Plateau Formation Research Articles

First fruit record of Pterocarya (Juglandaceae) from the upper Eocene of the central Qinghai-Tibetan Plateau, China

The Juglandaceae family experienced significant diversification during the early Tertiary, as evidenced by fossil records showing a broad expansion of both extant and extinct taxa. The genus Pterocarya is characterized by its distinctive fruit with butterfly-shaped wings and a small nutlet. Macrofossil records suggest that this genus was distributed widely in the Northern Hemisphere. However, the fossil record of Pterocarya in China is limited. In this study, we describe a well-preserved Pterocarya fossil winged fruit from the middle-upper member of the Niubao Formation (the upper Eocene) of the central Qinghai-Tibetan Plateau, China. The winged fruit is identified as Pterocarya liae sp. nov. based on detailed morphological comparison, representing the earliest known record of Pterocarya winged fruit in Asia. The new finding extends the paleobiogeographic distribution of Pterocarya during the Eocene and provides new insights into the early stage of the diversification of this genus.

Modifying Polymer-Based Hard Carbons for Enhanced Understanding of Sodium Storage Properties

Numerous theories on the storage of sodium in hard carbons can be found in the literature. In particular, understanding the contributions of (heteroatom) doping, porosity and graphitic layers is of great importance. Much of the current literature on hard carbons uses different biomaterials as precursors in order to improve the sustainability of the synthesis. However, large differences in the composition of the starting materials and the presence of foreign atoms make a systematic investigation of the storage process extremely difficult.Therefore, a hard carbon material based on furan resins was used in this work to obtain a well-defined starting material that can be modified systematically. This allows a detailed investigation of the effects caused by those modifications. Modifications can be achieved by directly adding various template materials to the polymerization process. Both doping with heteroatoms by adding template chemicals such as boric acid and the introduction of graphitic layers by adding high-purity graphite during polymerization were investigated.Addition of boron and phosphorus heteroatoms led to an increase in reversible capacity up to 240 mAh g-1 from 150 mAh g-1 for carbonization temperatures as low as 650°C. Formation of a potential plateau was observed for boron doping, which is usually found at higher carbonization temperature surpassing 1000°C. Utilizing Raman and XRD spectroscopy, crystallite size was found to be decreasing with phosphorus doping, while boron doping led to an increase. This increase could be a possible explanation for the observed capacity plateau.The addition of high-purity carbon samples, such as KS6L graphite or graphene, allowed for a targeted introduction of single- and multi-layer graphitic domains without alteration of additional properties. Increasing graphite content up to 5 wt-% during polymerization resulted in enhanced electrochemical characteristics, including increased sodium intercalation into the lattice and shift of the sloping proportion to lower potentials. Further increase up to 10 wt-% led to a vanishing of the plateau potential and a lowering of the reversible capacity. The results indicate that the interlayer spacings has now decreased below a threshold, which prohibits the sodium from intercalation between the graphitic layers. Additionally, doping Hard Carbons with graphene revealed a capacity decrease at content ratios as low as 2 wt-%, emphasizing the significance of both the stacking and interlayer spacing of the graphitic lattice, as well as the chemical composition, for efficient sodium storage.In summary the results presented provide an enhanced understanding into the sodium storage properties of Hard Carbons, which help improve the design of synthesis processes for more cost-efficient and high-performance carbon materials. Figure 1

Plateau formation on Venus similar to early continent formation on Earth

Plateau formation on Venus similar to early continent formation on Earth

Improved Mechanical Strength without Sacrificing Li-Ion Transport in Polymer Electrolytes.

Next-generation batteries demand solid polymer electrolytes (SPEs) with rapid ion transport and robust mechanical properties. However, many SPEs with liquid-like Li+ transport mechanisms suffer a fundamental trade-off between conductivity and strength. Dynamic polymer networks can improve bulk mechanics with minimal impact to segmental relaxation or ionic conductivity. This study demonstrates a system where a single polymer-bound ligand simultaneously dissociates Li+ and forms long-lived Ni2+ networks. The polymer comprises an ethylene oxide backbone and imidazole (Im) ligands, blended with Li+ and Ni2+ salts. Ni2+-Im dynamic cross-links result in the formation of a rubbery plateau resulting in, consequently, storage modulus improvement by a factor of 133× with the introduction of Ni2+ at rNi = 0.08, from 0.014 to 1.907 MPa. Even with Ni2+ loading, the high Li+ conductivity of 3.7 × 10-6 S/cm is retained at 90 °C. This work demonstrates that decoupling of ion transport and bulk mechanics can be readily achieved by the addition of multivalent metal cations to polymers with chelating ligands.

