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Oceanic-plates vertical tearing is seismically-identified in the present-day Earth. This type of plate tearing is frequently reported in horizontally-oblique subduction zones where transform-faulted oceanic plates are subducting (or subducted). However, the mechanisms behind vertical slab tearing are still poorly understood, thus we utilize 3D time-dependent Stokes’ flow thermo-mechanical models to further study this problem. We find that (i) the age offset of transform fault and (ii) the horizontal obliqueness of subduction fundamentally control the tearing behavior of two generic, materially-homogeneous oceanic slabs separated by a low-viscosity zone. The overriding-continental plate bends one slab first, which combined with the age-thickness difference between slabs, causes the differential sinking of them. Based on the modeling results, well-developed slabs vertical tearing would happen when the oblique angle of subduction is ≥30° or the age ratio of the secondly-bent to firstly-bent slab being ~20°) tend to produce fault-parallel tearing, related to differential slab-hinge retreat or rollback. Correlations between slabs’ (i) computed tearing horizontal-width and (ii) scaling-theory forms of their subduction-velocity differences, are reasonable (0.76-0.97). Our numerically-predicted scenarios are reasonably consistent with plate-tear imaging results from at least 4 natural subduction zones. Our modeling also suggests that continual along-trench variation in subduction dip angle may be related to a special case of oblique subduction.

The continental collision-induced far-field intraplate deformation may be topographically separated from or coherent with the collision front, the mechanism of which is poorly constrained. Here, we build a series of 2D thermo–mechanical models to explore the controlling factors of distal orogenesis in the framework of a composite terrane sandwiched between two strong continental blocks. The model results suggest that the development of distal orogenesis requires a strong rheological heterogeneity in the overriding lithosphere. Two types of far-field collisional effects with distinct patterns of topographic evolution are identified, characterized by (I) a delayed and discrete distal orogenesis separated from the collision front by a low-relief, less-deformed terrane interior, and (II) an instant distal orogenesis subsequently integrated into a progressively growing plateau. These two types of far-field orogenesis are revealed to be analogous to the development of the Kopet Dagh and northern Tibet. The comparisons between model results and geological observations provide significant constraints on the dynamics of crustal-scale deformation propagation and the formation of distinct lithospheric architectures.

The interaction between the Earth's surface and deep geodynamic processes has a great influence on sedimentary patterns and characteristics of sedimentary systems, especially in the continental margin, such as the southern part of the East China Sea Continental Shelf Basin (ECSCSB). However, the exact processes and dynamics are poorly understood. The numerical tool (Badlands) was adopted to simulate the geological evolution of the southern ECSCSB during the Mesozoic transitional regime of the West Pacific continental margin, between 200 and 100 Ma. The numerical model involving four-dimensional (4D) sequence stratigraphy was validated by comparing with the tectono-morphology, sedimentary environments and sediment distribution. According to our findings, the transition was mainly controlled by three structural stages. The first transitional stage of the southern ECSCSB was mainly controlled by lithospheric-scale tectonic evolution. In the second stage, the dynamic topography contributed to slow regional uplift, while the last stage showed mantle-induced dynamic subsidence. The model results on 4D geomorphic characteristics, sediment distribution of basin evolution and deep dynamic topography, provided a quantitative image for geological evolution of the West Pacific continental margin in the Mesozoic.

The Wilson cycle predicted that the passive continental margin finally collapses and forms a new subduction zone, because the transition between oceanic and continental lithosphere provides as a natural boundary with great density and rheology contrasts. However, this process is hardly constrained, due to the lack of obvious Cenozoic examples in the natural Earth. The rather stable passive margin of Atlantic Ocean, without any clear sign for subduction initiation (SI), also challenges this hypothesis. In this study, we have reviewed the main ideas and models for the SI at passive margin, which are classified into two categories, i.e. driven by either local forces or external forces. The local forces, mainly due to the local gravitational instability, are generally insufficient to break the lithosphere and lead to SI on the present Earth, although they are possible driving mechanisms for the SI in early Earth with higher potential temperature of the mantle. The external forces may come from the push of mid-ocean ridge and/or mantle plume, the lateral drag of neighboring sinking slab, as well as the basal drag of large-scale mantle convection. They are feasible to drive SI for young oceanic basins with thin and weak lithosphere on the present Earth. But the old and stable Atlantic type margin with high rheological strength is difficult for SI, which requires pre-existing weakness and/or significant weakening mechanism. Previous numerical studies have generally focused on the geodynamic conditions of SI. However, the SI for either present or early Earth is still not well constrained, especially in the aspects of geological responses and possible petrological records, which thus requires further systematic comparative studies between numerical models and geological records.

