TY - GEN A1 - Rodriguez Piceda, Constanza A1 - Scheck Wenderoth, Magdalena A1 - Gomez Dacal, Maria Laura A1 - Bott, Judith A1 - Prezzi, Claudia Beatriz A1 - Strecker, Manfred T1 - Lithospheric density structure of the southern Central Andes constrained by 3D data-integrative gravity modelling T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The southern Central Andes (SCA) (between 27 degrees S and 40 degrees S) is bordered to the west by the convergent margin between the continental South American Plate and the oceanic Nazca Plate. The subduction angle along this margin is variable, as is the deformation of the upper plate. Between 33 degrees S and 35 degrees S, the subduction angle of the Nazca plate increases from sub-horizontal (< 5 degrees) in the north to relatively steep (similar to 30 degrees) in the south. The SCA contain inherited lithological and structural heterogeneities within the crust that have been reactivated and overprinted since the onset of subduction and associated Cenozoic deformation within the Andean orogen. The distribution of the deformation within the SCA has often been attributed to the variations in the subduction angle and the reactivation of these inherited heterogeneities. However, the possible influence that the thickness and composition of the continental crust have had on both short-term and long-term deformation of the SCA is yet to be thoroughly investigated. For our investigations, we have derived density distributions and thicknesses for various layers that make up the lithosphere and evaluated their relationships with tectonic events that occurred over the history of the Andean orogeny and, in particular, investigated the short- and long-term nature of the present-day deformation processes. We established a 3D model of lithosphere beneath the orogen and its foreland (29 degrees S-39 degrees S) that is consistent with currently available geological and geophysical data, including the gravity data. The modelled crustal configuration and density distribution reveal spatial relationships with different tectonic domains: the crystalline crust in the orogen (the magmatic arc and the main orogenic wedge) is thicker (similar to 55 km) and less dense (similar to 2900 kg/m(3)) than in the forearc (similar to 35 km, similar to 2975 kg/m(3)) and foreland (similar to 30 km, similar to 3000 kg/m(3)). Crustal thickening in the orogen probably occurred as a result of stacking of low-density domains, while density and thickness variations beneath the forearc and foreland most likely reflect differences in the tectonic evolution of each area following crustal accretion. No clear spatial relationship exists between the density distribution within the lithosphere and previously proposed boundaries of crustal terranes accreted during the early Paleozoic. Areas with ongoing deformation show a spatial correlation with those areas that have the highest topographic gradients and where there are abrupt changes in the average crustal-density contrast. This suggests that the short-term deformation within the interior of the Andean orogen and its foreland is fundamentally influenced by the crustal composition and the relative thickness of different crustal layers. A thicker, denser, and potentially stronger lithosphere beneath the northern part of the SCA foreland is interpreted to have favoured a strong coupling between the Nazca and South American plates, facilitating the development of a sub-horizontal slab. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1369 KW - Central andes KW - Lithospheric structure KW - Crustal density KW - Gravity KW - modelling KW - Subduction Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-562628 SN - 1866-8372 IS - 7 ER - TY - JOUR A1 - Rodriguez Piceda, Constanza A1 - Scheck Wenderoth, Magdalena A1 - Gomez Dacal, Maria Laura A1 - Bott, Judith A1 - Prezzi, Claudia Beatriz A1 - Strecker, Manfred T1 - Lithospheric density structure of the southern Central Andes constrained by 3D data-integrative gravity modelling JF - International journal of earth sciences N2 - The southern Central Andes (SCA) (between 27 degrees S and 40 degrees S) is bordered to the west by the convergent margin between the continental South American Plate and the oceanic Nazca Plate. The subduction angle along this margin is variable, as is the deformation of the upper plate. Between 33 degrees S and 35 degrees S, the subduction angle of the Nazca plate increases from sub-horizontal (< 5 degrees) in the north to relatively steep (similar to 30 degrees) in the south. The SCA contain inherited lithological and structural heterogeneities within the crust that have been reactivated and overprinted since the onset of subduction and associated Cenozoic deformation within the Andean orogen. The distribution of the deformation within the SCA has often been attributed to the variations in the subduction angle and the reactivation of these inherited heterogeneities. However, the possible influence that the thickness and composition of the continental crust have had on both short-term and long-term deformation of the SCA is yet to be thoroughly investigated. For our investigations, we have derived density distributions and thicknesses for various layers that make up the lithosphere and evaluated their relationships with tectonic events that occurred over the history of the Andean orogeny and, in particular, investigated the short- and long-term nature of the present-day deformation processes. We established a 3D model of lithosphere beneath the orogen and its foreland (29 degrees S-39 degrees S) that is consistent with currently available geological and geophysical data, including the gravity data. The modelled crustal configuration and density distribution reveal spatial relationships with different tectonic domains: the crystalline crust in the orogen (the magmatic arc and the main orogenic wedge) is thicker (similar to 55 km) and less dense (similar to 2900 kg/m(3)) than in the forearc (similar to 35 km, similar to 2975 kg/m(3)) and foreland (similar to 30 km, similar to 3000 kg/m(3)). Crustal thickening in the orogen probably occurred as a result of stacking of low-density domains, while density and thickness variations beneath the forearc and foreland most likely reflect differences in the tectonic evolution of each area following crustal accretion. No clear spatial relationship exists between the density distribution within the lithosphere and previously proposed boundaries of crustal terranes accreted during the early Paleozoic. Areas with ongoing deformation show a spatial correlation with those areas that have the highest topographic gradients and where there are abrupt changes in the average crustal-density contrast. This suggests that the short-term deformation within the interior of the Andean orogen and its foreland is fundamentally influenced by the crustal composition and the relative thickness of different crustal layers. A thicker, denser, and potentially stronger lithosphere beneath the northern part of the SCA foreland is interpreted to have favoured a strong coupling between the Nazca and South American plates, facilitating the development of a sub-horizontal slab. KW - Central andes KW - Lithospheric structure KW - Crustal density KW - Gravity KW - modelling KW - Subduction Y1 - 2020 U6 - https://doi.org/10.1007/s00531-020-01962-1 SN - 1437-3254 SN - 1437-3262 VL - 110 IS - 7 SP - 2333 EP - 2359 PB - Springer CY - New York 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 - Prezzi, Claudia Beatriz A1 - Uba, Cornelius Eji A1 - Götze, Hans-Jürgen T1 - Flexural isostasy in the Bolivian Andes : Chaco foreland basin development N2 - The Chaco foreland basin was initiated during the late Oligocene as a result of thrusting in the Eastern Cordillera in response to Nazca-South America plate convergence. Foreland basins are the result of the flexural isostatic response of an elastic plate to orogenic and/or thrust sheet loading. We carried out flexural modelling along a W-E profile (21.4 degrees S) to investigate Chaco foreland basin development using new information on ages of foreland basin strata, elastic and sedimentary thicknesses and structural histories. It was possible to reproduce present-day elevation, gravity anomaly, Moho depth, elastic thicknesses, foreland sedimentary thicknesses and the basin geometry. Our model predicted the basin geometry and sedimentary thicknesses for different evolutionary stages. Measured thicknesses and previously proposed depozones were compared with our predictions. Our results shed more light on the Chaco foreland basin evolution and suggest that an apparent decrease in elastic thickness beneath the Eastern Cordillera and the Interandean Zone could have occurred between 14 and 6 Ma. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00401951 U6 - https://doi.org/10.1016/j.tecto.2009.04.037 SN - 0040-1951 ER -