Effects of sex differences on osteoarthritic changes after anterior cruciate ligament reconstruction in rats

The prevalence of primary osteoarthritis is higher in females than males. However, it remains unclear if there are sex differences in the incidence of post-traumatic osteoarthritis after anterior cruciate ligament (ACL) reconstruction. In this study, we aimed to investigate the effects of sex on osteoarthritic changes after ACL reconstruction using an animal model. Rats were divided into the following four groups: male control, male ACL reconstruction, female control, and female ACL reconstruction. ACL reconstruction surgery was performed on the right knees of rats in the ACL reconstruction groups, while rats in the control groups did not undergo knee surgery. At 1, 4, and 12 weeks after surgery, cartilage degeneration in the medial tibial plateau and osteophyte formation in the proximal tibia were histologically assessed. After ACL reconstruction, an increase in the Mankin score, cartilage fissures, and osteophyte formation were detected within 12 weeks in both male and female rats, with similar degrees of these changes between males and females. However, changes in cartilage thickness and chondrocyte density after ACL reconstruction differed between males and females. Cartilage thickening was observed in male rats but not in female rats. The increase in chondrocyte density in the anterior region was detected in both males and females but was more pronounced in female rats. In conclusion, osteoarthritic changes were observed after ACL reconstruction in both male and female rats, but differences in changes in cartilage thickness and chondrocyte density were observed between males and females.

The first Protosiren remains preserved in ornamental limestones, Middle Eocene, North Eastern Desert, Egypt

A recent revelation has come to our attention, revealing the remarkably well-preserved post-cranial remains belonging to Protosiren. These remains include vertebrae, ribs, and fragmentary bones, and were discovered from two different horizons located in the Mokattam Formation of El-Galala Plateau, North Eastern Desert of Egypt. The first specimen, GCU0101, is identified as Protosiren sp., whereas the GCU0201 specimen is recognised as Protosiren cf. P. fraasi due to certain distinguishing features. These include vertebrae with wide keyhole-shaped neural canals, reduced tuberculum on the ribs, lack of pachyostotic ribs, and the possession of rugose articular rib head. This discovery is remarkable, as it offers a unique opportunity to study the ancient marine mammal's morphology and osteology, shedding light on its evolutionary history and ecological niche. The study documents the first occurrence of Protosiren from an ornamental limestone of the Middle Eocene (Bartonian) Observatory Formation from El-Galala Plateau, Northeastern Desert, Egypt.

Mississippian olistostromes of Iberia revisited: tectonic drivers of synorogenic carbonate platform/reef destruction

This paper reviews the synorogenic basins formed on the Gondwana side of the Variscan Orogen of Iberia, highlighting the widespread occurrence of calciturbiditic formations and olistostromes containing reef limestone olistoliths in Iberia's Variscan basins. Using key examples from the Variscan Orogen for comparison (the Azrou–Khenifra and Rhenohercynian basins), the significance of these olistostromes and flyschoid deposits is discussed. Our tectonic models of the Variscan belt in Iberia propose possible drivers of synorogenic carbonate platform/reef destruction responsible for the origin of calciturbidites and olistostromes. One model proposes the formation of an orogenic plateau via the lateral flow of partially molten orogenic roots in the context of Laurussia–Gondwana convergence following the destruction of the Rheic Ocean and slab retreat of the Gondwana (lower) plate. An alternative model invokes subduction of Palaeotethys oceanic lithosphere beneath the Gondwana (upper) plate. Both emphasize the Mississippian occurrence of a significant thermal anomaly beneath Gondwana that favoured strong lithosphere thinning, creating ideal conditions for synorogenic carbonate platform/reef destruction and the formation of calciturbidite deposits and olistostromes in Iberia. The Variscan palaeotopography would look similar in both situations. Distinguishing between these models is therefore not straightforward, with differences in the kinematics of regional tectonic transport in the superstructure of Mississippian gneiss domes. Thematic collection: This article is part of the Ophiolites, melanges and blueschists collection available at: https://www.lyellcollection.org/topic/collections/ophiolites-melanges-and-blueschists

