Michael Heim

The thermal springs of Bockfjord, Svalbard : Occurrence and major ion hydrochemistry

The Troll and Jotun thermal springs of northern Svalbard, with temperatures of up to 25.6°C, are derived from a major fault forming the junction between Devonian sandstones and Proterozoic marbles, mica schists and gneisses. The Troll waters are dominated by Na–HCO3 compositions and the Jotun waters by Na–Cl compositions. The pristine thermal water source has a sub-neutral pH and is highly reducing. Taken at face value, common geothermometers suggest temperatures at depth of 130–180°C for the Troll springs (corresponding to a depth of 1.6–2.3 km), with 10–30% thermal water diluted by 70–90% cold water. Such geothermometers may, however, be inappropriate to the cool, high CO2 waters of Bockfjord, and real temperatures at depth and dilution factors are probably considerably lower. The salinity of the thermal water appears to be only partially derived from water–rock interaction; BrCl ratios suggest that seawater or possibly evaporites may be a source of chloride salinity.

The thermal springs of Bockfjorden, Svalbard: II: selected aspects of trace element hydrochemistry

Waters from the Trollkjeldene (Troll springs) and Jotunkjeldene (Jotun springs) thermal springs on northern Svalbard have been analysed by ICP-AES, ICP-MS and IC techniques for a wide range of major and trace elements. Although it is plausible that the thermal waters originate from a deep reservoir in siliceous rocks, it appears that a significant component of their hydrochemical signature is derived from dissolution of higher-level Hecla Hoek marbles. Rare earth elements (REEs) show some degree of enrichment of heavy REEs in the water phase, relative to the marbles and to the travertines that precipitate from the waters. A strong positive Eu anomaly is also observed in the waters, suggesting preferential mobilisation of Eu under reducing conditions. The ratio Nb/Ta is rather well-preserved between the marbles, the waters and the travertines.

The water balance of an arctic lake and its dependence on climate change: Tvillingvatnet in Ny-Ålesund, Svalbard

Lake Tvillingvatnet is the water supply to the arctic research settlement Ny-Ålesund in Svalbard. In the period 1920-1930 it was observed that the lake received groundwater from a sandstone-aquifer underlying the lake. Recent water balance studies indicate that there is no longer any groundwater flow of that type into the lake. This change can be explained by a warmer climate resulting in a fast retreat of the glaciers after the Little Ice Age. Large amounts of melt water combined with a steep hydraulic gradient may have caused partial melting of permafrost along the front of the Brøggerbreen Glacier, which was situated c . 0.5 km west of Lake Tvillingvatnet at that time. Today, the glacier front is more than a kilometre SW of the lake. The formation of new permafrost has resulted in freezing of the previously active groundwater outflow channels. The present flow of water into Tvillingvatnet during the autumn is probably due to shallow groundwater in the active layer along the talus of the Zeppelinfjellet Mountain.

Apatite–Biotite–Carbonatite (Stjernøy, N-Norway): Potential and Obstacles Regarding a Multinutrient Rock-Fertilizer

Apatite–biotite–carbonatite (ABC) from the Lillebukt alkaline complex (N-Norway) contains 42 wt% calcite, 30% biotite, and 7.5% apatite. Agrochemically, it is lime with a K, P, and Mg nutrient potential. Previous K-fertilizing trials with ABC rock-powder have provided good results, and renewed experiments have started to examine the overall effect of ABC rock-powder on soil and plants.The underlying problems with ABC rock-fertilizer are (i) Potential ecotoxicity of high barium and strontium of up to 15 g/kg, substituting K in biotite and Ca in calcite, respectively. An in situ soil and vegetation study on Stjernoy has shown that Ba-content in plants is related to plant species and Ca in plant. Highest Ba-concentration showed the nitrogen-fixing legume Vicia cracca L., lowest grasses. Strontium follows mainly Ca-content in plants. (ii) Low plant availability of P from magmatic apatite at high pH, when applying whole-rock powder. (iii) To find adequate dry mineral separation methods, in particular, to separate calcite and apatite, with the aim to increase nutrient concentration in possible fertilizer products. Vegetation study, plant and soil experiments, and mineral separation tests will hopefully give a decision base for application of ABC as rock-fertilizer.

Release of Copper, Zinc, and Manganese from Rock Powder with Organic Materials Applied to Soils

An incubation experiment was conducted using a sandy (Fluvic Cambisol) and a silty (Endostagnic Cambisol) soil to determine the release of copper (Cu), zinc (Zn), and manganese (Mn) from a sulfide-rich rock powder (grain size <0.5 mm), applied either alone or mixed with organic materials. Finely ground legume straw, wheat straw, and cow dung from an organic farm were used as organic materials. Rock powder and organic materials were mixed thoroughly with soils, moistened to field capacity, and incubated for 42 days. Soil samples were collected at weekly intervals for analysis. The solubility of Cu in soils increased over time with the addition of rock powder but decreased significantly if soils were mixed with organic materials. Treatments with organic materials alone show a lower release than the combination treatments with rock powder. These trends were similar for both soils. Although the solubility of Mn was very high in the sandy soil, it was not significantly affected either by the time of incubation or by the treatments applied. Zinc solubility was greater in organic material treatments than in the combined treatments in either soil. There were significant changes in pH with time as pH decreased in rock powder treatments. This study shows that the rock powder used here could be a potential source of soluble Cu, when used in combination with organic manure, though for Zn and Mn results are not conclusive.