed intensity increases of ≈120%–150% in the Mg, Ca K and Hα narrow band filters during the flare. Intensity increases for the flare observed in the SDO EUV channels were several times larger, and the X-rays, as recorded by GOES, increased over a factor of 30 for the harder band. Only a modest delay was found between the onset of flare ribbons of a nearby sympathetic flare and the main flare ribbons observed in these narrow band filters. The peak flare emission occurred within a few seconds for the Ca K, Mg and Hα bands. Timedistance techniques indicate propagation velocities of ≈60 km s~(-1) for the main flare ribbon and as high as300 km s~(-1) for smaller regions, which we attribute to filament eruptions. This result and delays and velocities observed with SDO(≈100 km s~(-1)) for different coronal heights agree well with the simple model of energy propagation versus height, although a more detailed model for the flaring solar atmosphere is needed. Finally, we detected marginal quasi-periodic pulsations(QPPs) in the 40–60 s range for the Ca K,Mg and Hα bands, and such measurements are important for disentangling the detailed flare-physics.     

Co-management of sea turtle fisheries: Biogeography versus geopolitics

Co-management between local communities and government agencies is promoted as a strategy to improve fisheries management. This paper considers the potential for co-management of sea turtle fisheries within four UK Overseas Territories (OTs) in the Caribbean, and for co-ordinated management among those territories. We focus on fisher incentives for engaging in co-management and on the potential to scale up co-management to a regional level. This paper presents data from Anguilla, British Virgin Islands, Montserrat, and Turks and Caicos Islands, where 110 turtle fishers participated in a socio-economic survey undertaken as part of the ‘Turtles in the UK Overseas Territories in the Caribbean’ project. Based on three established criteria for co-management (perceived crisis in stock, willingness to participate and community cohesion), results suggest that fisher support for co-management exists within each OT, but the extent of support for and views of specific management interventions varies among OTs. The implications of results for co-management in each territory, and for establishing co-ordinated management regimes in the region, are discussed in the context of current debates about the nature of resources and scalar (mis)matches between resource and management regimes.     

Critical metals in the critical zone: controls,resources and future prospectivity of regolith-hosted rare earth elements

The rare earth elements (REE) are a group of 17 metals that include the lanthanides, Sc and Y, which are critical for many modern technologies including consumer electronics, medicine and communication. One of the major controls on the concentrations of the REE in regolith material (including soils) is the abundance of these elements in the parent material. It is known that REE concentrations are largely inherited from the protolith rather than acquired during pedogenic processes but our understanding of how pedogenesis affects fractionation and accumulation of REE to produce potentially economic deposits of these critical metals is limited. This study provides a review of (1) the biogeochemical controls on REE distribution and mobility during pedogenesis and (2) the potential for REE extraction from regolith material. Factors that control mobilisation of REE during weathering include (1) the initial distribution of the REE in protolith minerals and the resistivity of these phases to weathering, (2) adsorption and absorption of REE to Fe- and Mn oxides, clay minerals and organic matter and (3) variations in pH and Eh conditions. We also discuss the relative importance of biogeochemical controls on REE mobility in soils in southern Australia, where REE concentrations are demonstrated to be largely a function of weathering of REE-enriched protoliths, the sorption of REE to weathering products and the accumulation of resistant minerals in soils.     

The walking school bus: extending children's geographies?

In many Western cities, the journey between home and school has become problematic, due to intensifying traffic and growing fears for children's safety. Accordingly, many parents now chauffeur their children to and from school. This situation has compounded congestion, prompting efforts to identify safe alternatives. One recent innovation is the walking school bus (WSB). In this paper we report on the development of this initiative, and its adoption at a primary school in Auckland, New Zealand. We conclude that although WSBs extend children's geographies they are, at best, an ambivalent response to the hegemony of motorized transport.     

