ERC FUNDED PROJECTS

Rapid changes in ocean circulation and climate have been observed in marine sediment and ice cores, notably over the last 60 thousand years (ky), highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing. To date, these rapid changes in climate and ocean circulation are still not fully explained. Two main obstacles prevent going beyond the current state of knowledge: - Paleoclimatic proxy data are by essence only indirect indicators of the climatic variables, and thus can not be directly compared with model outputs; - A 4-D (latitude, longitude, water depth, time) reconstruction of Atlantic water masses over the past 40 ky is lacking: previous studies have generated isolated records with disparate timescales which do not allow the causes of circulation changes to be identified. Overcoming these two major limitations will lead to major breakthroughs in climate research. Concretely, I will create the first database of Atlantic deep-sea records over the last 40 ky, and extract full climatic information from these records through an innovative model-data integration scheme using an isotopic proxy forward modeling approach. The novelty and exceptional potential of this scheme is twofold: (i) it avoids hypotheses on proxy interpretation and hence suppresses or strongly reduces the errors of interpretation of paleoclimatic records; (ii) it produces states of the climate system that best explain the observations over the last 40 ky, while being consistent with the model physics. Expected results include: • The elucidation of the mechanisms explaining rapid changes in ocean circulation and climate over the last 40 ky, • Improved climate model physics and parameterizations, • The first projections of future climate changes obtained with a model able to reproduce the highly non linear behavior of the climate system observed over the last 40 ky.

3 000 000 €

Start date: 2014-02-01, End date: 2019-01-31

The onset of the systematic consumption of marine resources is thought to mark a turning point for the hominin lineage. To date, this onset cannot be traced, since classic isotope markers are not preserved beyond 50 - 100 ky. Aquatic food products are essential in human nutrition as the main source of polyunsaturated fatty acids in hunter-gatherer diets. The exploitation of marine resources is also thought to have reduced human mobility and enhanced social and technological complexification. Systematic aquatic food consumption could well have been a distinctive feature of Homo sapiens species among his fellow hominins, and has been linked to the astonishing leap in human intelligence and conscience. Yet, this hypothesis is challenged by the existence of mollusk and marine mammal bone remains at Neanderthal archeological sites. Recent work demonstrated the sensitivity of Zn isotope composition in bioapatite, the mineral part of bones and teeth, to dietary Zn. By combining classic (C and C/N isotope analyses) and innovative techniques (compound specific C/N and bulk Zn isotope analyses), I will develop a suite of sensitive tracers for shellfish, fish and marine mammal consumption. Shellfish consumption will be investigated by comparing various South American and European prehistoric populations from the Atlantic coast associated to shell-midden and fish-mounds. Marine mammal consumption will be traced using an Inuit population of Arctic Canada and the Wairau Bar population of New Zealand. C/N/Zn isotope compositions of various aquatic products will also be assessed, as well as isotope fractionation during intestinal absorption. I will then use the fully calibrated isotope tools to detect and characterize the onset of marine food exploitation in human history, which will answer the question of its specificity to our species. Neanderthal, early modern humans and possibly other hominin remains from coastal and inland sites will be compared in that purpose.

1 361 991 €

Start date: 2019-03-01, End date: 2024-02-29

This interdisciplinary proposal stems from our recent discovery of deep-branching cyanobacteria that form intracellular Ca-Mg-Sr-Ba carbonates. So far, calcification by cyanobacteria was considered as exclusively extracellular, hence dependent on external conditions. The existence of intracellularly calcifying cyanobacteria may thus deeply modify our view on the role of cyanobacteria in the formation of modern and past carbonate deposits and the degree of control they achieve on this geochemically significant process. Moreover, since these cyanobacteria concentrate selectively Sr and Ba over Ca, it suggests the existence of processes that can alter the message conveyed by proxies such as Sr/Ca ratios in carbonates, classically used for paleoenvironmental reconstruction. Finally, such a biomineralization process, if globally significant may impact our view of how an ecosystem responds to external CO2 changes in particular by affecting most likely a key parameter such as the balance between organic carbon fixed by photosynthesis and inorganic carbon fixed by CaCO3 precipitation. Here, I aim to bring a qualitative jump in the understanding of this process. The core of this project is to provide a detailed picture of intracellular calcification by cyanobacteria. This will be achieved by studying laboratory cultures of cyanobacteria, field samples of modern calcifying biofilms and ancient microbialites. Diverse tools from molecular biology, biochemistry, mineralogy and geochemistry will be used. Altogether these techniques will help unveiling the molecular and mineralogical mechanisms involved in cyanobacterial intracellular calcification, assessing the phylogenetic diversity of these cyanobacteria and the preservability of their traces in ancient rocks. My goal is to establish a unique expertise in the study of calcification by cyanobacteria, the scope of which can be developed and broadened in the future for the study of interactions between life and minerals.

