@article{YuanSobolevKindetal.2000, author = {Yuan, X. H and Sobolev, Stephan Vladimir and Kind, Rainer and Oncken, Onno and Bock, G{\"u}nter and Asch, G{\"u}nter and Schurr, B. and Gr{\"a}ber, F. and Rudloff, Alexander and Hanka, W. and Wylegalla, Kurt and Tibi, R. and Haberland, Christian and Rietbrock, Andreas and Giese, Peter and Wigger, Peter and Rower, P. and Zandt, G. and Beck, S. and Wallace, T. and Pardo, M. and Comte, D.}, title = {Subduction and collision processes in the Central Andes constrained by converted seismic phases}, year = {2000}, language = {en} } @article{WeberAbuAyyashAbueladasetal.2004, author = {Weber, Michael H. and Abu-Ayyash, Khalil and Abueladas, Abdel-Rahman and Agnon, Amotz and Al-Amoush, H. and Babeyko, Andrey and Bartov, Yosef and Baumann, M. and Ben-Avraham, Zvi and Bock, G{\"u}nter and Bribach, Jens and El-Kelani, R. and Forster, A. and F{\"o}rster, Hans-J{\"u}rgen and Frieslander, U. and Garfunkel, Zvi and Grunewald, Steffen and Gotze, Hans-J{\"u}rgen and Haak, Volker and Haberland, Christian and Hassouneh, Mohammed and Helwig, S. and Hofstetter, Alfons and Jackel, K. H. and Kesten, Dagmar and Kind, Rainer and Maercklin, Nils and Mechie, James and Mohsen, Amjad and Neubauer, F. M. and Oberh{\"a}nsli, Roland and Qabbani, I. and Ritter, O. and Rumpker, G. and Rybakov, M. and Ryberg, Trond and Scherbaum, Frank and Schmidt, J. and Schulze, A. and Sobolev, Stephan Vladimir and Stiller, M. and Th,}, title = {The crustal structure of the Dead Sea Transform}, year = {2004}, abstract = {To address one of the central questions of plate tectonics-How do large transform systems work and what are their typical features?-seismic investigations across the Dead Sea Transform (DST), the boundary between the African and Arabian plates in the Middle East, were conducted for the first time. A major component of these investigations was a combined reflection/ refraction survey across the territories of Palestine, Israel and Jordan. The main results of this study are: (1) The seismic basement is offset by 3-5 km under the DST, (2) The DST cuts through the entire crust, broadening in the lower crust, (3) Strong lower crustal reflectors are imaged only on one side of the DST, (4) The seismic velocity sections show a steady increase in the depth of the crust-mantle transition (Moho) from 26 km at the Mediterranean to 39 km under the Jordan highlands, with only a small but visible, asymmetric topography of the Moho under the DST. These observations can be linked to the left-lateral movement of 105 km of the two plates in the last 17 Myr, accompanied by strong deformation within a narrow zone cutting through the entire crust. Comparing the DST and the San Andreas Fault (SAF) system, a strong asymmetry in subhorizontal lower crustal reflectors and a deep reaching deformation zone both occur around the DST and the SAF. The fact that such lower crustal reflectors and deep deformation zones are observed in such different transform systems suggests that these structures are possibly fundamental features of large transform plate boundaries}, language = {en} } @article{TutuSteinbergerSobolevetal.2018, author = {Tutu, Anthony Osei and Steinberger, Bernhard and Sobolev, Stephan Vladimir and Rogozhina, Irina and Popov, Anton A.}, title = {Effects of upper mantle heterogeneities on the lithospheric stress field and dynamic topography}, series = {Solid earth}, volume = {9}, journal = {Solid earth}, number = {3}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1869-9510}, doi = {10.5194/se-9-649-2018}, pages = {649 -- 668}, year = {2018}, abstract = {The orientation and tectonic regime of the observed crustal/lithospheric stress field contribute to our knowledge of different deformation processes occurring within the Earth's crust and lithosphere. In this study, we analyze the influence of the thermal and density structure of the upper mantle on the lithospheric stress field and topography. We use a 3-D lithosphere-asthenosphere numerical model with power-law rheology, coupled to a spectral mantle flow code at 300 km depth. Our results are validated against the World Stress Map 2016 (WSM2016) and the observation-based residual topography. We derive the upper mantle thermal structure from either a heat flow model combined with a seafloor age model (TM1) or a global S-wave velocity model (TM2). We show that lateral density heterogeneities in the upper 300 km have a limited influence on the modeled horizontal stress field as opposed to the resulting dynamic topography that appears more sensitive to such heterogeneities. The modeled stress field directions, using only the mantle heterogeneities below 300 km, are not perturbed much when the effects of lithosphere and crust above 300 km are added. In contrast, modeled stress magnitudes and dynamic topography are to a greater extent controlled by the upper mantle density structure. After correction for the chemical depletion of continents, the TM2 model leads to a much better fit with the observed residual topography giving a good correlation of 0.51 in continents, but this correction leads to no significant improvement of the fit between the WSM2016 and the resulting lithosphere stresses. In continental regions with abundant heat flow data, TM1 results in relatively small angular misfits. For example, in western Europe the misfit between the modeled and observation-based stress is 18.3°. Our findings emphasize that the relative contributions coming from shallow and deep mantle dynamic forces are quite different for the lithospheric stress field and dynamic topography.