Nick Rast and the recognition of the Avalonian Arc

Recognition of the eastern (Avalonian) margin of the northern Appalachian orogen as a Late Precambrian microcontinental arc terrane, rather than the opposing passive margin of the Proto-Atlantic (Iapetus) Ocean to that of eastern Laurentia, constituted a fundamental advance in Appalachian geology that profoundly influenced subsequent models for the orogen's plate tectonic evolution. This advance was first clearly articulated by Nick Rast and his students in 1976, who, by correlating rocks of the Avalon Platform with those of the British Midlands, established the Avalonian volcanic belt as a Japan-like microcontinent. Contrary to contemporary views of the Avalon Platform, which favored an extensional, Basin and Range-like setting for its volcanism, Rast argued on the basis of this correlation that the association of Avalonian volcanism with compressional orogeny, widespread calc-alkaline plutonism and, in Angelsey, with blueschists and ophiolitic rocks, indicated a convergent plate margin setting. Rast further proposed that the Avalonian volcanic belt was ensialic, and was bordered to the northwest and southeast by Precambrian oceanic domains. Contemporary reconstructions of the Avalonian and Cadomian belts as fragments of a Cordilleran-like accretionary orogen that developed along an active margin of Neoproterozoic Gondwana owe their origin to these early ideas and, while far removed from the tectonic model that Rast envisaged, are a direct heritage of his recognition of the Avalonian volcanic belt as a microcontinental arc terrane.     

Contrasting modes of supercontinent formation and the conundrum of Pangea

Repeated cycles of supercontinent amalgamation and dispersal have occurred since the Late Archean and have had a profound influence on the evolution of the Earth's crust, atmosphere, hydrosphere, and life. When a supercontinent breaks up, two geodynamically distinct tracts of oceanic lithosphere exist: relatively young interior ocean floor that develops between the dispersing continents, and relatively old exterior ocean floor, which surrounded the supercontinent before breakup. The geologic and Sm/Nd isotopic record suggests that supercontinents may form by two end-member mechanisms: introversion (e.g. Pangea), in which interior ocean floor is preferentially subducted, and extroversion (e.g. Pannotia), in which exterior ocean floor is preferentially subducted.The mechanisms responsible remain elusive. Top–down geodynamic models predict that supercontinents form by extroversion, explaining the formation of Pannotia in the latest Neoproterozoic, but not the formation of Pangea. Preliminary analysis indicates that the onset of subduction in the interior (Rheic) ocean in the early Paleozoic, which culminated in the amalgamation of Pangea, was coeval with a major change in the tectonic regime in the exterior (paleo-Pacific) ocean, suggesting a geodynamic linkage between these events. Sea level fall from the Late Ordovician to the Carboniferous suggests that the average elevation of the oceanic crust decreased in this time interval, implying that the average age of the oceanic lithosphere increased as the Rheic Ocean was contracting, and that subduction of relatively new Rheic Ocean lithosphere was favoured over the subduction of relatively old, paleo-Pacific lithosphere. A coeval increase in the rate of sea floor spreading is suggested by the relatively low initial ⁸⁷Sr/⁸⁶Sr in late Paleozoic ocean waters. We speculate that superplumes, perhaps driven by slab avalanche events, can occasionally overwhelm top–down geodynamics, imposing a geoid high over a pre-existing geoid low and causing the dispersing continents to reverse their directions to produce an introverted supercontinent.     

http://www.sciencedirect.com/science/article/pii/S1674987111001113

The Rheic Ocean was one of the most important oceans of the Paleozoic Era.It lay between Laurentia and Gondwana from the Early Ordovician and closed to produce the vast Ouachita-Alleghanian -Variscan orogen during the assembly of Pangea.Rifting began in the Cambrian as a continuation of Neoproterozoic orogenic activity and the ocean opened in the Early Ordovician with the separation of several Neoproterozoic arc terranes from the continental margin of northern Gondwana along the line of a former suture.The rapid rate of ocean opening suggests it was driven by slab pull in the outboard lapetus Ocean.The ocean reached its greatest width with the closure of lapetus and the accretion of the periGondwanan arc terranes to Laurentia in the Silurian.Ocean closure began in the Devonian and continued through the Mississippian as Gondwana sutured to Laurussia to form Pangea.The ocean consequently plays a dominant role in the Appalachian-Ouachita orogeny of North America,in the basement geology of southern Europe,and in the Paleozoic sedimentary,structural and tectonothermal record from Middle America to the Middle East.Its closure brought the Paleozoic Era to an end.     

