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Nature study Deep Diamond With Perovskite

Deep into the Earth: diamonds and surficial carbon down to 800 km depth in the Earth’s lower mantle.

A team of geologists from Italy (University of Padova, University of Pavia and CNR-IGG Padova), Canada (University of British Columbia and University of Alberta), UK (University College London), and South Africa (University of Cape Town and Rhodes University) definitively proved what geophysicists indirectly predicted so far, i.e. the oceanic crust and surficial carbon can reach the lower mantle (below 660 km depth) by subduction processes.
The discovery, published in Nature was possible thanks to the study of a special “super-deep” diamond from the famous Cullinan mine (South Africa), where the world’s largest 3107-carats Cullinan diamond was found more than 140 years ago. In detail, the research team, including Dr Martha Pamato from the Department of Earth Sciences at UCL, discovered, the first natural CaSiO3 mineral with a perovskite crystal structure still trapped within the diamond. Many deep Earth scientists had predicted that this mineral would never be found at the Earth’s surface, even though there are zetta tonnes (1021 tonnes) of this material buried deep in the Earth. This very high-pressure form of calcium silicate (CaSiO3) can be stable only from about 600 km depth in Earth’s mantle, continuing to be stable right through the lower mantle. This specific inclusion within diamond shows a chemical composition which would indicate that the diamond formed at about 780 km depth in the Earth’s lower mantle and, at the same time, that the inclusion is derived from oceanic crust (see the cartoon). The research team analysed the carbon forming the diamond, and this indicates its surficial derivation. The discovery is the first definitive prove of oceanic crust and surficial carbon recycled by subduction into Earth’s lower mantle as predicted by seismic images and geodynamic modelling.


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Planetary Ices Researchers:

Dr Dominic Fortes. UCL ES and Birkbeck E&PS

My research covers the icy satellites of the Gas Giants and their constituent ice and hydrate phases. This includes the application of neutron and X-ray diffraction techniques to determine the structure, phase behaviour and elastic properties of 'ices' at high pressures and low temperatures.


Prof Ian Wood.  UCL ES

Research areas incluce: Crystallography, X-ray and Neutron Powder Diffraction, High Pressure and High/Low Temperature Diffraction Experiments, Clay Minerals and Planetary Ices.


Dr Peter Grindrod.  Birkbeck E&PS

I’m a planetary scientist specialising in terrestrial planets and icy moons. I’m currently funded by the UK Space Agency on an Advanced Aurora Research Fellowship. My research combines experiments, theory, and observations, to better understand the geological evolution of solar system bodies.


Prof. Lidunka Vocadlo.  UCL ES

Research themes include ab initio simulation of the thermoelastic, melting and dynamic properties of planet-forming materials; high pressure experiments from cryogenic to high temperatures on planet-forming materials.


Prof. John Brodholt. UCL ES

Reasearch areas include Geophysics and Mineral Physics


Prof. David Dobson. UCL ES

My research focuses on high-pressure experiments on deep Earth materials; synthesis and properties of new Fe-alloy phases relevant to the core; transport properties of mantle rocks and minerals and deep seismicity.

Dario Alfe

Prof. Dario Alfé. UCL ES & LCN

My research focuses on materials modelling with various first principles techniques, including density functional theory and quantum Monte Carlo to determine material properties under high pressure and high temperature. I'm working with external collaborators on a number of projects aimed at understanding water, ice and water clusters.

Lars Stixrude

Prof. Lars Stixrude. UCL ES

My research program seeks to understand large-scale planetary processes through investigations of the fundamental atomic-scale physics of Earth- and planet-forming materials. Fields of interests include mineral physics, Earth and planetary liquids and fluids, condensed matter physics, high pressure physics, planetary structure and evolution.


Prof. Peter Sammonds. UCL ES

My research aims are to investigate the mechanics of the Earth's crust and ice sheets by studying the fundamental physics and mechanics of geological materials. The Earth's crust and ice sheets are the parts of the solid Earth with which humankind interact directly, and therefore of the greatest interest to me.


Dr Tom Nordheim, UCL MSSL

I am interested in moon-magnetosphere interactions at Saturn and Jupiter, space-weathering effects on unmagnetized bodies, modelling of cosmic ray interactions in neutral atmospheres and planetary robotics

Current PhD Students:
Gillian Sclater (Birkbeck E&PS). Properties of methane clathrate relevant to modelling the internal dynamics of icy satellites.