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
The salt tectonics of the Glueckstadt Graben has been investigated in relation to major tectonic events within the basin.
The lithologic features of salt sections from Rotliegend, Zechstein and Keuper show that almost pure salt is prominent in
the Zechstein, dominating diapiric movements that have influenced the regional evolution of the Glueckstadt Graben. Three
main phases of growth of the salt structures have been identified from the analysis of the seismic pattern. The strongest
salt movements occurred at the beginning of the Keuper when the area was affected by extension. This activation of salt tectonics
was followed by a Jurassic extensional event in the Pompeckj Block and Lower Saxony Basin and possibly in the Glueckstadt
Graben. The Paleogene–Neogene tectonic event caused significant growth and amplification of the salt structures mainly at
the margins of the basin. This event was extensional with a possible horizontal component of the tectonic movements. 3D modelling
shows that the distribution of the initial thickness of the Permian salt controls the structural style of the basin, regionally.
Where salt was thick, salt diapirs and walls formed and where salt was relatively thin, simple salt pillows and shallow anticlines
developed. 相似文献
Based on a series of experiments conducted by two regional climate models (RCA4 and LMDZ) with and without soil moisture-atmosphere coupling, we investigate the role of soil moisture on the occurrence of surface air temperature extremes and its persistence in Southeastern South America. Our analysis reveals that both factors, soil moisture-atmosphere coupling and relatively drier soil conditions, enhance the temperature extremes. In addition, the existence of soil-atmosphere coupling and the associated soil moisture variability is crucial for the development of the extremes in SESA. The key role of soil-atmosphere coupling is also reflected in the intrinsic persistence of hot days, which is greater in simulations with interactive soil moisture than in those with prescribed soil conditions. In the absence of soil-atmosphere coupling, the imprint of the anomalous dry (and also wet) soil conditions on the intensity and persistence of hot days is weaker.
Understanding the interplay between hydrological flushing and biogeochemical cycling in streams is now possible owing to advances in high-frequency water quality measurements with in situ sensors. It is often assumed that storm events are periods when biogeochemical processes become suppressed and longitudinal transport of solutes and particulates dominates. However, high-frequency data show that diel cycles are a common feature of water quality time series and can be preserved during storm events, especially those of low-magnitude. In this study, we mine a high-frequency dataset and use two key hydrochemical indices, hysteresis and flushing index to evaluate the diversity of concentration-discharge relationships in third order agricultural stream. We show that mobilization patterns, inferred from the hysteresis index, change on a seasonal basis, with a predominance of rapid mobilization from surface and near stream sources during winter high-magnitude storm events and of delayed mobilization from subsurface sources during summer low-magnitude storm events. Using dynamic harmonic regression, we were able to separate concentration signals during storm events into hydrological flushing (using trend as a proxy) and biogeochemical cycling (using amplitude of a diel cycle as a proxy). We identified three groups of water quality parameters depending on their typical c-q response: flushing dominated parameters (phosphorus and sediments), mixed flushing and cycling parameters (nitrate nitrogen, specific conductivity and pH) and cycling dominated parameters (dissolved oxygen, redox potential and water temperature). Our results show that despite large storm to storm diversity in hydrochemical responses, storm event magnitude and timing have a critical role in controlling the type of mobilization, flushing and cycling behaviour of each water quality constituent. Hydrochemical indices can be used to fingerprint the effect of hydrological disturbance on freshwater quality and can be useful in determining the impacts of global change on stream ecology. 相似文献
Based on a numerical model of the Northeast German Basin (NEGB), we investigate the sensitivity of the calculated thermal field as resulting from heat conduction, forced and free convection in response to consecutive horizontal and vertical mesh refinements. Our results suggest that computational findings are more sensitive to consecutive horizontal mesh refinements than to changes in the vertical resolution. In addition, the degree of mesh sensitivity depends strongly on the type of the process being investigated, whether heat conduction, forced convection or free thermal convection represents the active heat driver. In this regard, heat conduction exhibits to be relative robust to imposed changes in the spatial discretization. A systematic mesh sensitivity is observed in areas where forced convection promotes an effective role in shorten the background conductive thermal field. In contrast, free thermal convection is to be regarded as the most sensitive heat transport process as demonstrated by non-systematic changes in the temperature field with respect to imposed changes in the model resolution. 相似文献
We analyse the effect of fluid flow on the recent thermal field for the Brandenburg region (North German Basin) which is strongly affected by salt structures. The basin fill is modified by a thick layer of mobilized salt (Zechstein, Upper Permian) that decouples the overburden from deeper parts of the lithosphere and is responsible for thermal anomalies since salt has a distinctly higher thermal conductivity than the surrounding sediments and is impermeable to fluid flow. Numerical simulations of coupled fluid flow and heat transfer are carried out to investigate the influence of fluid flow on the shallow temperature field above the Zechstein salt, based on the finite element method. A comparison of results from conductive and coupled modelling reveals that the temperature field down to the low-permeable Triassic Muschelkalk is influenced by fluids, where the shallow low-permeable Tertiary Rupelian-clay is absent. Overall cooling is induced by forced convective forces, the depth range of which is controlled by the communication pathways between the different aquifers. Moreover, buoyancy-induced effects are found in response to temperature-dependent differences in the fluid density where forced convective forces are weak. The range of influence is controlled by the thickness and the permeability of the permeable strata above the Triassic Muschelkalk. With increasing depth, thermal conduction mainly controls the short-wavelength pattern of the temperature distribution, whereas the long-wavelength pattern results from interaction between the highly conductive crust and low-conductive sediments. Our results provide generic implications for basins affected by salt tectonics. 相似文献
The deep thermal field in sedimentary basins can be affected by convection, conduction or both resulting from the structural inventory, physical properties of geological layers and physical processes taking place therein. For geothermal energy extraction, the controlling factors of the deep thermal field need to be understood to delineate favorable drill sites and exploitation compartments. We use geologically based 3-D finite element simulations to figure out the geologic controls on the thermal field of the geothermal research site Groß Schönebeck located in the E part of the North German Basin. Its target reservoir consists of Permian Rotliegend clastics that compose the lower part of a succession of Late Carboniferous to Cenozoic sediments, subdivided into several aquifers and aquicludes. The sedimentary succession includes a layer of mobilized Upper Permian Zechstein salt which plays a special role for the thermal field due to its high thermal conductivity. Furthermore, the salt is impermeable and due to its rheology decouples the fault systems in the suprasalt units from subsalt layers. Conductive and coupled fluid and heat transport simulations are carried out to assess the relative impact of different heat transfer mechanisms on the temperature distribution. The measured temperatures in 7 wells are used for model validation and show a better fit with models considering fluid and heat transport than with a purely conductive model. Our results suggest that advective and convective heat transport are important heat transfer processes in the suprasalt sediments. In contrast, thermal conduction mainly controls the subsalt layers. With a third simulation, we investigate the influence of a major permeable and of three impermeable faults dissecting the subsalt target reservoir and compare the results to the coupled model where no faults are integrated. The permeable fault may have a local, strong impact on the thermal, pressure and velocity fields whereas the impermeable faults only cause deviations of the pressure field. 相似文献