A 36 kilometer long high resolution 2D seismic reflection profile was acquired in the summer of 2010 to be used in the planning of the COSC (Collisional Orogeny in the Scandinavian Caledonides) Deep ...Drilling Project. Two fully cored boreholes, each to c. 2.5km depth, are planned for the Åre-Mörsil area of west-central Sweden in order to increase our understanding of orogenic processes and, in particular, the tectonic evolution of the Scandinavian Caledonides.
Besides providing important sub-surface structural information in the vicinity of the potential drill sites, the seismic profile also provides detailed, high resolution images previously not available for the uppermost few kilometers in the region. The subsurface is highly reflective and very complex down to at least 9km depth (the limit of decoded data) with clear reflections spanning the entire length of the profile.
Correlation with previous regional reflection seismic and magnetotelluric surveys has been achieved by acquisition of a short (7km) connecting profile. A clearly defined reflection, present in the new profile at depths between c. 2.5km in the east and c. 4.5km in the west and with an average westwards dip of c. 3.5°, apparently defines the base of the Lower Allochthon. Closer to the Caledonian front, this sole thrust overlies the Cambrian alum shale formation, which rests unconformably on the autochthonous Precambrian crystalline basement. The latter is remarkable for its deep internal reflectivity which is probably related to mafic intrusions in a dominantly granitic host-rock; their deformation may be of both Caledonian and older (e.g. Sveconorwegian) age.
The new high resolution seismic data provide the basis for locating the first borehole in the Seve Nappe Complex. They also demonstrate that the second hole, designed to penetrate the Caledonian basement, will have to be located further east than was originally planned.
► COSC aims to further our understanding of the Caledonides and collisional orogens. ► A reflection seismic site survey reveals a highly reflective subsurface. ► The Seve nappe is easily distinguishable, correlating well with surface geology. ► The basal décollement is found at 1.5km in the east and at 4.5km in the west. ► On the basis of the new data, two locations are proposed for the two core-holes.
The connectivity of macropore networks is thought to exert an important control on preferential flow in soil, although little progress has been made towards incorporating an understanding of these ...effects into management-oriented flow and transport models. In principle, concepts from percolation theory should be well suited to quantify the connectivity of preferred flow pathways, but so far its relevance for natural soils in the field has not been tested. To investigate this question, X-ray tomography was used to measure soil pore space architecture at an image resolution of 65μm for 64 samples taken in two consecutive years in the harrowed and ploughed layers of a silt loam soil a few weeks after spring cultivation. The results showed that the pore networks displayed key features predicted by classical percolation theory: a strong relationship was found between the percolating fraction and the imaged porosity, with a percolation threshold of ca. 0.04 to 0.06m3m−3 in the harrowed layer. A percolation threshold was less clearly identifiable in topsoil that had not been recently tilled, although this may probably be attributed to finite size sampling effects in this layer, which showed a more heterogeneous and structured distribution of the pore space. Although further work on more strongly structured soil horizons, especially subsoils, would be desirable, it is tentatively suggested that percolation concepts could prove useful to estimate the conducting macroporosity in management models of preferential flow and transport.
•Percolation concepts describe the connectivity of X-ray imaged macropore networks.•A percolation threshold of 4-6% was found for imaged porosity in harrowed soil.•The homogenizing effect of harrowing on the structural pore space was quantified.•Effects of the finite sample size were noted in the more structured ploughed layer.
Microorganisms produce and consume methane in terrestrial surface environments, sea sediments and, as indicated by recent discoveries, in fractured crystalline bedrock. These processes in the ...crystalline bedrock remain, however, unexplored both in terms of mechanisms and spatiotemporal distribution. Here we have studied these processes via a multi-method approach including microscale analysis of the stable isotope compositions of calcite and pyrite precipitated in bedrock fractures in the upper crust (down to 1.7 km) at three sites on the Baltic Shield. Microbial processes have caused an intriguing variability of the carbon isotopes in the calcites at all sites, with δ13C spanning as much as −93.1‰ (related to anaerobic oxidation of methane) to +36.5‰ (related to methanogenesis). Spatiotemporal coupling between the stable isotope measurements and radiometric age determinations (micro-scale dating using new high-spatial methods: LA-ICP-MS U–Pb for calcite and Rb–Sr for calcite and co-genetic adularia) enabled unprecedented direct timing constraints of the microbial processes to several periods throughout the Phanerozoic eon, dating back to Devonian times. These events have featured variable fluid salinities and temperatures as shown by fluid inclusions in the calcite; dominantly 70–85 °C brines in the Paleozoic and lower temperatures (<50–62 °C) and salinities in the Mesozoic. Preserved organic compounds, including plant signatures, within the calcite crystals mark the influence of organic matter in descending surficial fluids on the microbial processes in the fracture system, thus linking processes in the deep and surficial biosphere. These findings substantially extend the recognized temporal and spatial range for production and consumption of methane within the upper continental crust.
