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| Open AccessMethane-hydrogen-rich fluid migration may trigger seismic failure in subduction zones at forearc depths
This study provides evidence for the migration of deep energy sources along tectonic discontinuities in subduction zones and suggests causal relationships with brittle failure of hard rocks that may trigger seismic activity.
- Francesco Giuntoli
- , Luca Menegon
- & Alberto Vitale Brovarone
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| Open AccessEvidence for structural control of mare volcanism in lunar compressional tectonic settings
On the Moon, evidence has been found for the preexisting fault reactivation origin (tectonic inversion) of contractional wrinkle ridges in mare basins and the consequent structural control of volcanic eruptions in compressional tectonic settings.
- Feng Zhang
- , Alberto Pizzi
- & Yongliao Zou
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| Open AccessNew constraints on Cenozoic subduction between India and Tibet
By evaluating model predictions with multiple geological data, the study shows that Tibetan tectonism is most consistent with the initial indentation of a cratonic terrane, followed by subduction of a buoyant tectonic plate resembling a continental margin.
- Liang Liu
- , Lijun Liu
- & Ling Chen
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| Open AccessSurface faulting earthquake clustering controlled by fault and shear-zone interactions
The mechanisms responsible for clustering of surface fault earthquakes are often unclear. Here the authors find that differential stress fluctuates during fault/shear-zone interactions which can produce changes in strain-rate and slip-rate changes leading to earthquake clustering.
- Zoë K. Mildon
- , Gerald P. Roberts
- & Eutizio Vittori
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| Open AccessFeedbacks between sea-floor spreading, trade winds and precipitation in the Southern Red Sea
Testing feedbacks between climatic and geological processes are challenging. Here, the authors show that geomorphological features of the southern Red Sea margin are best interpreted by a feedback cycle between orographic precipitation, mid-ocean spreading and coastal magmatism, and that the feedback is enhanced by the trade wind.
- Kurt Stüwe
- , Jörg Robl
- & Finlay M. Stuart
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Article
| Open AccessInferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu
Asteroid interiors are key to understand their formation and evolution. Here, the authors show that numerically simulated low-cohesion and low-friction structures with several high-cohesion internal zones can explain asteroid Bennu’s geophysical characteristics and the absence of the moons.
- Yun Zhang
- , Patrick Michel
- & Dante S. Lauretta
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| Open AccessDuctile deformation during carbonation of serpentinized peridotite
Mantle rocks can efficiently bind carbon by reaction with CO2 if fluid pathways remain open. This study of samples from Oman demonstrates that coupling of synchronous reaction and deformation facilitates fluid flow and massive carbon sequestration.
- Manuel D. Menzel
- , Janos L. Urai
- & Peter B. Kelemen
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| Open AccessThe cryptic seismic potential of the Pichilemu blind fault in Chile revealed by off-fault geomorphology
Cryptic faults concern earthquake scientists, since they pose a hidden seismic potential which is hard to identify. To address this, the authors here study off-fault deformed geomorphic markers such as marine terraces using high-resolution LiDAR topography, optical dating of sediments and space geodetic observations.
- J. Jara-Muñoz
- , D. Melnick
- & M. R. Strecker
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| Open AccessA strength inversion origin for non-volcanic tremor
Subduction plate boundaries have enigmatic seismic tremor that is often associated with surges in creep across these boundaries. Here, the authors use multiple approaches to show how blocks of weak rocks in a stronger matrix can explain both the occurrence and characteristics of tremor events.
- Paola Vannucchi
- , Alexander Clarke
- & Jason P. Morgan
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| Open AccessPace of passive margin tectonism revealed by U-Pb dating of fracture-filling calcite
It is thought that Atlantic style passive margins have experienced episodes of uplift and volcanism in response to changes in mantle circulation. The authors here employ U-Pb dating of calcite in faults and fractures along the eastern North American margin and find a 40 Myr long period of fracturing and faulting from 115 to 75 Ma.
- William H. Amidon
- , Andrew R. C. Kylander-Clark
- & David P. West Jr.
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| Open AccessEpisodic back-arc spreading centre jumps controlled by transform fault to overriding plate strength ratio
Back-arc spreading centre jumps have been suggested to be controlled by a number of different drivers. Here, the authors, using 3D numerical models, show that transform faults can trigger back-arc spreading centre jumps, without the need of any ad hoc factors.
- Nicholas Schliffke
- , Jeroen van Hunen
- & Frédéric Gueydan
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| Open AccessFault rock heterogeneity can produce fault weakness and reduce fault stability
This paper shows that faults comprised of heterogeneously distributed materials, as is typical for tectonic faults in nature, are weaker and more unstable than equivalent faults where the materials are homogeneously mixed together.
- John D. Bedford
- , Daniel R. Faulkner
- & Nadia Lapusta
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Article
| Open AccessLarge impact cratering during lunar magma ocean solidification
Lunar impact basins formed during the magma ocean solidification should have formed almost unidentifiable topographic and crustal thickness signatures, thus may escape detection. This result allows for a higher impact flux in the earliest epoch of Earth-Moon evolution.
