Description du projet
Une nouvelle approche pour mesurer la vitesse d’altération des roches et de réduction du CO2
La transformation naturelle des roches en sol par voie d’altération chimique régule le CO2 atmosphérique. Bien que le basalte et le carbonate soient particulièrement bien altérés, les techniques actuelles de mesure de la vitesse s’avèrent inefficaces sur ces types de roches. Le projet DEVENDRA, financé par le CER, fera figure de pionner scientifique en créant un système universel de mesure de la vitesse d’érosion et d’altération fondé sur la comparaison des isotopes du béryllium. Pour ce faire, il utilisera différents échantillons de sols et de bassins hydrographiques afin de déterminer les lois régissant l’altération lithologique et la réduction du CO2. Cette approche permettra d’obtenir une quantification fine du cycle mondial du carbone à des échelles de temps géologiques et offrira une extrapolation du devenir des émissions de CO2 d’origine anthropique au cours des siècles à venir. Le projet facilitera également l’évaluation de la réduction active du CO2 par une altération améliorée artificiellement à l’aide de basalte.
Objectif
The chemical weathering of rocks on the Earth’s surface draws down atmospheric CO2, balancing emissions from volcanoes and maintaining habitable temperatures. Basalt and carbonate rocks are particularly crucial in this balance, because they are efficiently weathered: as estimated from studies of the dissolved elements in rivers, basalt accounts for 20-35% of modern global silicate weathering and CO2 consumption flux, despite only covering 5% of Earth’s surface. To formulate sensitivities and feedbacks between weathering of these rocks and climate, we need an accurate description of the exact processes that drive the conversion of rock to soil by weathering. Besides water flow, erosion rate and vegetation are thought to exercise significant control. Currently, however, we lack the tools needed to decipher these controls, because the preferred approach used to quantify erosion and weathering rates – cosmogenic nuclides, produced in situ in quartz – does not work in basalt and carbonate lithologies. The aim of DEVENDRA, dedicated to the pioneer of cosmogenic nuclide geochemistry Devendra Lal (1920 – 2012), is to eliminate this blind spot using a novel method never applied to basalt and carbonate lithologies: the ratio of cosmogenic beryllium-10 rained out from the atmosphere to stable beryllium-9 released by weathering. DEVENDRA will develop this system as a novel erosion and weathering rate meter for these rocks, and will use this new method to calibrate – using globally-distributed soil profiles and catchments of differing climate and erosion rate – the laws that govern weathering and CO2 drawdown in these rocks. The outcomes from DEVENDRA will refine the global weathering models that are used to understand Earth’s carbon cycle on geological time scales, to predict the trajectory of anthropogenic CO2 in coming centuries, and to estimate the potential for negative CO2 emissions by artificially-enhanced weathering of basalts.
Champ scientifique
- natural sciencesearth and related environmental sciencesgeologylithology
- natural sciencesearth and related environmental sciencesgeochemistry
- natural scienceschemical sciencesinorganic chemistryinorganic compounds
- natural sciencesearth and related environmental sciencesgeologyvolcanology
- social scienceslaw
Programme(s)
- HORIZON.1.1 - European Research Council (ERC) Main Programme
Thème(s)
Régime de financement
HORIZON-ERC - HORIZON ERC GrantsInstitution d’accueil
14195 Berlin
Allemagne