•Widespread signs of ancient anaerobic oxidation of methane in the crystalline crust.•Microbial oxidation of biogenic methane evidenced by 13C-depleted calcite (−93.1‰).•First direct timing of methane oxidation in the crystalline crust, as old as Devonian.•Methanogenesis evidenced by extremely 13C-rich carbonates (up to +36.5‰).•Methane cycling restricted to the upper 800 m of fractured granitic basement.
Permafrost peatlands are found in high-latitude regions and store globally-important amounts of soil organic carbon. These regions are warming at over twice the global average rate, causing ...permafrost thaw, and exposing previously inert carbon to decomposition and emission to the atmosphere as greenhouse gases. However, it is unclear how peatland hydrological behaviour, vegetation structure and carbon balance, and the linkages between them, will respond to permafrost thaw in a warming climate. Here we show that permafrost peatlands follow divergent ecohydrological trajectories in response to recent climate change within the same rapidly warming region (northern Sweden). Whether a site becomes wetter or drier depends on local factors and the autogenic response of individual peatlands. We find that bryophyte-dominated vegetation demonstrates resistance, and in some cases resilience, to climatic and hydrological shifts. Drying at four sites is clearly associated with reduced carbon sequestration, while no clear relationship at wetting sites is observed. We highlight the complex dynamics of permafrost peatlands and warn against an overly-simple approach when considering their ecohydrological trajectories and role as C sinks under a warming climate.
This third edition of Historical Dictionary of Sweden contains a chronology, an introduction, appendixes, an extensive bibliography, and a dictionary section with more than 300 cross-referenced ...entries on important personalities, politics, economy, foreign relations, religion, and culture. This book is an excellent access point for students, researchers, and anyone wanting to know more about Sweden. --Publisher
Analysing parliamentary references to the people, this book provides a more nuanced interpretation of eighteenth-century re-evaluations of democracy. It shows how interaction between parliamentarians ...and the public sphere in different political cultures produced more modern conceptions of the legitimacy of political power.
Centered on the trajectory of the emancipation of Roma people in Scandinavia, Romani Liberation is a powerful challenge to the stereotype describing Romani as passive and incapable of responsibility ...and agency. The author also criticizes benevolent but paternalistic attitudes that center on Romani victimhood. The first part of the book offers a comprehensive overview of the chronological phases of Romani emancipation in Sweden and other countries. Underscoring the significance of Roma activism in this process, Jan Selling profiles sixty Romani activists and protagonists, including numerous original photos. The narrative is followed by an analysis of the concepts of historical justice and of the process of decolonizing Romani Studies. Selling highlights the impact of the historical contexts that have enabled or impeded the success of the struggles against discrimination and for equal rights, emphasizing Romani activism as a precondition for liberation. The particular Swedish framework is accentuated by a stimulating preface by the international activist Nicoleta Bitu, and afterwords by two prominent Romani advocates, the politician Soraya Post and the singer, author, and elder Hans Caldaras.
The Lanna area in the province of Närke, south-central Sweden, hosts a succession of cool-water carbonate strata that are largely devoid of tectonic and diagenetic alteration, and span the Floian ...through lower Darriwilian Global stages (Ottenbyan–Kundan Regional stages). In this study we assess the integrated biostratigraphic and chemostratigraphic framework for the Ordovician sequence at Lanna, utilizing trilobites and conodonts coupled with bulk-rock carbon and oxygen isotopes (δ13Ccarb and δ18Ocarb). The local succession is thin but relatively complete; biostratigraphic details are similar to coeval successions in Baltoscandia. The new high-resolution δ13C and δ18O data are broadly consistent with other chemostratigraphic records at the regional scale, but notable differences in δ13C are obvious compared to global records. δ13C trends diverge markedly in the Dapingian and intra- and inter-regional differences become increasingly pronounced through younger strata. This may largely be explained by an overall low eustatic sea level, which led to more widespread oceanic restriction of epeiric seas. As a result, δ13C records became more influenced by local variables, muddling the global δ13C signal. This, in turn, suggests that sea level played a larger role than long-term changes within the global carbon cycle for regulating local–regional δ13C gradients in the Middle Ordovician. Regardless of the underlying cause(s), the documented variability poses significant challenges for using δ13C as a tool for detailed stratigraphic correlations. The limited expression of many named ‘carbon isotope excursions’ (CIEs) in the studied interval indicate that they are artefacts of local overprinting rather than reflective of changes to the global carbon cycle. Thus, these CIEs are of questionable correlative importance and validity. Although the scatter in numeric values is relatively large, long-term δ18O trends are overall consistent at the global scale, tentatively supporting the notion that climate cooled during the studied time interval.
•High-resolution integrated biostratigraphy and chemostratigraphy.•δ13Ccarb and δ18Ocarb show limited variations through the Floian–lower Darriwilian.•Significant regional–global variability complicates δ13Ccarb-based correlations.•Global δ13Ccarb signal commonly severely overprinted by local–regional influences.•δ18Ocarb trends indicate cooling climate and latitudinal gradients.
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