}, language = {en} } @article{TutuSobolevSteinbergeretal.2018, author = {Tutu, Anthony Osei and Sobolev, Stephan Vladimir and Steinberger, Bernhard and Popov, A. A. and Rogozhina, Irina}, title = {Evaluating the Influence of Plate Boundary Friction and Mantle Viscosity on Plate Velocities}, series = {Geochemistry, geophysics, geosystems}, volume = {19}, journal = {Geochemistry, geophysics, geosystems}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1002/2017GC007112}, pages = {642 -- 666}, year = {2018}, abstract = {Lithospheric plates move over the low-viscosity asthenosphere balancing several forces, which generate plate motions. We use a global 3-D lithosphere-asthenosphere model (SLIM3D) with visco-elasto-plastic rheology coupled to a spectral model of mantle flow at 300 km depth to quantify the influence of intra-plate friction and asthenospheric viscosity on plate velocities. We account for the brittle-ductile deformation at plate boundaries (yield stress) using a plate boundary friction coefficient to predict the present-day plate motion and net rotation of the lithospheric plates. Previous modeling studies have suggested that small friction coefficients (mu < 0.1, yield stress similar to 100 MPa) can lead to plate tectonics in models of mantle convection. Here we show that in order to match the observed present-day plate motion and net rotation, the frictional parameter must be less than 0.05. We obtain a good fit with the magnitude and orientation of the observed plate velocities (NUVEL-1A) in a no-net-rotation (NNR) reference frame with mu < 0.05 and a minimum asthenosphere viscosity of similar to 5 . 10(19) Pas to 10(20) Pas. Our estimates of net rotation (NR) of the lith-osphere suggest that amplitudes similar to 0.1-0.2 (degrees/Ma), similar to most observation-based estimates, can be obtained with asthenosphere viscosity cutoff values of similar to 10(19) Pas to 5 . 10(19) Pas and friction coefficients mu < 0.05.}, language = {en} } @article{SobolevMuldashev2017, author = {Sobolev, Stephan Vladimir and Muldashev, Iskander A.}, title = {Modeling Seismic Cycles of Great Megathrust Earthquakes Across the Scales With Focus at Postseismic Phase}, series = {Geochemistry, geophysics, geosystems}, volume = {18}, journal = {Geochemistry, geophysics, geosystems}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1002/2017GC007230}, pages = {4387 -- 4408}, year = {2017}, language = {en} } @article{SobolevBrown2019, author = {Sobolev, Stephan Vladimir and Brown, Michael}, title = {Surface erosion events controlled the evolution of plate tectonics on Earth}, series = {Nature : international weekly journal of science}, volume = {570}, journal = {Nature : international weekly journal of science}, number = {7759}, publisher = {Nature Publ. Group}, address = {London}, issn = {0028-0836}, doi = {10.1038/s41586-019-1258-4}, pages = {52 -- +}, year = {2019}, abstract = {Plate tectonics is among the most important geological processes on Earth, but its emergence and evolution remain unclear. Here we extrapolate models of present-day plate tectonics to the past and propose that since about three billion years ago the rise of continents and the accumulation of sediments at continental edges and in trenches has provided lubrication for the stabilization of subduction and has been crucial in the development of plate tectonics on Earth. We conclude that the two largest surface erosion and subduction lubrication events occurred after the Palaeoproterozoic Huronian global glaciations (2.45 to 2.2 billion years ago), leading to the formation of the Columbia supercontinent, and after the Neoproterozoic 'snowball' Earth glaciations (0.75 to 0.63 billion years ago). The snowball Earth event followed the 'boring billion'—a period of reduced plate tectonic activity about 1.75 to 0.75 billion years ago that was probably caused by a shortfall of sediments in trenches—and it kick-started the modern episode of active plate tectonics.}, language = {en} } @article{PetruninRiosecoSobolevetal.2012, author = {Petrunin, Alexey G. and Rioseco, Ernesto Meneses and Sobolev, Stephan Vladimir and Weber, Michael H.