This is the dataset for the paper "Dynamics of oceanic slab tearing during transform-fault oblique subduction: Insights from 3D numerical modeling"

Thisisthedatasetforthepaper "Continental mid-lithosphere discontinuity: a water collector during craton evolution"

The supra-subduction zone ophiolite or ophiolitic mélange formed in the forearc setting is generally considered to be a key geological record for subduction initiation (SI) with petrological characteristics comparable to the SI-related rock sequence from forearc basalt (FAB) to boninite in the Izu-Bonin-Mariana subduction zone. Nevertheless, the standard FAB and boninite are generally difficult to observe in the forearc rocks generated during SI. Yet, a typical rock sequence indicating the SI of the western Proto-Tethys Ocean is reported for the first time in the Qimanyute intra-oceanic forearc system in the western Kunlun Orogen, Northwest Tibetan Plateau. The magmatic compositions, which range from less to more high field strength element (HFSE)-depleted and large ion lithophile element (LILE)-enriched, are changing from oceanic plagiogranites (ca. 494 Ma) to forearc basalt-like gabbros (FAB-Gs, ca. 487 Ma), boninites, and subsequent Nb-enriched gabbros (NEGs, ca. 485 Ma), which are thus consistent with the Izu-Bonin-Mariana forearc rocks as well as the Troodos and Semail supra-subduction zone-type ophiolites. The geochemical data from the chemostratigraphic succession indicate a subduction initiation process from a depleted mid-oceanic-ridge (MORB)-type mantle source with no detectable subduction input to gradual increasing involvement of subduction-derived materials (fluid/melts and sediments). The new petrological, geochemical, and geochronological data, combined with the regional geology, indicate that the well-sustained FAB-like intrusive magmas with associated boninites could provide crucial evidence for SI and further reveal that the SI of the western Proto-Tethys Ocean occurred in the Late Cambrian (494–485 Ma).

In this study, we aimed to identify the specific microRNAs (miRNAs) that are involved in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) from ovariectomized (OVX) mice, and to further explore the mechanism by which these miRNAs regulate osteogenic differentiation. Based on the existing studies, the expression of seven miRNAs in BMSCs from OVX mice was evaluated using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The expression of miR-133a-3p and osteogenesis-related genes (runt-related transcription factor 2 (Runx2), Osterix, alkaline phosphatase (ALP), and osteopontin) in BMSCs treated with miR-133a-3p mimics or inhibitors was detected by qRT-PCR or Western blotting. Osteogenesis efficiency was determined using ALP and alizarin red staining. The effector-target relationship between miR-133a-3p and ankyrin repeat domain 44 (ANKRD44) was confirmed by bioinformatics and a dual luciferase assay. Among the seven selected miRNAs, miR-133a-3p expression was significantly increased in BMSCs from OVX mice. Overexpression of miR-133a-3p dramatically inhibited the expression of osteogenesis-related genes in BMSCs and reduced ALP activity and mineralization. However, these processes were markedly ameliorated upon miR-133a-3p inhibition. Moreover, miR-133a-3p appeared to target ANKRD44, and the ANKRD44 expression was negatively regulated by miR-133a- 3p. Furthermore, ANKRD44 upregulation eliminated the anti-osteogenic differentiation effects of miR-133a-3p in BMSCs. Thus, our results indicated that miR-133a-3p inhibits the osteogenic differentiation of BMSCs by suppressing ANKRD44.

Weathering plays a significant role in the Earth system through the exchange of material among the lithosphere, atmosphere, hydrosphere, and biosphere. Variation of continental weathering in deep-time, however, remains elusive. This work investigates continental weathering recorded by detrital zircon. Zircon can record the oxygen isotopic composition ( δ 18 O) of its parent crust at the time of crystallization, the value of which principally reflects the time-integrated effect of crustal alteration. The Hf isotopes and U-Pb isotopes of zircon also help to constrain the alteration history between crust generation and zircon crystallization. A new algorithm is introduced to reconstruct the average δ 18 O alteration rate of continental crust (Rδ18O-CC) through time by solving a set of linear equations based on a large population of detrital zircons with varying temporal coverage across the history of crustal alteration. A nearly three-billion-year history of Rδ18O-CC from 3.2 Ga to 0.3 Ga can be reconstructed using more than 5,000 globally distributed detrital zircons with coupled U-Pb-Hf-O isotopic records. The reconstructed Rδ18O-CC shows an overall bell-shape long-term evolution centered at ∼2 Ga superposed with variations that are coupled with supercontinental assembly cycles. The long-term evolution of the reconstructed Rδ18O-CC seems to be correlated with solid-earth CO2 degassing expected from the age distribution of deleted mantle and the supercontinental cycles. Thus, the Rδ18O-CC is interpreted to reflect weathering considering the control of solid-earth CO2 degassing on the total weathering flux of continental crust. However, independent evidence on the solid-earth CO2 degassing is unavailable, interpreting Rδ18O-CC as a weathering record requires further testing. Nevertheless, this work provides an example of how the time-integrated signal, with large noise-to-signal ratio, preserved in geological archives can be deconvolved using a large dataset. The result also demonstrates the great potential that weathering history may have in reconstructing the operation of the Earth system across deep-time.