1 659 478 €

Start date: 2013-02-01, End date: 2018-01-31

Few geophysical phenomena are as spectacular as tropical cyclones, with their eye surrounded by sharp cloudy eyewalls. There are other types of spatially organised convection (convection refers to overturning of air within which clouds are embedded), in fact organised convection is ubiquitous in the tropics. But it is still poorly understood and poorly represented in convective parameterisations of global climate models, despite its strong societal and climatic impact. It is associated with extreme weather, and with dramatic changes of the large scales, including drying of the atmosphere and increased outgoing longwave radiation to space. The latter can have dramatic consequences on tropical energetics, and hence on global climate. Thus, convective organisation could be a key missing ingredient in current estimates of climate sensitivity from climate models. CLUSTER will lead to improved fundamental understanding of convective organisation to help guide and improve convective parameterisations. It is closely related to the World Climate Research Programme (WCRP) grand challenge: Clouds, circulation and climate sensitivity. Grand challenges identify areas of emphasis in the coming decade, targeting specific barriers preventing progress in critical areas of climate science. Until recently, progress on this topic was hindered by high numerical cost and lack of fundamental understanding. Advances in computer power combined with new discoveries based on idealised frameworks, theory and observational findings, make this the ideal time to determine the fundamental processes governing convective organisation in nature. Using a synergy of theory, high-resolution cloud-resolving simulations, and in-situ and satellite observations, CLUSTER will specifically target two feedbacks recently identified as being essential to convective aggregation, and assess their impact on tropical cyclones, large-scale properties including precipitation extremes, and energetics of the tropics.

1 078 021 €

Start date: 2019-06-01, End date: 2024-05-31

This project aims at simulating the processes that took place in the early Solar System to determine how these processes shaped the chemical and isotope compositions of solids that accreted to ultimately form terrestrial planets. Planetary materials exhibit mass dependent and mass independent isotope signatures and their origin and relationships are not fully understood. This proposal will be based on new experiments reproducing the conditions of the solar nebula in its first few million years and on a newly designed Knudsen Effusion Mass Spectrometer (KEMS) that will be built for the purpose of this project. This project consists of three main subprojects: (1) we will simulate the effect of particle irradiation on solids to examine how isotopes can be fractionated by these processes to identify whether this can explain chemical variations in meteorites. We will examine whether particle irradiation can cause mass independent fractionation, (2) the novel KEMS instrument will be used to determine the equilibrium isotope fractionation associated with reactions between gas and condensed phases at high temperature. It will also be used to determine the kinetic isotope fractionation associated with evaporation and condensation of solids. This will provide new constraints on the thermodynamic conditions, T, P and fO2 during heating events that have modified the chemical composition of planetary materials. These constraints will also help identify the processes that cause the depletion in volatile elements and the fractionation in refractory elements observed in planetesimals and planets, (3) we will examine the effect of UV irradiation on chemical species in the vapour phase as an attempt to reproduce observed isotope compositions found in meteorites or their components. These results may radically change our view on how the protoplanetary disk evolved and how solids were transported and mixed.

3 106 625 €

Start date: 2016-10-01, End date: 2021-09-30

Ancient records of the geomagnetic field intensity provide the unique source of information on the evolution of the geodynamo. The paleomagnetic data contain a broad spectrum of dipole moment fluctuations with polarity reversals and excursions that typically occur during periods of very low field intensity, but the amplitude and the timing of the variations as well as critical features remain debated. The variability of the dipole with rapid fluctuations combined with long-term changes must be clarified to understand what controls the dipole strength, why it fluctuates and what is the cause of polarity reversals. Much has been learned for the past 30 years from records of paleointensity relying on natural remanent magnetization of sediments and lava flows, but large uncertainties persist and major features of the field remain poorly documented, pointing out the limits of the approach. As an alternative to magnetization, changes in geomagnetic intensity can be reconstructed from the production of cosmogenic 10Be. The 10Be production can be measured with confidence from sedimentary sequences. Our main objective is to build up a worldwide database of the dipole field changes for the past 5 Ma by acquiring high resolution records of 10Be production from a worldwide set of selected sediment cores. The Accelerator mass spectrometry national facility « ASTER» at CEREGE dedicated to 10Be measurements offers this unique opportunity. Accurate time control will be obtained by astronomical calibration of paleoenvironmental records. In parallel, we will focus on the short-term field changes occurring during geomagnetic reversals. This will be addressed by combining detailed paleomagnetic records of reversals from volcanic sequences with high resolution 10Be measurements from marine cores that recorded the same reversals. Predictions of numerical geodynamo simulations will be tested against the data.

2 499 600 €

Start date: 2014-06-01, End date: 2019-05-31

This proposal focuses on two of climate science’s most fundamental questions: How sensitive is Earth's surface temperature to radiative forcing? and What governs the organization of the atmosphere into rain bands, cloud clusters and storms? These seemingly different questions are central to an ability to assess climate change on regional and global scales, and are in large part tied to a single and critical gap in our knowledge: A poor understanding of how clouds and atmospheric circulations interact. To fill this gap, my goal is to answer three questions, which are critical to an understanding of cloud-circulation coupling and its role in climate: (i) How strongly is the low-clouds response to global warming controlled by atmospheric circulations within the first few kilometres of the atmosphere? (ii) What controls the propensity of the atmosphere to aggregate into clusters or rain bands, and what role does it play in the large-scale atmospheric circulation and in climate sensitivity? (iii) How much do cloud-radiative effects influence the frequency and strength of extreme events? I will address these questions by organising the first airborne field campaign focused on elucidating the interplay between low-level clouds and the small-scale and large-scale circulations in which they are embedded, as this is key for questions (i) and (ii), by analysing data from other field campaigns and satellite observations, and by conducting targeted numerical experiments with a hierarchy of models and configurations. This research stands a very good chance to reduce the primary source of the forty-year uncertainty in climate sensitivity, to demystify long-standing questions of tropical meteorology, and to advance the physical understanding and prediction of extreme events. EUREC4A will also support, motivate and train a team of young scientists to exploit the synergy between observational and modelling approaches to answer pressing questions of atmospheric and climate science.

