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1.
Twenty paleogeographic maps are presented for Middle Eocene (Lutetian) to Late Pliocene times according to the stratigraphical data given in the companion paper by Berger et al. this volume. Following a first lacustrine-continental sedimentation during the Middle Eocene, two and locally three Rupelian transgressive events were identified with the first corresponding with the Early Rupelian Middle Pechelbronn beds and the second and third with the Late Rupelian Serie Grise (Fischschiefer and equivalents). During the Early Rupelian (Middle Pechelbronn beds), a connection between North Sea and URG is clearly demonstrated, but a general connection between North Sea, URG and Paratethys, via the Alpine sea, is proposed, but not proved, during the late Rupelian. Whereas in the southern URG, a major hiatus spans Early Aquitanian to Pliocene times, Early and Middle Miocene marine, brackish and freshwater facies occur in the northern URG and in the Molasse Basin (OMM, OSM); however, no marine connections between these basins could be demonstrated during this time. After the deposition of the molasse series, a very complex drainage pattern developed during the Late Miocene and Pliocene, with a clear connection to the Bresse Graben during the Piacenzian (Sundgau gravels). During the Late Miocene, Pliocene and Quaternary sedimentation persisted in the northern URG with hardly any interruptions. The present drainage pattern of the Rhine river (from Alpine area to the lower Rhine Embayment) was not established before the Early Pleistocene.  相似文献   

2.
The changing palaeogeographical pattern of Alpine deposits across the European forelands can be traced by identifying mineral assemblages and establishing the chronology of Pliocene-Pleistocene deposits in Alpine foreland. In the late Miocene, the upper courses of the Rhine and the Aar flowed east from the Swiss molasse plain towards the Danube. In the early Pliocene (Brunssumian, 5-3.2 Ma), these same rivers headed north wards towards the Rhine Graben of Alsace. In the early Reuverian, these streams were captured south of the Rhine Graben by the Doubs. They ceased their northward flow and headed west to feed the Bresse Graben. This phase is dated to the Lower and Middle Reuverian (3.2-2.6 Ma). From the Upper Reuverian (2.6 Ma) to the present day, the Rhine has adapted approximately its present course towards the North Sea, south to north along the Rhine Graben and across the Rhine Schist Massif to feed the Dutch Grabens. This changing pattern of capture and alteration of the hydrographic system of the upper reaches of the Rhine and the Aar can be explained by local tectonic movements.  相似文献   

3.
We present a general stratigraphic synthesis for the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB) from Eocene to Pliocene times. The stratigraphic data were compiled both from literature and from research carried out by the authors during the past 6 years ; an index of the stratigraphically most important localitites is provided. We distinguish 14 geographical areas from the Helvetic domain in the South to the Hanau Basin in the North. For each geographical area, we give a synthesis of the biostratigraphy, lithofacies, and chronostratigraphic ranges. The relationships between this stratigraphic record and the global sea-level changes are generally disturbed by the geodynamic (e.g., subsidence) evolution of the basins. However, global sea-level changes probably affected the dynamic of transgression–regression in the URG (e.g., Middle Pechelbronn Beds and Serie Grise corresponding with sea-level rise between Ru1/Ru2 and Ru2/Ru3 sequences, respectively) as well as in the Molasse basin (regression of the UMM corresponding with the sea-level drop at the Ch1 sequence). The URGENT-project (Upper Rhine Graben evolution and neotectonics) provided an unique opportunity to carry out and present this synthesis. Discussions with scientists addressing sedimentology, tectonics, geophysics and geochemistry permitted the comparison of the sedimentary history and stratigraphy of the basin with processes controlling its geodynamic evolution. Data presented here back up the palaeogeographic reconstructions presented in a companion paper by the same authors (see Berger et al. in Int J Earth Sci 2005).  相似文献   

4.
Recently released seismic reflection data, together with previous seismic and well data, are used to describe the development of the Dannemarie basin, in the SW end of the Upper Rhine Graben. The Dannemarie Basin was formed during the main rifting phase of the Upper Rhine Graben as an asymmetrical graben trending NE–SW. Post-rift tectonism shifted the depocenter southward and changed the overall shape of the basin. Miocene Jura compression did not result in the formation of folds, as in the adjacent Mulhouse Horst. Strike slip faulting was dominant in the post-rift period and new faults were created, most notably the north trending and transpressional Belfort Fault. The boundary of the Dannemarie Basin with the Vosges Mountains is part of a restraining bend, which may account for the uplift of the southernmost part of the Vosges Mountains.  相似文献   