The continental craton is generally considered to be stable, due to its low-density and high viscosity; however, the thinning and destruction of cratonic lithosphere have been observed at various parts of the globe, for example, the eastern North China Craton (NCC). Although a large number of geological and geophysical data have been collected to study the NCC, the mechanisms and dynamic processes are still widely debated. In this study, using 2-D high-resolution thermo-mechanical models, we systematically explore the key constraints on the destruction of cratonic lithosphere. The model results indicate that the craton destruction processes can be strongly influenced by the presence of the so-called mid-lithosphere discontinuity (MLD), and its interaction with subduction. The properties of the MLD layer and the density contrast between the lithospheric mantle and asthenosphere play significant roles in the destruction processes. Specifically, the presence of a deep and low-viscosity MLD layer within the cratonic lithosphere tends to enhance instability of the craton, making it easier for lithosphere destruction. In addition, a relatively thick oceanic crust, high convergence rate, and large initial subduction angles favor the craton destruction. Finally, we compare the model results with the observations of NCC, which indicate that the interaction between the Paleo-Pacific subduction and the MLD layer in the cratonic lithosphere has played an important role in the observed large-scale lithospheric removal of the eastern North China Craton.

The accretion of oceanic plateaus has played a significant role in continental growth during Earth's history, which is evidenced by the presence of oceanic island basalts (OIB) and plume-type ophiolites in many modern orogens. However, oceanic plateaus can also be subducted into the deeper mantle, as revealed by seismic tomography. The controlling factors of accretion versus subduction of oceanic plateaus remain unclear. Here, we investigate the dynamics of oceanic plateau accretion at active continental margins using a thermo-mechanical numerical model. Three major factors for the accretion of oceanic plateaus are studied: (1) a thinned continental margin of the overriding plate, (2) “weak” layers in the oceanic lithosphere, and (3) a young oceanic plateau. For a large oceanic plateau, the modes of oceanic plateau accretion can be classified into one-sided and two-sided subduction–collisional regimes, which mainly depend on the geometry of the continental margin (normal or thinned). For smaller-sized seamounts, accretion occurs only if all three factors are satisfied, of which a thinned continental margin is the most critical. Possible geological analogues for the two-sided subduction–collisional mode include the Taiwan orogenic belt and subduction of the Ontong Java Plateau. The accretion model for small oceanic plateaus applies to the Nadanhada Terrane in Northeast China.

According to the plate tectonics theory, continental crust (CC), especially the felsic upper and middle continental crust (UCC and MCC), cannot subduct due to its buoyancy. Therefore, most, if not all, of the felsic crustal mass will be preserved in continental collision zones or eroded by the surface process. Consequently, the continent-continent convergence is generally slower and more short-lived than oceanic plate subduction. However, the long-duration, fast convergence, and imbalance of crustal mass in the India-Asia collisional system challenge the classical rules of plate tectonics. Systematic compilation and calculations indicate ~20-47% of the felsic crust in Greater India is missing during collision. Based on the phase equilibria modeling and density calculations, we explore the pressure-temperature-dependent density evolutions of UCC and MCC and demonstrate they are denser than the surrounding mantle at P >7-8 GPa when the phase transition from coesite to stishovite occurs. The phase equilibria induced density evolution is further integrated into the thermo-mechanical model, which confirm the deep subduction of Greater Indian continent with its felsic UCC and MCC. Analytical studies of the slab-pull forces in the subduction zone indicate the Greater Indian continent can subduct spontaneously under its own negative buoyancy when it is dragged to a depth of ~170 km by the preceding oceanic slab. The great slab-pull force, induced by the negative buoyancy of UCC and MCC below 170 km, not only contributes to the long-lasting fast convergence between India and Asia, but also explains the crustal mass imbalance during the Himalayan orogeny.

Thisisthedatasetforthepaper"Along-strike variation of convergence rate and pre-existing weakness control tearing of underthrusting Indian lithosphere beneath weak Tibetan plateau"

