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Gabriel G.,Leibniz Institute for Applied Geophysics | Ellwanger D.,Regierungsprasidium Freiburg | Hoselmann C.,Hessisches Landesamt fur Umwelt und Geologie | Weidenfeller M.,Landesamt fur Geologie und Bergbau Rheinland Pfalz | Wielandt-Schuster U.,Regierungsprasidium Freiburg
Quaternary International | Year: 2013

The Heidelberg Basin, in the German part of the northern Upper Rhine Graben, hosts one of the thickest successions of Plio-/Pleistocene sediments in Central Europe. From reflection seismic surveys and new research boreholes, it is known that Pleistocene sediments amount to more than 500 m thickness. The basin sediments originated both from local source areas, i.e. the highlands along the graben shoulders, and from regional source areas, i.e. the Alps. Although temporal hiatuses probably exist, the deposits are expected to be more or less complete because this part of the Upper Rhine Graben has undergone continuous subsidence in the past.Currently, the Heidelberg Basin is under investigation by a scientific drilling project. New cored boreholes have been realized at three different locations, spaced 15 km from each other. This concept provides complementing information and enables a detailed characterization of the predominantly fluvial deposits. The project aims to develop a stratigraphic reference profile of the Quaternary for this region north of the Alps, to understand how the sedimentation was controlled by tectonics and past climate change, and to derive proxy data of environmental changes.The new core material demonstrates that the Heidelberg Basin would be a possible key location for Quaternary stratigraphy in Central Europe. Information about Pleistocene periods of cold and warm climate is found within this one sediment succession in superposition; the temporal resolution of the sediment succession is high. Due to its mid-continental location it links northern and southern Europe, as well as western and eastern Europe. Based on a detailed analysis of the new drill cores a new lithostratigraphy for the northern part of the Upper Rhine Graben is developed in a first step. With the Mannheim Formation, the Ludwigshafen Formation, the Viernheim Formation, and the Iffezheim Formation, four new lithostratigraphic units of the northern Upper Rhine Graben are officially introduced. Furthermore, a new debate about identification of Basal Quaternary arises from the new research boreholes. Whereas during the last decades petrological markers were used to define Basal Quaternary, i.e. the first deposition of Alpine sediments or carbonate content, this definition fails in the depocentre of the basin. Several rock physical properties, e.g. the natural gamma radiation and the magnetic susceptibilities, reveal significant changes at the Basal Quaternary. The driving forces of these changes have to be studied in more detail in the future. © 2012 Elsevier Ltd and INQUA.

Kuhn P.,University of Tübingen | Techmer A.,Leibniz Institute For Angewandte Geophysik | Weidenfeller M.,Landesamt fur Geologie und Bergbau Rheinland Pfalz
Quaternary Science Reviews | Year: 2013

Lower to middle Weichselian loess, loess derivatives and buried soils of the loess-paleosol sequence Alsheim (Central Europe) were characterised by particle size distribution, geochemical and micromorphological data. High rates of sedimentation with alternating phases of relocation are the main cause for a much less differentiation into Middle and Upper Weichselian loess-paleosol units of the Alsheim loess-paleosol sequence compared to other loess-paleosol sequences (e.g. Nussloch near Heidelberg), whereas the Lower Weichselian has distinct phases of pedogenesis resulting in Ah, Bw and Btw horizons.To distinguish between different loess deposits locally and intraregional, the degree of fineness is an easily applicable and suitable tool, though inappropriate for interregional comparisons. The chemical index of alteration (CIA) is low (<50=no weathering) for loess deposits in the Alsheim loess-paleosol sequence, which is in contrast to the worldwide compiled loess samples with CIA values ranging from >53 to <70 (Gallet etal., 1998). The highest weathering was detectable for Btw horizons with CIA values >70.A direct quantitative estimation of mean annual palaeotemperature and mean annual palaeoprecipitation can be provided by calculations based on geochemistry of soil horizons and sediments. The present mean annual precipitation (MAP) in the Mainz Basin is 789mm. In contrast, palaeoprecipitation data suggest a 150mm higher amount for the Last Interglacial (Btw horizon), a much lower amount of around 300-400mm MAPP (periods of loess and sandy loess deposition) and a MAPP of <500mm for Weichselian Interstadials (humus zones and Bw horizons). The calculated mean annual palaeotemperature (MAPT) for Interstadials with 8.9°C for Bw horizons or with 9.6°C for humus zones (or to 2K lower, considering the relation of the present MAT of the Mainz Basin with the MAT of Germany) seems to be a good approximation of the MAPT for Lower and Middle Weichselian Interstadials. A MAPT of 8.7°C (or 6.7°C) for Stadials (loess and sandy loess samples) is higher than other temperature estimations for Weichselian Stadials in Europe.Micromorphology shows compacted granular structure and moderately to strongly developed pedality as characteristic properties for aquatic loess, whereas channel microstructure with no pedality is typical for loess deposits. Spongy microstructure suggests a classification of the Lower Weichselian Mosbach Humus Zones as Chernozems. The Eemian paleosol (Btw horizon in Als III) has only weak clay illuviation, characteristic for drier regions in Europe.Palaeoclimate and soil formation of the Last Glacial-Interglacial cycle calculated from geochemistry and micromorphological data are in good accordance with other proxy data in Central Europe. This suggests that paleoclimate reconstruction based on palaeopedological analyses could be successfully implemented in Europe. Such data may provide a useful alternative to other proxies for correlating European records. © 2013 Elsevier Ltd.

