Soil information system as part of a municipal environmental information system

 The objectives of the interdisciplinary pilot project "Development of a municipal environmental information system" in Hannover encompassed the development, modification and improvement of data acquisition methods and methods for describing the environment on the basis of this data, as well as methods for evaluating the data as a basis for measures affecting the environment taken by the community. The subproject "Urban Soils" had the following two main objectives: (i) development of a data acquisition method for soils in municipal areas and a method for evaluating this data, and (ii) development of methods for making this information available to local government in the form of a "soil information system" for urban areas. To achieve these objectives, the following work was carried out: (1) a factor analysis to determine which factors affect the soil in an urban area; (2) study of methods for mapping soils in cities; (3) development of a concept for a soil information system; and (4) evaluation of environmental problems of the municipality using the soil information system. Data acquisition was done in two steps: First, soil-relevant data was selected, standardized, digitized and stored in an alphanumeric and a graphic database for a factor analysis. By intersection of the eight information levels, the factors affecting the soil were determined for the city of Hannover (200 km²). To test the hypothesis that the results for one site can be transferred to another site with the same combination of factors, 43 test sites typical of urban land use were selected. These test sites were mapped in a way to fulfill geostatistical requirements; physical and chemical analyses of the soils were made. A prognosis of soil distribution and properties was made on the basis of the factor analysis. and compared with the actual conditions. Concurrent with the pedological research, a prototype soil information system was developed. The system consists of databases, a methodbase, a geometrical tool, and a control system. Alphanumeric data is stored in a relational database, the geometric data in ISAM files. Methods for determining soil parameter values were selected and tested for their applicability. Using the pedological data and the soil information system, information can be obtained about soil conditions in Hannover as well as about soil processes (e.g. infiltration rates) and interaction with the atmosphere, hydrosphere, etc. This information can be obtained in the form of thematic maps and statistical representations, which can be used by decision-makers at the municipal level. Received: 3 September 1994 · Accepted: 19 December 1995     

Analysis of the water column oxic/anoxic interface in the Black and Baltic seas with a numerical model

A 1D hydrophysical-biogeochemical model was developed to study the cycling of the main elements in the pelagic redox layer in seas with anoxic conditions. The formation and decay of organic matter; the reduction and oxidation of nitrogen, sulfur, manganese, and iron species; and the transformation of phosphorus species were parameterized. Temporal and spatial developments of the model's variables were described by a system of horizontally integrated vertical diffusion equations for non-conservative substances. The calculated spatial and temporal distributions of the above-mentioned parameters were in good agreement with observed vertical distribution patterns of these processes.     

Contrasting sedimentary processes along a convergent margin: the Lesser Antilles arc system

Sedimentation processes occurring in an active convergent setting are well illustrated in the Lesser Antilles island arc. The margin is related to westward subduction of the North and/or the South America plates beneath the Caribbean plate. From east to west, the arc can be subdivided into several tectono-sedimentary depositional domains: the accretionary prism, the fore-arc basin, the arc platform and inter-arc basin, and the Grenada back-arc basin. The Grenada back-arc basin, the fore-arc basin (Tobago Trough) and the accretionary prism on the east side of the volcanic arc constitute traps for particles derived from the arc platform and the South American continent. The arc is volcanically active, and provides large volumes of volcaniclastic sediments which accumulate mainly in the Grenada basin by volcaniclastic gravity flows (volcanic debris avalanches, debris flows, turbiditic flows) and minor amounts by fallout. By contrast, the eastern side of the margin is fed by ash fallout and minor volcaniclastic turbidites. In this area, the dominant component of the sediments is pelagic in origin, or derived from South America (siliciclastic turbidites). Insular shelves are the locations of carbonate sedimentation, such as large platforms which develop in the Limestone Caribbees in the northern part of the margin. Reworking of carbonate material by turbidity currents also delivers lesser amounts to eastern basins of the margin. This contrasting sedimentation on both sides of the arc platform along the margin is controlled by several interacting factors including basin morphology, volcanic productivity, wind and deep-sea current patterns, and sea-level changes. Basin morphology appears to be the most dominant factor. The western slopes of the arc platform are steeper than the eastern ones, thus favouring gravity flow processes.     

Ein Vertikal-Einstab-Pendel zur Messung der Erdgezeitenbedingten Lotschwankungen

Резюме Возможно наблюдать приливнЫе изменения положения стержня с карданной подвеской с помощью соответственно направленнЫх измерительнЫх датчиков. По этому принципу временные изменения направления отвеса измерялисЯ в шахте в г. Фрейберг. Сообщаются и обсуждаются результаты этих исследований.

---

---

Anschrift: Gustav-Zeuner-Strasse, Freiberg/Sa, DDR.     

Modeling the built environment for local to global earthquake risk assessment

Carbonation-induced corrosion of the steel reinforcement is the major deterioration factor of the RC infrastructures in urban areas. Carbonation progress in concrete is influenced by the exposure and environmental conditions prevailing at each area. Therefore, the rate of deterioration due to carbonation varies at different areas. Field measurements can quantify this carbonation progress for specific structures and areas. However, the scattered nature of individual field data offers little information to be considered for the assessment of existing structures or the design of new structures. This study aims to bridge this gap and shows that individual field data can be combined to characterise an area using GIS mapping tools. A generated map can depict the variability of carbonation progress with the geographical location. Measurements of the carbonation depth of several buildings at different locations in the Limassol district have been provided by a construction laboratory. Such information can be used to depict the carbonation progress on each structure through the calculation of the carbonation factor and then portray its value using mapping techniques. The result is a corrosion risk map of the Limassol district depicting the variability of carbonation progress with geographical locations. This can be used by engineers and managing authorities as a prediction tool for the initiation of carbonation-induced corrosion in existing structures and also at design stage to set the durability requirements of the concrete cover depth.     

