Yazar "Şengül Uluocak, Ebru" seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A Discussion on Geodynamic Modeling Methodology: Inferences from Numerical Models in the Anatolian Plate(Tmmob Jeoloji Mühendisleri Odası, 2024) Şengül Uluocak, EbruNumerical models have found widespread use in geosciences, mainly due to high-resolution datasets and the development of supercomputing facilities with powerful data processing and storage capabilities during the past two decades. Instantaneous and time-dependent geodynamic modeling studies were carried out in many regions of the Alpine-Himalayan orogenic belt, including the Anatolian Plate, to investigate mantle dynamics such as lower lithosphere deformation, upper mantle flow, and their surface implications. This study focuses on the instantaneous numerical modeling technique by considering multidimensional thermomechanical models in the Central and East Anatolian plateaus. To this end, conventional geodynamic modeling processes are explained with a conceptual flow chart that shows a feed-forward backpropagation modeling architecture which is nonlinearly fed by a large parameter space. While addressing a complex natural phenomenon controlled by variables on a wide range of space-time scales, the limitations as well as advantages of numerical models are analyzed. In addition to conventional techniques, systematic data improvement is discussed as a new strategy in data/ parameter-dependent numerical model design through an iterative process based on the Grounded Theory method for the construction of an explanatory theory from the model. This involves not refinement but (re)construction of the data (i.e., measurement/analysis/scaling) as an effective way to reveal theory/information grounded in data. It is speculated that this procedure, which includes problem-oriented data reconstruction accompanying the numerical modeling process, may provide an integrated perspective for instantaneous numerical modelling.Öğe Geodynamics of East Anatolia-Caucasus Domain: Inferences From 3D Thermo-Mechanical Models, Residual Topography, and Admittance Function Analyses(John Wiley and Sons Inc, 2021) Şengül Uluocak, Ebru; Göğüş, Oğuz H.; Pysklywec, Russell N.; Chen, BoWe investigate anomalous topography in the Anatolia-Caucasus domain of the Arabian-Eurasian plate convergence zone. To achieve this aim, we use three-dimensional (3D) geodynamic modeling in addition to analyses of the non-isostatic components of surface topography based on residual topography and free-air gravity admittance functions. The numerical experiments are based on two different temperature models obtained from P-wave tomography data that are sensitive respectively to large and small-scale variations of upper mantle structures. Our results suggest a long-wavelength convective support of topography, which is in general agreement with the uncompensated pattern of residual topography and free-air admittance values, as well as previous modeling studies. At shorter wavelengths, we provide new constraints on the regional dynamic processes related to 3D variations of the upper mantle flow vectors and associated surface deflections. Positive dynamic topography is found over the East Anatolian Plateau (∼400 m to ∼1.2 km) that is consistent with inferred lithospheric thinning processes pertinent to the tectonic evolution of the Tethyan orogenic system. We further show dynamic topography in the plateau (≥500 m) that may account for extensional tectonics in the Lake Van region interpreted from local kinematic and geophysical studies. In conjunction with the observations, negative anomaly patterns are estimated in the western part of the Black Sea (∼−2 km), the eastern Pontides arc (∼−200 m), and the northeast Arabian Plate (∼−1 to −2.3 km). Our model results also suggest a link between large-scale mantle flow and SW-NE-directed general pattern of the SKS-based anisotropy beneath the region. © 2021. American Geophysical Union.Öğe Multistage lithospheric drips control active basin formation within an uplifting orogenic plateau(Nature Portfolio, 2024) Andersen, A. Julia; Göğüş, Oğuz Hakan; Pysklywec, Russell N.; Şengül Uluocak, Ebru; Santimano, TascaAccording to GNSS/INSAR measurements, the Konya Basin in Central Anatolia is undergoing rapid subsidence within an uplifting orogenic plateau. Further, geophysical studies reveal thickened crust under the basin and a fast seismic wave speed anomaly in the underlying mantle, in addition to a localised depression in calculated residual topography (down to 280 m) over the Konya Basin, based on gravity-topography considerations. Using scaled laboratory (analogue) experiments we show that the active formation of the Konya Basin may be accounted for by the descent of a mantle lithospheric drip causing local circular-shaped surface subsidence. We interpret that the Konya Basin is developing through a secondary drip pulse that is contemporaneous with broad plateau uplift caused by a larger-scale lithospheric drip since the Miocene. The research reveals that basin evolution and plateau uplift may be linked in a multistage process of lithospheric removal during episodic development of orogenic systems. Active subsidence of the Konya region, Turkiye, is attributed to descent of a lithospheric drip into the mantle, according to analogue models, and suggests that major tectonic events may be linked to multistage dynamic flow processes in the mantle.Öğe The Role of Upper Mantle Forces in Post-Subduction Tectonics: Plumelet and Active Rifting in the East Anatolian Plateau(Amer Geophysical Union, 2024) Şengül Uluocak, Ebru; Pysklywec, Russell N.; Sembroni, Andrea; Brune, Sascha; Faccenna, ClaudioThe spatiotemporal interaction of large- and regional-scale upper mantle forces can prevail in collisional settings. To better understand the role of these forces on post-subduction tectonics, we focus on mantle dynamics in the East Anatolian Plateau, a well-documented segment of the Arabian-Eurasian continental collision zone. Specifically, we analyze multiple forces in the upper mantle, which have not been considered in previous studies in this region. To this end, we use a state-of-the-art 3D instantaneous geodynamic model to quantify the dynamics of thermally defined upper mantle structures derived from seismic tomography data. Results reveal a prominent SW-NE-oriented mantle flow from the Arabian foreland to the Greater Caucasus–a plumelet–through a lithospheric channel under the East Anatolian Plateau. This plumelet induces localized dynamic topography (∼500 m) around the extensional Lake Van province, favoring NE-directed compression and westward escape of the Anatolian plate. We suggest that the Lake Van region is an active magma-rich intraplate rift in the Africa-Arabia-Anatolian plume-rift system. The rift zone was probably initiated by Neotethyan subduction-related forces and has been reactivated and/or sustained by the plumelet-induced convective support. Our findings are consistent with numerous observations, including the recent low-ultralow seismic velocities with a SW-NE splitting anisotropy pattern, geochemical and petrological studies, and local kinematics showing upper mantle-induced extensional tectonics in the collisional region.