Unveiling voltage evolution during Li plating-relaxation-Li stripping cycling of lithium-ion batteries

The unwanted Li plating on graphite anode surface in lithium-ion batteries causes poor cycling performance along with raised safety risk once Li dendrites penetrate separator. Voltage characteristics during relaxation and discharging have been recognized as the most direct and convenient indictor for Li plating detection, where unveiling voltage evolution during plating-relaxation-stripping cycling needs to be emphasized to facilitate Li plating detection. This study fabricates Li|graphite cells to implement Li plating-relaxation-stripping protocols through over-lithiation before internal short circuit, and the Li nucleation-growth process is linked to voltage evolution assisting with the post-mortem approaches. The Li plating voltage initially displays continuous decline indicated as Li nucleation, until the formation of Li plating plateau indicated as Li growth. The plating-relaxation-stripping voltage patterns show highly correlation that the occurrence of Li plating plateau exactly corresponds to the appearance of a mixed relaxation plateau attributed to the equilibrium of Li stripping and Li re-intercalation into graphite, while the disappearance of the mixed relaxation plateau just corresponds to the advent of Li stripping plateau. Three stages are finally divided associated with characteristic Li plating -relaxation-stripping voltage patterns, where Stage I indicates the occurrence of Li plating plateau behaving as predominant LixC6; Stage II is characterized as the occurrence of mixed relaxation plateau manifested as Li coexisting with LixC6; Stage III is distinguished by the appearance of Li stripping plateau indicated as predominant Li and dead Li. This work proposes underlying evolution mechanism of Li plating-relaxation-stripping cycling, which contributes to sufficient evidence for reliable Li plating detection.

Effect of potassium titanate fibres and metal sulphides in the tribological behaviour of brake friction composites

In a brake system, brake friction composites are essential for converting kinetic energy into frictional heat. An optimal brake friction composite should ensure a stable coefficient of friction under extreme operational conditions. This study examines the tribological performance of brake friction composites incorporating potassium titanate fibres and metal sulphide lubricants in standard brake pad formulation. Brake friction composites were engineered by varying the potassium titanate fibre content from 10 to 30 %, while the lubricant mixture (comprising graphite, MoS2, Bi2S3 and Sb2O3) was proportionally adjusted from 27 to 7 %, with the filler and binder concentrations held constant throughout the formulation. The phenolic resin-based composites were characterised for their physical, chemical and mechanical properties in accordance with the IS 2742 (Part 4) standard. The tribological performance of the fabricated composites was evaluated using a rotating drum setup, following the SAE J661 procedure. The worn surfaces of the samples were analysed to identify wear mechanisms utilising scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The results demonstrated that the optimal combination of potassium titanate fibres and metal sulphide lubricants significantly influences wear resistance and friction stability, with varying degrees of primary and secondary plateau formation observed. This comprehensive characterisation provides valuable insights into the material's behaviour under operational conditions, guiding the development of advanced brake friction composites.

Late Cenozoic geomorphic evolution in the northeastern Tibetan Plateau: Constraints on U-Pb age spectra of detrital zircons in the Wuwei Basin, NW China

Basin deposits of the northeastern Tibetan Plateau provide an ideal record for understanding the uplift and the geomorphic evolution in NW China. In this study, we present U-Pb age spectra of detrital zircon from the borehole WW-01 in the Wuwei Basin in the northeastern Tibetan Plateau. The results indicate that: (1) The dominant provenance of the Wuwei Basin was derived from Qilianshan Orogenic Belt (QOB) at 10.34–9.51 Ma, 8.18 Ma, 2.02–0.09 Ma, and the Alxa Block (AB) at 8.69 Ma and 8.14–4.51 Ma. (2) The transitions in the dominant provenance area, at 9.51–8.69 Ma and 8.18–8.14 Ma, were controlled by the closely related to the pre-existing landforms of the basin and its periphery. And the transitions of 8.69–8.18 Ma and 4.51–2.02 Ma were prevailing in the uplift of the northeastern Tibetan Plateau. (3) Provenance analysis, integrated with the sedimentary and structural analysis, show that the initial uplift of the northeastern Tibetan Plateau in the Cenozoic occurred at ca. 8.25 Ma, and the last uplift occurred at ca. 2.58 Ma, corresponding to the geomorphological formation of the northeastern Tibetan Plateau.