}, title = {Thermomechanical model reconciles contradictory geophysical observations at the Dead Sea Basin}, series = {Geochemistry, geophysics, geosystems}, volume = {13}, journal = {Geochemistry, geophysics, geosystems}, number = {8}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1029/2011GC003929}, pages = {15}, year = {2012}, abstract = {The Dead Sea Transform (DST) comprises a boundary between the African and Arabian plates. During the last 15-20 m.y. more than 100 km of left lateral transform displacement has been accumulated on the DST and about 10 km thick Dead Sea Basin (DSB) was formed in the central part of the DST. Widespread igneous activity since some 20 Ma ago and especially in the last 5 m.y., thin (60-80 km) lithosphere constrained by seismic data and absence of seismicity below the Moho, seem to be quite natural for this tectonically active plate boundary. However, surface heat flow values of less than 50-60 mW/m(2) and deep seismicity in the lower crust (deeper than 20 km) reported for this region are apparently inconsistent with the tectonic settings specific for an active continental plate boundary and with the crustal structure of the DSB. To address these inconsistencies which comprise what we call the "DST heat-flow paradox," we have developed a numerical model that assumes an erosion of initially thick and cold lithosphere just before or during the active faulting at the DST. The optimal initial conditions for the model are defined using transient thermal analysis. From the results of our numerical experiments we conclude that the entire set of observations for the DSB can be explained within the classical pull-apart model assuming that the lithosphere has been thermally eroded at about 20 Ma and the uppermost mantle in the region have relatively weak rheology consistent with experimental data for wet olivine or pyroxenite.}, language = {en} } @article{OnckenLuschenMechieetal.1999, author = {Oncken, Onno and Luschen, Ewald and Mechie, James and Sobolev, Stephan Vladimir and Schulze, Albrecht and Gaedicke, Christoph and Grunewald, Steffen and Bribach, Jens and Asch, G{\"u}nter and Giese, Peter and Wigger, Peter and Schmitz, Michael and Lueth, Stefan and Scheuber, Ekkehard and Haberland, Christian and Rietbrock, Andreas and G{\"o}tze, Hans-J{\"u}rgen and Brasse, Heinrich and Patzwahl, Regina and Chong, Guillermo and Wilke, Hans-Gerhard and Gonzalez, Gabriel and Jensen, Arturo and Araneda, Manuel and Vieytes, Hugo and Behn, Gerardo and Martinez, Eloy}, title = {Seismic reflection image revealing offset of Andean subduction-zone earthquake locations into oceanic mantle}, year = {1999}, language = {en} } @article{MulyukovaSteinbergerDabrowskietal.2015, author = {Mulyukova, Elvira and Steinberger, Bernhard and Dabrowski, Marcin and Sobolev, Stephan Vladimir}, title = {Survival of LLSVPs for billions of years in a vigorously convecting mantle: Replenishment and destruction of chemical anomaly}, series = {Journal of geophysical research : Solid earth}, volume = {120}, journal = {Journal of geophysical research : Solid earth}, number = {5}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9313}, doi = {10.1002/2014JB011688}, pages = {3824 -- 3847}, year = {2015}, abstract = {We study segregation of the subducted oceanic crust (OC) at the core-mantle boundary and its ability to accumulate and form large thermochemical piles (such as the seismically observed Large Low Shear Velocity Provinces (LLSVPs)). Our high-resolution numerical simulations of thermochemical mantle convection suggest that the longevity of LLSVPs for up to three billion years, and possibly longer, can be ensured by a balance in the rate of segregation of high-density OC material to the core-mantle boundary (CMB) and the rate of its entrainment away from the CMB by mantle upwellings. For a range of parameters tested in this study, a large-scale compositional anomaly forms at the CMB, similar in shape and size to the LLSVPs. Neutrally buoyant thermochemical piles formed by mechanical stirringwhere thermally induced negative density anomaly is balanced by the presence of a fraction of dense anomalous materialbest resemble the geometry of LLSVPs. Such neutrally buoyant piles tend to emerge and survive for at least 3Gyr in simulations with quite different parameters. We conclude that for a plausible range of values of density anomaly of OC material in the lower mantleit is likely that it segregates to the CMB, gets mechanically mixed with the ambient material, and forms neutrally buoyant large-scale compositional anomalies similar in shape to the LLSVPs.