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Temperature difference between both scenarios of high and low Malm permeabilities under paleoclimatic conditions (i.e. difference between model runs E and D introduced in Fig. 3): a 80 ka ago (time = 50,000 a), b 20 ka ago (time = 1.1E5 a), and c at present (time = 1.3E5 a). Vertical exaggeration equals three
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The Molasse Basin in Southern Germany is part of the North Alpine Foreland Basin and hosts the largest accumulation of deep geothermal production fields in Central Europe. Despite the vast development of geothermal energy utilization projects especially in the Munich metropolitan region, the evolution of and control factors on the natural geotherma...
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The perforated Pediastrum Meyen s.l. species are recorded for the first time in the basal levels of the Tithonian Vaca Muerta Formation, extending its first stratigraphical record to ages as old as Late Jurassic times. Based on the ecological requirements of Pediastrum simplex var. clathratum and P. simplex var. biwaense, the previously warm paleoc...
Citations
... The Franconian Basin deposition spans from Permian (Rotliegend) to Cretaceous and is formed of sandstones, siltstones, mudstones and limestones (Schröder, 1987;Schäfer et al. 2000, Freudenberger et al. 2013Kämmlein et al. 2017). The outcrops of interest lie within the Malm (Upper Jurassic) limestone unit deposited as an extensive carbonate-dominated platform (Franconian Platform) along the passive Tethyian margin (Meyer & Schmidt-Kaler, 1990;Ziegler 1990;Schintgen & Moeck, 2021). ...
... Recent studies have primarily focused on characterizing and modelling the deep geothermal potential of the granite systems; however, little research has been undertaken to explore the fractured sedimentary cover and the influence of the fracture networks on geothermal flow (Kämmlein et al. 2017;de Wall et al. 2019;Bohnsack et al. 2020). In the Molasse Basin ( Fig. 1) to the south, the Malm unit is currently utilized for geothermal energy where structural features (fractures, faults and karst) play a key role in producing high flow rates up to 10 −4 m s −1 to the north of the basin (Birner et al. 2012;Birner, 2013;Przybycin et al. 2017;Bohnsack et al. 2020;Schintgen & Moeck, 2021). It is therefore important that geothermal flow through fractured networks of the Franconian Basin be better understood for future exploration. ...
... Therefore, the fault directly influences the orientation of the permeability tensors and ellipses and thus fluid flow. Fluid flow orientation is important within the reservoir, particularly when primary permeability is controlled by structural features rather than sedimentological properties as observed within the Malm (Birner et al. 2012;Schintgen and Moeck 2021). ...
Faulted and fractured systems form a critical component of fluid flow, especially within low-permeable reservoirs. Therefore, developing suitable methodologies for acquiring structural data and simulating flow through fractured media is vital to improve efficiency and reduce uncertainties in modelling the subsurface. Outcrop analogues provide excellent areas for the analysis and characterization of fractures within the reservoir rocks where subsurface data are limited. Variation in fracture arrangement, distribution and connectivity can be obtained from 2D fractured cliff sections and pavements. These sections can then be used for efficient discretization and homogenization techniques to obtain reliable predictions on permeability distributions in the geothermal reservoirs. Fracture network anisotropy in the Malm reservoir unit is assessed using detailed structural analysis and numerical homogenization of outcrop analogues from an open pit quarry within the Franconian Basin, Germany. Several events are recorded in the fracture networks from the Late Jurassic the Alpine Orogeny and are observed to be influenced by the Kulmbach Fault nearby with a reverse throw of 800 m. The fractured outcrops are digitized for fluid flow simulations and homogenization to determine the permeability tensors of the networks. The tensors show differences in fluid transport direction where fracture permeability is controlled by orientation compared to a constant value. As a result, it is observed that the orientation of the tensor is influenced by the Kulmbach Fault, and therefore faults within the reservoirs at depth should be considered as important controls on the fracture flow of the geothermal system.
