Geodynamics

  • Article
    | Open Access

    Episodic magmatism of the early Andes is the result of a complex interplay between mantle, crust, slab and sediment contributions that can be traced using zircon chemistry. An external (tectonic) model is argued for the episodic plutonism in this extensional continental arc.

    • José Joaquín Jara
    • , Fernando Barra
    •  & Diego Morata
  • Article
    | Open Access

    We discover a pervasive subduction influence in the Arctic, Atlantic and Indian mantle, which is nearly absent in the Pacific mantle. Such a hemispheric-scale upper mantle heterogeneity reflects the control of a “subduction shield” that has surrounded the Pacific Ocean for 180 Myr.

    • A. Y. Yang
    • , C. H. Langmuir
    •  & Z. Chen
  • Article
    | Open Access

    The relative role of individual forcing events in long-term landscape evolution is challenging to measure in the field. Badlands offer special opportunities to quantify common, natural landscape dynamics on observational time scales.

    • Ci-Jian Yang
    • , Jens M. Turowski
    •  & Kuo-Jen Chang
  • Article
    | Open Access

    Experiments and buoyancy calculations reveal that subduction of limestone results in massive carbon storage in arc lithosphere, forming an important carbon reservoir in convergent margins. Remobilization of this carbon reservoir during arc magma ascent may dominate carbon emissions at volcanic arcs.

    • Chunfei Chen
    • , Michael W. Förster
    •  & Yongsheng Liu
  • Article
    | Open Access

    Seismic imaging of subducted plates offers a way to improve plate tectonic reconstructions. Here, Braszus et al. use new ocean-bottom seismometer data from the Lesser Antilles to locate subducted spreading centres and faults thus providing a new understanding of the evolution of the Caribbean plate.

    • Benedikt Braszus
    • , Saskia Goes
    •  & Marjorie Wilson
  • Article
    | Open Access

    Constraining the thermal state of the lithosphere is crucial to understanding geodynamic regime in early Earth. Here the authors reconstruct ~2.9–2.5 Ga thermal structure of continental lithosphere of the North China Craton using TTG and propose a systematic Archean geodynamic evolution process.

    • Guozheng Sun
    • , Shuwen Liu
    •  & Fangyang Hu
  • Article
    | Open Access

    The authors present a high-resolution palaeomagnetic record for a Late Cretaceous limestone in Italy. They claim that their record robustly shows a ~12° true polar wander oscillation between 86 and 78 Ma, with the greatest excursion at 84–82 Ma.

    • Ross N. Mitchell
    • , Christopher J. Thissen
    •  & Joseph L. Kirschvink
  • Article
    | Open Access

    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
  • Article
    | Open Access

    Here, the authors compile a global geochemical database of Neogene-Quaternary intraplate volcanism. By comparing the distribution and composition of these rocks with tomographic models they show that intraplate volcanism can be used to constrain upper-mantle structure at the time of eruption.

    • P. W. Ball
    • , N. J. White
    •  & S. N. Stephenson
  • Article
    | Open Access

    Here, the authors follow a new approach using analytic solutions for Poiseuille-Couette channel flow to compute asthenospheric viscosities under the Caribbean. Active asthenospheric flow observed under the Caribbean contradicts the traditional view that the asthenosphere is only a passive lubricating layer for Earth’s tectonic plates.

    • Yi-Wei Chen
    • , Lorenzo Colli
    •  & Hejun Zhu
  • Article
    | Open Access

    The interplay between continental subduction exhumation dynamics and the obduction of ophiolite sheets remains enigmatic. Here, the authors show that the extrusion of the subducted continental upper crust triggers the necking and breaking of the oceanic upper plate and leads to far-travelled ophiolite sheet emplacement.

    • Kristóf Porkoláb
    • , Thibault Duretz
    •  & Ernst Willingshofer
  • Article
    | Open Access

    The configuration of past ice sheets, and therefore sea level, is highly uncertain. Here, the authors provide a global reconstruction of ice sheets for the past 80,000 years that allows to test proxy based sea level reconstructions and helps to reconcile disagreements with sea level changes inferred from models.

    • Evan J. Gowan
    • , Xu Zhang
    •  & Gerrit Lohmann
  • Article
    | Open Access

    Crustal doubling in Tibet and the Himalayas by underthrusting of the Indian plate is thought to require the presence of a mafic layer above the Moho. Here, the authors present seismic data which shows that the middle Lhasa Terrane has very low velocity (Vp < 6.7 km/s) throughout the 80 km thick crust, which they suggest is predominantly felsic in composition.

