Institut de Physique du Globe de Paris 1, rue Jussieu-75005 Paris www.ipgp.fr

The G2E TEAM Geochemistry of the External Earth

The G2E team works on the geologic consequences of the Earth’s water cycle.

When exposed at the Earth’s surface, chemical reactions among rock, water and atmospheric gases weather the rock releasing solutes to aquifers and streams. Erosion simultaneously sculpts the Earth surface, thereby releasing sediment to rivers.

These continental fragments are transported to the 2015) (June river Amazon The oceans, where sedimentary deposits record the chemical composition. The fate of these sedimentary deposits are well suited to fundamental questions including: how fast do continents weather and erode? What are the climatic and tectonic factors that control these rates? How can we use sedimentary archives to retrieve such rates in the geolo- gical past? These questions lie at the core of the scientific interests of the G2E team at the Institut de Physique du Globe de Paris. Answers to these motivating questions no only reveal the past of our planet, but also to our present environment and to its future evolution. The research undertaken by the G2E team hinges on Geochemistry - both elemental and isotope Geochemistry - as well as rock magne- tism, applied to a large range of geological ob- jects such as continental waters (soil, ground, and river water), river sediments, and sedi- mentary deposits. Emblematic of the G2E’s approach is the focus on large river systems as «integrators» of Earth surface processes. Large rivers overcome spatial variability and provide insight at an appropriate scale for ad- dressing geologic questions. The team members have access to a unique instrumental platform at IPGP compri- sing ICP and gas-source mass spectrometers, laser ablation devices, and clean labs to separate chemical elements from matrix material. Our “routine” toolbox for investiga- ting surficial processes include «non-traditional stable» isotopes (e.g., boron, lithium, magnesium, silicon, transition metals), radiogenic isotope systems (strontium, neody- mium, lead, U-series) and noble gas cosmogenic isotopes augmented by the continuous development of new techniques. Institut de Physique du Globe de Paris 1, rue Jussieu-75005 Paris www.ipgp.fr

Our team members are involved in the international Critical Zone initiative, IODP international program, and the French network of river catchments («RBV»). Strong collaborations exist with geophysicists and hydrologists for the development of en- vironmental sensors to explore the Critical Zone through an ambitious equipment program («CRITEX»). This level of engagment provides us unique opportunities of interdisciplinary international collaboration.

Primary research areas of the G2E team: - Rock-to-sediment transformation - Biological recycling of metal nutrients - Global controls on soil formation rates - Links between hydrology and rock weathering

- Large river geochemistry («potamochemistry») IODP cruise - Hydrothermal processes of continental volcanic centers - Relationship between climate and tectonics - Global carbon cycle and (modern and past changes - at geological time scales) - Tracing anthropogenic pollution using metal isotopes - Origin of sedimentary rocks and reconstruction of the past environments using sedimentary archives - Sedimentary magnetism - Reconstructing ocean pH in the geological past - Biomineralization processes The G2E Team in July 2016 July in Team G2E The Faculty members to contact for PhD or post-doc opportunities: Julien Bouchez, CNRS researcher ([email protected]), chemical potamology Céline Dessert, Assistant professor ([email protected]), isotope geochemistry Jérôme Gaillardet, professor ([email protected]) chemical potamology Eric Gayer, Assistant professor ([email protected]), geomorphology and cosmogenic isotopes Pascale Louvat, CNRS engineer ([email protected]), isotope geochemistry Laure Meynadier, professor ([email protected]), chemical oceanography Claire Rollion-Bard, CNRS engineer ([email protected]), biomineralization and in-situ isotopic geochemistry.