An integrated kinematic and geochemical model to determine lithospheric extension and mantle temperature from syn-rift volcanic composition

Dean, S. M. and Murton, B. J. and Minshull, T. A. and Henstock, T. J. and White, R. S. (2009) An integrated kinematic and geochemical model to determine lithospheric extension and mantle temperature from syn-rift volcanic composition. Earth and Planetary Science Letters, 278 (1-2). pp. 26-39. DOI 10.1016/j.epsl.2008.11.012

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Official URL: http://dx.doi.org/10.1016/j.epsl.2008.11.012

Abstract

We present an integrated kinematic and geochemical model that determines the composition of melts and their residual source rocks generated by decompression melting of the mantle during continental rifting. Our approach is to construct a unified numerical solution that merges an established lithospheric stretching model which determines the rate and depth at which melting occurs, with several compositional parameterisations of mantle melting to predict the composition of primary melts. We also incorporate a parameterisation for the rare earth elements. Using our approach, we are able to track the composition of the melt fractions and mantle residues as melting progresses. Our unified model shows that primary melt composition is sensitive to rift duration and mantle temperature, with rapid rifting and higher mantle temperatures producing larger melt fractions, at a greater mean pressure of melting, than slower/cooler rifting. Comparison of the model results with primitive basalts recovered from oceanic spreading ridges and rifted margins in the North Atlantic indicates that rift duration and synrift mantle temperature can be inferred independently from the appropriate geochemical data.

Item Type: Article
Uncontrolled Keywords: 08AREP IA57
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Earth and Planetary Science Letters
Volume: 278
Page Range: pp. 26-39
Identification Number: 10.1016/j.epsl.2008.11.012
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:02
Last Modified: 23 Jul 2013 10:06
URI: http://eprints.esc.cam.ac.uk/id/eprint/238

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