3 013 334 €

Start date: 2016-08-01, End date: 2021-07-31

The recent September 2017, magnitude 7.1, central Mexico earthquake that caused 370 casualties reminds us that earthquakes are among the most dramatic natural disasters worldwide. Causal physical processes are not instantaneous and laboratory and numerical experiments predict that earthquakes should be preceded by a detectable slow preparation phase. Despite considerable efforts, however, robust geophysical precursors have not yet been observed before damaging earthquakes. My FaultScan project will revolutionize our ability to directly observe transient deformation within the core of active faults and provide unprecedented accuracy in the detection of earthquake precursors. My ambition is to develop a new, noise-based, high resolution, seismic monitoring approach. I intend to grasp the opportunity of a recent step change in seismic instrumentation and data processing capabilities to achieve a dream for seismologists: reproduce repeatable, daily, virtual seismic sources that can probe the core of active faults at seismogenic depths using only passive seismic records. I plan to target the San Jacinto Fault (a branch of the San Andreas Fault system) that is currently believed to pose one of the largest seismic risks in California. It is an ideal fault for this project because it is very active, already extensively studied and easily accessible for the pilot field data acquisition work. This project is in collaboration with the Univ. of South. California, the Univ. of Cal. San Diego and specialists in earthquake mechanics and will include earthquake preparation processes and seismic modeling that will guide us for our long-term (3 years), breakthrough, passive seismic experiment and further data analysis and interpretation. I strongly believe that this project has a very high potential for providing fundamental results on the physics of earthquakes and faults and that it will have a major impact on earthquake prediction worldwide in the near future.

2 524 630 €

Start date: 2019-06-01, End date: 2024-05-31

Many major and devastating floods have occurred around the world recently. Their number and magnitude seems to have increased but such changes are not clear. More surprisingly, the exact causes of changes remain a mystery. Although, drivers such as climate and land use change are known to play a critical role, their complex interactions in flood generation have not been disentangled. The main objectives of this project are to understand how changes in land use and climate translate into changes in river floods, what are the factors controlling this relationship and what are the uncertainties involved. We decipher the relationship between changes in floods and their drivers by analysing the processes separately for different flood types such as flash floods, rain-on-snow floods and large scale synoptic floods. We then use data from catchments in transects across Europe to build a probabilistic flood-change model that explicitly describes the change mechanisms. The model is unconventional as it does not take a reductionist approach but conceptualises the dominant flood change processes at the catchment scale. We test the model on long high-quality flood data series. We use the model as well as the temporal and spatial data variability to quantify the sensitivity of floods to climate and land use change and estimate the uncertainties involved. The data are already available to me or will be made available through my excellent contacts in Europe. For the first time, it will be possible to systematise the effects of land use and climate on floods which will provide a vital step towards predicting how floods will change in the future.

2 263 565 €

Start date: 2012-04-01, End date: 2017-03-31

Recent space-based geodetic measurements of ground deformation suggest a paradigm shift is required in our understanding of the behaviour of active tectonic faults. The classic view of faults classified in two groups – the locked faults prone to generate earthquakes and the creeping faults releasing stress through continuous aseismic slip – is now obscured by more and more studies shedding light on a wide variety of seismic and aseismic slip events of variable duration and size. What physical mechanism controls whether a tectonic fault will generate a dynamic, catastrophic rupture or gently release energy aseismically? Answering such a fundamental question requires a tool for systematic and global detection of all modes of slip along active faults. The launch of the Sentinel 1 constellation is a game changer as it provides, from now on, systematic Radar mapping of all actively deforming regions in the world with a 6-day return period. Such wealth of data represents an opportunity as well as a challenge we need to meet today. In order to expand the detection and characterization of all slip events to a global scale, I will develop a tool based on machine learning procedures merging the detection capabilities of all data types, including Sentinel 1 data, to build time series of ground motion. The first step is the development of a geodetic data assimilation method with forecasting ability toward the first re-analysis of active fault motion and tectonic phenomena. The second step is a validation of the method on three faults, including the well-instrumented San Andreas (USA) and Longitudinal Valley faults (Taiwan) and the North Anatolian Fault (NAF, Turkey). I will deploy a specifically designed GPS network along the NAF to compare with outputs of our method. The third step is the intensive use of the algorithm on a global scale to detect slip events of all temporal and spatial scales for a better understanding of the slip behaviour along all active continental faults.

