Melt instabilities in an intraplate lithosphere and implications for volcanism in the Harrat Ash-Shaam volcanic field (NW Arabia)

Regenauer-Lieb, Klaus, Rosenbaum, Gideon, Lyakhovsky, Vladimir, Liu, Jie, Weinberg, Roberto, Segev, Amit and Weinstein, Yishai (2015) Melt instabilities in an intraplate lithosphere and implications for volcanism in the Harrat Ash-Shaam volcanic field (NW Arabia). Journal of Geophysical Research B: Solid Earth, 120 3: 1543-1558. doi:10.1002/2014JB011403


Author Regenauer-Lieb, Klaus
Rosenbaum, Gideon
Lyakhovsky, Vladimir
Liu, Jie
Weinberg, Roberto
Segev, Amit
Weinstein, Yishai
Title Melt instabilities in an intraplate lithosphere and implications for volcanism in the Harrat Ash-Shaam volcanic field (NW Arabia)
Journal name Journal of Geophysical Research B: Solid Earth   Check publisher's open access policy
ISSN 2169-9356
2169-9313
Publication date 2015-03-27
Year available 2015
Sub-type Article (original research)
DOI 10.1002/2014JB011403
Open Access Status
Volume 120
Issue 3
Start page 1543
End page 1558
Total pages 16
Place of publication Wiley-Blackwell Publishing
Publisher Hoboken, NJ, United States
Collection year 2016
Language eng
Formatted abstract
We investigate melt generation in a slowly extending lithosphere with the aim of understanding the spatial and temporal relationships between magmatism and preexisting rift systems. We present numerical models that consider feedback between melt generation and lithospheric deformation, and we incorporate three different damage mechanisms: brittle damage, creep damage, and melt damage. Melt conditions are calculated with a Helmholtz free energy minimization method, and the energy equation is solved self-consistently for latent heat and shear heating effects. Using a case of a slowly extending (1–1.5 mm/yr) continental lithosphere with a relatively low surface heat flow (~50 mW/m2), we show that melt-rich shear bands are nucleated at the bottom of the lithosphere as a result of shear heating and damage mechanisms. Upon further deformation, melt zones intersect creep damage zones, thus forming channels that may be used for the melt to migrate upward. If a preexisting structure resides only in the brittle crust, it does not control the path of melt migration to the surface, and melt-filled channels propagate from the bottom upwards, independently of upper crustal structures. In contrast, a preexisting weak structure that reaches a critical depth of 20 km allows fast (~2 Ma) propagation of melt-filled channels that link melt damage from the bottom of the lithosphere to near-surface structures. Our model results may explain the short time scale, volume, and magma extraction from the asthenosphere through a low surface heat flow lithosphere, such as observed, for example, in the Harrat Ash-Shaam volcanic field (northwestern Arabia), which developed in the Arabian Plate and is spatially linked to the Azraq-Sirhan Graben.
Keyword Continental rifting
Melt instability
Numerical simulations
Damage rheology
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Early View: Online Version of Record published before inclusion in an issue

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
Official 2016 Collection
 
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Created: Wed, 25 Feb 2015, 08:13:39 EST by Dr Gideon Rosenbaum on behalf of School of Earth Sciences