Subduction-transition zone interaction: A review
Reads0
Chats0
TLDR
A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20-50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of -1 to -2 MPa/K) suffice to stagnate slabs as mentioned in this paper.Abstract:
As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20–50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of –1 to –2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ∼2 orders of magnitude higher than background mantle (effective yield stresses of 100–300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.read more
Citations
More filters
LLNL-G3Dv3: global P-wave tomography model for improved regional and teleseismic travel time prediction
TL;DR: The LLNL G3Dv3.interpolated.txt as discussed by the authors model file is named "Layer{n}_{Layer Descriptor}.txt" where "n" is the layer number from the top of Earth's surface to the core-mantle boundary.
Journal ArticleDOI
Reconstructing Greater India : Paleogeographic, kinematic, and geodynamic perspectives
Douwe J.J. van Hinsbergen,Peter C. Lippert,Shihu Li,Shihu Li,Wentao Huang,Eldert L. Advokaat,Wim Spakman,Wim Spakman +7 more
TL;DR: In this article, the Indian plate lithosphere was reconstructed from paleo-geographic, kinematic, and geodynamic perspectives and the evolution scenario that is consistent with all three perspectives was studied.
Compositional mantle layering revealed by slab stagnation at ~1,000 km depth
TL;DR: In this article, the authors reconcile cosmochemical and geophysical constraints using the stagnation of some slab segments at ~1000-km depth as the key observation, and show that lower-mantle enrichment in intrinsically dense basaltic lithologies can render slabs neutrally buoyant in the uppermost lower mantle.
Journal ArticleDOI
Southward propagation of Nazca subduction along the Andes.
Yi-Wei Chen,Jonny Wu,John Suppe +2 more
TL;DR: The model suggests that Nazca subduction has not been fully continuous since the Mesozoic but instead included episodic divergent phases, and it is found that foredeep sedimentation and the initiation of Andean compression are both linked to interactions between the Nazca slab and the lower mantle, consistent with previous modelling.
References
More filters
Journal ArticleDOI
The composition of the Earth
William F. McDonough,Shen-Su Sun +1 more
TL;DR: In this paper, the authors compared the relative abundances of the refractory elements in carbonaceous, ordinary, and enstatite chondritic meteorites and found that the most consistent composition of the Earth's core is derived from the seismic profile and its interpretation, compared with primitive meteorites, and chemical and petrological models of peridotite-basalt melting relationships.
Book
Geodynamics applications of continuum physics to geological problems
TL;DR: A comprehensive and quantitative study of the fundamental aspects of plate tectonics is presented in this paper, with an introduction to heat flow, elasticity and flexure, fluid mechanics, faulting, gravity, and flow in porous media.
Journal ArticleDOI
Age, spreading rates, and spreading asymmetry of the world's ocean crust
TL;DR: In this article, the authors present a digital model of the age, spreading rate, and asymmetry at each grid node by linear interpolation between adjacent seafloor isochrons in the direction of spreading.
Journal ArticleDOI
Subduction and Slab Detachment in the Mediterranean-Carpathian Region
M. J. R. Wortel,Wim Spakman +1 more
TL;DR: Seismic tomography models of the three-dimensional upper mantle velocity structure of the Mediterranean-Carpathian region provide a better understanding of the lithospheric processes governing its geodynamical evolution.
Related Papers (5)
Subducted slabs stagnant above, penetrating through, and trapped below the 660 km discontinuity
Yoshio Fukao,Masayuki Obayashi +1 more