Dittrich D.,Landesamt fur Geologie und Bergbau Rheinland Pfalz | Hermle S.,Dominicusstr. 52
Mainzer Geowissenschaftliche Mitteilungen | Year: 2010

By means of different tracer tests the hydraulic connection between a swallow of the little river Enz south of Enzen and the Holsthum Mill in the Prüm valley has been proven repeatedly. Several swallow holes exist where the Enz crosses a major fault zone and steps into the jointed dolomites of the Upper Muschelkalk. Karstphenomena known from adjacent areas in the Trier-Luxemburg Embayment are described. Along the old tectonic lineaments the joint related karstification has been especially effective. Vertical and horizontal tectonic movements have generated distinct joint sets of different directions. The subterranean water current towards the spring at Holsthum is described by means of joint diagrams and a very detailed subsurface contour map. The most important aquifer layer is the dolomite succession of the Upper Ceratitenschichten (mo2C2). The underlying aquitard is formed by marls and dolomites of the Lower Ceratitenschichten (mo2C1). In the study area a regional division of the subterraneous water system of the Upper Muschelkalk resulted. This fact is confirmed by well data.

In the southeastern Trier-Luxemburg Embayment six events of compressive deformation have taken place since Upper Jurassic. In this paper they are reconstructed and numbered as DI to DVI. They are assigned to the Upper Jurassic, the late Lower Cretaceous, the lower to middle Eocene, the Upper Oligocene, the lower Miocene and finally to the subrecent plio-pleisto-holocene time span. The structural results of each deformation in the study area are described and illustrated by tectonic maps. Proven compressional structures are horizontal stylolites, slickolite striae.

The Tectonic development in the Palatine Forest (Pfälzerwald) with its adjacent regions was studied. Own structural measurements and tectonic data derived from regional literature have been interpreted. Not only normal faulting but especially remains of horizontal crustal motions were analysed. The latter comprised strikeslip faults and accompanying shear joints and planes with oblique resp. horizontal slip striations. At the edge of the Upper Rhine Graben even folds and (oblique) thrust faults occur in the covering rocks of late permian and early triassic age. All these structures can be assigned to several different paleostress fields, which occured between Upper Jurassic and today (fig. 8 and 26). Especially accentuated were the strike-slip movements of early eocene times. They were caused by North-South-directed compressional stresses, slowly rotating clockwise (sl striking 161° to 10°). The horizontal fault throws reach 1.7 km. The shear tectonics of upper jurassic (sl: 80 to 95°) and upper oligocene age (sl: 35 to 45°) are noticeable, but of lower importance. The shear strains of lower cretaceous, middle miocene and subrecent age appear relatively weak. Important extensional phases happened in middle jurassic and in lower oligocene times. Interfering extension can also be traced in the Upper Pliocene-Pleistocene-Holocene time span. WSW-ENE striking structures of the basement, which had already been slightly active in lower Triassic times, were traced into the covering rocks of the (early) mesozoic Pfälzerwald-succession during middle Jurassic times and mobilized in different ways afterwards. Northwest-Southeast striking faults (so-called Querstörungen) are due to late variscan transfer faults (sensu STOLLHOFEN 1998) in the Paleozoic basement. They were traced into the covering rocks during Upper Jurassic while they have carried out sinistral shear motions. During early eocene times they were dextrally inverted and then, during Neogene, extensionally overprinted. Their traced fractures formed tectonical mobile zones of different width and consiseness, which are of high diagnostic value.