5.
We present a synoptic overview of the Miocene-present development of the northern Alpine foreland basin (Molasse Basin), with special attention to the pattern of surface erosion and sediment discharge in the Alps. Erosion of the Molasse Basin started at the same time that the rivers originating in the Central Alps were deflected toward the Bresse Graben, which formed part of the European Cenozoic rift system. This change in the drainage direction decreased the distance to the marine base level by approximately 1,000 km, which in turn decreased the average topographic elevation in the Molasse Basin by at least 200 m. Isostatic adjustment to erosional unloading required ca. 1,000 m of erosion to account for this inferred topographic lowering. A further inference is that the resulting increase in the sediment discharge at the Miocene–Pliocene boundary reflects the recycling of Molasse units. We consider that erosion of the Molasse Basin occurred in response to a shift in the drainage direction rather than because of a change in paleoclimate. Climate left an imprint on the Alpine landscape, but presumably not before the beginning of glaciation at the Pliocene–Pleistocene boundary. Similar to the northern Alpine foreland, we do not see a strong climatic fingerprint on the pattern or rates of exhumation of the External Massifs. In particular, the initiation and acceleration of imbrication and antiformal stacking of the foreland crust can be considered solely as a response to the convergence of Adria and Europe, irrespective of erosion rates. However, the recycling of the Molasse deposits since 5 Ma and the associated reduction of the loads in the foreland could have activated basement thrusts beneath the Molasse Basin in order to restore a critical wedge. In conclusion, we see the need for a more careful consideration of both tectonic and climatic forcing on the development of the Alps and the adjacent Molasse Basin.  相似文献   

6.
Re-evaluation of the river history, palaeosurface levels and exhumation history in northern Switzerland for the last 10 million years reveals that distinct morphotectonic events about 4.2 and 2.8 million years ago (Ma) caused major reorganisation of river networks and morphosculpture. As a result of the earlier formation of the Swiss Jura, potential relief energy in the piggy-back North Alpine Foreland Basin (NAFB) of northern central Switzerland south of the Jura fold belt was built up after 11–10 Ma. It was suddenly released by river capture at about 4.2 Ma when the Aare-Danube was captured by a tributary of the Rhône-Doubs river system which rooted southeast of the Black forest. This event triggered rapid denudation of weakly consolidated Molasse sediments, in the order of about 1 km, as constrained by apatite fission track data from drillholes in the NAFB. Likely mechanisms of river capture are (a) headward erosion of Rhône-Doubs tributaries, (b) uplift and rapidly increasing erosion of the Swiss Alps after about 5.3 Ma, and (c) gravel aggradation at the eastern termination of the Jura fold belt in the course of eastward and northward tilt of the piggy-back NAFB. A morphotectonic event between 4.2 and 2.5 Ma, probably at about 2.8 Ma, caused a phase of planation, accompanied by local gravel aggradation and temporary storage of Alpine debris. Between 2.8 and 2.5 Ma, the Aare-Rhône river system is cannibalised by the modern Rhine River, the latter later connecting with the Alpine Rhine River.  相似文献   

7.
The Upper Rhine Graben (URG) is characterized by a thickness of up to 500 m of unconsolidated Quaternary sediments, providing excellent records of the Rhine river system and its responses to tectonic and climatic changes. The most complete Quaternary sequence of fluvial and limnic-fluvial deposits is found in the Heidelberg Basin, due to its long-term subsidence since the mid-Eocene. The aim of this study is to provide a chronological framework using optically stimulated luminescence (OSL) dating of aeolian and fluvial sands derived from the upper 33 m of a sediment core, which was drilled into the Heidelberg Basin infill close to the village of Viernheim, Germany. The OSL ages demonstrate that the dated fluvial sediments were deposited during the last glacial period (Weichselian) and that there were at least three aggradation periods during this episode. The coversands that cap the sequence were emplaced during the early Holocene.  相似文献   