1 499 125 €

Start date: 2018-01-01, End date: 2022-12-31

Carbonaceous chondrites (CC) are believed to be fragments of carbonaceous asteroids from the asteroidal belt. They contain up to 4wt% of organic compounds, showing a huge diversity and extremely variable H and N isotope compositions. These isotope compositions can relate to synthesis environments but the exact nature of the processes that influenced the formation of organic compounds in CC remains unresolved. Part of the issue comes from the occurrence of hydrothermal alteration on the chondrites that exhibit the largest content in organic matter. Hydrothermalism may have modified the chemical and isotopic signature of organic molecules, but the extent of these modifications is not yet constrained, leaving a lot of uncertainties on the interpretation of H and N isotope ratios. The HYDROMA project aims at determining the effects of hydrothermalism on the D/H and 15N/14N ratios of organic molecules in CC. This project will rely on an innovative experimental approach to quantify isotopic exchange of hydrogen and nitrogen between organic compounds and the hydrothermal fluid. HYDROMA will provide a self-consistent determination of the extent and kinetics of the modification of the isotopic signatures recorded in organic molecules. Hence, it will improve the understanding of H and N-isotope systematics of organic matter in CC. HYDROMA will permit using isotope composition of organic compounds to constrain the hydrothermal events (duration, temperature) on carbonaceous asteroids. This multidisciplinary research will shed new light on the origin and reprocessing of organic matter in the early solar system, and its delivery to rocky planets, including the Earth, thus disclosing the origin of prebiotic molecules on our planet.

1 994 351 €

Start date: 2019-09-01, End date: 2024-08-31

IASI - Flux and temperature July 2016 was Earth's warmest month on record. The first six months of 2016 were also the warmest six-month period since modern meteorology observations began. This, along with the recent so-called “hiatus” in the warming trend, and the Paris climate agreement, all attracted scientific and public attention as to how reliable the historical temperature record is, and to the level of confidence in future model climate projections. Although the role of satellites in observing the variability and change of the Earth system has increased in recent decades, remotely-sensed observations are still underexploited to accurately assess climate change fingerprints. The IASI - Flux and Temperature (IASI-FT) project aims at providing new benchmarks for top-of-atmosphere radiative flux and temperature observations using the calibrated radiances measured twice a day at any location by the IASI instrument on the suite of MetOp satellites. The main challenge is to achieve the stringent accuracy and stability necessary for climate studies, particularly for climate trends. Building upon the expertise accumulated by my group during the last 10 years, I propose the development of innovative algorithms and statistical tools to generate climate data records at the global scale, of (1) spectrally resolved outgoing radiances, (2) land and sea skin surface temperatures, and (3) temperatures at selected altitudes. Time series of these quantities will be compared with in situ and other satellite observations if available, atmospheric reanalyses, and climate model simulations. The observed trends will be analyzed at seasonal and regional scales in order to disentangle natural (weather/dynamical) variability and human-induced climate forcings. This project, while clearly research-oriented, will lead towards an operational integrated observational strategy for the Earth climate system, given that the IASI program started in 2006 and will last until 2040 at least.

2 200 000 €

Start date: 2017-10-01, End date: 2022-09-30

The Quaternary period (last 2600 thousands of years, hereafter ka) is the ideal period to evaluate our understanding of climate processes with general circulation models (GCM) used for prediction of future climate. During this period, the largest climate changes are glacial – interglacial transitions, hereafter terminations, the last termination being a classical benchmark for GCM. The rhythm of terminations changed from a world associated with a 40 ka periodicity to a world associated with a 100 ka glacial – interglacial periodicity between 1250 and 700 ka. The cause for this transition is a long debated question highlighting that the causes and mechanisms of terminations are still poorly understood. The timing and amplitudes of terminations indeed result from multiple influences of insolation forcing, ice sheet size, atmospheric greenhouse gases (GHG) concentration as well as shorter (millennial) scale climate variability. The big challenge of ICORDA consists in solving major puzzles on the mechanisms of terminations by deciphering these different influences using two key Antarctic ice core records: EPICA Dome C covering the last 800 ka and an ice core to be drilled in the coming years and covering the last 1500 ka. While ice cores provide unique continuous and high resolution climatic and GHG records, they are still too poorly dated on long timescales to address the aforementioned challenge. ICORDA aims at rethinking the way ice core chronology is built for decreasing drastically the associated uncertainties. This will be done by (1) developing a mechanistic approach for the interpretation of isotopic tracers used for ice core dating and (2) combining numerous low to mid latitude ice core tracers to provide a global picture of climate change during terminations. The strategy involves interdisciplinarity between climate, geochemistry, ecophysiology and innovative instrumental developments as well as field, laboratory experiments and modeling.

1 994 100 €

Start date: 2019-12-01, End date: 2024-11-30

The main geochemical features of the mantles of terrestrial planets and asteroids can be attributed to differentiation events that occurred during or shortly after the formation of the Solar System. Numerous questions remain regarding the Earth’s bulk composition and the most likely scenario for its evolution prior to the last major differentiation event caused by a giant impact leading to the formation of the Moon. The aim of this five-year project is to evaluate the state-of-the-art models of the Earth’s early evolution with the following main objectives: (i) Defining precisely the age of the Moon’s formation, (ii) Refining the giant impact model and the Earth-Moon relationship, (iii) Dating the successive magmatic ocean stages on Earth, and (iv) Constraining the Earth mantle’s composition in terms of rare earth element concentrations. These different questions will be addressed using trace elements, radiogenic isotopic systematics (146Sm-142Nd, 147Sm-143Nd, 138La-138Ce) and stable isotopes. ISOREE is a multi-disciplinary project that combines isotope and trace element geochemistry, experimental geochemistry and spectroscopy. A large number of samples will be analysed, including terrestrial rocks with ages up to 3.8 Ga, chondrites, achondrites and lunar samples. This proposal will provide the tools to tackle a vast topic from various angles, using new methodologies and instrumentation and promoting innovation and creativity in European research. This research program is essential to further constrain the major events that occurred very early on in the Earth’s history, such as the Earth’s cooling, its crustal growth, the surface conditions and development of potential habitats for life.