In this first contribution (part I) the southeastern part of the Southern Eifel is studied. It comprises parts of the Trier Embayment and the peripheral area of the Wittlich Basin. New geological mapping informations make a regional synoptic interpretation possible now. In this region fault tectonics are much more complex than those in northwestern and central parts of the Trier Embayment, which have already been described in previous papers. Inherited large paleohighs and -lows, long since known in the adjacent areas in the west, now are traced and described in the fault pattern of the eastern Trier Embayment as well. They represent tectonic elements, which have already been mobile in triassic times. In addition they are superimposed by 20-30° striking fault lines. Shear motions with varying orientations have taken place. They are proven by numerous findings of (sub-)horizontal striations (slickensides, slip striae) and slickolites. Moreover some indications for upfaulting exist. A 30 m broad shear zone was newly exposed in the dolomite quarry near Sülm. It is located exactly at a striking elongation of a sinistral strike-slip fault, which had been reconstructed by DITTRICH (2009). A compressive tectonic overprint on the fault pattern of the mesozoic rocks of the Trier Embayment is obvious. Originally the fault pattern had been conditioned by extension. In the Trier area also exist arch-shaped fault lines. In several cases they are arranged like Riedel shears and accompanied by ore veins along the fault planes. It has to be examined whether they indicate (former) pull-apart structures. Further examinations and tentative datings of the particular deformation processes will be given in part III. The second part of this paper will describe indications for compressional strain and shear tectonics in southeastern Luxemburg and in the german Saargau.

This second part of the trisected paper describes the structural characteristics of the southeastern Trier Embayment. This comprises the german Saargau (the area between the rivers Saar and Mosel) and southeastern Luxemburg. A comprehensive compilation of the tectonic results makes a modernized synoptic interpretation possible now. The newly mapped fault pattern of the Saargau differs clearly from those of older geological maps. Rhenish and "diagonal" (northeast-southwest) striking fault lines dominate. Inherited large paleohighs and -lows are reflected. In the area north of the Sierck High WSW-ENE ("variszisch") striking fault zones are developed quite indistinct. They are assumed to be structurally overprinted. Moreover 20-30° trending fault lines exist. Long and narrow graben structures of all those directional systems appear remarkably widespread. Quite often indications for horizontal movements have been noticed. They are stated by means of special investigations in geological literature and mapping records and by own results. Arch-shaped shear planes, that are often still recognizable striated horizontally, small upthrows and intensely fractured fault zones are proven. Several planes of normal faults reveal additional horizontal fault movements and were affected by a secondary compressive overprint. Additionally fold structures of varying dimensions appear as well as negative flower structures and narrow downthrown blocks which look like pull-apart structures. Horizontal stylolites, slickolites, striations and and a few preserved horizontal slickensides complete this structural assemblage. Several successive phases of compressive tectonic events with different horizontal movements are documented. Their succession and the particular paleostress fields will be interpreted and discussed in the third part of this paper.

The aquifer system of the Bunter reach thicknesses in the order of about 300 m. It is of great importance for the drinking water supply in the Grünstadt area. A systematic collection and documentation of groundwater data in terms of quantity and quality has not yet been carried out. So far the locally available data and time series are presented and discussed in temporal and spatial relation. In the present the water management is focusing on the local water catchment areas. Based on the presented observations it is recommended to understand the Bunter as large scale hydraulically communicating aquifer system and to manage it in this sense. For this additional hydrogeological investigations are required.

The results of tectonic outcrop measurements in the southeastern Trier Embayment, which were particularly described in the two preceding parts of this publication, and additional new results will be analyzed now. The relevant horizontal stress data are classified and graded. Compressional phenomena of different ages and sinistral resp. dextral shear movements are listed and depicted graphically. Furthermore the actual regional geological maps are interpreted. Fold structures and several strike-slip faults of varying directions are obvious. The horizontal throws amount to several hundreds of meters, often the kilometer-scale is reached (maximum: 3.2 km). Relations of age can also be recognized. The huge number of observations allows the identification of five groups of strain. They all comprise a former direction of maximal horizontal compression and the appropriate conjugated dextral and sinistral shear plane sets. One of these directional groups is documented twice, it characterizes subrecent times and a quite old episode. The next step of investigation is the chronological rating of these groups. For this the results from adjacent regions are taken into consideration. Six events of compressive deformation are reconstructed. They can be assigned to Upper Jurassic, early Lower Cretaceous, lower to middle Eocene, upper Oligocene, lower Miocene and a time span of plio-pleisto-holocene age (fig. 85, tab. 2).

Long term changing groundwater conditions in the Grünstadt Area are the trigger for current hydrogeological studies of the state water authority. In this context data from the archives of the Landesamt für Geologie und Bergbau (Department for Geology and Mining of Rhineland-Palatinate) were used to estimate rock permeabilities. The results are presented and discussed with reference to data given in the literature.

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