TY - JOUR A1 - Freymark, Jessica A1 - Bott, Judith A1 - Cacace, Mauro A1 - Ziegler, Moritz 0. A1 - Scheck-Wenderoth, Magdalena T1 - Influence of the Main Border Faults on the 3D Hydraulic Field of the Central Upper Rhine Graben JF - Geofluids N2 - The Upper Rhine Graben (URG) is an active rift with a high geothermal potential. Despite being a well-studied area, the three-dimensional interaction of the main controlling factors of the thermal and hydraulic regime is still not fully understood. Therefore, we have used a data-based 3D structural model of the lithological configuration of the central URG for some conceptual numerical experiments of 3D coupled simulations of fluid and heat transport. To assess the influence of the main faults bordering the graben on the hydraulic and the deep thermal field, we carried out a sensitivity analysis on fault width and permeability. Depending on the assigned width and permeability of the main border faults, fluid velocity and temperatures are affected only in the direct proximity of the respective border faults. Hence, the hydraulic characteristics of these major faults do not significantly influence the graben-wide groundwater flow patterns. Instead, the different scenarios tested provide a consistent image of the main characteristics of fluid and heat transport as they have in common: (1) a topography-driven basin-wide fluid flow perpendicular to the rift axis from the graben shoulders to the rift center, (2) a N/NE-directed flow parallel to the rift axis in the center of the rift and, (3) a pronounced upflow of hot fluids along the rift central axis, where the streams from both sides of the rift merge. This upflow axis is predicted to occur predominantly in the center of the URG (northern and southern model area) and shifted towards the eastern boundary fault (central model area). Y1 - 2019 U6 - https://doi.org/10.1155/2019/7520714 SN - 1468-8115 SN - 1468-8123 PB - Wiley-Hindawi CY - London ER - TY - GEN A1 - Gholamrezaie, Ershad A1 - Scheck-Wenderoth, Magdalena A1 - Bott, Judith A1 - Heidbach, Oliver A1 - Strecker, Manfred T1 - 3-D crustal density model of the Sea of Marmara T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Abstract. The Sea of Marmara, in northwestern Turkey, is a transition zone where the dextral North Anatolian Fault zone (NAFZ) propagates westward from the Anatolian Plate to the Aegean Sea Plate. The area is of interest in the context of seismic hazard of Istanbul, a metropolitan area with about 15 million inhabitants. Geophysical observations indicate that the crust is heterogeneous beneath the Marmara basin, but a detailed characterization of the crustal heterogeneities is still missing. To assess if and how crustal heterogeneities are related to the NAFZ segmentation below the Sea of Marmara, we develop new crustal-scale 3-D density models which integrate geological and seismological data and that are additionally constrained by 3-D gravity modeling. For the latter, we use two different gravity datasets including global satellite data and local marine gravity observation. Considering the two different datasets and the general non-uniqueness in potential field modeling, we suggest three possible “end-member” solutions that are all consistent with the observed gravity field and illustrate the spectrum of possible solutions. These models indicate that the observed gravitational anomalies originate from significant density heterogeneities within the crust. Two layers of sediments, one syn-kinematic and one pre-kinematic with respect to the Sea of Marmara formation are underlain by a heterogeneous crystalline crust. A felsic upper crystalline crust (average density of 2720 kgm⁻³) and an intermediate to mafic lower crystalline crust (average density of 2890 kgm⁻³) appear to be cross-cut by two large, dome-shaped mafic highdensity bodies (density of 2890 to 3150 kgm⁻³) of considerable thickness above a rather uniform lithospheric mantle (3300 kgm⁻³). The spatial correlation between two major bends of the main Marmara fault and the location of the highdensity bodies suggests that the distribution of lithological heterogeneities within the crust controls the rheological behavior along the NAFZ and, consequently, maybe influences fault segmentation and thus the seismic hazard assessment in the region. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 737 KW - North Anatolian Fault KW - Shear Zone KW - Northwestern Anatolia KW - Geomechanical Model KW - Tectonic Evolution KW - Slip Distribution KW - Middle Strand KW - Pull-Apart KW - Long-Term KW - NW Turkey Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-434661 SN - 1866-8372 IS - 737 SP - 785 EP - 807 ER - TY - JOUR A1 - Gholamrezaie, Ershad A1 - Scheck-Wenderoth, Magdalena A1 - Bott, Judith A1 - Heidbach, Oliver A1 - Strecker, Manfred T1 - 3-D crustal density model of the Sea of Marmara JF - Solid Earth N2 - Abstract. The Sea of Marmara, in northwestern Turkey, is a transition zone where the dextral North Anatolian Fault zone (NAFZ) propagates westward from the Anatolian Plate to the Aegean Sea Plate. The area is of interest in the context of seismic hazard of Istanbul, a metropolitan area with about 15 million inhabitants. Geophysical observations indicate that the crust is heterogeneous beneath the Marmara basin, but a detailed characterization of the crustal