- K. Miljković
- , M. A. Wieczorek
- & M. T. Zuber
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| Open AccessRheological inheritance controls the formation of segmented rifted margins in cratonic lithosphere
The evolution of rifts and rifted margins is controlled by the rheology of the lithosphere. Thus, pre-existing lateral rheological variations can dominate the rifting process and lead to margin segmentation, with along-strike changes in crustal structure and nature and timing of continental breakup.
- M. Gouiza
- & J. Naliboff
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| Open AccessDifferentiating induced versus spontaneous subduction initiation using thermomechanical models and metamorphic soles
The mechanism of subduction initiation is a key to modern plate tectonics. Here, using numerical modeling and geological observations, the authors find that the majority of active and paleo subduction zones with metamorphic soles likely formed during induced subduction initiation that involved a young overriding plate.
- Xin Zhou
- & Ikuko Wada
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| Open AccessFluid pressurisation and earthquake propagation in the Hikurangi subduction zone
Laboratory experiments reproducing earthquake slip in non cohesive fault rocks under fluid pressurised conditions are challenging. Thanks to these experiments, the authors show that earthquake slip occurring in tsunamigenic subduction zone faults is controlled by dilatancy and pressurisation processes.
- S. Aretusini
- , F. Meneghini
- & G. Di Toro
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| Open Access13 million years of seafloor spreading throughout the Red Sea Basin
Here, based on earthquake data, vertical gravity gradient data and high-resolution bathymetry, the authors show that the Red Sea is not in transition from rifting to spreading as previously proposed. They instead suggest it to be a mature ocean basin in which continuous seafloor spreading began quasi-instantaneously along its entire length around 13 Ma ago.
- Nico Augustin
- , Froukje M. van der Zwan
- & Bryndís Brandsdóttir
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| Open AccessFirst look by the Yutu-2 rover at the deep subsurface structure at the lunar farside
The authors here report results from the ground-penetrating radar onboard the Yutu-2 rover from the Chagn’E 4 mission. The study presents up to 330 m deep subsurface structure of the Von Karman Crater inside the South Pole Aitken Basin.
- Jialong Lai
- , Yi Xu
- & Luyuan Xu
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| Open AccessVictoria continental microplate dynamics controlled by the lithospheric strength distribution of the East African Rift
One of the largest continental microplates on Earth is situated in the center of the East African Rift System, and oddly, the Victoria microplate rotates counterclockwise with respect to the neighboring African tectonic plate. Here, the authors' modelling results suggest that Victoria microplate rotation is caused by edge-driven lithospheric processes related to the specific geometry of rheologically weak and strong regions.
- Anne Glerum
- , Sascha Brune
- & Manfred R. Strecker
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| Open AccessGeophysical imaging of ophiolite structure in the United Arab Emirates
The Semail ophiolite provides evidence for geological processes that form oceanic crust, however, its deep structure remains debated. Here, the authors use geophysical imaging to determine that the ophiolite is bound by a thrust fault in the west, and a normal fault in the east, bounding a rapidly subsiding basin, implying the ophiolite may not be rooted in the Gulf of Oman crust.
- M. Y. Ali
- , A. B. Watts
- & T. Ambrose
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| Open AccessEarthquake nucleation in the lower crust by local stress amplification
This study investigates deep intracontinental earthquakes. Based on field data from exhumed lower crustal pseudotachylytes and mylonites from Lofoten, northern Norway, the authors describe a novel model of earthquake nucleation in the lower crust as a transient consequence of ongoing localised aseismic creep.
- L. R. Campbell
- , L. Menegon
- & G. Pennacchioni
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| Open AccessRipplocations provide a new mechanism for the deformation of phyllosilicates in the lithosphere
Phyllosilicate minerals are critical components of seismogenic fault, shear and subduction zones. Here, the authors provide a new deformation mechanism for phyllosilicates, based on newly discovered crystallographic defects in biotite (ripplocations), affecting our understanding of fault zone processes.
- Joe Aslin
- , Elisabetta Mariani
- & Michel W. Barsoum
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| Open AccessEarthquake lubrication and healing explained by amorphous nanosilica
Tectonic faults weaken during slip in order to accelerate and produce earthquakes. Here the authors show a mechanism for weakening faults through the transformation of quartz to amorphous nanoparticulate wear powders that lubricate friction experiments, and transform back to quartz under geologic conditions.
- Christie D. Rowe
- , Kelsey Lamothe
- & Stefano Aretusini
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| Open AccessLower-crustal earthquakes in southern Tibet are linked to eclogitization of dry metastable granulite
The triggering mechanism of deep seismicity in Tibet remains unclear. Here the authors use experiments to show that granulite when deformed becomes brittle as it passes into the ecologite stability field developing macroscopic riedel fault zones thus providing an explanation for deep seismicity in Southern Tibet.
