Early Solar System Evolution
Aqueous alteration of the CM carbonaceous chondrites
The CM carbonaceous chondrites are samples of C type asteroids. Their primitive bulk chemical composition suggests that they have changed little since accretion at the birth of the solar system, yet these rocks contain abundant phyllosilicates and carbonates that have formed in asteroidal interiors by the action of liquid water. The focus of our work is on understanding the processes and chronologies of water-rock interaction via petrographic and isotopic (16,17,18O; 53Mn-53Cr, 39Ar-40Ar) analysis of fine-grained carbonate- and phyllosilicate-rich meteorite matrices. We are also studying meteorite petrofabrics using X-ray computed tomography, and the mineralogy of pristine chondrules.
Timescales for cooling of the H-chondrite parent body
The early solar system was a turbulent and violent place, with a complex interplay between numerous processes including radioactive heating, thermal diffusion, and massive impact events. Knowledge of the timescales and prevalence of such processes is crucial to understand the formation of the rocky planets and asteroids. In this study we are investigating the cooling history of the H chondrites – the most common type of meteorite. In particular, we aim to determine if cooling was consistent with heat diffusion only (the onion-skinned model), or if cooling was enhanced, for example, via excavation by impacts.
History of the atmosphere, lithosphere and biosphere of Mars
Shergottites: from old Mars or young Mars?How old is the surface of Mars? The bulk of the red planet is heavily cratered, indicating ancient terranes exposed for more than 3 billion years. In contrast, the majority of martian meteorites (the shergottites) apparently have much younger ages as recent as 180 million years ago. We aim to develop a robust chronology to allow for investigation of this shergottite age paradox¹, and to understand the chronology of martian meteorites within the broader context of martian geology.
Water-mediated alteration of the nakhlite meteoritesThe nakhlite group of martian meteorites are a very important tool for understanding the evolution of the planet’s hydrosphere. They contain a suite of minerals that crystallized from liquid water ~600 million years ago, and we are working to unravel the sequence in which these minerals formed in order to develop and refine models of interaction of crustal water with the igneous crust of Mars.
Martian carbon in the Tissint meteorite
We are using a wide range of analytical techniques to distinguish between indigenous Martian carbon and terrestrial contaminants in Tissint (the most recent, most pristine Martian meteorite). The overall aim is to assess whether any native carbon present is of biotic or abiotic origin, and therefore whether Mars could have been (or could currently be) capable of supporting life.