8.
A large-scale transfer zone subdivides the northern parts of the Upper Rhine Graben into a northern and a southern sub-basin. These sub-basins display the geometry of asymmetric half-grabens with opposing tilt directions. The transfer zone connects the western master fault of the northern half-graben with the eastern master fault of the southern half-graben. In the northern Upper Rhine Graben early syn-rift sedimentation (Late Priabonian to Late Rupelian) was controlled by the tectonically induced subsidence of these half-grabens (autogenetic), as well as by regional third-order sea level variations (allogenetic). Within the graben, lateral changes in subsidence rates (in dip and strike direction of fault blocks) controlled the development of accommodation space and thus, sediment thickness and facies. Furthermore, a low-displacement segment along the western border fault acted as a sediment entry point. Tectonics controlled the distribution of early syn-rift deposits and the palaeogeography of the northern Upper Rhine Graben.  相似文献   

9.
In the northern part of the Upper Rhine Graben (URG), a high-resolution seismic reflection survey was carried out on the Rhine River over a length of 80 km, and on its tributary Neckar over a length of 25 km. The seismic investigation provides new results to redefine the base of Quaternary fluvial sediments from Oppenheim upstream to the south of Mannheim. The standard Quaternary thickness map of Bartz (1974) was partially revised and completed. Maximum Pleistocene sediment thickness is documented in the area of Mannheim with approximately 225 m. The top of the Pliocene in this area is sub-horizontal and not faulted, and rises downstream continuously towards the fault block of Worms. Intercalated lacustrine pelitic layers play a main role in defining the litho-stratigraphy in this part of the URG. In the north of Worms, Pleistocene sediments are mainly coarse-grained. In the area of Worms, a Pleistocene tectonic phase along N–S striking normal faults with variable displacement along the strike is obvious.  相似文献   

10.
In order to study the ongoing tectonic deformation in the Rhine Graben area, we reconstruct the local crustal velocity and the strain rate field from GPS array solutions. Following the aim of this work, we compile the velocities of permanent GPS stations belonging to various networks (EUREF, AGNES, REGAL and RGP) in central western Europe. Moreover, the strain rate field is displayed in terms of principal axes and values, while the normal and the shear components of the strain tensor are calculated perpendicular and parallel to the strike of major faults. The results are compared with the fault plane solutions of earthquakes, which have occurred in this area. A broad-scale kinematic deformation model across the Rhine Graben is provided on the basis of tectonics and velocity results of the GPS permanent stations. The area of study is divided into four rigid blocks, between which there might be relative motions. The velocity and the strain rate fields are reconstructed along their borders, by estimating a uniform rotation for each block. The tectonic behaviour is well represented by the four-block model in the Rhine Graben area, while a more detailed model will be needed for a better reconstruction of the strain field in the Alpine region.
Magdala TesauroEmail:
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11.
The lithosphere of the Northern Alpine foreland has undergone a polyphase evolution during which interacting stress-induced intraplate deformation and upper mantle thermal perturbations controlled folding of the thermally weakened lithosphere. In this paper we address relationships among deeper lithospheric processes, neotectonics and surface processes in the Northern Alpine foreland with special emphasis on tectonically induced topography. We focus on lithosphere memory and neotectonics, paying special attention to the thermo-mechanical structure of the Rhine Graben System and adjacent areas of the northern Alpine foreland lithosphere. We discuss implications for mechanisms of large-scale intraplate deformation and links with surface processes and topography evolution.  相似文献   

12.
This paper integrates the results of different techniques—local and regional travel time tomography, reflection seismics, and surface geology. With this integration of different techniques, working on different scales, it is possible to derive a comprehensive picture of the present-day structures in the lithosphere of the Upper Rhine Graben. It is shown that the stucture of the lithosphere is dominated by structures related to the Variscan orogeny. Late stage strike-slip reactivation of the internal faults of the Rhine Graben is observed in the field. This reactivation is of dominant influence on the geomorphology in the southern end of the Upper Rhine Graben.  相似文献   

