Plate Kinematics Research Articles

Playing jigsaw with Large Igneous Provinces—A plate tectonic reconstruction of Ontong Java Nui, West Pacific

AbstractThe three largest Large Igneous Provinces (LIP) of the western Pacific—Ontong Java, Manihiki, and Hikurangi Plateaus—were emplaced during the Cretaceous Normal Superchron and show strong similarities in their geochemistry and petrology. The plate tectonic relationship between those LIPs, herein referred to as Ontong Java Nui, is uncertain, but a joined emplacement was proposed by Taylor (2006). Since this hypothesis is still highly debated and struggles to explain features such as the strong differences in crustal thickness between the different plateaus, we revisited the joined emplacement of Ontong Java Nui in light of new data from the Manihiki Plateau. By evaluating seismic refraction/wide‐angle reflection data along with seismic reflection records of the margins of the proposed “Super”‐LIP, a detailed scenario for the emplacement and the initial phase of breakup has been developed. The LIP is a result of an interaction of the arriving plume head with the Phoenix‐Pacific spreading ridge in the Early Cretaceous. The breakup of the LIP shows a complicated interplay between multiple microplates and tectonic forces such as rifting, shearing, and rotation. Our plate kinematic model of the western Pacific incorporates new evidence from the breakup margins of the LIPs, the tectonic fabric of the seafloor, as well as previously published tectonic concepts such as the rotation of the LIPs. The updated rotation poles of the western Pacific allow a detailed plate tectonic reconstruction of the region during the Cretaceous Normal Superchron and highlight the important role of LIPs in the plate tectonic framework.

Experimental identification and associated model of the dissipation in the electric cables of a satellite structure

This paper presents a first experimental identification of the effects of electric cables on the damping of a satellite structure. The dissipation due to both the curvature of the cables and the slippage of the cables in their fasteners was taken into account based on classical plate kinematics. In order to validate a damping model for the cables, we developed tests to quantify the influence of the amplitude of the movement on the energy dissipated. Two cable sizes and three cable fastener heights were tested using a specific setup which made the curvature uniform along the whole length of the cables. The results show that while the dissipation is a function of the curvature the specific damping capacity is almost constant. However, the dissipation differs depending on the type of cable. Very small cables do not dissipate at all, but large cables can induce significant damping depending on the mode of vibration concerned.

Slip rates and locking depth variation along central and easternmost segments of North Anatolian Fault

While the kinematics of Anatolia plate and the North Anatolian Fault System (NAFS) has been studied extensively, the slip rate and locking depth along the NAFS are usually assumed constant in the analyses due to the lack of sufficient data. This is also partly due to the reasonably good fit of Euler small circle and partly due to the lack of spatial resolution of observations to determine slip rates independently from locking depths. On the other hand, recent geodetic studies show a contrast for locking depth between Marmara and other parts of the NAFS, implying a non-uniform locking depth across the NAFS. In this study, we analyse new GPS data and homogenously combine available data sets covering the eastern part of the NAFS to form the most complete data set. In particular, we incorporate the first results of Turkish Real-Time Kinematic GPS Network (CORS-TR) into our data set. A detailed analysis of three profiles within the NAFS reveals an increase of locking depth in the middle profile to 19.1 ± 3.4 km from 11.9 ± 3.5 km in the easternmost profile while the slip rate is nearly constant (20–22 mm yr−1), which implies a variation of strain rate of ∼100 nanostrain yr−1. Assuming a constant locking depth throughout whole NAFS gives an average locking depth of 14.3 ± 1.7 km. Our best estimates of slip rates in block modelling which takes the variation of locking depths into account are in the range between 22.5 and 22.8 mm yr−1 over eastern part of the NAFS.