Gas geochemical evidence for the India-Asia lithospheric transition boundary near the Karakorum fault in western Tibet

The lithospheric structure of the Tibetan Plateau plays a key role in explaining the underlying plateau formation mechanism(s) and growth history. Although many studies have focused on the Moho discontinuity, lithosphere boundary, and lithospheric structure of central and eastern Tibet, there are few corresponding constraints for western Tibet. In this contribution, we systematically investigated the lithosphere in western Tibet by analyzing the He and C isotopes of seven hydrothermal spring systems along the southeastern segment of the Karakorum fault. We found a high Rc/Ra ratio (1.298) for springs along the Karakorum fault, suggesting that the fault plays a key role as a lithospheric-scale conduit for fluid uplift after mantle degassing. In addition, we identified two different origins of the gases at thermal springs, which may reflect two distinct mantle sources. We infer that the locations of these springs reflect the boundary between the Indian and Asian mantles, which is consistent with the geophysics-based interpretations of a “mantle suture” along the Karakorum fault. Our work confirms the boundary between the Indian and Asian mantle, which provides geochemical support to the model of the subduction of Indian lithosphere.

Kinetic study of the bifurcation of resonant magnetic perturbations for edge localized mode suppression in ASDEX Upgrade

The correlation between the bifurcation of resonant magnetic perturbations (RMPs) to the unshielded state and edge localized mode (ELM) suppression in ASDEX Upgrade is studied using a kinetic plasma response model numerically and analytically. For the numerical studies, the linear kinetic Maxwell solver KiLCA for cylindrical geometry and the quasilinear transport code QL-Balance are used in combination with the ideal MHD solver GPEC to account for realistic tokamak geometry. Based on this modelling, a numerical local bifurcation criterion is introduced which estimates the effect of RMP-induced temperature plateau formation in the resonant layer. Its analytical form is derived in constant-psi approximation. The kinetic model reproduces the known gyrocenter resonance, Er=0 , and the electron fluid resonance. In contrast to MHD theory, the latter is located at the zero of the perpendicular electron fluid velocity computed only with half of the electron temperature gradient. The application of the criterion to experimental data shows a correlation between bifurcation and the ELM suppression phase. Moreover, an electron density limit is found resembling the one observed in experiments.

Shape variation and flat plateau formation of a frozen nanofluid droplet

Droplet freezing is a phenomenon of great interest, not only from a fundamental perspective, but also due to its significant contributions to various industrial and ecological processes. Despite the extensive research on pure water droplet freezing, the freezing dynamics of nanofluid droplets have not been investigated to the same extent. It has been observed that frozen nanofluid droplets exhibit a distinctive flat plateau shape at their apex, in contrast to the pointed tip observed in pure water droplets. Our experimental investigation has revealed that when the vertical velocity of nanofluid droplet's freezing front is lower than a critical value, nanoparticles are expelled from the freezing liquid and aggregate at the freezing front to form a particle layer. This layer causes a deviation between the motion direction of the tri-junction line and the interface curve of the unfrozen liquid, resulting in an increased angle growth and the formation of a plateau at the top of the frozen droplet. The critical freezing velocity was found to be independent of the contact angle but showed a slight increase with subfreezing temperature. As the subfreezing temperature rises, the flat plateau of the frozen droplet transitions to a pointed tip. To further explore the freezing dynamics of nanofluid droplets, we conducted a statistical analysis of the cone angle at the apex of the frozen droplets. Our results indicates that in most cases, the cone angle is greater than the universal value observed for pure water droplets. And the cone angle is effected by the droplet volume size and subfreezing temperature.

Self-Consistent Simulation of the Excitation of Compressional Alfvén Eigenmodes and Runaway Electron Diffusion in Tokamak Disruptions.

