A note on the computation of Meissl’s smoothing coefficients βℓ

This note gives a new, short and non-recursive formula for Meissl’s smoothing coefficients β_?.     

Trace metal occurrence in a mineralised and a non-mineralised spodosol in northern Sweden

In order to determine the metal-bearing phases with special emphasis on Cu, a sequential extraction has been carried out on seven soil samples from a sulphide-bearing spodosol profile in Liikavaara Östra, close to the Aitik Copper Mine in northern Sweden. A reference spodosol profile with very low abundances of sulphides located far from anthropogenic emissions was also studied. Five fractions were selected for the extraction: (I) CH₃COONa-extractable (exchangeable/adsorbed/carbonate); (II) Na₄P₂O₇-extractable (labile organics); (III) 0.25 M NH₂OH·HCl-extractable (amorphous Fe oxyhydroxides/Mn oxides); (IV) 1 M NH₂OH·HCl-extractable (crystalline Fe oxides); and (V) KClO₃/HCl-extractable (organics and sulphides). The distribution of trace elements (Co, Cr, Cu, Ni, Pb and Zn) in the profile in Liikavaara Östra is different from that in the reference profile. Possible explanations for these differences are (i) the presence of sulphides in the soil, (ii) atmospheric deposition of dust derived from mining activities at the Aitik Copper Mine, and (iii) mineralogical heterogeneities inherited from the deposition of the till. There is no straightforward correlation between the amount of the extracted phases and the metal extractability in the soils. This fact indicates that other factors are important for the retention of trace metals as well. The data presented in this study suggest that Co, Cr and Ni, to a fairly large extent, are associated with the organic matter in the B-horizon in both profiles, while in the C-horizon in Liikavaara Östra, sulphides are probably the more important carriers of these elements. For Co and Ni, Fe oxyhydroxides seem to be important. Most of the Cr occurred in the residual remaining after the leaching procedure. Copper and Zn seem to be associated with the organic matter to some extent in the B-horizon. The concentration of Cu in the C-horizon in Liikavaara Östra is high (2310 ppm), but only a very small fraction is likely to be hosted by sulphides. It is concluded that the major part of Cu in the C-horizon and a prominent fraction in the B-horizon in Liikavaara Östra are associated with some secondary phase that is extractable during extractions III and IV. Possible candidates for this phase are goethite and inclusions of native Cu in weathered biotite.     

Seed-like hydroptilid larval cases (Insecta: Trichoptera) from Holocene freshwater deposits

The seed-like larval cases of hydroptilid caddis flies may be mistaken for plant remains in subfossil studies. However, being correctly identified, they may be important for the interpretation of former freshwater environments. Two such subfossil caddis fly remains from Holocene lake sediments and river deposits are described morphologically and their palaeoecological significance interpreted.     

Spatial patterns of frequent floods in Switzerland

This study investigates the spatial dependence of high and extreme streamflows in Switzerland across different scales. First, using 56 runoff time series from Swiss rivers, we determined the average length of high-streamflow events for different levels of extremeness. Second, a dependence measure that expressed the probability that streamflow peaks would meet or exceed streamflow peaks at a conditioning site was used to describe and map the spatial extent of joint streamflow-peak occurrences across Switzerland. Third, we analysed the spatial patterns of jointly occurring high streamflows using cluster analysis to identify groups that react similarly in terms of flood frequency at different sites. The results indicate that, on a coarse scale, high and extreme streamflows are asymptotically independent in the main Swiss basins. Additionally, mesoscale tributaries in the main basins show distinct flood regions across river systems.     

Holocene sedimentary and environmental development of Aarhus Bay,Denmark – a multi-proxy study

Holocene sedimentation patterns and environmental development in Aarhus Bay, Denmark, were reconstructed based on proxy analyses of two sediment cores (M1 and M5). Together, the two cores offer an opportunity to examine the history of the area during the past c. 10 000 years. The investigation consisted of acoustic mapping and multi-proxy analyses of the sediment cores including macrofossils, sediment physical properties, sediment accumulation rates, grain size, and X-ray fluorescence elemental counts. Radiocarbon dating of the two sediment successions revealed that they cover the periods c. 10 000–3700 cal. a BP (M1) and c. 4400 cal. a BP to the present (M5). The data from the M1 site indicate the presence of a near-shore lake environment between c. 10 000 and 9000 cal. a BP. The first intrusion of marine water into the area is dated to c. 9000 cal. a BP. In the following c. 1300 years, brackish-water conditions prevailed in the area characterized by a mixture of taxa from marine, limnic and terrestrial habitats, reflecting a shallow estuarine environment. Around 7700 cal. a BP full marine conditions were established, accompanied by a marked increase in sedimentation rates. The changes to full marine conditions and higher sedimentation rates are probably due to a significant sea-level rise leading to flooding of former land areas and intensified erosion. A subsequent distinct decrease in sedimentation rates around 6350 cal. a BP is presumably linked to a previously documented sea-level drop about this time. Continuous sedimentation ceased around 3700 cal. a BP in the central part of the bay, most probably due to a major sea-level lowering involving widespread erosion. In the eastern and deeper part of the bay, sedimentation continued until today. Fully marine conditions prevailed there for at least the last 4400 years.     

An empirical model for predicting flakiness in cone crushing

A fundamental understanding of the factors influencing particle shape is of central importance for optimisation of the output quality from crushing plants for aggregate production. The literature reports that the wear on and setting of a cone crusher influence particle shape, The fact that wear on and the setting of a cone crusher influence particle shape is considered common knowledge and is also reported in the literature. To date, no mathematical model for predicting particle shape has been presented.     

Modelling heat and fluid flow in sedimentary basins by the finite element method

In this article we solve the equations for a 2D model of compaction of sedimentary basins saturated with water by the finite-element method. This compaction model considers the rock described by the porosity as a function of effective stress, and both the anisotropic permeability and the anisotropic heat conductivity as functions of porosity. The water density is approximated linearly in the water pressure and temperature, and the water viscosity is a function of temperature. The main variables in the model are the water excess pressure and the temperature, and we account for an implicit solution scheme where we solve for both main variables simultaneously. The non-linearities in the model are either dealt with by the Newton method or by fixed-point iterations. We compare the coupled solution of temperature and pressure with the same decoupled equations. Then we study the contribution to the temperature by convection, the effect of the non-constant water density, and some anisotropic case examples.     

Fluorine in Twenty-Two International Reference Rock Samples and a Compilation of Fluorine Values for the USGS Reference Samples

Fluorine in 22 international reference samples has been determined with an ion selective electrode following fusion with a Na₂bCO₃-ZnO mixture. To eliminate the effect of fluorine complexes in the solutions, the results presented are means of fluoride determinations from a standard calibration curve and from the method of standard addition. Together with these new determinations an updated compilation of USGS-I reference samples is presented.