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Hot primary melts and mantle source for the Paraná-Etendeka flood basalt province: New constraints from Al-in-olivine thermometry

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Jennings, ES 
Gibson, SA 

Abstract

Continental flood basalts (CFB) are amongst the most voluminous volcanic eruptions in Earth's history. They are rapidly emplaced, and in rare cases the thick lava piles are associated with primitive magmas that have high MgO contents. The compositions of these primitive melts are consistent with a deep-sourced, high-temperature mantle plume origin. Whilst the association of CFBs with impacting mantle plumes is widely accepted, the magnitude of the thermal anomaly is not yet resolved. The development of Al-in-olivine thermometry, however, allows the crystallisation temperature of (near-)liquidus olivine to be determined without using the composition of the co-existing melt. This provides both a robust minimum estimate of mantle temperature and a value from which potential temperature (TP) can be back-calculated. This technique has previously confirmed that crystallisation temperatures in CFB settings can be a few hundred degrees greater than those estimated for MORB, and the results hint at a diversity in crystallisation temperatures between different CFB settings.

Description

Keywords

Olivine, Thermometry, Al-in-olivine, Continental flood basalt, Parana-Etendeka, Mantle plume, Mantle temperature

Journal Title

Chemical Geology

Conference Name

Journal ISSN

0009-2541
1872-6836

Volume Title

529

Publisher

Elsevier BV
Sponsorship
Natural Environment Research Council (NE/J021539/1)