}, language = {en} } @article{MohsenKindSobolevetal.2006, author = {Mohsen, Ayman and Kind, Rainer and Sobolev, Stephan Vladimir and Weber, Michael}, title = {Thickness of the lithosphere east of the Dead Sea Transform}, series = {Geophysical journal international}, volume = {167}, journal = {Geophysical journal international}, number = {2}, publisher = {Blackwell}, address = {Oxford}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2006.03185.x}, pages = {845 -- 852}, year = {2006}, abstract = {We use the S receiver function method to study the lithosphere at the Dead Sea Transform (DST). A temporary network of 22 seismic broad-band stations was operated on both sides of the DST from 2000 to 2001 as part of the DESERT project. We also used data from six additional permanent broad-band seismic stations at the DST and in the surrounding area, that is, in Turkey, Saudi Arabia, Egypt and Cyprus. Clear S-to-P converted phases from the crust-mantle boundary (Moho) and a deeper discontinuity, which we interpret as lithosphere-asthenosphere boundary (LAB) have been observed. The Moho depth (30-38 km) obtained from S receiver functions agrees well with the results from P receiver functions and other geophysical data. We observe thinning of the lithosphere on the eastern side of the DST from 80 km in the north of the Dead Sea to about 65 km at the Gulf of Aqaba. On the western side of the DST, the few data indicate a thin LAB of about 65 km. For comparison, we found a 90-km-thick lithosphere in eastern Turkey and a 160-km-thick lithosphere under the Arabian shield, respectively. These observations support previous suggestions, based on xenolith data, heat flow observations, regional uplift history and geodynamic modelling, that the lithosphere around DST has been significantly thinned in the Late Cenozoic, likely following rifting and spreading of the Red Sea.}, language = {en} } @article{KoulakovSobolevWeberetal.2006, author = {Koulakov, Ivan and Sobolev, Stephan Vladimir and Weber, Bernd and Oreshin, Sergey and Wylegalla, Kurt and Hofstetter, Rami}, title = {Teleseismic tomography reveals no signature of the Dead Sea Transform in the upper mantle structure}, series = {Earth and planetary science letters}, volume = {252}, journal = {Earth and planetary science letters}, number = {1-2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2006.09.039}, pages = {189 -- 200}, year = {2006}, abstract = {We present results of a tomographic inversion of teleseismic data recorded at 48 stations of a temporary network which was installed in the area of the Dead Sea Transform (DST) and operated for 1 yr in the framework of the multidisciplinary DESERT Project. The 3366 teleseismic P and PKP phases from 135 events were hand picked and corrected for surface topography and crustal thickness. The inversion shows pronounced low-velocity anomalies in the crust, beneath the DST, which are consistent with recent results from local-source tomography. These anomalies are likely related to the young sediments and fractured rocks in the fault zone. The deeper the retrieved anomalies are quite weak. Most prominent is the high-velocity strip-like anomaly striking SE-NW. We attribute this anomaly to the inherited heterogeneity of lithospheric structure, with a possible contribution by the shallow Precambrian basement east of the DST and to lower crustal heterogeneity reported in this region by other seismic studies. We do not observe reliable signature of the DST in the upper mantle structure. Some weak indications of low-velocity anomalies in the upper mantle beneath the DST may well result from the down-smearing of the strong upper crustal anomalies. We also see very little topography of the lithosphere-asthenosphere boundary beneath the DST, which would generate significant horizontal velocity variations. These results are consistent with predictions from a recent thereto-mechanical model of the DST. Our tomographic model provides some indication of hot mantle flow from the deeper upper mantle rooted in the region of the Red Sea. However, resolution tests show that this anomaly may well be beyond resolution of the model. (c) 2006 Elsevier B.V. All rights reserved.}, language = {en} } @article{IbarraLiuMeessenetal.2019, author = {Ibarra, Federico and Liu, Sibiao and Meeßen, Christian and Prezzi, Claudia Beatriz and Bott, Judith and Scheck-Wenderoth, Magdalena and Sobolev, Stephan Vladimir and Strecker, Manfred}, title = {3D data-derived lithospheric structure of the Central Andes and its implications for deformation: Insights from gravity and geodynamic modelling}, series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, volume = {766}, journal = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0040-1951}, doi = {10.1016/j.tecto.2019.06.025}, pages = {453 -- 468}, year = {2019}, abstract = {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.}, language = {en} } @article{GeryaSternBaesetal.2015, author = {Gerya, Taras V. and Stern, Robert J. and Baes, Marzieh and Sobolev, Stephan Vladimir and Whattam, Scott A.