2 200 000 €

Start date: 2016-09-01, End date: 2021-08-31

Mass-independent fractionation (MIF) of isotopes in terrestrial geochemical processes was first observed in 1983 for oxygen and in 2000 for sulfur isotopes. Recently mercury (Hg) was added to this shortlist when isotopic anomalies were observed for Hg s two odd isotopes, 199Hg and 201Hg in biological tissues. The objective of the MERCURY ISOTOPES project is to take Hg MIF beyond the initial discovery, and use it to address major outstanding scientific questions of societal and philosophical interest. Similar to the profound insights that carbon and oxygen isotope systematics have brought to climate research, we propose to use variations in Hg isotopic compositions to fingerprint natural and anthropogenic sources, quantify isotope fractionation processes, and provide new constraints on models of mercury cycling. The MERCURY ISOTOPES project centres on the use of mercury MIF to understand global Hg dynamics at different time scales, from the Pleistocene to modern times. Three main themes will be investigated: 1. the modern Hg cycle focusing on Asian urban-industrial emissions related to coal burning, 2. recent atmospheric Hg deposition in the Arctic, recent Arctic Ocean Hg records from archived biological tissues, and post-glacial Hg deposition from 10,000 yr old ombrotrophic peat records along a mid-latitude sub-Arctic gradient. 3 Continuous atmospheric Hg speciation and isotopic monitoring at the Pic du Midi Observatory (Pyrenees). By tapping information from the isotopic dimension of Hg cycling, including revolutionary mass-independent effects, I expect a maximum scientific impact while supporting a socially relevant and urgently needed investigation at the frontier of isotope geosciences.

1 176 924 €

Start date: 2010-12-01, End date: 2015-11-30

The last seismic sequence in Italy, responsible for 298 fatalities and important economic loss, remind us how urgent it is to improve our knowledge about earthquake physics to advance earthquake forecasting. While direct observations during laboratory earthquakes permit us to derive exhaustive physical models describing the behaviour of rocks and to forecast incoming lab-earthquakes, the complex physics governing the nucleation of earthquakes remain poorly understood in real Earth, and so does our ability to forecast earthquakes. I posit that this ‘ignorance’ emerges from our limited ability to unravel information about fault physics from geophysical data.The objective of this proposal is to introduce a new and integrated methodology to monitor the spatiotemporal evolution of elastic properties on real faults using seismological and geodetic data. We will apply machine learning and covariance matrix factorization for improved earthquake detection, and to discover ‘anomalous’ seismological signals, which will reveal unknown physical processes on faults. These novel observations will be integrated with time dependent measurements of rheology and deformation, obtained from cutting-edge techniques applied to continuous seismological and geodetic data. Our integrated monitoring approach will be applied to study how faults respond to known stress perturbations (as Earth tides). In parallel, we will analyse periods preceding significant earthquakes to assess how elastic properties and deformation evolve while a fault is approaching a critical (near rupture) state. Our natural laboratory will be Italy, given its excellent geodetic and seismological instrumentation, deep knowledge about faults geometry and the relevant risk posed by earthquakes. Our research will provide new insights about the complex physics of faults at critical state, necessary to understand how real earthquakes nucleate. This project will also have a major impact on observational earthquake forecast.

1 393 174 €

Start date: 2019-01-01, End date: 2023-12-31

This proposal has the objective to greatly enhance our understanding of sources, sinks and processes fixing the composition of the atmosphere at different time periods of time, from 3.8 Gyr ago to Present. For achieving this goal, I shall develop the high precision analysis of noble gases, which are key tracers of atmospheric evolution. The core of the proposal is : (i) the development of multi-collector mass spectrometry analysis of noble gas isotopes coupled with standard bracketing, aimed at reaching the per mil or better precision level, which will constitute a world premiere, (ii) the analysis of unique cometary samples, of ancient sediments already partly available at my laboratory, and of present-day air sampled at different geographical and altitudinal scales, (iii) the quantification of sources and sinks of atmospheric volatiles through the study of the fluxes of noble gas isotopes. With this proposal, I develop a new and extremely competitive area of geochemistry, aimed at better understanding the early evolution of our planet habitability, as well as at improving our knowledge of fluxes of volatile elements triggering anthropogenic climate change. This proposal will establish the leadership of Europe in high precision geochemistry of exceptional tracers, the noble gases.

2 281 806 €

Start date: 2011-01-01, End date: 2016-12-31

Light elements such as hydrogen and nitrogen present large isotope variations among solar system objects and reservoirs (including planetary atmospheres) that remain unexplained at present. Works based on theoretical approaches are model-dependent and do not reach a consensus. Laboratory experiments are required in order to develop the underlying physical mechanisms. The aim of the project is to investigate the origins of and processes responsible for isotope variations of the light elements and noble gases in the Solar System through an experimental approach involving ionization of gaseous species. We will also investigate mechanisms and processes of isotope fractionation of atmophile elements in planetary atmospheres that have been irradiated by solar UV photons, with particular reference to Mars and the early Earth. Three pathways will be considered: (i) plasma ionisation of gas mixtures (H2-CO-N2-noble gases) in a custom-built reactor; (ii) photo-ionisation and photo-dissociation of the relevant gas species and mixtures using synchrotron light; and (iii) UV irradiation of ices containing the species of interest. The results of this study will shed light on the early Solar System evolution and on processes of planetary formation.