Dissipative Homogenised Reinforced Concrete (DHRC) constitutive model dedicated to reinforced concrete plates under seismic loading

A new stress resultant nonlinear dissipative constitutive model for reinforced concrete (RC) plates under cyclic solicitations is presented. This constitutive model, named DHRC for Dissipative Homogenised Reinforced Concrete, is expressed within the usual thin plate kinematics framework. It is built by a periodic homogenisation approach using the averaging method and it couples concrete damage and periodic debonding between steel rebar and surrounding concrete. The generality of the proposed method leads to a generic closed-form for the Helmholtz strain energy density function and the two dissipation pseudo-potentials that can be adapted to any material with an internal structure similar to the RC structural element one. A restricted number of geometric and material characteristics are needed from which the whole set of model parameters are identified through an automatic numeric procedure performed on a Representative Volume Elements (RVEs) of the RC plate. Finally, comparisons of finite element simulations with experimental results concerning the seismic behaviour of reinforced concrete wall made structures are proposed and discussed.

Semiautomatic fracture zone tracking

AbstractOceanic fracture zone traces are widely used in studies of seafloor morphology and plate kinematics. Satellite altimetry missions have resulted in high‐resolution gravity maps in which all major fracture zones and other tectonic fabric can be identified, and numerous scientists have digitized such lineaments. We have initiated a community effort to maintain low‐cost infrastructure that allows seafloor fabric lineaments to be stored, accessed, and updated. A key improvement over past efforts is our processing software (released as a GMT5 supplement) that allows for semiautomatic corrections to previously digitized fracture zone traces given improved gridded data sets. Here we report on our seafloor fabric processing tools, which complement our database of seafloor fabric lineations, magnetic anomaly identifications, and plate kinematic models.

Dynamics of intraoceanic subduction initiation: 2. Suprasubduction zone ophiolite formation and metamorphic sole exhumation in context of absolute plate motions

AbstractAnalyzing subduction initiation is key for understanding the coupling between plate tectonics and the underlying mantle. Here we focus on suprasubduction zone (SSZ) ophiolites and how their formation links to intraoceanic subduction initiation in an absolute plate motion frame. SSZ ophiolites form the majority of exposed oceanic lithosphere fragments and are widely recognized to have formed during intraoceanic subduction initiation. Structural, petrological, geochemical, and plate kinematic constraints on their kinematic evolution show that SSZ crust forms at fore‐arc spreading centers at the expense of a mantle wedge, thereby flattening the nascent slab. This leads to the typical inverted pressure gradients found in metamorphic soles that form at the subduction plate contact below and during SSZ crust crystallization. Former spreading centers are preserved in forearcs when subduction initiates along transform faults or off‐ridge oceanic detachments. We show how these are reactivated when subduction initiates in the absolute plate motion direction of the inverting weakness zone. Upon inception of slab pull due to, e.g., eclogitization, the sole is separated from the slab, remains welded to the thinned overriding plate lithosphere, and can become intruded by mafic dikes upon asthenospheric influx into the mantle wedge. We propound that most ophiolites thus formed under special geodynamic circumstances and may not be representative of normal oceanic crust. Our study highlights how far‐field geodynamic processes and absolute plate motions may force intraoceanic subduction initiation as key toward advancing our understanding of the entire plate tectonic cycle.

The tectonic evolution of the southeastern Terceira Rift/São Miguel region (Azores)

The eastern Azores Archipelago with São Miguel being the dominant subaerial structure is located at the intersection of an oceanic rift (Terceira Rift) with a major transform fault (Gloria Fault) representing the westernmost part of the Nubian–Eurasian plate boundary. The evolution of islands, bathymetric highs and basin margins involves strong volcanism, but the controlling geodynamic and tectonic processes are currently under debate. In order to study this evolution, multibeam bathymetry and marine seismic reflection data were collected to image faults and stratigraphy. The basins of the southeastern Terceira Rift are rift valleys whose southwestern and northeastern margins are defined by few major normal faults and several minor normal faults, respectively. Since São Miguel in between the rift valleys shows an unusual W–E orientation, it is supposed to be located on a leaky transform. South of the island and separated by a N120° trending graben system, the Monacco Bank represents a N160° oriented flat topped volcanic ridge dominated by tilted fault blocks. Up to six seismic units are interpreted for each basin. Although volcanic ridges hamper a direct linking of depositional strata between the rift and adjacent basins, the individual seismic stratigraphic units have distinct characteristics. Using these units to provide a consistent relative chrono-stratigraphic scheme for the entire study area, we suggest that the evolution of the southeastern Terceira Rift occurred in two stages. Considering age constrains from previous studies, we conclude that N140° structures developed orthogonal to the SW–NE direction of plate-tectonic extension before ~10Ma. The N160° trending volcanic ridges and faults developed later as the plate tectonic spreading direction changed to WSW–ENE. Hence, the evolution of the southeastern Terceira Rift domain is predominantly controlled by plate kinematics and lithospheric stress forming a kind of a re-organized rift system.