}, title = {Plate tectonics on the Earth triggered by plume-induced subduction initiation}, series = {Nature : the international weekly journal of science}, volume = {527}, journal = {Nature : the international weekly journal of science}, number = {7577}, publisher = {Nature Publ. Group}, address = {London}, issn = {0028-0836}, doi = {10.1038/nature15752}, pages = {221 -- +}, year = {2015}, abstract = {Scientific theories of how subduction and plate tectonics began on Earth-and what the tectonic structure of Earth was before this-remain enigmatic and contentious(1). Understanding viable scenarios for the onset of subduction and plate tectonics(2,3) is hampered by the fact that subduction initiation processes must have been markedly different before the onset of global plate tectonics because most present-day subduction initiation mechanisms require acting plate forces and existing zones of lithospheric weakness, which are both consequences of plate tectonics(4). However, plume-induced subduction initiation(5-9) could have started the first subduction zone without the help of plate tectonics. Here, we test this mechanism using high-resolution three-dimensional numerical thermomechanical modelling. We demonstrate that three key physical factors combine to trigger self-sustained subduction: (1) a strong, negatively buoyant oceanic lithosphere; (2) focused magmatic weakening and thinning of lithosphere above the plume; and (3) lubrication of the slab interface by hydrated crust. We also show that plume-induced subduction could only have been feasible in the hotter early Earth for old oceanic plates. In contrast, younger plates favoured episodic lithospheric drips rather than self-sustained subduction and global plate tectonics.}, language = {en} } @article{DannbergSobolev2015, author = {Dannberg, Juliane and Sobolev, Stephan Vladimir}, title = {Low-buoyancy thermochemical plumes resolve controversy of classical mantle plume concept}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/ncomms7960}, pages = {9}, year = {2015}, abstract = {The Earth's biggest magmatic events are believed to originate from massive melting when hot mantle plumes rising from the lowermost mantle reach the base of the lithosphere. Classical models predict large plume heads that cause kilometre-scale surface uplift, and narrow (100 km radius) plume tails that remain in the mantle after the plume head spreads below the lithosphere. However, in many cases, such uplifts and narrow plume tails are not observed. Here using numerical models, we show that the issue can be resolved if major mantle plumes contain up to 15-20\% of recycled oceanic crust in a form of dense eclogite, which drastically decreases their buoyancy and makes it depth dependent. We demonstrate that, despite their low buoyancy, large enough thermochemical plumes can rise through the whole mantle causing only negligible surface uplift. Their tails are bulky (4200 km radius) and remain in the upper mantle for 100 millions of years.}, language = {en} } @article{BaesSobolevQuinteros2018, author = {Baes, Marzieh and Sobolev, Stephan Vladimir and Quinteros, Javier}, title = {Subduction initiation in mid-ocean induced by mantle suction flow}, series = {Geophysical journal international}, volume = {215}, journal = {Geophysical journal international}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0956-540X}, doi = {10.1093/gji/ggy335}, pages = {1515 -- 1522}, year = {2018}, abstract = {Pre-existing weakness zones in the lithosphere such as transform faults/fracture zones and extinct mid-oceanic ridges have been suggested to facilitate subduction initiation in an intra-oceanic environment. Here, we propose that the additional forcing coming from the mantle suction flow is required to trigger the conversion of a fracture zone/transform fault into a converging plate boundary. This suction flow can be induced either from the slab remnants of former converging plate boundaries or/and from slabs of neighbouring active subduction zones. Using 2-D coupled thermo-mechanical models, we show that a sufficiently strong mantle flow is able to convert a fracture zone/transform fault into a subduction zone. However, this process is feasible only if the fracture zone/transform fault is very close to the mid-oceanic ridge. Our numerical model results indicate that time of subduction initiation depends on the velocity, domain size and location of mantle suction flow and age of the oceanic plate.