13.
The Glueckstadt Graben is one of the deepest post-Permian structures within the Central European Basin system and is located right at its “heart” at the transition from the North Sea to the Baltic Sea and from the Lower Saxony Basin to the Rynkoebing–Fyn High.The Mesozoic to recent evolution is investigated by use of selected seismic lines, seismic flattening and a 3D structural model. A major tectonic event in the latest Middle–Late Triassic (Keuper) was accompanied by strong salt tectonics within the Glueckstadt Graben. At that time, a rapid subsidence took place within the central part, which provides the “core” of the Glueckstadt Graben. The post-Triassic tectonic evolution of the area does not follow the typical scheme of thermal subsidence. In contrast, it seems that there is a slow progressive activation of salt movements triggered by the initial Triassic event. Starting with the Jurassic, the subsidence centre partitioned into two parts located adjacent to the Triassic “core.” In comparison with other areas of the Central European Basin system, the Glueckstadt Graben was not strongly affected by additional Jurassic and Cretaceous events. During the late Jurassic to Early Cretaceous, the area around the Glueckstadt Graben was affected by relative uplift with regional erosion of the elevated relief. However, subsidence was reactivated and accelerated during the Cenozoic when a strong subsidence centre developed in the North Sea. During Paleogene and Quaternary–Neogene, the two centres of sedimentation moved gradually towards the flanks of the basin.The data indeed point toward a control of post-Permian evolution by gradual withdrawal of salt triggered by the initial exhaustion along the Triassic subsidence centre. In this sense, the Glueckstadt Graben was formed at least partially as “basin scale rim syncline” during post-Permian times. The present day Hamburger, East and Westholstein Troughs are the actual final state of this long-term process which still may continue and may play a role in terms of young processes and, e.g., for coastal protection.  相似文献   

14.
Eocene to Early Oligocene syn-rift deposits of the southern Upper Rhine Graben (URG) accumulated in restricted environments. Sedimentation was controlled by local clastic supply from the graben flanks, as well as by strong intra-basinal variations in accommodation space due to differential tectonic subsidence, that in turn led to pronounced lateral variations in depositional environment. Three large-scale cycles of intensified evaporite sedimentation were interrupted by temporary changes towards brackish or freshwater conditions. They form three major base level cycles that can be traced throughout the basin, each of them representing a stratigraphic sub-unit. A relatively constant amount of horizontal extension (ΔL) in the range of 4–5 km has been estimated for the URG from numerous cross-sections. The width of the rift (L f ), however, varies between 35 and more than 60 km, resulting in a variable crustal stretching factor between the bounding masterfaults. Apart from block tilting, tectonic subsidence was, therefore, largely controlled by changes in the initial rift width (L 0). The along-strike variations of the graben width are responsible for the development of a deep, trough-like evaporite basin (Potash Basin) in the narrowest part of the southern URG, adjacent to shallow areas in the wider parts of the rift such as the Colmar Swell in the north and the Rhine Bresse Transfer Zone that delimits the URG to the south. Under a constant amount of extension, the along-strike variation in rift width is the principal factor controlling depo-centre development in extensional basins.  相似文献   

15.
《Earth》2006,74(3-4):127-196
Research on neotectonics and related seismicity has hitherto been mostly focused on active plate boundaries that are characterized by generally high levels of earthquake activity. Current seismic hazard estimates for intraplate domains are mainly based on probabilistic analyses of historical and instrumental earthquake catalogues. The accuracy of such hazard estimates is limited by the fact that available catalogues are restricted to a few hundred years, which, on geological time scales, is insignificant and not suitable for the assessment of tectonic processes controlling the observed earthquake activity. More reliable hazard prediction requires access to high quality data sets covering a geologically significant time span in order to obtain a better understanding of processes controlling on-going intraplate deformation.The Alpine Orogen and the intraplate sedimentary basins and rifts in its northern foreland are associated with a much higher level of neotectonic activity than hitherto assumed. Seismicity and stress indicator data, combined with geodetic and geomorphologic observations, demonstrate that deformation of the Northern Alpine foreland is still on-going and will continue in the future. This has major implications for the assessment of natural hazards and the environmental degradation potential of this densely populated area. We examine relationships between deeper lithospheric processes, neotectonics and surface processes in the northern Alpine Foreland, and their implications for tectonically induced topography.For the Environmental Tectonics Project (ENTEC), the Upper and Lower Rhine Graben (URG and LRG) and the Vienna Basin (VB) were selected as natural laboratories. The Vienna Basin developed during the middle Miocene as a sinistral pull-apart structure on top of the East Alpine nappe stack, whereas the Upper and Lower Rhine grabens are typical intracontinental rifts. The Upper Rhine Graben opened during its Late Eocene and Oligocene initial rifting phase by nearly orthogonal crustal extension, whereas its Neogene evolution was controlled by oblique extension. Seismic tomography suggests that during extension the mantle-lithosphere was partially decoupled from the upper crust at the level of the lower crust. However, whole lithospheric folding controlled the mid-Miocene to Pliocene uplift of the Vosges–Black Forest Arch, whereas thermal thinning of the mantle–lithosphere above a mantle plume contributed substantially to the past and present uplift of the Rhenish Massif. By contrast, oblique crustal extension, controlling the late Oligocene initial subsidence stage of the Lower Rhine Graben, gave way to orthogonal extension at the transition to the Neogene.The ENTEC Project integrated geological, geophysical, geomorphologic, geodetic and seismological data and developed dynamic models to quantify the societal impact of neotectonics in areas hosting major urban and industrial activity concentrations. The response of Europe's intraplate lithosphere to Late Neogene compressional stresses depends largely on its thermo-mechanical structure, which, in turn, controls vertical motions, topography evolution and related surface processes.  相似文献   