FREE VIBRATION AND BUCKLING ANALYSIS OF HIGHER ORDER LAMINATED COMPOSITE PLATES USING THE ISOGEOMETRIC APPROACH

This research paper presents a higher order isogeometric laminated composite plate finite element formulation. The isogeometric formulation is based on NURBS (non-uniform rational B-splines) basis functions of varying degree. Plate kinematics is based on the third order shear deformation theory (TSDT) of Reddy in order to avoid shear locking. Free vibration and the buckling response of laminated composite plates are obtained and efficiency of the method is considered. Numerical results with different element order are presented and the obtained results are compared to analytical and conventional numerical results as well as existing isogeometric plate finite elements.

Buckling failure analysis of cracked functionally graded plates by a stabilized discrete shear gap extended 3-node triangular plate element

We present new numerical results in buckling failure analysis of cracked composite functionally graded plates subjected to uniaxial and biaxial compression loads. An accurate extended 3-node triangular plate element in the context of the extended finite element method (XFEM) is developed, integrating the discrete shear gap method (DSG) to eliminate shear-locking. The plate kinematics is based on the Reissner–Mindlin theory, and material properties are assumed to vary through thickness direction, obeying a power law distribution. The developed DSG-XFEM is found to be effective and accurate as it owns many desirable advantages: conveniently representing crack geometry which is independent of the mesh; shear-locking effect is no longer valid; mesh distortion is insensitive and controllable; thin plates is possible; triangular elements are easily generated for problems even with complex geometries; and high accuracy. All these arisen features are demonstrated through numerical examples and the effects of crack-length, material gradation, mesh distortion, inclined angles of cracks, boundary conditions, width-to-thickness ratio, length ratio, etc. on the critical buckling coefficient (CBC) are analyzed. Numerical results reveal that the material gradation, crack-length, thickness, length ratios, etc. have a strong effect on the behavior of CBC. This phenomenon is mainly attributed to the plate stiffness degradation due to the presence of local defects and material composition. Also, the boundary conditions greatly alter the CBC whereas the inclination of cracked angle is found to be insignificant.

