Setting the Holocene clock using varved lake sediments in Sweden

The aim of this thesis was to study annually laminated (varved) Holocene lake sediment in Sweden, their formation and their potential as chronological and palaeoecological archives. Five lakes with continuous Holocene varved lake sediment sequences in northern (Västerbotten) and west central Sweden (Värmland) were investigated. Three of these sequences were discovered during this study, which identified the climatic and environmental prerequisites for the formation of varves and, therefore, provides a tool for finding annually laminated sediments in the Swedish boreal environment. Varve chronologies, supported by other independent dating methods, i.e. radiocarbon dating, tephra isochrones and paleomagnetic secular variations were established for two sediment sequences in Värmland. These are the longest geological records with an annual resolution known to exist in Sweden. Three mid-Holocene Icelandic tephra horizons were identified within 1-cm horizons, corresponding to c. 20 years of sediment accumulation and the varve chronologies were used to assign calendar years ages to the tephra isochrones with a precision better than ± 110 varve years. Paleomagnetic secular variation curves (both directions and intensity) presented in this thesis can be used to correlate and relatively date Holocene sedimentary sequences in Northwest and Central Europe. The accuracy and precision of the method is determined by errors associated with the varve chronologies (i.e. c. 1-2%), sampling resolution (c. 50-100 years), definition uncertainties and possible remanence lock-in effects. Comparison between the paleomagnetic secular variation curves in this study and previous obtained records from Northwest Europe suggests that no significant westwards drift of the non-dipole field has occurred in this region during the majority of the Holocene. Reconstructed virtual geomagnetic pole positions for the last c. 9000 show that the Magnetic North Pole has changed its position significantly during the Holocene. Relative palaeointensities imply that sub-millennial-scale variations in the strength of the geomagnetic dipole have taken place during the Holocene. These changes would have modulated the production of cosmogenic nuclides in combination with solar variability. The “8.2 ka cold event” was recorded as a c. 300-year long period of distinctly colder climate conditions centred at c. 7800 cal. BP in the two varved lake sediment sequences in N Sweden. Pollen influx rates indicate that the regional vegetation in this area responded rapidly (within 75 years) to the onset and end of this 300-year long cold climate anomaly and that the forest ecosystem was severely stressed

Den obarocka fabeln – eller den barocka? : Några turer kring en genre och ett litteraturhistoriskt begrepp

As a contribution to the discussion on the relevance of the baroque concept in Swedish literary history, the article conducts a case study by testing the concept on the history of a specific genre: the Aesopic fable. The argument takes its starting point in the analysis of German fable history by the pioneering baroque scholar Wolfgang Kayser who asserted a lack of German fable writing during the baroque era of the seventeenth century. Applying Kayser’s rather narrow criteria of fable writing and the baroque to Swedish conditions, and, subsequently, altering some of them, the article reaches three conclusions: firstly, fable writing was absent also during the baroque epoch in Sweden; secondly, a baroque period in Swedish fable history could be uncovered, somewhat questionably, during the late eighteenth century; and, thirdly, an extensive, pragmatically aiming fable literature was, in fact, in circulation in seventeenth-century Sweden, though it is doubtful whether it should be termed ‘baroque’. In a second move, the case study tries out three more recent definitions of the baroque. Apparent correspondences are shown between on the one hand fable literature of the Swedish seventeenth century, and on the other hand, José Antonio Maravall’s view of the baroque as a conservative culture, Thomas Althaus’s conception of epigrammatic thought during the baroque, and John D. Lyons’s idea of a baroque anthropology of duplicity. However, the article concludes, none of these correspondences—all of which indicate a high functionality of the fable in a seventeenth century context—have to be explained with reference to the concept of the baroque

Er polvendingen nær? - sandsynligheden palæomagnetisk set

Jordens magnetfelt er aftaget 10 procent over de sidste 170 år. Nye målinger fra blandt andet den danske Ørsted-satellit viser, at de magnetiske poler nu flytter sig ca. 50 km om året. Men er det usædvanligt hurtigt? Nogle forskere mener ja. De tolker ændringerne som tegn på, at Jordens magnetfelt er på vej mod en polvending (se Peter Staunings artikel i GeologiskNyt nr. 5, 2004)

International Children’s Rights: Reflections on a Complex, Dynamic, and Relatively Young Area of Law