heterogeneities is still missing. To assess if and how crustal heterogeneities are related to the NAFZ segmentation below the Sea of Marmara, we develop new crustal-scale 3-D density models which integrate geological and seismological data and that are additionally constrained by 3-D gravity modeling. For the latter, we use two different gravity datasets including global satellite data and local marine gravity observation. Considering the two different datasets and the general non-uniqueness in potential field modeling, we suggest three possible “end-member” solutions that are all consistent with the observed gravity field and illustrate the spectrum of possible solutions. These models indicate that the observed gravitational anomalies originate from significant density heterogeneities within the crust. Two layers of sediments, one syn-kinematic and one pre-kinematic with respect to the Sea of Marmara formation are underlain by a heterogeneous crystalline crust. A felsic upper crystalline crust (average density of 2720 kgm⁻³) and an intermediate to mafic lower crystalline crust (average density of 2890 kgm⁻³) appear to be cross-cut by two large, dome-shaped mafic highdensity bodies (density of 2890 to 3150 kgm⁻³) of considerable thickness above a rather uniform lithospheric mantle (3300 kgm⁻³). The spatial correlation between two major bends of the main Marmara fault and the location of the highdensity bodies suggests that the distribution of lithological heterogeneities within the crust controls the rheological behavior along the NAFZ and, consequently, maybe influences fault segmentation and thus the seismic hazard assessment in the region. KW - North Anatolian Fault KW - Shear Zone KW - Northwestern Anatolia KW - Geomechanical Model KW - Tectonic Evolution KW - Slip Distribution KW - Middle Strand KW - Pull-Apart KW - Long-Term KW - NW Turkey Y1 - 2019 U6 - https://doi.org/10.5194/se-10-785-2019 SN - 1869-9510 SN - 1869-9529 VL - 10 SP - 785 EP - 807 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Gomez-Garcia, Angela Maria A1 - Meeßen, Christian A1 - Scheck-Wenderoth, Magdalena A1 - Monsalve, Gaspar A1 - Bott, Judith A1 - Bernhardt, Anne A1 - Bernal, Gladys T1 - 3-D Modeling of Vertical Gravity Gradients and the Delimitation of Tectonic Boundaries: The Caribbean Oceanic Domain as a Case Study JF - Geochemistry, geophysics, geosystems N2 - Geophysical data acquisition in oceanic domains is challenging, implying measurements with low and/or nonhomogeneous spatial resolution. The evolution of satellite gravimetry and altimetry techniques allows testing 3-D density models of the lithosphere, taking advantage of the high spatial resolution and homogeneous coverage of satellites. However, it is not trivial to discretise the source of the gravity field at different depths. Here, we propose a new method for inferring tectonic boundaries at the crustal level. As a novelty, instead of modeling the gravity anomalies and assuming a flat Earth approximation, we model the vertical gravity gradients (VGG) in spherical coordinates, which are especially sensitive to density contrasts in the upper layers of the Earth. To validate the methodology, the complex oceanic domain of the Caribbean region is studied, which includes different crustal domains with a tectonic history since Late Jurassic time. After defining a lithospheric starting model constrained by up-to-date geophysical data sets, we tested several a-priory density distributions and selected the model with the minimum misfits with respect to the VGG calculated from the EIGEN-6C4 data set. Additionally, the density of the crystalline crust was inferred by inverting the VGG field. Our methodology enabled us not only to refine, confirm, and/or propose tectonic boundaries in the study area but also to identify a new anomalous buoyant body, located in the South Lesser Antilles subduction zone, and high-density bodies along the Greater, Lesser, and Leeward Antilles forearcs. KW - Vertical Gravity Gradients KW - Gravity modelling KW - Crustal structure KW - Caribbean KW - Tectonic boundaries KW - 3D lithospheric model Y1 - 2019 U6 - https://doi.org/10.1029/2019GC008340 SN - 1525-2027 VL - 20 IS - 11 SP - 5371 EP - 5393 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Ibarra, Federico A1 - Liu, Sibiao A1 - Meeßen, Christian A1 - Prezzi, Claudia Beatriz A1 - Bott, Judith A1 - Scheck-Wenderoth, Magdalena A1 - Sobolev, Stephan Vladimir A1 - Strecker, Manfred T1 - 3D data-derived lithospheric structure of the Central Andes and its implications for deformation: Insights from gravity and geodynamic modelling JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - We present a new three-dimensional density model of the Central Andes characterizing the structure and composition of the lithosphere together with a geodynamic simulation subjected to continental intraplate shortening. The principal aim of this study is to assess the link between heterogeneities in the lithosphere and different deformation patterns and styles along the orogen-foreland system of the Central Andes. First, we performed a 3D integration of new geological and geophysical data with previous models through forward modelling of Bouguer anomalies. Subsequently, a geodynamic model was set-up and parametrized from the previously obtained 3D structure and composition. We do