Tectonic speed limits from plate kinematic reconstructions

The motion of plates and continents on the planet's surface are a manifestation of long-term mantle convection and plate tectonics. Present-day plate velocities provide a snapshot of this ongoing process, and have been used to infer controlling factors on the speeds of plates and continents. However, present-day velocities do not capture plate behaviour over geologically representative periods of time. To address this shortcoming, we use a plate tectonic reconstruction approach to extract time-dependent plate velocities and geometries from which root mean square (RMS) velocities are computed, resulting in a median RMS plate speed of ∼4 cm/yr over 200 Myr. Linking tectonothermal ages of continental lithosphere to the RMS plate velocity analysis, we find that the increasing portions of plate area composed of continental and/or cratonic lithosphere significantly reduces plate speeds. Plates with any cratonic portion have a median RMS velocity of ∼5.8 cm/yr, while plates with more than 25% of cratonic area have a median RMS speed of ∼2.8 cm/yr. The fastest plates (∼8.5 cm/yr RMS speed) have little continental fraction and tend to be bounded by subduction zones, while the slowest plates (∼2.6–2.8 cm/yr RMS speed) have large continental fractions and usually have little to no subducting part of plate perimeter. More generally, oceanic plates tend to move 2–3 times faster than continental plates, consistent with predictions of numerical models of mantle convection. The slower motion of continental plates is compatible with deep keels impinging on asthenospheric flow and increasing shear traction, thus anchoring the plate in the more viscous mantle transition zone. We also find that short-lived (up to ∼10 Myr) rapid accelerations of Africa (∼100 and 65 Ma), North America (∼100 and 55 Ma) and India (∼130,80 and 65 Ma) appear to be correlated with plume head arrivals as recorded by large igneous province (LIPs) emplacement. By evaluating factors influencing plate speeds over the Mesozoic and Cenozoic, our temporal analysis reveals simple principles that can guide the construction and evaluation of absolute plate motion models for times before the Cretaceous in the absence of hotspot tracks and seafloor spreading histories. Based on the post-Pangea plate motions, one principle that can be applied to pre-Pangea times is that plates with less than ∼50% continental area can reach RMS velocities of ∼20 cm/yr, while plates with more than 50% continental fraction do not exceed RMS velocities of ∼10 cm/yr. Similarly, plates with large portions of continental or cratonic area with RMS velocities exceeding ∼15 cm/yr for more than ∼10 Myr should be considered as potential artefacts requiring further justification of plate driving forces in such scenarios.

Slip re-orientation in oblique rifts

Oblique extension is expected to result in a combination of dip-slip and strike-slip displacement along faults with strike orthogonal and oblique to the extension direction, respectively. This general concept is in disagreement with observations from natural oblique rifts, where faults show dip-slip kinematics indicating pure extension irrespective of the fault strike with respect to the regional extension direction. Consequently, along oblique structures, slip is re-oriented, and oblique to the applied extension direction. Besides, at fault scale, slip is re-oriented along strike such that it is dip slip at the fault center and becomes highly oblique slip toward the fault tips. Here, we use analogue experiments to show that this discrepancy can be resolved when a preexisting weak zone (WZ) is present in the crust at the onset of oblique extension. The WZ is implemented within the lower crust and strikes oblique to the extension direction. Our experimental results show that an inherited WZ within the ductile crust favors the re-orientation of slip such that oblique extension results in pure dip-slip displacement on faults that strike oblique with respect to the extension direction. Furthermore, we show that slip is re-oriented along strike of major faults, such that the fault center shows dip-slip kinematics, whereas its tips display strike-slip kinematics. These findings call into question the use of paleostress reconstructions to constrain plate kinematics in oblique extensional tectonic settings.

Genetic sources and tectonophysical regularities of divisibility of the lithosphere into blocks of various ranks at different stages of its formation: tectonophysical analysis