}, language = {en} } @misc{BaesSobolevGeryaetal.2020, author = {Baes, Marzieh and Sobolev, Stephan Vladimir and Gerya, Taras V. and Brune, Sascha}, title = {Plume-induced subduction initiation}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {2}, issn = {1866-8372}, doi = {10.25932/publishup-52274}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-522742}, pages = {21}, year = {2020}, abstract = {Initiation of subduction following the impingement of a hot buoyant mantle plume is one of the few scenarios that allow breaking the lithosphere and recycling a stagnant lid without requiring any preexisting weak zones. Here, we investigate factors controlling the number and shape of retreating subducting slabs formed by plume-lithosphere interaction. Using 3-D thermomechanical models we show that the deformation regime, which defines formation of single-slab or multi-slab subduction, depends on several parameters such as age of oceanic lithosphere, thickness of the crust and large-scale lithospheric extension rate. Our model results indicate that on present-day Earth multi-slab plume-induced subduction is initiated only if the oceanic lithosphere is relatively young (<30-40 Myr, but >10 Myr), and the crust has a typical thickness of 8 km. In turn, development of single-slab subduction is facilitated by older lithosphere and pre-imposed extensional stresses. In early Earth, plume-lithosphere interaction could have led to formation of either episodic short-lived circular subduction when the oceanic lithosphere was young or to multi-slab subduction when the lithosphere was old.}, language = {en} } @article{BaesSobolev2017, author = {Baes, Marzieh and Sobolev, Stephan Vladimir}, title = {Mantle Flow as a Trigger for Subduction Initiation: A Missing Element of the Wilson Cycle Concept}, series = {Geochemistry, geophysics, geosystems}, volume = {18}, journal = {Geochemistry, geophysics, geosystems}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1002/2017GC006962}, pages = {4469 -- 4486}, year = {2017}, abstract = {The classical Wilson Cycle concept, describing repeated opening and closing of ocean basins, hypothesizes spontaneous conversion of passive continental margins into subduction zones. This process, however, is impeded by the high strength of passive margins, and it has never occurred in Cenozoic times. Here using thermomechanical models, we show that additional forcing, provided by mantle flow, which is induced by neighboring subduction zones and midmantle slab remnants, can convert a passive margin into a subduction zone. Models suggest that this is a long-term process, thus explaining the lack of Cenozoic examples. We speculate that new subduction zones may form in the next few tens of millions of years along the Argentine passive margin and the U.S. East Coast. Mantle suction force can similarly trigger subduction initiation along large oceanic fracture zones. We propose that new subduction zones will preferentially originate where subduction zones were active in the past, thus explaining the remarkable colocation of subduction zones during at least the last 400 Myr.}, language = {en} } @article{BaesGeryaSobolev2016, author = {Baes, Marzieh and Gerya, Taras V. and Sobolev, Stephan Vladimir}, title = {3-D thermo-mechanical modeling of plume-induced subduction initiation}, series = {Earth \& planetary science letters}, volume = {453}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2016.08.023}, pages = {193 -- 203}, year = {2016}, abstract = {Here, we study the 3-D subduction initiation process induced by the interaction between a hot thermochemical mantle plume and oceanic lithosphere using thermo-mechanical viscoplastic finite difference marker-in-cell models. Our numerical modeling results show that self-sustaining subduction is induced by plume-lithosphere interaction when the plume is sufficiently buoyant, the oceanic lithosphere is sufficiently old and the plate is weak enough to allow the buoyant plume to. pass through it. Subduction initiation occurs following penetration of the lithosphere by the hot plume and the downward displacement of broken, nearly circular segments of lithosphere (proto-slabs) as a result of partially molten plume rocks overriding the proto-slabs. Our experiments show four different deformation regimes in response to plume-lithosphere interaction: a) self-sustaining subduction initiation, in which subduction becomes self-sustaining; b) frozen subduction initiation, in which subduction stops at shallow depths; c) slab break-off, in which the subducting circular slab breaks off soon after formation; and d) plume underplating, in which the plume does not pass through the lithosphere and instead spreads beneath it (i.e., failed subduction initiation). These regimes depend on several parameters, such as the size, composition, and temperature of the plume, the brittle/plastic strength and age of the oceanic lithosphere, and the presence/absence of lithospheric heterogeneities. The results show that subduction initiates and becomes self-sustaining when the lithosphere is older than 10 Myr and the non dimensional ratio of the plume buoyancy force and lithospheric strength above the plume is higher than approximately 2. The outcomes of our numerical experiments are applicable for subduction initiation in the modern and Precambrian Earth and for the origin of plume-related corona structures on Venus. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} }