SUMMARY Thinning of the lithosphere under continental collisional orogens is often attributed to delamination or convective thinning. Both processes remove part or all of the mantle lithosphere that has become denser and gravitationally unstable. Previous studies mostly focused on the different thermomagmatic consequences of these two processes; the dynamic links between them, and the critical conditions for one or the other process to dominate lithosphere thinning, remain uncertain. Here, we used high-resolution thermomechanical models with various rheology (linear viscous, power-law viscous and/or the extended Drucker–Prager plasticity) to systematically investigate the dynamics of delamination and convective thinning under collisional orogens. Our results show that convective thinning is favoured in models of linear (Newtonian) viscous rheology and low viscosity $({10^{19}}\!-\! {10^{20}}\,\,{\rm{Pa}} \, {\rm{s}})$. Power-law viscous rheology promotes strain localization, which reduces the effective viscosity and may lead to localized rising of the asthenosphere to the crustal base, thus triggering delamination. Further strain localization and stronger delamination are predicted with inclusion of plastic rheology in the model. These results indicate that convective thinning and delamination are dynamically linked and can occur in the same orogeny. Their relative dominance during orogenesis may be distinguished by the resulting spatiotemporal evolutions of thermal perturbation, magmatism and elevation changes. We applied the models to show that the evolution of the Central Anatolian Plateau is consistent with the dominance of convective thinning, whereas delamination played a major role in thinning the mantle lithosphere under central-northern Tibetan Plateau.

Two distinct styles of continental collision are observed in nature, i.e. lithospheric-scale subduction versus crustal-scale underthrusting. The former refers to a collision scenario where the lower plate subducts below the lithospheric mantle of the overriding plate, whereas the latter is characterized by the underthrusting of the subducting plate beneath the crust of the overriding plate. Systematic numerical models were constructed to study the dynamics of these two different collision modes. The model results indicate that low convergence rate and cold overriding plate contribute to the lithospheric-scale subduction, which incorporates limited shortening of the overriding lithosphere during collision. In contrast, the crustal-scale underthrusting requires relatively high convergence rate and hot/weak overriding plate, in which the thickened lithospheric mantle of the overriding plate is progressively delaminated from the overlying crust and is replaced by the sub-horizontally underthrusted plate. The model results were systematically compared with four ongoing collisional orogens along the Alpine–Himalayan belt, i.e. the central-western Alps, the East Anatolian plateau, the Zagros–Iranian plateau, and the southern Tibetan plateau. It indicates that the lithospheric-scale subduction is widely observed and generally consistent with the natural orogens, for example, the Alps, Anatolia, and Zagros. On the other hand, the crustal-scale underthrusting is reconciled with the India–Asia collision zone, with respect to the geodynamic conditions, crustal-lithospheric structure, as well as the uplift history.

The oceanic plateau subduction and resulted terrane accretion have played significant roles in the continental crustal growth; however, the modes and dynamics of plateau accretion during subduction remains poorly understood. The oceanic subduction can be driven by the combined effects of slab pull, ridge push, as well as the possible overriding plate push. The latter one has been rarely studied, but can be the case during the multiple Tethyan slabs subduction and terranes accretion for the formation of Tibetan lithosphere in the Mesozoic. Using 2-D petrological-thermo-mechanical models, we systematically investigated the modes and dynamics of terrane accretion during the dominant seaward continental drifting and oceanic plateau subduction. The model results show that the plateau with continental crustal affinity favors accretion to the overriding plate during the subduction process. Three distinct terrane accretion modes are identified: frontal accretion, bottom accretion, and a transitional mode with both the frontal and bottom accretion. In contrast, the plateau with oceanic crustal affinity generally favors subduction and recycling into the deeper mantle, rather than accretion, which is mainly due to the higher density and possible eclogitization of the oceanic crustal materials during subduction. The numerical simulations further reveal that the controlling factor for the subduction style, i.e. flat versus steep subduction, is the age of the oceanic slab and the seaward overriding plate motion. The rheological properties and the convergence rate play minor roles in affecting the subducting slab angle. The model results are further compared with the Jurassic magmatic rock distribution and geochemical characteristics of the Lhasa Terrane in Tibet, which reveals (1) the transition from flat to steep subduction of the southward Bangong-Nujiang Tethyan slab; and (2) the mechanism of Jurassic crustal growth in the central Lhasa subterrane which may be strongly correlated with the bottom accretion of the subducted oceanic plateau.

The Tibetan plateau is manifested by contrasting along-strike lithospheric structures, but its formation mechanism and the relationship with the heterogeneous multi-terrane configuration is a challenging problem. Here we conduct systematic numerical modeling to explore the roles of width, density, and rheological properties of the multiple terranes in the lithospheric evolution of the Tibetan plateau, which reveals two distinct collision modes. In Mode-I, the lithospheric mantles of both the strong and weak terranes in the Tibetan plate are completely detached, followed by the underthrusting of Indian lithosphere beneath the whole plateau. Alternatively, Mode-II is characterized by full detachment of the weak terranes, but (partial) residue of the strong terranes during collision. These two contrasting modes, broadly consistent with the lithospheric structures of western and central–eastern Tibetan plateau, respectively, are strongly dependent on the along-strike variation of the width of the strong Lhasa–Qiangtang terranes., Nature Communications, 9, ISSN:2041-1723