The paper presents the first tectonophysical reconstruction of initial divisibility of the protolithosphere as a result of convection in the cooling primitive mantle. Initial division of the protolithosphere into separate masses, i.e. prototypes of the blocks, and their size are predetermined by the emerging Rayleigh-Benard convection cells. In studies of geology and geodynamics, the Rayleigh-Benard convection cells were first referred to as a factor to explain the formation of initial continental cores. Considering the Rayleigh-Benard cells and their structural relics can help clarify initial divisibility of the protolithosphere and the origin of the major lithospheric plates, i.e. prototypes of continents. In our opinion, the initial mega-scale block structure of the protolithosphere and the emerging lithosphere were predetermined by the Rayleigh-Benard cells as they were preserved in the emerging lithosphere and their lower boundaries corresponded to the core-mantle boundary, i.e. one of the major discontinuities of the planet. Our theoretical estimations are in good agreement with the number and sizes of the Earth's theorized first supercontinents, Vaalbara and Ur. In our tectonophysical discussion of the formation of the lithospheric block structure, we analyze in detail the map of modern lithospheric plates [ Bird , 2003 ] in combination with the materials from [ Sherman et al., 2000 ]. In the hierarchy of the blocks comprising the contemporary lithosphere, which sizes are widely variable, two groups of blocks are clearly distinguished. The first group includes megablocks with the average geometric size above 6500 km. Their formation is related to convection in the Earth mantle at the present stage of the geodynamic evolution of the Earth, as well as at all the previous stages, including the earliest one, when the protolithosphere emerged. The second group includes medium-sized blocks with the average geometric size of less than 4500 km and those with minimum sizes, such as rock lumps. They reflect primarily the degradation of megablocks as a result of their destruction due to high stresses in excess of the tensile strength of the medium. This group may also include blocks which formation is related to convection in the upper mantle layer, asthenosphere. There are grounds to assume that through the vast intermediate interval of geologic time, including supercycles of Kenorlend, Rodin, and and partically Pangea, the formation of the large lithospheric blocks was controlled by convection, and later on, they were 'fragmented' under the physical laws of destruction of solid bodies. However, it is difficult to clearly distinguish between the processes that predetermine the hierarchy of formation of the block structures of various origins – sizes of ancient lithospheric blocks cannot be estimated unambiguously. Thus, mantle convection is a genetic endogenous source of initial divisibility of the cooling upper cover of the Earth and megablock divisibility of the lithosphere in the subsequent and recent geodynamic development stages. At the present stage, regular patterns of the lithospheric block divisibility of various scales are observed at all the hierarchic levels. The areas of the lithospheric megaplates result from regular changes of convective processes in the mantle, which influenced the formation of plates and plate kinematics. Fragmentation of the megaplates into smaller ones is a result of destruction of the solid lithosphere under the physical laws of destruction of solid bodies under the impact of high stresses.

Spatial and temporal evolution of hyperextended rift systems: Implication for the nature, kinematics, and timing of the Iberian-European plate boundary

We focus on the Iberian-European plate boundary (IEPB), whose nature, age, and evolution are strongly debated. In contrast to previous interpretations of the IEPB as a major lithospheric-scale left-lateral strike-slip fault, we propose a more complex deformation history. The mapping of rift domains at the transition between Iberia and Europe emphasizes the existence of spatially disconnected rift systems. Based on their restoration, we suggest that the deformation was partitioned between a set of distinct left-lateral transtensional rift systems from the Late Jurassic to Early Cretaceous. A plate kinematic reorganization at Aptian-Albian time resulted in the onset of sea-floor spreading in the western Bay of Biscay and extreme crustal and lithosphere thinning in intra-continental rift basins to the east. The formation and reactivation of the IEPB is interpreted as the result of the polyphase evolution of a diffuse transient plate boundary that failed to localize. The results of this work may provide new insights on (1) processes preceding breakup and the initiation of segmented and strongly oblique shear margins, (2) the deformation history of nascent divergent plate boundaries, and (3) the kinematics of the southern North Atlantic and Alpine domain in western Europe.

Kinematics of Neogene to Recent upper-crustal deformation in the southern Central Andes (23°–28°S) inferred from fault–slip analysis: Evidence for gravitational spreading of the Puna Plateau

Elucidating the tectono-morphologic evolution of the Central Andes is important for understanding the mechanical behaviour of non-collisional orogens at convergent plate boundaries. Fault-kinematic data from the southern Central Andes are generally interpreted in terms of changes in plate (boundary) kinematics or vertical-axis rotation associated with the formation of the Andean orocline. However, none of these hypotheses accounts adequately for Neogene to Recent horizontal extension and vertical shortening of upper crust documented from the Puna Plateau and the adjacent Eastern Cordillera. Based on new and compiled fault-kinematic data, in total 4746 brittle faults at 317 stations, we propose that strain axis configurations in the southern Central Andes are controlled by (1) local deformation kinematics, (2) the far-field deformation caused either by the orogen-normal shortening component of plate convergence or by removal of lithospheric mantle and (3) differences in lithospheric thickness and respective surface elevation, i.e., gravitational potential energy. Specifically, the Puna Plateau and Eastern Cordillera have been undergoing horizontal shortening and gravitational spreading of the upper crust, whereas the topographically lower Pampean Ranges continue to undergo horizontal shortening only. Although less apparent in the fault-kinematic data than the E–W and NW–SE extension, orogen-parallel extension is inherent to the Puna Plateau and Eastern Cordillera and compensates likely for overall WNW–ESE shortening and enhanced surface elevation. The importance of orogen-parallel extension in the deformation kinematics of topographically elevated parts of the southern Central Andes is underscored by the strike–slip components on prominent reverse and thrust faults. The data supports geodynamic interpretations in which the evolution of topography and lithospheric thickness influence significantly changes in upper-crustal kinematics of the southern Central Andes.