2 810 229 €

Start date: 2017-01-01, End date: 2021-12-31

We propose a simple idea: to reproduce earthquakes in the laboratory. Because earthquakes are spectacular examples of uncontrollable catastrophes, the opportunity to study them under controlled conditions in the laboratory is unique and is, in fact, the only way to understand the details of the earthquake source physics. The aim of the project is interdisciplinary, at the frontiers between Rock Fracture Mechanics, Seismology, and Mineralogy. Its ultimate goal is to improve, on the basis of integrated experimental data, our understanding of the earthquake source physics. We have already shown that both deep and shallow laboratory earthquakes are not mere `analogs’ of earthquakes, but are real events – though very small [Passelègue et al. 2013, Schubnel et al. 2013]. During laboratory earthquakes, by measuring all of the physical quantities related to the rupturing process, we will unravel what controls the rupture speed, rupture arrest, the earthquake rupture energy budget, as well as the common role played by mineralogy in both shallow and deep earthquakes. We will also perform some experiments on rock samples drilled from actual active fault zones. Our work will provide insights for earthquake hazard mitigation, constrain ubiquitously observed seismological statistical laws (Omori, Gutenberg-Richter) and produce unprecedented data sets on rock fracture dynamics at in-situ conditions to test seismic slip inversion and dynamic rupture modelling techniques. The new infrastructure we plan to install will reproduce the temperatures and pressures at depths where earthquakes occur in the crust as well as in the upper mantle of the Earth, with never achieved spatio-temporal imaging resolution to this day. This will be a valuable research asset for the European community, as it will eventually open the door to a better understanding of all the processes happening under stress within the first hundreds of kilometres of the Earth.

2 748 188 €

Start date: 2016-10-01, End date: 2021-09-30

A better comprehension of the rheology of the lithosphere is required to relate long and short term deformation regimes and describe the succession of events leading to earthquakes. But our vision of the rheology is blurred because gaps exist between visions of geologists, experimentalists and modellers. Geologists describe the evolution of a structure at regional-scale within geological durations. Specialists of experimental rheology control most parameters, but laboratory time constants are short and they often work on simple synthetic rocks. Specialists of modelling can choose any time- and space-scales and introduce in the model any parameter, but the resolution of their models is low compared to natural observations, and mixing short-term and long-term processes is uneasy. It seems now clear that there is not one rheological model applicable to all contexts and that rheological parameters should be adapted to each situation. We will work on exhumed crustal-scale shear zones and describe them in their complexity, focussing on strain localisation and high strain structures that can lead to fast slip events. A number of objects will be studied, starting from geological description (3D geometry, P-T-fluids estimates and dating), experimental studies of rheological properties of natural sampled rocks and numerical modelling. We will set an Argon-dating lab to work on dense sampling for dating along strain gradients in order to overcome local artefacts and quantify rates of strain localisation. We will deform in the lab natural rocks taken from the studied objects to retrieve adapted rheological parameters. We will model processes at various scales, from the lab to the lithosphere in order to ensure a clean transfer of rheological parameters from one scale to another.

2 645 000 €

Start date: 2012-08-01, End date: 2017-07-31

Earth, as a whole, can be considered as a living organism emitting gases and particles in its atmosphere, in order to regulate its own temperature (Lovelock, 1988). In particular oceans, which cover 70% of the Earth, may respond to climate change by emitting different species under different environmental conditions. At the global scale, a large fraction of the aerosol number concentration is formed by nucleation of low-volatility gas-phase compounds, a process that is expected to ultimately determine the concentrations of Cloud Condensation Nuclei (CCN). Nucleation occurrence over open oceans is still debated, due to scarce observational data sets and instrumental limitations, although our recent findings suggest biologically driven nucleation from seawater emissions. Marine aerosol can also be emitted to the atmosphere as primary particles via bubble bursting, among which living microorganisms are suspected to act as excellent ice nuclei (IN) and impact clouds precipitation capacities. The main goal of this proposal is to investigate how marine emissions from living microorganisms can influence CCN, IN and ultimately cloud properties. We will investigate the whole process chain of gas-phase emissions, nucleation and growth through the atmospheric column, and impact on the CCN population. We will also quantify marine primary bioaerosol emissions and evaluate how they impact IN and cloud precipitation capabilities. Experiments will be performed in the Southern Hemisphere, especially sensitive to the natural aerosol concentration variability. We will use an original approach of field mesocosms enclosing the air-sea interface, to link marine emissions to the biogeochemical properties of natural seawater, combined with ambient aerosol measurements simultaneously at low and high altitude sites. At last, a modelling study will help merging process studies and ambient measurements, and assess the role of biologically driven marine emissions on cloud properties.

