Deep Slab folding and the deformation of the Persian domain

Author(s):  
Alexandre Boutoux ◽  
Arthur Briaud ◽  
Claudio Faccenna ◽  
Paolo Ballato ◽  
Federico Rossetti ◽  
...  

<ul><li>To unravel the Neotethys subduction history and the evolution of the slab morphology at depth since the mid-Cretaceous, we produced a synthesis of the main events affecting the Persian domain. This synthesis is focused on the upper and lower plates (i.e. the Persian and the Neotethys ocean, respectively) of the subduction system and is based on the compilation of available structural, geochemical and geochronological data. Overall, this compilation allows exploring the structural evolution of the Persian domain and the Neotethys oceanic lithosphere on map view and along selected cross-sections.</li> <li>Furthermore, we performed a 2D single-sided numerical model where we explored the slab behavior at depth and its influence on upper plate deformation. The model suggests that episodic deformation is driven by the folding slab behavior at the mantle transition zone. We combine our data and numerical model into a conceptual scenario to overcome the complexity of the kinematics of the Neotethys slab since the Early Cretaceous. Our modeling approach shows that back-arcs opening and associated extensional deformation are driven by the roll-back of the folded slab into the mantle transition zone. In contrast, back-arc closure and upper plate shortening are triggered by the roll-over of the folding slab. Finally, we associate the widespread, upper plate, Early Miocene marine flooding event to the Neotethys slab avalanche into the lower mantle.</li> </ul>

2020 ◽  
Vol 6 (51) ◽  
pp. eabd0953
Author(s):  
Ben R. Mather ◽  
R. Dietmar Müller ◽  
Maria Seton ◽  
Saskia Ruttor ◽  
Oliver Nebel ◽  
...  

Long-lived, widespread intraplate volcanism without age progression is one of the most controversial features of plate tectonics. Previously proposed edge-driven convection, asthenospheric shear, and lithospheric detachment fail to explain the ~5000-km-wide intraplate volcanic province from eastern Australia to Zealandia. We model the subducted slab volume over 100 million years and find that slab flux drives volcanic eruption frequency, indicating stimulation of an enriched mantle transition zone reservoir. Volcanic isotope geochemistry allows us to distinguish a high-μ (HIMU) reservoir [>1 billion years (Ga) old] in the slab-poor south, from a northern EM1/EM2 reservoir, reflecting a more recent voluminous influx of oceanic lithosphere into the mantle transition zone. We provide a unified theory linking plate boundary and slab volume reconstructions to upper mantle reservoirs and intraplate volcano geochemistry.


Lithos ◽  
2017 ◽  
Vol 292-293 ◽  
pp. 379-387 ◽  
Author(s):  
Yanfei Zhang ◽  
Chao Wang ◽  
Zhenmin Jin ◽  
Lüyun Zhu

2021 ◽  
Author(s):  
Ben Mather ◽  
Dietmar Muller ◽  
Maria Seton ◽  
Saskia Ruttor ◽  
Oliver Nebel ◽  
...  

<p><span><span>Long-lived, widespread intraplate volcanism without age progression is one of the most controversial features of plate tectonics. The eastern margin of Australia and Zealandia has experienced extensive mafic volcanism </span><span>over the last 100 million years</span><span>. A plume origin has been proposed for </span><span>three distinct chains of volcanoes,</span> <span>however</span><span>, the majority of eruptions exhibit no clear age progression. Previously proposed edge-driven convection, asthenospheric shear, and lithospheric detachment fail to explain the non age-progressive eruptions </span><span>across the </span><span>~5000 km wide intraplate volcanic province from Eastern Australia to Zealandia. We model the subducted slab volume over 100 million years and find that slab flux drives volcanic eruption frequency, indicating stimulation of an enriched mantle transition zone reservoir. Volcanic isotope geochemistry allows us to distinguish a HIMU reservoir (>1 Ga old) in the slab-poor south, from a northern EM1/EM2 reservoir, reflecting a more recent voluminous influx of oceanic lithosphere into the mantle transition zone. We provide a unified theory linking plate boundary and slab volume reconstructions to upper mantle reservoirs and intraplate volcano geochemistry.</span></span></p>


2016 ◽  
Vol 155 (2) ◽  
pp. 250-279 ◽  
Author(s):  
ANNA MARIA MAROTTA ◽  
MANUEL RODA ◽  
KATYA CONTE ◽  
MARIA IOLE SPALLA

AbstractWe develop a two-dimensional thermo-mechanical numerical model in which the formation of oceanic crust and serpentinite due to the hydration of the uprising mantle peridotite has been implemented, with the aim of discussing the behaviour of the lithosphere of the Alps and Northern Apennines during the transition from continental rifting to ocean spreading of the Alpine Tethys. The predictions of the model are compared with natural data related to the Permian–Triassic high-temperature – low-pressure (HT-LP) metamorphism affecting the continental lithosphere and data from the JurassicP–Tevolution of the oceanic lithosphere from the Alps and the Northern Apennines. Our analysis indicates that a thinned continental crust, an ocean–continent transition zone and an oceanic lithosphere characterize the final structure of the system in a poor magma rift pre-Alpine configuration. We also find that mantle serpentinization starts before crustal break-up and that denudation occurs before ocean spreading. The mantle denudation starts several million years before the gabbros/basalt formation, generating an ocean–continent transition zone from the passive continental margin to the oceanic lithosphere of size 160–280 km. The comparative analysis shows that the extension of a hot and weak lithosphere, which promotes the development of hyperextended Alpine margins, better agrees with the natural data. Finally, our comparative analysis supports the hypothesis that the lithospheric extension preceding the opening of the Alpine Tethys did not start in a stable continental lithosphere, but developed by recycling part of the old Variscan collisional suture.


Author(s):  
B. B. Shkursky

Theoretical modeling of regular olivine grains misorientations in mimetic paramorphoses after ringwoodite and wadsleyite, the formation of which during the ascension of matter from the Mantle Transition Zone is expected, has been carried out. The coordinates of the misorientation axes and the misorientation angles, characterizing 10 operations of alignment in the pair intergrowths of olivine grains, eight of which are twins, are calculated. Possible conditions for the formation of mimetic paramorphoses predicted here, and the chances of their persistence are discussed. The calculated orientations are compared with the known twinning laws of olivine.


Nature ◽  
2021 ◽  
Vol 589 (7843) ◽  
pp. 562-566
Author(s):  
Matthew R. Agius ◽  
Catherine A. Rychert ◽  
Nicholas Harmon ◽  
Saikiran Tharimena ◽  
J.-Michael Kendall

1986 ◽  
Vol 123 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Robert W. H. Butler

AbstractA model is proposed whereby the Caledonian metamorphic basement-cover complex of northwest Scotland (the Moine) is considered as a linked thrust system. This system lies between the Moine thrust at its base and the Naver–Sgurr Beag slide at its top. Ductile fold and thrust zones, which developed at mid crustal levels at metamorphic grades from greenschist to amphibolite facies, are interpreted as decoupling from a detachment presently situated at relatively shallow depths. This model is illustrated by two preliminary balanced cross-sections. These imply shortening across the northwest Scottish Caledonides in excess of 130 km and probably over 200 km. When these structures are restored onto a crustal template a considerable quantity of lower crust is found to be required at depth. The most likely location for the lower crustal wedge is beneath the Grampian Highlands.


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