Variable kinematics models and finite elements for nonlinear analysis of multilayered smart plates

A variable kinematics approach for moderately large deflection analysis of smart magneto-electro-elastic multilayered plates is presented. The approach is based on the condensation of the electro-magnetic state into the plate kinematics, whose nonlinear strain–displacement relationships are expressed in the von Karman sense. This leads to models resulting in an effective mechanical plate, which takes the multifield coupling effects into account by the plate stiffness, inertia and loading characteristics, consistently defined as combinations of the layers material properties. By a unified approach, both equivalent single layer and layerwise models are developed formulating the associated isoparametric finite elements. Results are presented for different kinematics with through-the-thickness expansion up to the fourth order with the aim of validating the modeling strategy and showing its features for the investigation of smart plates geometrical nonlinear behaviour.

Placing limits to shortening evolution in the Pyrenees: Role of margin architecture and implications for the Iberia/Europe convergence

Estimating shortening in collision belts is critical to reconstruct past plate motions. Balanced cross-section techniques are efficient in external domains but lack resolution in the hinterland. The role and the original extent of the continental margins during the earliest stages of continental convergence are debated. Here we combine existing and new sequentially restored cross sections in the central Pyrenees, with Iberia/Europe (IB/EU) plate kinematic reconstructions and new apatite fission track, zircon (U-Th)/He, and U/Pb ages to discuss higher and lower bounds of crustal shortening and determine the amount of distal margin sutured during collision. We show that after extension in the Albian (~110 Ma), a 50 km wide extremely thinned crustal domain underwent subduction at 83 Ma. Low-temperature data and thermal modeling show that synorogenic cooling started at 75–70 Ma. This date marks the transition from suturing of the highly extended margin to collision of the more proximal margin and orogenic growth. We infer a relatively low crustal shortening of 90 km (30%) that reflects the dominant thick-skinned tectonic style of shortening in the Pyrenees, as expected for young (Mesozoic) and weak lithospheres. Our proposed reconstruction agrees with IB/EU kinematic models that consider initially rapid convergence of Iberia, reducing from circa 70 Ma onward. This study suggests that plate reconstructions are consistent with balanced cross sections if shortening predicted by age-dependent properties of the continental lithosphere is taken into account.

Basin evolution in the Davis Strait area (West Greenland and conjugate East Baffin/Labrador passive margins) from thermostratigraphic and subsidence modelling of well data: Implications for tectonic evolution and petroleum systems

Abstract The sedimentary basins of the Davis Strait area developed mainly as a result of late Mesozoic and Cenozoic rifting processes that led to the formation of the West Greenland, southeast Baffin, and east Labrador continental margins. Recently acquired regional geophysical data in the area provide considerable new constraints on sedimentary basin and crustal thicknesses as well as plate kinematic reconstructions. Further, the chrono-stratigraphy and vitrinite reflectance data for several of the northern Labrador margin wells have been re-correlated and corrected. Given this, new 1-D models for the subsidence and thermal evolution of a number of the exploration wells located on the conjugate West Greenland and east Baffin/Labrador margins have been computed. Model predictions based on lithospheric extension agree well with observed stratigraphic and thermal data from West Greenland, southeast Baffin, and east Labrador wells. Calculated stretching factors for the wells are remarkably similar, except for those off southeast Baffin Island, which are higher. This implies that this area was subject to more intense rifting prior to the onset of magmatism in the early Paleocene. In turn, this may suggest that the magmatism was related to rifting and not, as commonly believed, linked to the arrival of a mantle plume at the beginning of the Paleocene. The modelled thermal histories indicate that maximum subsurface temperatures occurred at different times throughout the Cenozoic, depending mainly on the sedimentation (burial) histories, surface temperatures, and heat flow. Prediction of hydrocarbon generation in the area must therefore include these parameters.

