Dr Emma Tomlinson

Personal profile

Tephra research


Volcanic ash from highly explosive plinian and ultra-plinian volcanic eruptions falls indiscriminately in terrestrial, and marine environments forming isochronous marker layers, which allow the various sedimentary records to be linked (tephrostratigraphy). The NERC RESET consortium  aims to construct a new improved chronological framework for Europe by investigating the geochemistry of volcanic ash horizons. The resulting lattice will be used to investigate some of the long-standing questions about climate history.

 

Correlation of tephras is reliant upon geochemical analysis of juvenile magmatic material, such as ash, pumice, fiamme and obsdian. I work on European proximal volcanic deposits, including sources in Germany, Greece, Iceland, Italy and Turkey. The major differences between the products of eruptions from different volcanic regions are caused by differences in source composition, while differences between the eruptive products of a volcanic region or single volcano are often driven by high-level processes in the sub-volcanic magma chamber. 

 

Diamond research

 

Diamond is renowned as a material with superlative physical qualities: hardness, thermal conductivity and optical properties. Diamond also has many superlative physical qualities from the perspective of the earth scientist: it is mechanically strong and chemically inert, which make it a perfect vessel for the preservation of minerals and fluids from deep in the cratonic lithosphere – in the form of inclusions.

 

My particular interest is in mantle fluids: where do they come from - the lower mantle or subduction zones? What effects do they have on the host rock as they pervade through the mantle? do they cause melting in the mantle and are melting events expressed at the surface? Are these fluids related to the generation of kimberlite magma, which brings diamonds to the surface?

 

I use various techniques to investigate the compositions of mineral and fluid inclusions in diamond, including EMPA and LA-ICP-MS (major and trace element composition), and infrared and Raman spectroscopy (volatile composition). I also examine the composition of silicate mineral inclusions in diamond, which record evidence of having interacted with mantle fluids.

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