- Feng Shi
- , Yanbin Wang
- & Zhenmin Jin
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| Open AccessMixing instabilities during shearing of metals
The mechanisms behind deformation of multiphase solids are elusive. Here, the authors use X-rays and simulations to show that the same mechanisms causing rocks to fold occur at the micrometer scale in dual-metal lamellas of Ag/Cu and Al/Cu under high-pressure torsion, leading to vortices formation.
- Mohsen Pouryazdan
- , Boris J. P. Kaus
- & Horst Hahn
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| Open AccessWater pumping in mantle shear zones
Water plays a key role in many geological processes, including weakening crystals in the crust and mantle. Here, using amphibole distribution and olivine dislocation slip-systems, the authors show that ductile flow also has a dynamic control on water-rich fluid circulation in mantle shear zones.
- Jacques Précigout
- , Cécile Prigent
- & Anthony Pochon
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| Open AccessSouth-American plate advance and forced Andean trench retreat as drivers for transient flat subduction episodes
How flat slabs at subduction zones are created remains unclear. Here, the authors show that the Nazca slab has retreated at ∼2 cm per year since 50 Ma but no rollback has occurred in the last ∼12 Myr in the flat slab, implying that an overpressured sub-slab mantle can impede rollback and maintain a flat slab.
- Gerben Schepers
- , Douwe J. J. van Hinsbergen
- & Nadine McQuarrie
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| Open AccessDeformation-resembling microstructure created by fluid-mediated dissolution–precipitation reactions
Microstructural features of deformed rocks are used to reveal deformation stresses and temperatures. Here, the authors conduct experiments showing that misleading microstructures form during fluid-mediated mineral reactions under static conditions, and propose new criteria for microstructure identification.
- Liene Spruzeniece
- , Sandra Piazolo
- & Helen E. Maynard-Casely
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| Open AccessSecondary migration and leakage of methane from a major tight-gas system
As shale and tight gas basins are increasingly used to extract natural gas, understanding how gas migrates is important. Wood and Sanei find that secondary migration in a tight-gas basin leads to up-dip transmission of enriched methane into surficial strata which may leak into groundwater and the atmosphere.
- James M. Wood
- & Hamed Sanei
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| Open AccessDeconvoluting complex structural histories archived in brittle fault zones
Understanding when brittle rock faulting took place can help unravel the history of deformation in the Earth’s crust. The authors here develop a new approach to date faults using a combination of K-Ar isotopic dating of illite and structural analysis to provide high resolution dates of the faults.
- G. Viola
- , T. Scheiber
- & J. Knies
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| Open AccessPeak-ring structure and kinematics from a multi-disciplinary study of the Schrödinger impact basin
Impact basins on the Moon are considered as the best landing sites for the recovery of information about the lunar interior. To inform future lunar missions, Kringet al. combine remote sensing and numerical modelling to generate a geological map of the Schrodinger Impact Basin peak ring.
- David A. Kring
- , Georgiana Y. Kramer
- & Mitali Chandnani
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| Open AccessThe missing large impact craters on Ceres
Studying craters on atmosphere-less bodies can unlock information about planetesimal histories. Here, Marchi et al. present results from the NASA Dawn mission to Ceres showing that craters >100–150 km in size are largely absent, and find that Ceres’ internal evolution is responsible for their absence.
- S. Marchi
- , A. I. Ermakov
- & C. T. Russell
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| Open AccessLasting mantle scars lead to perennial plate tectonics
The causes of intraplate deformation remain poorly constrained. Heron et al. use numerical models to show that ancient plate tectonic processes produce mantle lithosphere structures that may be reactivated to generate intraplate deformation.
- Philip J. Heron
- , Russell N. Pysklywec
- & Randell Stephenson
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| Open AccessThe structure of slip-pulses and supershear ruptures driving slip in bimaterial friction
Friction commonly involves different material types (bimaterials) at their sliding interface. Here, in laboratory experiments Shlomai and Fineberg reveal effects uniquely due to biomaterial coupling, with slip-pulses and crack-like supershear fronts dominating opposing propagation directions.
- Hadar Shlomai
- & Jay Fineberg
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| Open AccessThe dune effect on sand-transporting winds on Mars
The absence of in situand long-term meteorological data hampers our understanding of wind movement on Mars. Here, the authors use 3D airflow modelling to investigate small scale ripple migration and suggest that local dune topography exerts a strong influence on wind speed and direction.
- Derek W. T. Jackson
- , Mary C Bourke
- & Thomas A. G. Smyth
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| Open AccessCrystal preferred orientation of an amphibole experimentally deformed by simple shear
Seismic anisotropy has been widely observed in the crust and mantle due to the crystal preferred orientation (CPO) of highly anisotropic minerals such as amphibole, though it is poorly constrained. Here, the authors present an experimental study showing that three CPOs exist depending on temperature and stress.
- Byeongkwan Ko
- & Haemyeong Jung