This chapter reflects on the aim of the International Children’s Rights volume to provide those wishing to study, research, and practice international children’s rights law with a contemporary and comprehensive legal text. It recaps on the themes that emerged from the process of commissioning and editing the various contributions from some of the world’s leading and emerging legal scholars in the area of children’s rights. It marks the progress that has been made in the implementation of children’s rights law and the many challenges that still exist in the implementation of the CRC and associated international instruments. It notes that legal scholarship in the field of children’s rights is still developing and that, although multidisciplinary research and analysis is valuable, it is important to reaffirm children’s rights as a field of law and legal practice. International children’s rights is a complex, dynamic, and relatively young area of law. As the contributions to the collection show, it is diverse and evolving, with many new aspects and issues worthy of analysis and scrutiny. This chapter encapsulates the aspiration of the volume editors that the book contribute to the scrutiny of the legal implications of the CRC, recognizing the unique features of international children’s rights law, adding to the ongoing development of this important area of law.Effective Protection of Fundamental Rights in a pluralist worl

Volcanic impacts on the Holocene vegetation history of Britain and Ireland? A review and meta-analysis of the pollen evidence

Volcanic ash layers show that the products of Icelandic volcanism reached Britain and Ireland many times during the Holocene. Historical records suggest that at least one eruption, that of Laki in a.d. 1783, was associated with impacts on vegetation. These results raise the question: did Icelandic volcanism affect the Holocene vegetation history of Britain and Ireland? Several studies have used pollen data to address this issue but no clear consensus has been reached. We re-analyse the palynological data using constrained ordination with various representations of potential volcanic impacts. We find that the palynological evidence for volcanic impacts on vegetation is weak but suggest that this is a case of absence of evidence and is not necessarily evidence of absence of impact. To increase the chances of identifying volcanic impacts, future studies need to maximise temporal resolution, replicate results, and investigate a greater number of tephras in a broader range of locations, including more studies from lake sediments

Tephrochronology and its application: A review

Tephrochronology (from tephra, Gk ‘ashes’) is a unique stratigraphic method for linking, dating, and synchronizing geological, palaeoenvironmental, or archaeological sequences or events. As well as utilising the Law of Superposition, tephrochronology in practise requires tephra deposits to be characterized (or ‘fingerprinted’) using physical properties evident in the field together with those obtained from laboratory analyses. Such analyses include mineralogical examination (petrography) or geochemical analysis of glass shards or crystals using an electron microprobe or other analytical tools including laser-ablation-based mass spectrometry or the ion microprobe. The palaeoenvironmental or archaeological context in which a tephra occurs may also be useful for correlational purposes. Tephrochronology provides greatest utility when a numerical age obtained for a tephra or cryptotephra is transferrable from one site to another using stratigraphy and by comparing and matching inherent compositional features of the deposits with a high degree of likelihood. Used this way, tephrochronology is an age-equivalent dating method that provides an exceptionally precise volcanic-event stratigraphy. Such age transfers are valid because the primary tephra deposits from an eruption essentially have the same short-lived age everywhere they occur, forming isochrons very soon after the eruption (normally within a year). As well as providing isochrons for palaeoenvironmental and archaeological reconstructions, tephras through their geochemical analysis allow insight into volcanic and magmatic processes, and provide a comprehensive record of explosive volcanism and recurrence rates in the Quaternary (or earlier) that can be used to establish time-space relationships of relevance to volcanic hazard analysis. The basis and application of tephrochronology as a central stratigraphic and geochronological tool for Quaternary studies are presented and discussed in this review. Topics covered include principles of tephrochronology, defining isochrons, tephra nomenclature, mapping and correlating tephras from proximal to distal locations at metre- through to sub-millimetre-scale, cryptotephras, mineralogical and geochemical fingerprinting methods, numerical and statistical correlation techniques, and developments and applications in dating including the use of flexible depositional age-modelling techniques based on Bayesian statistics. Along with reference to wide-ranging examples and the identification of important recent advances in tephrochronology, such as the development of new geoanalytical approaches that enable individual small glass shards to be analysed near-routinely for major, trace, and rare-earth elements, potential problems such as miscorrelation, erroneous-age transfer, and tephra reworking and taphonomy (especially relating to cryptotephras) are also examined. Some of the challenges for future tephrochronological studies include refining geochemical analytical methods further, improving understanding of cryptotephra distribution and preservation patterns, improving age modelling including via new or enhanced radiometric or incremental techniques and Bayesian-derived models, evaluating and quantifying uncertainty in tephrochronology to a greater degree than at present, constructing comprehensive regional databases, and integrating tephrochronology with spatially referenced environmental and archaeometric data into 3-D reconstructions using GIS and geostatistics