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Simon Matthews

Simon Matthews

Research Student 2015

Geochemistry

Petrology

M.01
Downing Street
Cambridge

CB2 3EQ
Office Phone: +44 (0) 1223 333432

Research Interests

My research interests are the physical and chemical processes in operation in the Earth's mantle, and how they can be explored by combining basalt geochemistry, and numerical models of mantle melting and melt transport. I am a NERC funded PhD student supervised by Oli Shorttle (CalTech), John Maclennan and John Rudge, and part of the 'Mantle Volatiles: processes, reservoirs and fluxes' consortium within the NERC Deep Volatiles Program.

Do Crystallisation Temperatures Reflect Mantle Temperature?

Temperature is a key control on the physical properties of the mantle, in particular the extent of melting during upwelling. Obtaining good estimates of mantle temperatures is important for understanding global mantle convection, as well as constraining the controls on melt generation. The geochemistry of crystals in basaltic eruptions can preserve information about the temperature at which they crystallised. By creating thermal models of mantle melting I seek to assess whether robust inferences about mantle temperature can be made from these crystallisation temperatures. I will be presenting this work at AGU 2015 (abstract) and VMSG 2016.

The Role of Lithological Heterogeneity in the Storage and Transport of Mantle Volatiles.

Throughout Earth’s history the mantle has been a major reservoir for volatile elements, with its thermal and chemical state having exercised a key control on the evolution of the terrestrial volatile cycle. However, the distribution and transport of volatile elements throughout the mantle remains poorly constrained. Element cycling between the surface and mantle (through melt removal and recycling of subducted lithosphere) has introduced pervasive fine scale mineralogical and geochemical heterogeneity. I am working on identifying how volatiles fit in to this lithological heterogeneity and what implications this has for the way in which volatiles are stored and transported in the mantle, and subsequently sampled by melting and volcanism. In order to do this I am using melt inclusion geochemistry to estimate the volatile composition of melts leaving the mantle, and through statistical modelling of mantle melting identify correlations with source mineralogy.