Changes in water quality and runoff in the Upper Oder River Basin

The aim of the study is the analysis of runoff and water quality changes in the Upper Oder River Basin above the Krapkowice gauging station (catchment area A = 10 720.6  km²).The issue of water quality is of particular importance to Poland, which has comparatively poor water resources compared with many countries of the European Union (EU). What is more, large pollutant loads in the upper course of the Oder pose huge problems for water consumers and users in its middle and lower course (including Germany) and pollute the Baltic Sea.Changes in 7 indices of water pollution, including BOD₅ and COD (synthetic indices), sulphates, chlorides and suspended matter (mineral substances) and nitrates and phosphates (biogenic substances), were investigated for 8 monitoring sites. The study spans the period before and after political transformation in Poland and the Czech Republic, which significantly altered the economies of these countries. In addition, the patterns of runoff changes were analysed at 3 gauging stations: Chałupki, Krzyżanowice and Miedonia, which were also water quality monitoring points. The analysis encompassed 2 periods: 1970–2000 and 1991–2000.The results demonstrated that poor water quality in the Oder improved significantly during the 1990s, as the result of closure of many industries and plants, improvement of sewage treatment and noticeable increases in runoff causing greater dilution of pollutants.As the EU Water Framework Directive is implemented, better water and sewage management can be expected that will contribute to further improvement of water quality in the Oder. However, problems that remain to be solved are the issues of saline mine waters and surface washings and the long-term accumulation of many hazardous substances in bottom sediments in rivers and reservoirs.     

Non‐Destructive or Noninvasive? The Potential Effect of X‐Ray Fluorescence Spectrometers on Luminescence Age Estimates of Archaeological Samples

The non‐destructive nature of X‐ray fluorescence (XRF) spectrometers is a principal reason for an increase in their use in archaeological science over the last 15 years, especially for analyzing museum‐curated artifacts and in situ site fabrics. Here, we show that low‐power XRF spectrometry can be detrimental for luminescence dating (surface applications such as mud‐wasp nest dating in particular). We investigated the effects of irradiation by X‐rays emitted from handheld and benchtop spectrometers on optically stimulated luminescence (OSL) signals. Measurements were taken using a portable OSL (pOSL) unit on the following unprepared archaeological materials: sedimentary quartz grains, pottery, a mud‐wasp nest, stone tools, and a rock flake with anthropogenically applied pigment and natural pigmentation (iron oxides). We observed an increase in luminescence compared to initial background counts for all materials tested, which could lead to overestimation of age determinations in some situations. Our experiment provides a reminder of the potential effects of X‐ray radiation, and the need for thorough documentation of all recording and analytical techniques applied to archaeological materials.     

A simple and inexpensive turbidity meter for the estimation of suspended sediment concentrations

The relatively high cost of commercially available turbidity meters has inhibited detailed and intensive research on spatiotemporal patterns of suspended sediment transport. We describe here the electronic and physical design of an inexpensive turbidity sensor which is easy to construct, simple to interface with portable millivolt meters, dataloggers, computers, or chart recorders, consumes exceptionally small currents, and is robust and reliable. the very low individual cost allows a large number of sensors to be distributed throughout the water body of interest to facilitate turbidity mapping. Turbidity profilers to detect vertical or lateral turbidity changes in rivers, lakes, estuaries, or near-shore zones are also shown to be feasible. Test data are presented from a highly turbid glacial river in southern Iceland.