Chemistry and genesis of garnets in metamorphic rocks

250 analyses of garnets in metamorphic pelitic, arkosic, and pyroclastic rocks from the Stavanger area have been made by means of a microprobe (ARL-EMX). The relations between chemistry and metamorphic grade are discussed. The dependence of the Mn content upon temperature, pressure, chemistry of the parent rocks and oxygen fugacity is a very sophisticated one.It is shown that the Mn content of the garnets depends on the oxygen fugacity of the system and that the oxygen fugacity is strongly linked to the behaviour of graphite during increasing metamorphism.Examples described by Miyashiro (1953) and Engel and Engel (1960) are in agreement with the model presented here.Some observations show an influence of primary sedimentary enrichments of manganese upon the first occurrence of garnets in the course of metamorphism.     

Modelling Fluxes and Concentrations of CO 2 , H 2 O and Sensible Heat Within and Above a Mountain Meadow Canopy: A Comparison of Three Lagrangian Models and Three Parameterisation Options for the Lagrangian Time Scale

Two simple analytical Lagrangian and a Lagrangian random walk model,together with three options for the parameterisation of the Lagrangian timescale, are compared in their ability to predict fluxes and scalar concentrationsof CO₂, H₂O and sensible heat within and above a mountain meadowin the eastern Alps. Results indicate that both scalar concentrations and ecosystemfluxes exhibit little sensitivity to the differences between the investigated modelsand may be predicted satisfactorily by one of the simpler models so long as thesource/sink strength is parameterised correctly. Model results also show littlesensitivity to the parameterisation of the vertical variation of the Lagrangiantime scale, yet the increase of the Lagrangian time scale towards the groundpredicted by one of the three investigated parameterisation options resulted inless agreement with measurements as compared to the other two, which assumedthe Lagrangian time scale to be either constant with height or to decay towardszero at the ground surface. Correspondence between simulated and measuredfluxes and scalar concentrations of CO₂, H₂O and sensible heat weregenerally satisfactory, except for shortly after the meadow was cut, when thesignificant increase of respiratory carbon losses could not be captured by themodel.     

An integrated approach for assessing the relative significance of human pressures and environmental forcing on the status of Large Marine Ecosystems

An ecosystem approach to the management of the marine environment has received considerable attention over recent years. However, there are few examples which demonstrate its practical implementation. Much of this relates to the history of existing marine monitoring and assessment programmes which (for many countries) are sectoral, making it difficult to integrate monitoring data and knowledge across programmes at the operational level.To address this, a scientific expert group, under the auspices of the International Council for the Exploration of the Sea (ICES), prepared a plan for how ICES could contribute to the development of an Integrated Ecosystem Assessment (IEA) for the North Sea by undertaking a pilot study utilising marine monitoring data. This paper presents the main findings arising from the expert group and in particular it sets out one possible integrated approach for assessing the relative significance of environmental forcing and fishing pressure on the ecological status of the North Sea, it then compares the findings with assessments made of other Large Marine Ecosystems (LMEs).We define the North Sea ecosystem on the basis of 114 state and pressure variables resolved as annual averages between 1983 and 2003 and at the spatial scale of ICES rectangles. The paper presents results of integrated time-series and spatial analysis which identifies and explains significant spatial and temporal gradients in the data. For example, a significant shift in the status of the North Sea ecosystem (based upon 114 state-pressure variables) is identified to have occurred around 1993. This corresponds to previously documented shifts in the environmental conditions (particularly sea surface temperature) and changes in the distribution of key species of plankton (Calanus sp.), both reported to have occurred in 1989. The difference in specific timing between reported regime shifts for the North Sea may be explained, in part, by time-lag dependencies in the trophic structure of the ecosystem with shifts in higher trophic levels occurring later than 1989.By examining the connection (or relatedness) between ecosystem components (e.g. environment, plankton, fish, fishery and seabirds) for the identified regime states (1983–1993; 1993–2003) we conclude that both the North Sea pelagic and benthic parts of the ecosystem were predominantly top-down (fishery) controlled between 1983 and 1993, whereas between 1993 and 2003 the pelagic stocks shifted to a state responding mainly to bottom-up (environment) influences. However, for the demersal fish stocks between 1993 and 2003 top-down (fishery) pressure dominated even though over this period significant reductions in fishing pressure occurred. The present analysis, therefore, provides further evidence in support of the need for precautionary management measures taken in relation to setting fishery quotas.     

Manganminerale vom Mooserboden bei Kaprun

Ohne ZusammenfassungMit 11 Textabbildungen.     

AffectRoute – considering people’s affective responses to environments for enhancing route-planning services

Humans perceive and evaluate environments affectively. Some places are experienced as unsafe, while some others as attractive and interesting. These affective responses to environments influence people’s daily behavior and decision-making in space, e.g., choosing which route to take, or which place to visit. In this article, we report on a methodology of using people’s affective responses to environments for enhancing computer-based route planning. More specifically, we explore a crowdsourcing approach to model and collect people’s affective responses to environments; an Affect-Space-Model and a mobile application are developed to facilitate this crowdsourcing approach; a routing algorithm (named AffectRoute) is then proposed to aggregate and integrate the collected data for automatic route planning. Evaluation with human participants shows that the routes generated by considering people’s affective responses to environments are significantly preferred over the conventional shortest ones, which are employed in car navigation systems and many online route planners. In conclusion, considering people’s affective responses to environments contributes to the improvement of automatic route planning. The proposed method can be integrated into existing route-planning services (e.g., location-based services) to provide users with more satisfying routing results.     

Deglacial land emergence and lateral upper-mantle heterogeneity in the Svalbard Archipelago—II. Extended results for high-resolution load models

In Paper I (Breuer & Wolf 1995), a preliminary interpretation of the postglacial land emergence observed at a restricted set of six locations in the Svalbard Archipelago was given. The study was based on a simple model of the Barents Sea ice sheet and suggested increases in lithosphere thickness and asthenosphere viscosity with increasing distance from the continental margin.
In the present paper, the newly developed high-resolution load model. BARENTS-2, and land-uplift observations from an extended set of 25 locations are used to study further the possibility of resolving lateral heterogeneity in the upper mantle below the northern Barents Sea. A comparison of the calculated and observed uplift values shows that the lithosphere thickness is not well resolved by the observations, although values above 110 km are most common for this parameter. In contrast to this, there are indications of a lateral variation of asthenosphere viscosity. Whereas values in the range 10¹⁸-10²⁰Pas are inferred for locations close to the continental margin, 10²⁰-10²¹ Pa s are suggested further away from the margin.
A study of the sensitivity of the values found for lithosphere thickness and asthenosphere viscosity to modifications of load model BARENTS-2 shows that such modifications can be largely accommodated by appropriate changes in lithosphere thickness, whereas the suggested lateral variation of asthenosphere viscosity is essentially unaffected. An estimate of the influence of the Fennoscandian. ice sheet leads to the conclusion that its neglect results in an underestimation of the thickness of the Barents Sea ice sheet by about 10 per cent.