not find a unambigous correlation between the resulting density configuration and terrane boundaries proposed by other authors. Our models reproduce the observed Bouguer anomaly and deformation patterns in the foreland. We find that thin-skinned deformation in the Subandean fold-and thrust belt is controlled by a thick sedimentary layer and coeval underthrusting of thin crust of the foreland beneath the thick crust of the Andean Plateau. In the adjacent thick-skinned deformation province of the inverted Cretaceous extensional Santa Barbara System sedimentary strata are much thinner and crustal thickness transitions from greater values in the Andean to a more reduced thickness in the foreland. Our results show that deformation processes occur where the highest gradients of lithospheric strength are present between the orogen and the foreland, thus suggesting a spatial correlation between deformation and lithospheric strength. KW - Central Andes KW - Lithospheric structure KW - Gravity modelling KW - Geodynamic modelling KW - Deformation Y1 - 2019 U6 - https://doi.org/10.1016/j.tecto.2019.06.025 SN - 0040-1951 SN - 1879-3266 VL - 766 SP - 453 EP - 468 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rodriguez Piceda, Constanza A1 - Scheck-Wenderoth, Magdalena A1 - Bott, Judith A1 - Gomez Dacal, Maria Laura A1 - Cacace, Mauro A1 - Pons, Michael A1 - Prezzi, Claudia A1 - Strecker, Manfred T1 - Controls of the Lithospheric Thermal Field of an Ocean-Continent Subduction Zone BT - the Southern Central Andes JF - Lithosphere / Geological Society of America N2 - In an ocean-continent subduction zone, the assessment of the lithospheric thermal state is essential to determine the controls of the deformation within the upper plate and the dip angle of the subducting lithosphere. In this study, we evaluate the degree of influence of both the configuration of the upper plate (i.e., thickness and composition of the rock units) and variations of the subduction angle on the lithospheric thermal field of the southern Central Andes (29 degrees-39 degrees S). Here, the subduction angle increases from subhorizontal (5 degrees) north of 33 degrees S to steep (similar to 30 degrees) in the south. We derived the 3D temperature and heat flow distribution of the lithosphere in the southern Central Andes considering conversion of S wave tomography to temperatures together with steady-state conductive thermal modeling. We found that the orogen is overall warmer than the forearc and the foreland and that the lithosphere of the northern part of the foreland appears colder than its southern counterpart. Sedimentary blanketing and the thickness of the radiogenic crust exert the main control on the shallow thermal field (<50km depth). Specific conditions are present where the oceanic slab is relatively shallow (<85 km depth) and the radiogenic crust is thin. This configuration results in relatively colder temperatures compared to regions where the radiogenic crust is thick and the slab is steep. At depths >50km, the temperatures of the overriding plate are mainly controlled by the mantle heat input and the subduction angle. The thermal field of the upper plate likely preserves the flat subduction angle and influences the spatial distribution of shortening. Y1 - 2022 U6 - https://doi.org/10.2113/2022/2237272 SN - 1941-8264 SN - 1947-4253 VL - 2022 IS - 1 PB - GeoScienceWorld CY - McLean ER - TY - JOUR A1 - Rodriguez Piceda, Constanza A1 - Scheck-Wenderoth, Magdalena A1 - Cacace, Mauro A1 - Bott, Judith A1 - Strecker, Manfred T1 - Long-Term Lithospheric Strength and Upper-Plate Seismicity in the Southern Central Andes, 29 degrees-39 degrees S JF - Geochemistry, geophysics, geosystems N2 - We examined the relationship between the mechanical strength of the lithosphere and the distribution of seismicity within the overriding continental plate of the southern Central Andes (SCA, 29 degrees-39 degrees S), where the oceanic Nazca Plate changes its subduction angle between 33 degrees S and 35 degrees S, from subhorizontal in the north (<5 degrees) to steep in the south (similar to 30 degrees). We computed the long-term lithospheric strength based on an existing 3D model describing variations in thickness, density, and temperature of the main geological units forming the lithosphere of the SCA and adjacent forearc and foreland regions. The comparison between our results and seismicity within the overriding plate (upper-plate seismicity) shows that most of the events occur within the modeled brittle domain of the lithosphere. The depth where the deformation mode switches from brittle frictional to thermally activated ductile creep provides a conservative lower bound to the seismogenic zone in the overriding plate of the study area. We also found that the majority of upper-plate earthquakes occurs within the realm of first-order contrasts in integrated strength (12.7-13.3 log Pam in the Andean orogen vs. 13.5-13.9 log Pam in the forearc and the foreland). Specific conditions characterize the mechanically strong northern foreland of the Andes, where seismicity is likely explained by the effects of slab steepening. KW - subduction zone KW - Andes KW - rheology KW - seismicity KW - flat-slab Y1 - 2022 U6 - https://doi.org/10.1029/2021GC010171 SN - 1525-2027 VL - 23 IS - 3 PB - American Geophysical Union CY - Washington ER -