Geochronological constraints on Caledonian strike–slip displacement in Svalbard,with implications for the evolution of the Arctic

The timing of Svalbard's assembly in relation to the mid‐Paleozoic Caledonian collision between Baltica and Laurentia remains contentious. The Svalbard archipelago consists of three basement provinces bounded by N–S‐trending strike–slip faults whose displacement histories are poorly understood. Here, we report microstructural and mineral chemistry data integrated with ⁴⁰Ar/³⁹Ar muscovite geochronology from the sinistral Vimsodden‐Kosibapasset Shear Zone (VKSZ, southwest Svalbard) and explore its relationship to adjacent structures and regional deformation within the circum‐Arctic. Our results indicate that strike–slip displacement along the VKSZ occurred in late Silurian–Early Devonian and was contemporaneous with the beginning of the main phase of continental collision in Greenland and Scandinavia and the onset of syn‐orogenic sedimentation in Silurian–Devonian fault‐controlled basins in northern Svalbard. These new‐age constraints highlight possible links between escape tectonics in the Caledonian orogen and mid‐Paleozoic terrane transfer across the northern margin of Laurentia.     

Constraining the degree of the dominant mode in QQ Vir

We present early results of the application of a method which uses multicolor photometry and spectroscopy for ? discrimination. This method has been successfully applied to the pulsating hot subdwarf Balloon?090100001. Here we apply the method to QQ?Vir (PG1325+101). This star was observed spectroscopically and photometrically in 2008. Details on spectroscopy can be found in Telting et al. (Astrophys. Space Sci. 2010, this volume), while photometry and preliminary results on ? discrimination are provided here. The main aim of this work was to compare the value of the ? parameter derived for the main mode in QQ?Vir to previously published values derived by using different methods.     

An attempt to dendroclimatic reconstruction of winter temperature based on multispecies tree-ring widths and extreme years chronologies (example of Upper Silesia, Southern Poland)

This study aims at investigating pre-instrumental tree-ring based winter thermal conditions from Upper Silesia, southern Poland. The Scots pine, pedunculate oak and sessile oak ring widths and the extreme index were used to reconstruct winter mean temperature back to A.D. 1770. The climate response analysis showed that the pine is the most sensitive to February (0.36) and March (0.41) temperature, the oaks were found to be sensitive to the previous December (0.27) and January (0.23) temperature. It was found out that the combination of temperature sensitive species and an additional extreme index in regression can improve the reconstruction, with an emphasis on more reliable reconstruction of extreme values. The elimination of variance reduction and precise reconstruction of actual values of temperature is possible by scaling. The obtained calibration/verification results suggest that, through the application of the long-term composite chronologies a detailed study of the climate variability in Upper Silesia in past centuries can be provided.     

The performance of single- and multi-proxy transfer functions (testate amoebae,bryophytes, vascular plants) for reconstructing mire surface wetness and pH

Peatlands are widely exploited archives of paleoenvironmental change. We developed and compared multiple transfer functions to infer peatland depth to the water table (DWT) and pH based on testate amoeba (percentages, or presence/absence), bryophyte presence/absence, and vascular plant presence/absence data from sub-alpine peatlands in the SE Swiss Alps in order to 1) compare the performance of single-proxy vs. multi-proxy models and 2) assess the performance of presence/absence models. Bootstrapping cross-validation showing the best performing single-proxy transfer functions for both DWT and pH were those based on bryophytes. The best performing transfer functions overall for DWT were those based on combined testate amoebae percentages, bryophytes and vascular plants; and, for pH, those based on testate amoebae and bryophytes. The comparison of DWT and pH inferred from testate amoeba percentages and presence/absence data showed similar general patterns but differences in the magnitude and timing of some shifts. These results show new directions for paleoenvironmental research, 1) suggesting that it is possible to build good-performing transfer functions using presence/absence data, although with some loss of accuracy, and 2) supporting the idea that multi-proxy inference models may improve paleoecological reconstruction. The performance of multi-proxy and single-proxy transfer functions should be further compared in paleoecological data.     

Fusing remote sensing with sparse demographic data for synthetic population generation: an algorithm and application to rural Afghanistan

We develop a new algorithm for population synthesis that fuses remote-sensing data with partial and sparse demographic surveys. The algorithm addresses non-binding constraints and complex sampling designs by translating population synthesis into a computationally efficient procedure for constrained network growth. As a case, we synthesize the rural population of Afghanistan, validate the algorithm with in-sample and out-of-sample tests, examine the variability of algorithm outputs over k-nearest neighbor manifolds, and show the responsiveness of our algorithm to additional data as a constraint on marginal population counts.     

The role of precursor emissions on ground level ozone concentration during summer season in Poland

Three online coupled chemical transport model simulations were analyzed for three summer months of 2015 in Poland. One of them was run with default emission inventory, the other two with NO_x and VOC emissions reduced by 30%, respectively. Obtained ozone concentrations were evaluated with data from air quality measurement stations and ozone sensitivity to precursor emissions was estimated by ozone concentration differences between simulations and with the use of indicator ratios. They were calculated based on modeled mixing ratios of ozone, total reactive nitrogen and its components, nitric acid and hydrogen peroxide. The results show that the model overestimates ozone concentrations with the largest errors in the morning and evening, which is primarily related to the way vertical mixing is resolved by the model. Better model performance for ozone is achieved in rural than urban environment, as PBL and mixing mechanisms play more significant role in urban areas. Modeled ozone shows mixed sensitivity to precursor concentrations, similarly to other European regions, but indicator ratios have different values than are found in literature, particularly H₂O₂/HNO₃ is larger than in southern Europe. However, indicator ratios often differ between locations and transition values need to be established individually for a given region.     

Deep Electrical Resistivity Structure of the European Lithosphere in Poland Derived from 3-D Inversion of Magnetotelluric Data

Surveys in Geophysics - This paper presents a three-dimensional (3-D) model of the resistivity distribution in the European lithosphere at the junction between the East European Craton, the...     

Application of Multichannel Analysis of Surface Waves to S-Phase Wave Anisotropy Estimation

The Multichannel Analysis of Surface Waves (MASW) is an increasingly used technique for recognition of a shallow geological structure and estimation of geotechnical parameters, e.g., S-wave velocity, layer density, layer thickness, shear modulus, estimated P-wave velocity, and estimated Poisson ratio. MASW surveys were carried out in two limestone quarries in the southern part of Poland. The experimental areas are characterised by a simple geological structure: consolidated Triassic limestone. Measurement profiles were arranged as a shapely six-pointed star. For each survey line, 12 geophones with 2-meter (Deposit 1) and 3-meter (Deposit 2) spacing were applied. The research allowed to compare P- and S-wave velocity changes with the main crack systems in the studied rock masses.