Research: Textural Development in High-Temperature Rocks
My research is concentrated on understanding the processes which occur during the melting and solidification of rocks – these include the formation and segregation of crustal melts, and the evolution of the crystal mush forming at the base of cooling magma chambers. I approach these problems using petrographic techniques coupled with geochemical analysis to decode rock history.
Current research includes:
I am using the mafic cumulates of the Rum and Skaergaard magma chambers as natural laboratories for a study of solidification. Detailed investigation of relationships between minerals demonstrates that the last phase to solidify pseudomorphs the final melt-filled porosity, providing information on the distribution of this last melt, and also on sub-solidus cooling rates. The sub-solidus cooling history can provide information on magma chamber replenishment events essential for understanding the evolution of open-system magma chambers.
Fragments of crystal-rich mushes formed at the base of currently active magma chambers are commonly entrained in erupted lavas. While the layered intrusions provide vital spatial information, glassy nodules give us an insight into the earliest stages of solidification.
Partially melted crustal rocks provide a complex story of melting, melt migration and subsequent solidification. This work is aimed at understanding the rates and mechanisms of segregation of crustal-derived melts: an essential step towards a complete model of crustal evolution.
Older Publications by Prof Marian Holness