    • Gaochun Wang
    • , Hans Thybo
    •  & Irina M. Artemieva
  • Article
    | Open Access

    The Greenland Ice Sheet is the largest land ice contributor to sea level rise and understanding the long-term glacier response to external forcing is key to improved projections. Here the authors show Greenland’s three largest outlet glaciers will likely exceed current worst-case scenario

    • Shfaqat A. Khan
    • , Anders A. Bjørk
    •  & Toni Schenk
  • Article
    | Open Access

    Knowledge of shear-wave anisotropy is important to understanding the structure and dynamics of the subduction zone mantle wedge. Here, the authors find unambiguous evidence that forearc anisotropy resides in the upper-plate crust, while weak anisotropy in the most seaward part of the mantle wedge indicates decoupling from the slab

    • Naoki Uchida
    • , Junichi Nakajima
    •  & Youichi Asano
  • Article
    | Open Access

    Although the surface deformation of tectonic plate boundaries is well determined by geological and geodetic measurements, the pattern of flow below the lithosphere remains poorly constrained. Here, the author finds that major earthquakes in California have occurred above the regions of current plastic strain accumulation in the mantle.

    • Sylvain Barbot
  • Article
    | Open Access

    Geological sources of H2 and abiotic CH4 have had a critical role in the evolution of life and sustainability of the deep subsurface biosphere, yet the origins of these sources remain largely unconstrained. Here the authors show that deep serpentinization (40–80 km) during subduction generates significant amounts of H2 and abiotic CH4, potentially providing energy to the overlying subsurface biosphere.

    • A. Vitale Brovarone
    • , D. A. Sverjensky
    •  & I. Daniel
  • Perspective
    | Open Access

    Despite numerous advances in our understanding of subduction since the theory of plate tectonics was established, the mechanisms of subduction zone initiation remain highly controversial. Here, the authors present a transdisciplinary and expandable community database of subduction zone initiation events in the last 100 Ma, which establishes a clear direction for future research.

    • Fabio Crameri
    • , Valentina Magni
    •  & Marcel Thielmann
  • Article
    | Open Access

    Trace amounts of water dissolved in minerals play an important role in global tectonics through changing the density, viscosity and melting behaviour of the Earth’s mantle. Here, the authors identify the presence of molecular hydrogen in nominally anhydrous ecolgite minerals from the Kaapvaal and Siberian cratons, indicating that the storage capacity of H in the mantle may have been underestimated.

    • B. N. Moine
    • , N. Bolfan-Casanova
    •  & J. Y. Cottin
  • Article
    | Open Access

    How Earth’s lithosphere first divided into tectonic plates remains uncertain. Here, the authors use 3D spherical shell models to demonstrate that anticipated warming of the early lithosphere should lead to thermal expansion and the initiation of a global network of rifts, dividing the lithosphere into tectonic plates.

    • C. A. Tang
    • , A. A. G. Webb
    •  & T. T. Chen
  • Article
    | Open Access

    Thermal conductivity of Earth’s core affects Earth’s thermal structure, evolution and dynamics. Based on thermal conductivity measurements of iron–silicon alloys at high pressure and temperature conditions, the authors here propose Earth’s inner core could be older than previously expected.

    • Wen-Pin Hsieh
    • , Alexander F. Goncharov
    •  & Jung-Fu Lin
  • Article
    | Open Access

    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
  • Article
    | Open Access

    Large-volume volcanic eruptions can occur despite only limited precursory activity. Here the authors show that modelling the combined effects of buoyant magma, viscoelastic earth behaviour, and sustained magma channels can explain such behaviour of volcanoes and gives an estimate of pressure evolution in magma bodies.

    • Freysteinn Sigmundsson
    • , Virginie Pinel
    •  & Tadashi Yamasaki
  • Article
    | Open Access

    Earth rotation variation reflects the physics, dynamics and the magnetic field changes of Earth’s interior. The authors find a significant ~8.6 year periodic increasing oscillation in length of day and its good link to geomagnetic jerks related to Earth’s core oscillations, which may be used to predict the future jerk timings.

    • Pengshuo Duan
    •  & Chengli Huang
  • Article
    | Open Access

    The dynamics of continental subduction is largely controlled by the rheological properties of rocks involved along the subduction channel. Here, the authors reveal a prominent, yet previously undetected, low-velocity body beneath the Western Alps, along the plate interface between the European slab and the overlying Adriatic mantle, which they interpret as a serpentinite layer.

    • Liang Zhao
    • , Marco G. Malusà
    •  & Stefano Solarino
  • Article
    | Open Access

    Retreating subduction zones are enabled by the development of faults at the edges of the slab, but the physical mechanisms controlling fault propagation remain debated. Here, the authors find that oceanic crust recycling is controlled by weakening of fractures forming at the edges of slabs.

