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Journal Articles Science Advances Year : 2022

Deep mantle origin of large igneous provinces and komatiites

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Rémy Pierru
Denis Andrault
Geeth Manthilake
Julien Monteux
Jean-Luc Devidal
Andrew King
Laura Henry

Abstract

Large igneous provinces (LIPs) resulted from intraplate magmatic events mobilizing volumes of magma up to several million cubic kilometers. LIPs and lavas with deep mantle sources have compositions ranging from komatiites found in Archean greenstone belts to basalts and picrites in Phanerozoic flood basalt and recent oceanic islands. In this study, we identify the mantle conditions appropriate to each type of lava based on an experimental study of the melting of pyrolite. The depth of the mantle source decreases from 600 to 700 km for the oldest komatiites to 100 to 300 km for picrites and basalts, and the extent of mantle melting ranges from 10 to 50%. We develop a geodynamical model that explains the origin of the hot mantle plumes capable of generating these melting P-T conditions. Within a superadiabatic temperature gradient persisting in the deep mantle, the ascent of hot mantle plumes creates excess temperatures up to 250 to 300 K by adiabatic decompression.
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Dates and versions

hal-03850999 , version 1 (14-11-2022)

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Attribution - NonCommercial - CC BY 4.0

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Rémy Pierru, Denis Andrault, Geeth Manthilake, Julien Monteux, Jean-Luc Devidal, et al.. Deep mantle origin of large igneous provinces and komatiites. Science Advances , 2022, 8 (44), ⟨10.1126/sciadv.abo1036⟩. ⟨hal-03850999⟩
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