1 999 329 €

Start date: 2018-07-01, End date: 2023-06-30

Seismic tremors form a broad class of signals generated by internal sources that are different from regular earthquakes. Volcanic tremors have been known for a long time, and tectonic tremors associated with seismogenic fault zones have been described more recently. While the physical origin of seismic tremors remains to be fully understood, they are related to slow transient energy release processes that occur in active geological systems during the accumulation of mechanical energy that is then released during catastrophic events, such as strong earthquakes or volcanic eruptions. Therefore, seismic tremors represent a unique source of information that can be used to understand the physics of these ‘preparation’ processes and to design new monitoring and forecasting approaches. Modern digital seismological networks record huge numbers of tremors in different active regions, and breakthroughs can be achieved with systematic exploration of these observations that includes data analysis and physical modeling. My goal is to undertake such an effort via the development of a new unified framework for the study of seismic tremors. I plan to combine advanced methods for data mining, signal processing, and numerical simulations of the generating processes, to apply these to different large datasets of volcanic and tectonic tremors. I will develop an innovative and holistic approach based on massive analysis of observations that requires high performance computing and will be combined with advanced physical modeling of the generating dynamical processes. This will produce the new framework that can be used on the one hand for an understanding of the physical tremor-generating mechanisms, and on other hand for the development of new adaptive methods for monitoring volcanoes and seismic faults. The implementation of these will involve machine learning approaches to gain information from continuous fluxes of data from dense seismological networks.

2 490 000 €

Start date: 2019-01-01, End date: 2023-12-31

Silver was the primary metal of economic exchange and military finances in ancient Mediterranean and Near-Eastern societies. Silver isotopes will help quantify monetization of these societies by identifying Ag mineral sources, monetary sinks, and its major transfer routes. High-precision stable Ag isotope analysis initiated in Lyon has shed new light on the provenance of silver coinage. This is because Ag isotopes are distinctive of coinage’s intrinsic value in contrast to traditionally-used Pb and Cu isotopes, which may characterize impurities or additives. The common belief that PbS (galena) ores accounted most of the silver mined in the antique world will be tested. We will extract Ag from ores around the Mediterranean and test PbS prevalence over As and Sb sulfosalts and low-temperature ores with Ag, Cu, and Pb isotopes and trace elements. Our work will address major questions: (i) understand the sources of unminted silver as a precursor to coinage; (ii) use Ag isotope fingerprinting of the earliest coinages of Athens to identify the contributions of Greek mines to the development of the world’s first democracy; (iii) map the Greek and Persian mines which sourced the treasure captured by Alexander the Great, and investigate the spread of its silver; (iv) study the causes of the monetary reform of the Roman Republic in 211 BC; and (v) model the silver cycle from mines to coinage and artefacts in its economic context. In the short term this project represents radical scientific innovation, which will pave the way for a global and quantitative understanding of the history of monetary development in the ancient Mediterranean. In the long term, it will contribute to the emergence of a community of analysts, numismatists and economic historians with shared expertise about the monetization of ancient societies and their management of precious metal resources.

2 496 243 €

Start date: 2017-10-01, End date: 2022-09-30

The goal of the project is to take a major step in improving the detection and understanding of landslides and their modelling at the field scale through the analysis of generated seismic waves. The seismic signal generated by landslides (i. e. landquakes) provides a unique tool to estimate the properties of the flow and its dynamics. Indeed, the stress applied by the landslide to the ground, which generates seismic waves, is highly sensitive to the flow history and therefore to the physical properties during mass emplacement. The strategy will be to combine a very accurate description of the landslide source, and the simulation and measurements of landquakes from the laboratory to the natural scale, by leading an ambitious interdisciplinary project involving numerical modelling, laboratory experiments and observation. The methodology will be to (1) develop thin layer models for granular flows over a complex 3D topography to alleviate the high computational costs related to the description of the real topography, taking into account the static/flowing transition and the fluid/grains mixture, both playing a key role in natural flows; (2) simulate the generated seismic waves by coupling landslide models to state-of-the-art wave propagation models. An ambitious objective will be to develop efficient coupling methods; (3) develop laboratory experiments of seismic emissions generated by granular flows to test the models and understand the physical processes at work; (4) analyse, simulate and invert natural landquakes making use of underexploited high-quality seismic and geomorphological data, in particular on volcanoes. An ultimate objective will be to design a new generation of landslides models, reliable methods and operational tools for detection of gravitational flows, and interpretation of seismic data in terms of landslide properties. This tools will be transferred to the scientific community and to the observatories in charge of monitoring landslide activity.

1 999 241 €

Start date: 2014-05-01, End date: 2020-04-30

Identifying Archean fossil remains from the Earth’s early biosphere is ambitious and determining the biological origin and the associated metabolic pathways present in these fossils is one outstanding question in the bigger quest of how life evolved on Earth. Stromatolites and Microbially Induced Sedimentary Structures (MISS) are considered as one of the earliest evidence of Life in Earth’s history, and can be found from the Archean to the present time. Stromatolites are “attached laminated, sedimentary growth structure accretionary away from a point of initiation”, and their morphological comparison with actual structure prevail for assessing the microbial origin of ancient stromatolite in the geological record. However, experimental studies have shown that abiotic precipitation can also form structures with a similar morphology. Therefore stable isotope proxies have been used to identify past microbial metabolisms even if abiotic processes can also produce similar isotope composition. Therefore new biogenicity criteria are needed to be determined by studying modern and ancient stromatolites and by comparing them to abiotic experiment. Stromatolites and MISS contain submicrometer sulfides (pyrite) that can have recorded large isotopic variations, interpreted as reflecting the influence of various microbial metabolisms like microbial sulfate reduction and iron respiration. STROMATA proposes to define new criteria based on actual stromatolite and to test the earliest traces of life by studying in situ these nano-pyrites in various emblematic and well-characterized samples from the Archean. STROMATA will be the first far-reaching scientific in situ study of nano-pyrite in ancient (3.4 to 1.9 Ga) and modern microbial mats and stromatolites and will compare the results with experimentally produced abiotic pyrite. Due to the small scale of the pyrite, STROMATA will develop an original in situ approach by combining state of art techniques, SIMS, NanoSIMS, FEG-TEM, XANES.

