Tectonics

  • 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

    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

    This paper placed the identified Mariana type ophiolite within a global tectonic re-organization at ca. 530-520 Ma. Similar ophiolites, together with other geological and chemical proxies, newly constrained the timing of establishment of modern plate tectonics, along with its links to surficial changes that characterize the contemporary Earth.

    • Jinlong Yao
    • , Peter A. Cawood
    •  & Peng Wang
  • Article
    | Open Access

    “Earth degassing is a critical carbon source, but its contribution to Cenozoic atmospheric CO2 variations is not well known. Here, the authors analyse CO2 fluxes on the Tibetan Plateau and suggest that the India-Asia collision was the primary driver of changes in atmospheric CO2 over the past 65 Ma.”

    • Zhengfu Guo
    • , Marjorie Wilson
    •  & Jiaqi Liu
  • Article
    | Open Access

    There is a lot of uncertainty about what Earth’s climate and geography were like in the early Cambrian, when animal life diversified throughout the oceans. Here we show that numeric comparisons of model simulations and climatically influenced rocks can help constrain geography and climate during this time.

    • Thomas W. Wong Hearing
    • , Alexandre Pohl
    •  & Thijs R. A. Vandenbroucke
  • Article
    | Open Access

    Why Earth’s crust only started becoming widely preserved in the Eoarchaean, 500 Ma after planetary accretion, is poorly understood. Here, the authors document a shift to juvenile magmatic sources in the early Eoarchaean, linking crustal preservation to the formation of stabilising melt-depleted mantle.

    • Jacob A. Mulder
    • , Oliver Nebel
    •  & Timothy J. Ivanic
  • 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

    Tectonomagmatic conditions in the Precambrian were hypothesized to be unfavorable for porphyry Cu deposit formation. Here, the authors show that metallogenic processes typify Phanerozoic porphyry Cu deposits operated by ~1.88 Ga, reflecting modification of mantle lithosphere by oxidized slab-derived fluids at that time.

    • Xuyang Meng
    • , Jackie M. Kleinsasser
    •  & Richard A. Stern
  • Article
    | Open Access

    This study shows how seismic and aseismic events are related in Mexico between 2017 and 2019. Based on a series of observations and models, the study suggests that the Mw 8.2 intraslab earthquake of 8 September 2017 severely altered the mechanical properties of the plate interface, facilitating the interaction between the events and disrupting the slow slip cycles at a regional scale.

    • V. M. Cruz-Atienza
    • , J. Tago
    •  & E. Kazachkina
  • 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 authors here present a multi-lake paleoseismological approach to evaluate the role of earthquakes in causing a spatio-temporal cluster of large, prehistoric rockslides between 3000 and 4200 years ago in the Eastern European Alps and for which the triggering mechanisms are still debated.

    • Patrick Oswald
    • , Michael Strasser
    •  & Jasper Moernaut
  • Article
    | Open Access

    The nature and evolution of Earth’s crust during the Hadean and Eoarchean is largely unknown due to the lack of preserved material from this period. Here, the authors document a period of crustal rejuvenation between 3.2 and 3.0 Ga, coincident with peak mantle potential temperatures that imply greater degrees of mantle melting and injection of hot mafic-ultramafic magmas into older Hadean-to-Eoarchean felsic crust at this time.

    • C. L. Kirkland
    • , M. I. H. Hartnady
    •  & J. A. Hollis
  • 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

    The transition from wide continental rift to continental break-up remains enigmatic. Here, the authors show that northern margin of the South China Sea records the transition between wide continental rift to a highly extended continental margin, with strikingly similar structures and metamorphic core complexes to those described from the North American Cordillera and the Aegean.

    • Hongdan Deng
    • , Jianye Ren
    •  & Pan Luo
  • Article
    | Open Access

    Here, the authors combine bathymetry and sediment echosound data to present a submarine, volcanic map of the Tristan de la Cunha region. They find that the youngest volcanic expression of the Tristan de la Cunha mantle plume is currently located to the (south-) west of the island.

    • Wolfram H. Geissler
    • , Paul Wintersteller
    •  & Wilfried Jokat
  • 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
  • Article
    | Open Access

    Plate tectonics necessitates mantle recycling throughout Earth’s history, yet direct geochemical evidence for mantle reprocessing remains elusive. Here, the authors present evidence of recycled supra-subduction zone mantle wedge peridotite dredged from the Mid-Atlantic Ridge near 16°30′N.