    • Jessica Munch
    • , Taras Gerya
    •  & Kosuke Ueda
  • Article
    | Open Access

    The authors here present a stress map of the North American crust that gives a new view of dynamics of the continent. The results can be applied to probabilistic seismic hazard analysis and resource development as well as to provide constraints for theoretical models of crustal dynamics.

    • Jens-Erik Lund Snee
    •  & Mark D. Zoback
  • Article
    | Open Access

    The magmatic progression produced during the initiation of the Izu-Bonin-Marianas subduction zone took place rapidly over 1 million years, but it has been unclear why. Here, using numerical models, the authors show that subduction initiation was dominated by vertical forces, internal to the system itself, progressing to self-sustained subduction.

    • B. Maunder
    • , J. Prytulak
    •  & M. Reagan
  • Article
    | Open Access

    Topography at active forearc margins is controlled by numerous competing tectonic and erosional processes acting at different timescales, yet separating their respective contribution remains a challenge. Here, the authors evidence Myr-scale, uplift-then-subsidence cycles controlled by transient accretion at the base of the forearc domain.

    • Armel Menant
    • , Samuel Angiboust
    •  & Raphael Grandin
  • Article
    | Open Access

    Seismology is a powerful tool to investigate Earth’s interior. Here, the authors combine numerical approaches with experimental results from previous studies to show a depth dependent behaviour of seismic waves in subducted oceanic crust in Earth’s mantle. The work challenges the currently accepted model of depth-independent seismic wave behaviour in oceanic crust.

    • Wenzhong Wang
    • , Yinhan Xu
    •  & Zhongqing Wu
  • Article
    | Open Access

    Cratons represent the ancient cores of continental plates and are generally thought to have been stable since the Archean. Here however, the authors combine seismic analysis with kimberlite data to infer complete destruction of cratonic lithosphere in some places of the African continent.

    • Nicolas Luca Celli
    • , Sergei Lebedev
    •  & Carmen Gaina
  • Article
    | Open Access

    The Paleocene-Eocene Thermal Maximum constitutes one of the largest climate perturbations in Earth’s history, but its exact causes are not well known. New estimates of greenhouse gas fluxes from the North Atlantic Igneous Province at high temporal resolution show that they could have initiated this event.

    • Stephen M. Jones
    • , Murray Hoggett
    •  & Tom Dunkley Jones
  • Article
    | Open Access

    Some of Earth’s earliest continental crust has been previously inferred to have formed from partial melting of hydrated mafic crust at pressures above 1.5 GPa (more than 50 km deep), pressures typically not reached in post-Archean continental crust. Here, the authors show that such high pressure signatures can result from melting of mantle sources rather than melting of crust, and they suggest there is a lack of evidence that Earth’s earliest crust melted at depths significantly below 40 km.

    • Robert H. Smithies
    • , Yongjun Lu
    •  & Marc Poujol
  • Article
    | Open Access

    The links between plate tectonics and deep mantle structure remain unclear. Here, the authors demonstrate that transition elements (Ni, Cr, and Fe/Mn) in basaltic rocks can be used as a tool to trace plume-related magmatism through Earth history, and their results indicate the presence of a direct relationship between the intensity of plume magmatism and the supercontinent cycle.

    • Hamed Gamal EL Dien
    • , Luc S. Doucet
    •  & Ross Mitchell
  • Article
    | Open Access

    The tectonic evolution of southwestern North America remains debated. Here, the authors present a complete time-dependent geodynamic model of the tectonic evolution of southwestern North America, which can explain the extensional collapse of the Basin and Range Province since the Late Eocene.

    • Alireza Bahadori
    •  & William E. Holt
  • Article
    | Open Access

    The elevation and high heat flow of Southern South Africa has controversially been attributed to a mantle plume. Here, the authors link degassed CO2 to a non-degassed mantle source rather than the convecting upper mantle, confirming plume-related mantle melting.

    • S. M. V. Gilfillan
    • , D. Györe
    •  & F. M. Stuart
  • Article
    | Open Access

    Diamonds can give us clues to the processes regulating deep carbon transport within the Earth. Here, the author discovers evidence from diamond coatings that organic compounds exist at great depth in Earth’s interior, and furthermore, that organic molecules may provide scaffolds for diamond nucleation and growth.

    • Maria Luce Frezzotti
  • Article
    | Open Access

    The India-Asia collision has formed the highest mountains on Earth and is associated with extensive intraplate deformation. Here, the authors present geodynamic experiments of continental deformation across Central, East, and Southeast Asia which suggest that the Pacfic and Sunda subduction zones played an active role during intraplate deformation.

    • W. P. Schellart
    • , Z. Chen
    •  & F. M. Rosas