Alfvénic modes in the current quench (CQ) stage of the tokamak disruption have been observed in experiments. In DIII-D the excitation of these modes is associated with the presence of high-energy runaway electrons (REs), and a strong mode excitation is often associated with the failure of RE plateau formation. In this work we present results of self-consistent kinetic-MHD simulations of RE-driven compressional Alfvén eigenmodes (CAEs) in DIII-D disruption scenarios, providing an explanation of the CQ modes. Simulation results reveal that high energy trapped REs can have resonance with the Alfvén mode through their toroidal precession motion, and the resonance frequency is proportional to the energy of REs. The mode frequencies and their relationship with the RE energy are consistent with experimental observations. The perturbed magnetic fields from the modes can lead to spatial diffusion of REs including the nonresonant passing ones, thus providing the theoretical basis for a potential approach for RE mitigation.

Plateau Formation Controlled by Lithospheric Foundering Under a Weak Crust

AbstractLithospheric foundering is hypothesized to contribute to the formation of Earth's largest continental plateaus, but the predicted effects remain poorly constrained, especially considering variations in crustal strength. Here we propose that lithospheric foundering involving a hot, weak crust can explain aspects of topography and crustal deformation in mountain belts. We explore this hypothesis using numerical models of orogenesis and foundering in the Southern Puna Plateau in the Central Andes. Contrary to previous models of foundering involving a strong crust, which are characterized by subsidence and shortening, a weak crust results in surface uplift and upper‐crustal horizontal extension, which is accommodated by horizontal shortening in peripheral regions. Our model explains data such as the timing and location of exhumation and basin sedimentation as a response to foundering. The model also shows that foundering is capable of converting a high‐relief, broken‐foreland region into a high‐elevation, low‐relief plateau in a convergent tectonic setting.

Alluvial development during climate fluctuations depicted with spectral decomposition of the Middle Triassic to Lower Jurassic post‐rift succession in the Horda Platform (Norway) and the impact on reservoir properties

AbstractFor the first time, this study presents interpretations of alluvial fans in spectral decomposition RGB Blends, analysed in seismic time slices from the Middle Triassic to Lower Jurassic stratigraphical interval of the Horda Platform (northern North Sea). The time slices record a shifting alluvial fan front, fluvial variability, uplift and erosion and reveals depositional elements that may set the common conception of the geological development of this area during the Early–Middle Mesozoic up for discussion. Results show that the Upper Triassic Lunde Formation in the eastern margin of the Horda Platform was characterized by the deposition of coalesced alluvial fans. A variable extent of the fan front through the Upper Triassic is linked to interplaying allogenic factors: uplifted source areas in the aftermath of Early–Middle Triassic rifting determined sediment availability; climate transitioning from arid to semi‐humid, with increasingly fluctuating precipitation, controlled sedimentation, and run‐off; provenance dictated bulk sedimentology and affected prevailing alluvial processes. An overall retreat of the fan system through the Late Triassic coincided with a significant change in landscape characteristics at the transition into the overlying Statfjord Group. Uplift and initial tilting of the Horda Platform caused landscape degradation and the formation of plateaus and incised valleys, contemporaneous with increased humidity and marine transgression, forming estuaries. The shift in depositional style has implications for reservoir properties, creating complexity and heterogeneity in terms of facies distribution and connectivity, which may benefit potential CO2 storage. Upper Triassic alluvial fan development in the Horda Platform (northern North Sea) depicted through spectral decomposition of seismic time slices Enhanced level of seismic stratigraphic interpretation with RGB blending Impact of allogenic factors on alluvial depositional development Implications of alluvial variability on reservoir properties

Nature and Origin of Magnetic Lineations Within Valdivia Bank: Ocean Plateau Formation by Complex Seafloor Spreading

AbstractValdivia Bank (VB) is a Late Cretaceous oceanic plateau formed by volcanism from the Tristan‐Gough hotspot at the Mid‐Atlantic Ridge (MAR). To better understand its origin and evolution, magnetic data were used to generate a magnetic anomaly grid, which was inverted to determine crustal magnetization. The magnetization model reveals quasi‐linear polarity zones crossing the plateau and following expected MAR paleo‐locations, implying formation by seafloor spreading over ∼4 Myr during the formation of anomalies C34n‐C33r. Paleomagnetism and biostratigraphy data from International Ocean Discovery Program Expedition 391 confirm the magnetic interpretation. Anomaly C33r is split into two negative bands, likely by a westward ridge jump. One of these negative anomalies coincides with deep rift valleys, indicating their age and mechanism of formation. These findings imply that VB originated by seafloor spreading‐type volcanism during a plate reorganization, not from a vertical stack of lava flows as expected for a large volcano.