16.
This study analyses the regressive phase of the marine Froidefontaine Subgroup and the subsequent fluvio-lacustrine Niederroedern formation in the southern Upper Rhine Graben during the Late Rupelian and the position of the Rupelian/Chattian boundary. The study is based on the sedimentary record and several microfossil groups from two boreholes, with a focus on new records of fish otoliths, Bolboforma and Charophyta. The biostratigraphic evaluation of these groups provides evidence for a position of the Rupelian/Chattian boundary within the upper Niederroedern Formation. This is contrary to the results from a previous sedimentological approach, which places the boundary at the base of the Niederroedern Formation. The fish fauna indicates a biogeographic relation to southern France, the Molasse Basin of Switzerland and southern Germany.  相似文献   

17.
In the Cenozoic, the Lower Rhine Basin formed as a rift at the southeastern terminus of the Dutch German Central Graben, while the Rhenish Massif was uplifted. The study focusses on the marginal marine and fluvial fill of the Lower Rhine Basin. A basin model is developed. Support for this study was given by extensive industry outcrop and well data, by new stratigraphical and sedimentological observations. The ingression and subsequent regression of the Cenozoic North Sea is analysed using the concept of base level cyclicity. As the geohistory of the basin was complex, a subsidence curve is constructed. Furthermore, an attempt is made to trace the simultaneous uplift of the Rhenish Massif.  相似文献   

18.
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19.
Deformation features on pebbles of the Alpine Molasse Basin are most clearly developed in carbonate components. Ductile distortion is small; most of the pebbles moved against each other to produce solution pits and slip-lineations on the pebble surfaces. The complete lineation field has a triaxial geometry. From a compressional axis of divergence with maximum solution, fields of diverging lineations extend to meet at a plane of convergence. Their ends bend away from an intermediate axis towards an (extensional) axis of convergence. The strain-symmetry is pure shear for orthogonal lineation-field axes, uniaxial compression and extension representing special cases. The angle α between the divergent and the convergent axes decreases from 90 to 0° with the transition from pure to simple shear. For Molasse pebbles α angles between 90 and 60° were usually observed. Regional compression developed perpendicular to the Alpine structures and parallel to bedding, with increasing deviations near the Alpine border. Zones are recorded of vertical and horizontal extension and of compression perpendicular to bedding and horizontal extension perpendicular to the Rhinegraben existing at the northern border of the Molasse Basin.  相似文献   

20.
在西藏安多地区进行活动断裂研究过程中,进行地表调查和探槽开挖,证实错那－安多地堑北缘主边界断裂上的最新地表断层陡坎实际是该区史前大地震的地表遗迹。根据地表观察和实地测量结果可知,该区最新古地震断坎的延伸范围可达 26～36km,平均垂直位移量达 1.0～1.4m。相关地层－地貌体的年代学测试结果和古地震破裂参数表明,最新的古地震发生在距今约 10.0～8.1ka期间,估计当时的古地震震级介于 6.9～7.3级之间,当时的极震区烈度可能≥Ⅸ度。此古地震破裂的发现表明,青藏高原中部正断层型大地震之后的沉寂时间可以长达近万年,明显长于藏南裂谷带上的正断层型古地震活动间隔。由于安多地区最新大地震之后的离逝时间已足以积累类似强度的大地震,因此,该区未来的大地震危险性较高。  相似文献   

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