Lithostratigraphy and U-Pb zircon dating in the overturned limb of the Siviez-Mischabel nappe: a new key for Middle Penninic nappe geometry.

Detailed field work and zircon analysis have improved the knowledge of the lithostratigraphy at the base of the Siviez-Mischabel nappe in the Mattertal (St-Niklaus-Törbel area). They confirm the existence of an overturned limb and clarify the structure of the St-Niklaus syncline. The following formations can be observed:

• Polymetamorphic gneisses; composed of paragneisses, amphibolites and micaschists (Bielen Unit, pre-Ordovician).
• Fine-grained, greyish quartzite and graywacke with kerogen-rich horizons (Törbel Formation, presumed Carboniferous).
• Green or white micaschists characterized by brown carbonate spots associated with white conglomeratic quartzites (Moosalp Formation, Early Permian).
• Massive, green or white, fine grained, microconglomeratic or conglomeratic quartzites with characteristic pink quartz pebbles (Bruneggjoch Formation, Late Permian-Early Triassic).

This coherent overturned sequence can be observed from the St-Niklaus area to the Moosalp pass to the north. Detailed mapping revealed that the St-Niklaus syncline is symmetrical and connects the overturned limb of the Siviez-Mischabel nappe to the normal series of the Upper Stalden zone. U-Pb zircon geochronology on magmatic and detrital zircons allowed constraining ages of these formations. Detrital zircons display ages ranging from 2900 ± 50 to 520 ± 4 Ma in the Törbel Formation, and from 514 ± 6 to 292 ± 9 Ma in the Moosalp Formation. In addition, the Permian Randa orthogneiss is intrusive into the polymetamorphic gneisses and into the Permo-Carboniferous metasediments of the overturned limb of the Siviez-Mischabel nappe. This revision clarified also the lithostratigraphy of the nearby and subjacent Lower Stalden zone composed of an overturned limb with Permo-Carboniferous formations. This has critical implications for the tectonic setting of the nappes in the region, speaking for few recumbent folds with well preserved normal and overturned limbs instead of a succession of imbricate thrust sheets in a normal stratigraphic position.     

Plumbotectonic aspects of polymetallic vein mineralization in Paleozoic sediments and Proterozoic basement of Moravia (Czech Republic)

A regional isotopic study of Pb and S in hydrothermal galenas and U–Pb and S in potential source rocks was carried out for part of Moravia, Czech Republic. Two major generations of veins, (syn-) Variscan and post-Variscan, are defined based on the Pb-isotope system together with structural constraints (local structures and regional trends). The Pb-isotopic compositions of galena plot in two distinct populations with outliers in ²⁰⁶Pb/²⁰⁴Pb–²⁰⁷Pb/²⁰⁴Pb space. Galena from veins hosted in greywackes provides a cluster with the lowest Pb–Pb ratios: ²⁰⁶Pb/²⁰⁴Pb = 18.15–18.27, ²⁰⁷Pb/²⁰⁴Pb = 15.59–15.61, ²⁰⁸Pb/²⁰⁴Pb = 38.11–38.23. Those hosted in both limestones and greywackes provide the second cluster: ²⁰⁶Pb/²⁰⁴Pb = 18.37–18.44, ²⁰⁷Pb/²⁰⁴Pb = 15.60–15.63, ²⁰⁸Pb/²⁰⁴Pb = 38.14–38.32. These clusters suggest model Pb ages as Early Carboniferous and Triassic–Jurassic, the latter associated with MVT-like deposits. Two samples from veins hosted in Proterozoic rocks lie outside the two clusters: in metagranitoid (²⁰⁶Pb/²⁰⁴Pb = 18.55, ²⁰⁷Pb/²⁰⁴Pb = 15.64, ²⁰⁸Pb/²⁰⁴Pb = 38.29) and in orthogneiss (²⁰⁶Pb/²⁰⁴Pb = 18.79, ²⁰⁷Pb/²⁰⁴Pb = 15.73, ²⁰⁸Pb/²⁰⁴Pb = 38.54). The results from these two samples suggest an interaction of mineralizing fluids with the radiogenic Pb-rich source (basement?). The values of δ³⁴S suggest the Paleozoic host rocks (mostly ?6.7 to +5.2‰ CDT) as the source of S for hydrothermal sulfides (mostly ?4.8 to +2.5‰ CDT). U–Pb data and Pb isotope evolutionary curves indicate that Late Devonian and Early Carboniferous sediments, especially siliciclastics, are the general dominant contributor of Pb for galena mineralization developed in sedimentary rocks. Plumbotectonic mixing occurred, it is deduced, only between the lower and the upper crust (the latter involving Proterozoic basement containing heterogeneous radiogenic Pb), without any significant input from the mantle. It is concluded that in the Moravo–Silesian and Rhenohercynian zones (including proximal districts in Poland) lead and sulfur have been mobilized from the adjacent rocks during multiple hydrothermal events in processes that are remarkably comparable in timing, geochemistry of fluids and nature of sources.