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Freiburg, Germany

Schneider-Ritter U.,Regierungsprasidium Freiburg
WasserWirtschaft | Year: 2011

The Water Framework Directive (WFD) aims at reaching the "good ecological status" in a water body. For this purpose, the quality of the habitat of animals and plants has to be evaluated. Using the example of the resettlement of migratory fish In the River Rhine, it can be demonstrated that the success of measures like fish ladders and bypasses mainly depends on whether the entire water system has been taken into account.

Franz M.,Regierungsprasidium Freiburg | Dietl G.,Staatliches Museum fur Naturkunde Stuttgart
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen | Year: 2014

We present the stratigraphical and regional distribution of ostracoda in the Bathonian and Early Callovian of Baden-Wuerttemberg, southern Germany. On the basis of 13 sections studied between the Upper Rhine Graben and the Eastern Swabian Alb, which yielded a total of 14,800 specimens, representing 59 genera and 163 species, an ostracod zonation for this time interval is erected, comprising 5 biozones and 2 subzones. The composition of the assemblages mirrors the facies variations within the Bathonian of southwestern Germany. The faunal relationships to the adjacent Middle Jurassic basins are briefly described. ©2014 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany

Microsedimentological analyses were used to examine the first 56m of a 500m core near Heidelberg, Germany, in the Upper Rhine Valley. This core chronostratigraphically stretches from present day to 450 ka and includes proxy evidence supporting the presence of Würmian, Eemian and likely components of the Riss and Hoβkirch Stages. The sediment in the core reflects the geomorphic, biotic, pedogenic, and climatic processes. The sediments were deposited in a fluvial environment, at times, within a broad floodplain in the main channel, and also, at other times, some distance from the main river. These upper sediments act as indirect proxy evidence that indicate changes in climate over time illustrative of cool periglacial tundra-like conditions and of milder forested temperate environments from Hoβkirch to present day times. Within the sediments evidence can be found of an interglacial fossil soil followed later by a Holocene temperate climate up to present day. A strong link can be ascertained between macro- and micro-stratigraphic evidence, the latter revealing detailed and invaluable sources of information. This analysis permits the reconstruction of past climate and paleoenvironmental conditions. The application of microsedimentological analyses to the Mannheim Formation reveals a store of data that has been largely hidden when using only macro-sedimentological methods. © 2015 Elsevier Ltd and INQUA.

Schadwinkel W.,Unger ingenieure Ingenieurgesellschaft mbH | Sandmann B.,Ingenieurgruppe Flosser GmbH | Lonsdorfer B.,Regierungsprasidium Freiburg
Bautechnik | Year: 2015

Abstract This report deals with the essential planning details of a new intake structure for a flood retention basin in the regulated area of the Rhine, as well as with the collaboration between hydraulic, structural and soil engineers. The particular position of the structure places high demands on various factors, ranging from flood safety, the safety of the excavation pit in the dam, which is also under strain from the pressure of the water, right up to safe energy conversion downstream from the structure. The structure is currently under construction and a fish pass is also being incorporated in it. Copyright © 2015 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Staude S.,University of Tubingen | Werner W.,Regierungsprasidium Freiburg | Mordhorst T.,University of Tubingen | Wemmer K.,Geowissenschaftliches Zentrum Gottingen | And 2 more authors.
Mineralium Deposita | Year: 2012

The Wittichen Co-Ag-Bi-U mining area (Schwarzwald ore district, SW Germany) hosts several unconformity-related vein-type mineralizations within Variscan leucogranite and Permian to Triassic redbeds. The multistage mineralization formed at the intersection of two fault systems in the last 250 Ma. A Permo-Triassic ore stage I with minor U-Bi-quartz-fluorite mineralization is followed by a Jurassic to Cretaceous ore stage II with the main Ag and Co mineralization consisting of several generations of gangue minerals that host the sub-stages of U-Bi, Bi-Ag, Ni-As-Bi and Co-As-Bi. Important ore minerals are native elements, Co and Ni arsenides, and pitchblende; sulphides are absent. The Miocene ore stage III comprises barite with the Cu-Bi sulfosalts emplectite, wittichenite and aikinite, and the sulphides anilite and djurleite besides native Bi, chalcopyrite, sphalerite, galena and tennantite. The mineral-forming fluid system changed from low salinity (<5 wt.% NaCl) at high temperature (around 300°C) in Permian to highly saline (around 25 wt.% NaCl + CaCl 2) at lower temperatures (50-150°C) in Triassic to Cretaceous times. Thermodynamic calculations and comparison with similar mineralizations worldwide show that the Mesozoic ore-forming fluid was alkaline with redox conditions above the hematite-magnetite buffer. We suggest that the precipitation mechanism for native elements, pitchblende and arsenides is a decrease in pH during fluid mixing processes. REE patterns in fluorite and the occurrence of Bi in all stages suggest a granitic source of some ore-forming elements, whereas, e.g. Ag, Co and Ni probably have been leached from the redbeds. The greater importance of Cu and isotope data indicates that the Miocene ore stage III is more influenced by fluids from the overlying redbeds and limestones than the earlier mineralization stages. © 2011 Springer-Verlag.

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