@phdthesis{Barrionuevo2020, author = {Barrionuevo, Mat{\´i}as}, title = {The role of the upper plate in the Andean tectonic evolution (33-36°S): insights from structural geology and numerical modeling}, doi = {10.25932/publishup-51590}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515909}, school = {Universit{\"a}t Potsdam}, pages = {148, S2}, year = {2020}, abstract = {Los Andes Centrales del Sur (33-36°S) son un gran laboratorio para el estudio de los procesos de deformaci{\´o}n orog{\´e}nica, donde las condiciones de borde, como la geometr{\´i}a de la placa subductada, imponen un importante control sobre la deformaci{\´o}n andina. Por otro lado, la Placa Sudamericana presenta una serie de heterogeneidades que tambi{\´e}n imparten un control sobre el modo de deformaci{\´o}n. El objetivo de esta tesis es probar el control de este {\´u}ltimo factor sobre la construcci{\´o}n del sistema orog{\´e}nico andino. A partir de la integraci{\´o}n de la informaci{\´o}n superficial y de subsuelo en el {\´a}rea sur (34°-36°S), se estudi{\´o} la evoluci{\´o}n de la deformaci{\´o}n andina sobre el segmento de subducci{\´o}n normal. Se desarroll{\´o} un modelo estructural que eval{\´u}a el estado de esfuerzos desde el Mioceno hasta la actualidad, el rol de estructuras previas y su influencia en la migraci{\´o}n de fluidos. Con estos datos y publicaciones previas de la zona norte del {\´a}rea de estudio (33°-34ºS), se realiz{\´o} un modelado num{\´e}rico geodin{\´a}mico para probar la hip{\´o}tesis del papel de las heterogeneidades de la placa superior en la evoluci{\´o}n andina. Se utilizaron dos c{\´o}digos (LAPEX-2D y ASPECT) basados en elementos finitos/diferencias finitas, que simulan el comportamiento de materiales con reolog{\´i}as elastoviscopl{\´a}sticas bajo deformaci{\´o}n. Los resultados del modelado sugieren que la deformaci{\´o}n contraccional de la placa superior est{\´a} significativamente controlada por la resistencia de la lit{\´o}sfera, que est{\´a} definida por la composici{\´o}n de la corteza superior e inferior y por la proporci{\´o}n del manto litosf{\´e}rico, que a su vez est{\´a} definida por eventos tect{\´o}nicos previos. Estos eventos previos tambi{\´e}n definieron la composici{\´o}n de la corteza y su geometr{\´i}a, que es otro factor que controla la localizaci{\´o}n de la deformaci{\´o}n. Con una composici{\´o}n de corteza inferior m{\´a}s f{\´e}lsica, la deformaci{\´o}n sigue un modo de cizalla pura mientras que las composiciones m{\´a}s m{\´a}ficas provocan un modo de deformaci{\´o}n tipo cizalla simple. Por otro lado, observamos que el espesor inicial de la lit{\´o}sfera controla la localizaci{\´o}n de la deformaci{\´o}n, donde zonas con lit{\´o}sfera m{\´a}s fina es propensa a concentrar la deformaci{\´o}n. Un l{\´i}mite lit{\´o}sfera-asten{\´o}sfera asim{\´e}trico, como resultado del flujo de la cu{\~n}a mant{\´e}lica tiende a generar despegues vergentes al E.}, language = {en} } @article{DuesterhoeftdeCapitani2013, author = {D{\"u}sterh{\"o}ft, Erik and de Capitani, Christian}, title = {Theriak_D - an add-on to implement equilibrium computations in geodynamic models}, series = {Geochemistry, geophysics, geosystems}, volume = {14}, journal = {Geochemistry, geophysics, geosystems}, number = {11}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1002/ggge.20286}, pages = {4962 -- 4967}, year = {2013}, abstract = {This study presents the theory, applicability, and merits of the new THERIAK_D add-on for the open source Theriak/Domino software package. The add-on works as an interface between Theriak and user-generated scripts, providing the opportunity to process phase equilibrium computation parameters in a programming environment (e. g., C or MATLABV (R)). THERIAK_D supports a wide range of features such as calculating the solid rock density or testing the stability of mineral phases along any pressure-temperature (P-T) path and P-T grid. To demonstrate applicability, an example is given in which the solid rock density of a 2-D-temperature-pressure field is calculated, portraying a simplified subduction zone. Consequently, the add-on effectively combines thermodynamics and geodynamic modeling. The carefully documented examples could be easily adapted for a broad range of applications. THERIAK_D is free, and the program, user manual, and source codes may be downloaded from http://www.min.unikiel.de/similar to ed/theriakd/.}, language = {en} } @article{LiuSobolevBabeykoetal.2022, author = {Liu, Sibiao and Sobolev, Stephan and Babeyko, Andrey and Pons, Micha{\"e}l}, title = {Controls of the foreland deformation pattern in the orogen-foreland shortening system}, series = {Tectonics}, volume = {41}, journal = {Tectonics}, number = {2}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1029/2021TC007121}, pages = {18}, year = {2022}, abstract = {Controls on the deformation pattern (shortening mode and tectonic style) of orogenic forelands during lithospheric shortening remain poorly understood. Here, we use high-resolution 2D thermomechanical models to demonstrate that orogenic crustal thickness and foreland lithospheric thickness significantly control the shortening mode in the foreland. Pure-shear shortening occurs when the orogenic crust is not thicker than the foreland crust or thick, but the foreland lithosphere is thin (<70-80 km, as in the Puna foreland case). Conversely, simple-shear shortening, characterized by foreland underthrusting beneath the orogen, arises when the orogenic crust is much thicker. This thickened crust results in high gravitational potential energy in the orogen, which triggers the migration of deformation to the foreland under further shortening. Our models present fully thick-skinned, fully thin-skinned, and intermediate tectonic styles in the foreland. The first tectonics forms in a pure-shear shortening mode whereas the others require a simple-shear mode and the presence of thick (>similar to 4 km) sediments that are mechanically weak (friction coefficient