1 060 250 €

Start date: 2018-02-01, End date: 2023-01-31

The Plate Tectonics Theory is the most important discovery in all of earth sciences. It is based on the concept of plates (lithosphere) that float over the asthenosphere. Although the lithosphere is a basic building block of the plate tectonics theory, its nature, its thickness, its boundary with the asthenosphere (LAB) are still matter of heated debates. Here we propose to image the LAB and internal structure of the lithosphere at a very high-resolution using a combination of different geophysical methods in a systematic manner across the Atlantic Ocean (Trans-Atlantic) for a lithosphere of 0-100 Ma age. Along with using seismological and magnetotelluric methods, we propose to use a technology newly developed for the oil and gas exploration that is capable of providing a seismic reflection image down to 120 km depth with a few hundred metres resolution, resolving the controversy on the formation and evolution of the oceanic lithosphere once and for all, filling the gap between seismological and seismic reflection methods, opening up a new frontier of research, and creating synergy between academic and industrial research to address fundamental scientific problems. These new seismic data should also provide images of melt lenses in the mantle beneath the spreading centre axis, if present, which will help us to build a new model of melt generation and migration from the mantle. We should also be able to image deep penetrating faults that might have been generated due to the cooling of the lithosphere as it moved away from the spreading centre, allowing the development of a new model of hydration of the oceanic lithosphere, which would be extremely valuable for the understanding of the earthquake process at subduction zones. The imaging of the structure down to 120 km in an oceanic environment would be a major breakthrough, and likely to open up new horizons for deep seismic imaging.

3 499 900 €

Start date: 2014-11-01, End date: 2019-10-31

The objective of project VOLATILIS is to investigate the origin(s) of volatile elements on Earth and other planetary bodies in the inner Solar System. Since primitive and differentiated asteroids, planetary embryos, and the Earth-Moon system represent different stages of planet formation, studies of chondritic meteorites and samples from Vesta, Mars, the Moon, and Earth can provide constraints on the evolution of planetary volatiles from primordial to present-day compositions. However, indigenous volatiles in extraterrestrial samples are often masked by solar and cosmogenic contributions. Only combined analyses of noble gases and other volatiles (N, H) allow the observed volatile signatures to be resolved into constituent components (atmospheric, solar, cosmogenic, indigenous). The Centre de Recherches Pétrographiques et Géochimiques (Nancy, France), the PI’s host institute, is the only laboratory that is equipped with static noble gas mass spectrometers for coupled N-noble analyses of small-sized samples, and with two secondary ionization mass spectrometers for non-destructive volatile element measurements. By coupling these high-precision analytical techniques, we will be able to reliably characterize indigenous planetary volatiles, and to assess the importance of volatile storage during primary accretion or late addition via comets and meteorites. Furthermore, we aim to develop the protocols for N isotope analysis by ion microprobe and by static mass spectrometry in multi-collection mode; these methods will allow us to target micron-sized samples (such as melt inclusions) for N analyses and to improve the analytical precision for coupled N-noble gas studies, respectively. The new data obtained here can be integrated as critical parameters into geochemical and astrophysical models of volatile accretion and fluxes in the inner Solar System, and they are expected to be of great interest to the geo-/cosmochemistry, astrophysics, and astrobiology communities.

1 396 300 €

Start date: 2017-02-01, End date: 2022-01-31

Since January 2011, the PI holds a faculty position at the Collège de France, this proposal will facilitate transferring and re-establishing her research program at IPG in Paris. The goal of the proposed research program is to investigate earth’s deep structure and dynamics using advanced seismological forward and inverse modeling techniques. The primary focus is on global and continental scale mantle structure, with a secondary focus on the earth’s core. The primary objective is to develop high resolution three-dimensional models of the present day thermal and compositional structure of the mantle through the development of forward and inverse seismic waveform modeling approaches. This will be pursued along two directions that will eventually be combined: (a) Using a spectral-element-based seismic waveform modeling approach, develop high resolution seismic models of 3D elastic, isotropic and anisotropic , and anelastic structure of the earth’s mantle, with particular emphasis at the global scale on the lower mantle and, at the tectonic plate scale, on lithosphere-asthenosphere structure; (b) Develop an approach to invert full seismic waveforms, combined with other seismic constraints (such as travel times and normal mode eigenfrequencies) directly for 3D thermal and compositional structure of the mantle, using the best available constraints from mineral physics and geodynamics. A secondary objective is to constrain inner core structure and anisotropy using a combination of free oscillation splitting measurements and travel times and amplitudes of inner core sensitive body waves, with the goal of better characterizing the mantle versus inner core origin of observed anomalies currently attributed to inner core anisotropy.

2 499 198 €

Start date: 2011-06-01, End date: 2017-05-31