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Fellows Directory

Marian Holness

Marian Holness

Professor Marian Holness FRS


Elected: 2020


Marian Holness has created a new approach to decoding rock history by combining detailed observations of grain-scale microstructure with more conventional field observations and geochemical analysis. She concentrates on understanding the evolution of bodies of magma trapped in the crust, in particular the way mixtures of crystals and liquid rock behave, which ultimately controls the eruptive behaviour of any overlying volcano.

Marian’s development of a quantitative understanding of previously overlooked microstructural features in now-solidified examples of ancient magmatic intrusions has enabled her to trace their cooling history, to measure the thickness of mushy crystal-rich zones on their margins, and to see whether or not the magma convected during solidification. She has also identified the microstructural signature of liquid immiscibility, when a magma splits into two like a mixture of oil and vinegar, and has documented the significant effects this un-mixing has on mass transport within intrusions.

Marian is President of the GMPV Division of the European Geosciences Union. She was elected a Fellow of the Mineralogical Society of America (2019), and was awarded the Murchison Medal of the Geological Society of London (2019).

Professional positions

Professor, Department of Earth Sciences (Downing Street), University of Cambridge

Interest and expertise

Subject groups

  • Earth and environmental sciences
    • Geochemistry, Geology
  • Other
    • History of science
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