Results 31 to 40 of about 17,487 (279)

A joint geochemical–geophysical record of time-dependent mantle convection south of Iceland [PDF]

open access: yes, 2014
The North Atlantic V-Shaped Ridges (VSRs) provide a spatially extensive and clear record of unsteady mantle convective circulation over >40 My>40 My.
Jones, S.M.; id_orcid   +16 more
core   +1 more source

Petrological and geochemical characteristics of flood and shield basalts from Kesem-Megezez section, northwestern Ethiopian Plateau: Implication for their mantle source variations

open access: yesHeliyon, 2023
The Kesem-Megezez Section is located on the western escarpment of the main Ethiopian rift, central Ethiopia, part of the northwestern Ethiopia plateau, and hosts both flood basalts (Kesem Oligocene basalts) and shield volcano basalts (Megezez Miocene ...
Birhane Girum   +2 more
doaj   +1 more source

Temperatures in ambient mantle and plumes: Constraints from basalts, picrites, and komatiites [PDF]

open access: yes, 2006
Several methods have been developed to assess the thermal state of the mantle below oceanic ridges, islands, and plateaus, on the basis of the petrology and geochemistry of erupted lavas. One leads to the conclusion that mantle potential temperature (i.e.
Lesher, C. M.   +25 more
core   +1 more source

Impact-induced changes in source depth and volume of magmatism on Mercury and their observational signatures

open access: yesNature Communications, 2017
Mantle partial melting produced the volcanic crust of Mercury. Here, the authors numerically model the formation of post-impact melt sheets and find that mantle convection was weak at around 3.7–3.8 Ga and that the melt sheets of Caloris and Rembrandt ...
Sebastiano Padovan   +3 more
doaj   +1 more source

Multiscale modeling of upper mantle plasticity: From single-crystal rheology to multiphase aggregate deformation [PDF]

open access: yes, 2014
We report a first application of an improved second-order (SO) viscoplastic self-consistent model for multiphase aggregates, applied to an olivine + diopside aggregate as analogue for a dry upper mantle peridotite deformed at 10 15 s 1 shear strain rate ...
CORDIER, Patrick   +6 more
core   +1 more source

A subduction and mantle plume origin for Samoan volcanism

open access: yesScientific Reports, 2018
The origin of Samoan volcanism in the southwest Pacific remains enigmatic. Whether mantle melting is solely caused by a mantle plume is questionable because some volcanism, here referred to as non-hotspot volcanism, defies the plume model and its linear ...
Vincent Strak, Wouter P. Schellart
doaj   +1 more source

melting of the Siberian Mantle Plume [PDF]

open access: yesGeophysical Research Letters, 1998
The Putorana basalts, comprising ∼90% of the Siberian Traps (ST), have had their chemistry modified from primary tholeiitic picritic magmas by ∼12% crystallization of olivine. Major‐trace element ratios, and Nd isotopes of these lavas are consistent with their origin from a relatively undepleted plume by 12–16% rapid decompressional melting at ∼50–80 ...
Asish R. Basu   +2 more
openaire   +1 more source

Partial melting in the deepest mantle [PDF]

open access: yesGeophysical Research Letters, 2002
We have compared the travel times of direct (P, S) and core‐reflected (PcP, ScS) phases recorded in southern Africa from earthquakes occurring in the Scotia Arc region. The low‐velocity region beneath the south Atlantic is explored by calculating ScS‐S and PcP‐P travel‐time residuals to determine the correlation and magnitude of Vs and Vp reductions in
N. A. Simmons, S. P. Grand
openaire   +1 more source

Noble Metals in Arc Basaltic Magmas Worldwide: A Case Study of Modern and Pre-Historic Lavas of the Tolbachik Volcano, Kamchatka

open access: yesFrontiers in Earth Science, 2021
Platinum-group elements (PGE) and gold are a promising tool to assess the processes of mantle melting beneath the subduction zones. However, fractionation processes in magmas inevitably overwrite the initial metal budgets of magmas, making constraints on
Anton Kutyrev   +8 more
doaj   +1 more source

Metallic melt for the mantle [PDF]

open access: yesScience, 2016
Geophysics Ultralow velocity zones (ULVZs) are distinct and dense patches at the very base of Earth's rocky mantle. Liu et al. suggest that iron carbide may be a vital component of ULVZs on the basis of measurements of iron carbide melting temperatures.
openaire   +1 more source

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