Earth and environmental sciences

The research consists in locating the remaining witnesses of these early periods, collecting rare field samples and measurements, analyzing them with the most exquisite modern techniques of imagery, isotope geochemistry, mineralogy in extreme pressure and temperature conditions, as is beginning to be carried out on cores from Australia and South Africa that date back to 2.7 billion years and more. Because we need to go back even further in the past, to the first billion years of Earth’s history, it requires pushing back the resolution limits of many current instruments and also improving our understanding of some basic physical, chemical and even biological principles, and producing when needed efficient numerical modeling of massive amounts of data.

But the Present and the Past are keys to one another, and understanding the distant past of the Earth requires even better understanding of the processes which are still currently active on Earth. This is for instance the case for active subduction of plates, a generator of dangerous, powerful earthquakes and volcanoes, but also the key operator allowing the formation of granitic crust, that is the precursors to continental fragments that generally remain afloat at the top of the mantle, to form buoyant continental plates. A case in point is the subduction of the American plates under the Caribbean, forming the active arc of the Antilles. Active volcanoes provide there field laboratories where large parts of our scientific endeavour can be tested. The processes of rock generation, fluid-rock interaction, alteration and erosion, and chemical input into the world’s ocean can be studied near the three volcanological observatories of Martinique, Guadeloupe and Montserrat, three cousin volcanoes (which our teams continuously monitor) in different stages of their volcanic life cycle. This also leads to yet another kind of catastrophe, with potentially dangerous consequences to the local populations, bridging for us the gap between fundamental research and applications in the form of protection to the local populations and advice to the authorities.