    • B. M. Urann
    • , H. J. B. Dick
    •  & J. F. Casey
  • Article
    | Open Access

    Regions of the subducting oceanic crust are often considered to be overpressured, owing to fluid trapped beneath an impermeable seal along the overlying inter-plate boundary. Here, the authors show that slow slip earthquakes at the Cascadia subduction zone occur immediately below a 6-10 km-thick shear zone, in which slab-derived fluids are likely trapped at near-lithostatic pore pressures.

    • Andrew J. Calvert
    • , Michael G. Bostock
    •  & Martyn J. Unsworth
  • 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

    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

    The Central Atlantic Magmatic Province is the most aerially extensive magmatic event in Earth’s history, yet few constraints exist on the volumes of intrusions at depth. Here, the authors find limited intrusive volumes beneath the South Georgia Rift, consistent with modest potential mantle temperatures (<1500 °C) related to syn-rift decompression melting.

    • R. E. Marzen
    • , D. J. Shillington
    •  & S. H. Harder
  • 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
  • Matters Arising
    | Open Access

    Recently, Pandey et al proposed relict subduction initiation occurred along a passive margin in the northwest Indian Ocean. Here, Clift et al question the evidence for subduction initiation, suggesting that simpler rifting-related processes can more simply explain the available data for the Laxmi Basin.

    • Peter D. Clift
    • , Gérôme Calvès
    •  & Tara N. Jonell
  • Matters Arising
    | Open Access

    Recently, Pandey et al. proposed relict subduction initiation occurred along a passive margin in the northwest Indian Ocean, however, Clift et al. questioned their evidence for subduction initiation, suggesting that simpler rifting-related processes could more simply explain the available data. Here, Pandey et al. reply to Clift et al.’s comment, and argue that geochemical and isotope data for Laxmi basin lavas distinctly imply relict subduction initiation.

    • Dhananjai K. Pandey
    • , Anju Pandey
    •  & Scott A. Whattam
  • Article
    | Open Access

    Feldspars are stable at pressures up to 3 GPa along the mantle geotherm, but they can persist metastably at higher pressures at colder conditions. Here, above 10 GPa the authors find  new high-pressure polymorphs of feldspars that could persist at depths corresponding to the Earth’s upper mantle, potentially influencing the dynamics and fate of cold subducting slabs.

    • Anna Pakhomova
    • , Dariia Simonova
    •  & Leonid Dubrovinsky
  • Article
    | Open Access

    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
  • Article
    | Open Access

    CH4 seepage mostly occurs in petroleum-bearing sedimentary basins, but the role of tectonics in degassing is mostly only known at a local scale. Here, the authors conduct a global scale analysis of seeps, faults, sedimentary basins, petroleum fields and heat flow, and find that geological CH4 seepage preferably develops in convergent basins, while gas seeps can occur along any brittle tectonic structure.

    • Giancarlo Ciotoli
    • , Monia Procesi
    •  & Guido Ventura
  • 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

    Indian continental subduction can explain crustal deformation, magmatic activity and uplift of the Tibetan Plateau following collision, however, the nature of the Indian subducting slab beneath Myanmar and the related tectonic regime remain unclear. Here, the authors present direct structural evidence of present-day Indian continental subduction beneath Asia.

    • Tianyu Zheng
    • , Yumei He
    •  & Myo Thant
  • 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

    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

    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
  • Article
    | Open Access

    The composition and tectonic affiliation of Earth's earliest crust remains disputed. Here, the authors find that Archean Jack Hills zircons crystallized from melts with compositions similar to andesite formed in modern subduction settings, which they suggest is consistent with an early onset of modern-style plate tectonics on Earth.

    • Simon Turner
    • , Simon Wilde
    •  & Yi-Jen Lai
  • Article
    | Open Access

    In this study, the authors investigate thermal alteration of organic biomarkers to detect paleo earthquakes in the Japan Trench. The study shows that large earthquakes like the 2011 Tohoku-Oki earthquake can slip through different types of sediment rather than being restricted to the weakest layers.

    • Hannah S. Rabinowitz
    • , Heather M. Savage
    •  & James D. Kirkpatrick
  • 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