Stepwise Widening of the Central Andes—The Role of the Lower Crust

AbstractThe outward growth of many orogens occurs through pulsed migration of the strain front. During Cenozoic shortening of the central Andes, the strain front abruptly migrated ∼400 km eastward across the Altiplano, isolating the plateau interior from major deformation. In contrast to the traditional critical wedge model that focuses on shallow crust deformation, our lithosphere‐scale numerical models show the ductile lower crust plays a key role in the dynamics of the orogen. As the orogen grows upward, the lower crust flows outward and causes stepwise expansion of the orogen through landward‐migrating deformation. The step length of the strain‐front migration increases with decreasing lower crustal strength. Topographically, a weaker crust promotes the formation of a smooth plateau and underthrusting of stronger foreland lithosphere. Our results indicate that the seemly unrelated physiography, deep‐lithosphere structure, and plateau‐wide strain migration in the Altiplano may all be the result of a weak lower crust.

Composition and Miocene deformation of the lithospheric mantle adjacent to the Marlborough Fault System in North Canterbury

ABSTRACT Mantle xenoliths in a nephelinite in the Little Lottery River provide insight into the Miocene mantle adjacent to the Australia-Pacific plate boundary in N Canterbury. The xenoliths comprise peridotite and pyroxenite extracted from depths of ∼ 40 to 60 km. The olivine Mg# < 89, a lack of spinel and occurrence of ilmenite, elevated bulk Cr and Al, light rare Earth element (REE)-enriched clinopyroxene, and 87Sr/86Sr15 Ma clinopyroxene populations (0.7029–0.7047) in most harzburgite and dunite samples, and in all lherzolite, wehrlite, olivine websterite and orthopyroxenites, indicate that most are the product of reaction of depleted peridotite with Fe, Ti, Al and light REE-bearing silicate melts of basaltic or similar composition. Available isotopic data indicate that the xenoliths could be derived from mantle lithosphere beneath the Hikurangi Plateau, in which case the reactive melts may have been associated with the Cretaceous plateau formation. Extensive recrystallisation of olivine indicates that portions of this lithosphere mantle were affected by the deformation close to the time of entrainment. Since the eruption occurred at ∼ 15 Ma, these textures require that the mantle lithosphere in this area was deforming before formation of today's expression of the proximal Hope Fault strand of the Australia-New Zealand plate boundary.

Seismic Azimuthal Anisotropy of Northeastern Tibetan Plateau From Ambient Noise Double Beamforming Tomography: Implications for Crustal Deformation

AbstractIn this study, we obtain a three‐dimensional (3‐D) high resolution seismic anisotropy model of NE Tibet using ambient noise double beamforming (DBF) tomography with ChinArray‐Himalaya II data. DBF tomography technique allows for the simultaneous derivation of local phase velocity and azimuthal anisotropy from ambient noise cross‐correlations without performing tomographic inversion. Based on the DBF tomography results, we have constructed a high resolution 3‐D azimuthal anisotropic shear wave velocity model of NE Tibet. Our model indicates the presence of prominent low velocities and strong azimuthal anisotropy in the mid‐to lower crust beneath the Songpan‐Ganzi belt, while the mid‐to lower crust of the Qilian belt exhibits relatively weak low velocity and azimuthal anisotropy. We propose that crustal channel flow may be the primary mechanism driving crustal deformation in the Songpan‐Ganzi belt, which is in the mature part of the plateau. As the Qilian belt is at an early stage of plateau formation, it is characterized by crustal shortening with the development of a sub‐vertical foliation. Additionally, the misalignment between predicted and observed shear wave splitting reveals decoupled crust and upper mantle deformation west of the Ordos block where eastward mantle flow is deflected by the lithospheric keel of Ordos.