Lithosphere destabilization by melt weakening and crust-mantle interactions-implications for generation of granite-migmatite belts

Kaislaniemi, L.; van Hunen, J.; Bouilhol, P.

Abstract

Orogenic crustal anatexis is a still poorly understood process due to the complexity of the thermal and geodynamical interaction between mantle and crustal processes during and after continental collision. Here, we present a novel conceptual model for the formation of granite migmatite belts: we propose that convective thinning of the lithosphere results in minor amounts of partial melts within the lowermost crust that trigger further instabilities. This will lead to a positive feedback effects between melt weakening, mantle upwelling and wholesale mantle lithosphere removal, causing a strong pulse of mantle and crustal melting. We test this model numerically, and results show that his process, taking between 20 and 50 Myrs in total, can explain the temporal evolution of melting in granite‐migmatite zones and associated mantle derived mafic rocks, and provides a heat source for crustal melting without the need for other processes, such as slab break‐off or increased radiogenic heating. Furthermore, the generation of a refractory residue after mantle and crustal melting is also shown to control the progress of the lithospheric mantle removal, providing another feedback mechanism between melting and lithospheric re‐equilibration.

Citation

Kaislaniemi, L., van Hunen, J., & Bouilhol, P. (2018). Lithosphere destabilization by melt weakening and crust-mantle interactions-implications for generation of granite-migmatite belts. Tectonics, 37(9), 3102-3116. https://doi.org/10.1029/2018tc005014

• Journal Article Type: Article
• Acceptance Date: Aug 31, 2018
• Online Publication Date: Sep 19, 2018
• Publication Date: Sep 19, 2018
• Deposit Date: Sep 15, 2018
• Publicly Available Date: Mar 19, 2019
• Journal: Tectonics
• Electronic ISSN: 1944-9194
• Publisher: European Geosciences Union
• Peer Reviewed: Peer Reviewed
• Volume: 37
• Issue: 9
• Pages: 3102-3116
• DOI: https://doi.org/10.1029/2018tc005014
• Public URL: https://durham-repository.worktribe.com/output/1314563