Constraining Cretaceous subduction polarity in eastern Pacific from seismic tomography and geodynamic modeling

AbstractInterpretation of recent mantle seismic images below the America ignited a debate on the Cretaceous subduction polarity in the eastern Pacific Ocean. The traditional view is that the massive vertical slab wall under eastern North America resulted from an eastward Farallon subduction. An alternative interpretation attributes this prominent seismic structure to a westward subduction of the North American Plate against a stationary intraoceanic trench. Here I design quantitative subduction models to test these two scenarios, using their implied plate kinematics as velocity boundary conditions. Modeling results suggest that the westward subduction scenario could not produce enough slab volume as seismic images reveal, as is due to the overall slow subduction rate (~2.5 cm/yr). The results favor the continuous eastward Farallon subduction scenario, which, with an average convergence rate of >10 cm/yr prior to the Eocene, can properly generate both the volume and the geometry of the imaged lower mantle slab pile. The eastward subduction model is also consistent with most Cretaceous geological records along the west coast of North America.

Research on the Kinematics of Line Heating Robot Based on SVM

The paper mainly analyzed the robot kinematics of the line heating plate. In order to realize the moving of complex trajectory for the robot, a forward kinematics modeling and the simulation of inverse kinematics are carried out. Firstly, with the D-H modeling method, the line heating plate robot forward kinematics equations and the spatial geometric model of the manipulator are set up, then multi-input multi-output systems based on support vector machines algorithm is used to establish the inverse kinematics model for the robot . At last, the simulations of tracing complex trajectory with the inverse kinematics model are carried out, and the results show that the model derived by SVM can trace the trajectory very well.

Late Cretaceous extension and Palaeogene rotation-related contraction in Central Anatolia recorded in the Ayhan-Büyükkışla basin

The configuration and evolution of subduction zones in the Eastern Mediterranean region in Cretaceous time accommodating Africa–Europe convergence remain poorly quantitatively reconstructed, owing to a lack of kinematic constraints. A recent palaeomagnetic study suggested that the triangular Central Anatolian Crystalline Complex (CACC) consists of three blocks that once formed an ~N–S elongated continental body, underthrusted below ophiolites in Late Cretaceous time. After extensional exhumation and upon Palaeogene collision of the CACC with the Pontides of the southern Eurasian margin, the CACC broke into three fragments that rotated and converged relative to each other. Here, we date the extension and contraction history of the boundary between two of the rotating massifs of the CACC by studying the Upper Cretaceous–Palaeogene Ayhan–Büyükkışla basin. We report an 40Ar/39Ar age of an andesite at the base of the sequence to show that the deposition started in an E–W extensional basin around 72.11 ± 1.46. The basin developed contemporaneously with regional exhumation of the CACC metamorphics. The lower basin sedimentary rocks were unconformably covered by mid-Eocene limestones and redbeds, followed by intense folding and thrust faulting. Two balanced cross-sections in the study area yield a minimum of 17–27 km of post-mid-Eocene ~N–S shortening. We thus demonstrate the Cenozoic compressional nature of the Kırşehir–Niğde-Hırkadağ block boundary and show that the extensional exhumation of the CACC predates collision-related contraction. A plate kinematic scenario is required to explain these observations that involves two Late Cretaceous–Palaeogene subduction zones to the north and south of the CACC, for which we show a possible plate boundary configuration.