Investigating the last deglaciation of the Scandinavian Ice Sheet in southwest Sweden with 10Be exposure dating

In this study we have obtained 17 cosmogenic exposure ages from three well‐developed moraine systems – Halland Coastal Moraines (HCM), Göteborg Moraine (GM) and Levene Moraine (LM) – which were formed during the last deglaciation in southwest Sweden by the Scandinavian Ice Sheet (SIS). The inferred ages of the inner HCM, GM and LM are 16.7 ± 1.6, 16.1 ± 1.4 and 13.6 ± 1.4 ka, respectively, which is slightly older than previous estimates of the deglaciation based on the minimum limiting radiocarbon ages and pollen stratigraphy. During this short interval from 16.7 ± 1.6 to 13.6 ± 1.4 ka a large part (100–125 km) of the marine‐based sector of the SIS in southwest Sweden was deglaciated, giving an average ice margin retreat between 20 to 50 m a^?1. The inception of the deglaciation pre‐dated the Bølling/Allerød warming, the rapid sea level rise at 14.6 cal. ka BP and the first inflow of warm Atlantic waters into Skagerrak. We suggest that ice retreat in southwest Sweden is mainly a dynamical response governed by the disintegration of the Norwegian Channel Ice Stream and not primarily driven by climatic changes. Copyright © 2011 John Wiley & Sons, Ltd.     

The role of permeability evolution in fault zones on the structural and hydro-mechanical characteristics of shortening basins

We examine the role of basin-shortening on the development of structural compartments in passive margin basins. A coupled flow-deformation model is used to follow the evolution of an idealized prismatic basin during lateral shortening. This includes the deformation-induced generation (lateral compaction) and dissipation (hydraulic fracturing) of pore fluid pressures and the resulting natural evolution of an underlying décollement and subsidiary fault structures. This model is used to examine the influence of strata stiffnesses, strain softening, permeability-strain dependence, permeability contrast between layers, and deformation rate on the resulting basin structure and to infer fluid charge within these structures. For a geometry with a permeability contrast at the base of the basin a basal décollement forms as the basin initially shortens, excess pore pressures build from the impeded drainage and hydrofracturing releases fluid mass and resets effective stresses. As shortening continues, thrust faults form, nucleating at the décollement. Elevated pore pressures approaching the lithostat are localized at the hanging wall boundary of the faults. Faults extend to bound blocks that are vertically offset to yield graben-like structural highs and lows and evolve with distinctive surface topography and separate pore pressure signatures. Up-thrust blocks have elevated fluid pressures and reduced effective stresses at their core, and down-thrust blocks the converse. The development of increased permeability on localized fault structures is a necessary condition to yield this up-thrust and down-thrust geometry. In the anti-physical case where evolution of permeability with shear strain is artificially suppressed, pervasive shear develops throughout the basin depth as fluid pressures are stabilized everywhere to the lithostat. Correspondingly, permeability evolution with shear is an important, likely crucial, feedback in promoting localization.     

Adolf Seilacher's fossil record

Adolf (Dolf) Seilacher, who died earlier this year at the age of 89, was a major figure in palaeontology on both sides of the Atlantic. His interests were diverse, including trace fossils, the processes involved in exceptional preservation, and the evolution of invertebrate morphology. But it is for his views on the nature of the extraordinary fossils of the Ediacaran that he is perhaps best known. His ideas—compelling and provocative—will continue to stimulate research for years to come, not least through the wide use of his terminology (e.g. Lagerstätten, morphodynamics, constructional morphology, vendobiont).     

Poverty, sustainability and human wellbeing: A social wellbeing approach to the global fisheries crisis

The purpose of this paper is to explore the extent to which a social wellbeing approach can offer a useful way of addressing the policy challenge of reconciling poverty and environmental objectives for development policy makers. In order to provide detail from engagement with a specific policy challenge it takes as its illustrative example the global fisheries crisis. This crisis portends not only an environmental disaster but also a catastrophe for human development and for the millions of people directly dependent upon fish resources for their livelihoods and food security. The paper presents the argument for framing the policy problem using a social conception of human wellbeing, suggesting that this approach provides insights which have the potential to improve fisheries policy and governance. By broadening the scope of analysis to consider values, aspirations and motivations and by focusing on the wide range of social relationships that are integral to people achieving their wellbeing, it provides a basis for better understanding the competing interests in fisheries which generate conflict and which often undermine existing policy regimes.     

Marine mammal co-management in Canada’s Arctic: Knowledge co-production for learning and adaptive capacity

This paper examines the challenge of knowledge co-production and the implications for learning and adapting in the context of a narwhal co-management in Nunavut, Canada. Knowledge co-production is the collaborative process of bringing a plurality of knowledge sources and types together to address a defined problem and build an integrated or systems-oriented understanding of that problem. The paper considers knowledge co-production by examining five interrelated dimensions: knowledge gathering, sharing, integration, interpretation, and application. Voices of hunters, community representatives, and managers engaged in co-management are highlighted to identify primary challenges and opportunities. The analysis reveals how compartmentalized views of knowledge continue to constrain adaptive and collaborative management. An understanding of knowledge co-production processes, however, may help to overcome the resilience of top-down management approaches.     

On-Orbit Degradation of Solar Instruments

We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing space missions.     

Mineralogy,petrology, and shock history of lunar meteorite Sayh al Uhaymir 300: A crystalline impact‐melt breccia

Abstract— Sayh al Uhaymir (SaU) 300 comprises a microcrystalline igneous matrix (grain size <10 μm), dominated by plagioclase, pyroxene, and olivine. Pyroxene geothermometry indicates that the matrix crystallized at ?1100 °C. The matrix encloses mineral and lithic clasts that record the effects of variable levels of shock. Mineral clasts include plagioclase, low‐ and high‐Ca pyroxene, pigeonite, and olivine. Minor amounts of ilmenite, FeNi metal, chromite, and a silica phase are also present. A variety of lithic clast types are observed, including glassy impact melts, impact‐melt breccias, and metamorphosed impact melts. One clast of granulitic breccia was also noted. A lunar origin for SaU 300 is supported by the composition of the plagioclase (average An₉₅), the high Cr content in olivine, the lack of hydrous phases, and the Fe/Mn ratio of mafic minerals. Both matrix and clasts have been locally overprinted by shock veins and melt pockets. SaU 300 has previously been described as an anorthositic regolith breccia with basaltic components and a granulitic matrix, but we here interpret it to be a polymict crystalline impact‐melt breccia with an olivine‐rich anorthositic norite bulk composition. The varying shock states of the mineral and lithic clasts suggest that they were shocked to between 5–28 GPa (shock stages S1–S2) by impact events in target rocks prior to their inclusion in the matrix. Formation of the igneous matrix requires a minimum shock pressure of 60 GPa (shock stage >S4). The association of maskelynite with melt pockets and shock veins indicates a subsequent, local 28–45 GPa (shock stage S2–S3) excursion, which was probably responsible for lofting the sample from the lunar surface. Subsequent fracturing is attributed to atmospheric entry and probable breakup of the parent meteor.