ERC FUNDED PROJECTS

This proposal wishes to fundamentally improve our understanding of the role of tropical freshwater ecosystems in carbon (C) cycling on the catchment scale. It uses an unprecedented combination of state-of-the-art proxies such as stable isotope, 14C and biomarker signatures to characterize organic matter, radiogenic isotope signatures to determine particle residence times, as well as field measurements of relevant biogeochemical processes. We focus on tropical systems since there is a striking lack of data on such systems, even though riverine C transport is thought to be disproportionately high in tropical areas. Furthermore, the presence of landscape-scale contrasts in vegetation (in particular, C3 vs. C4 plants) are an important asset in the use of stable isotopes as natural tracers of C cycling processes on this scale. Freshwater ecosystems are an important component in the global C cycle, and the primary link between terrestrial and marine ecosystems. Recent estimates indicate that ~2 Pg C y-1 (Pg=Petagram) enter freshwater systems, i.e., about twice the estimated global terrestrial C sink. More than half of this is thought to be remineralized before it reaches the coastal zone, and for the Amazon basin this has even been suggested to be ~90% of the lateral C inputs. The question how general these patterns are is a matter of debate, and assessing the mechanisms determining the degree of processing versus transport of organic carbon in lakes and river systems is critical to further constrain their role in the global C cycle. This proposal provides an interdisciplinary approach to describe and quantify catchment-scale C transport and cycling in tropical river basins. Besides conceptual and methodological advances, and a significant expansion of our dataset on C processes in such systems, new data gathered in this project are likely to provide exciting and novel hypotheses on the functioning of freshwater systems and their linkage to the terrestrial C budget.

1 745 262 €

Start date: 2009-10-01, End date: 2014-09-30

Dikes and sills are large sheet-like intrusions transporting and storing magma in the Earth’s crust. When propagating, they generate seismicity and deformation and may lead to volcanic eruption. The physics of magma-filled structures is similar to that of any fluid-filled reservoir, such as oil fields and CO2 reservoirs created by sequestration. This project aims to address old and new unresolved challenging questions related to dike propagation, sill emplacement and in general to the dynamics of fluid and gas-filled reservoirs. I propose to focus on crustal deformation, induced seismicity and external stress fields to study the signals dikes and sills produce, how they grow and why they reactivate after years of non-detected activity. I will combine experimental, numerical and analytical techniques, in close cooperation with volcano observatories providing us with the data necessary to validate our models. In the lab, I will simulate magma propagation injecting fluid into solidified gelatin. I will also contribute to a project, currently under evaluation, on the monitoring of a CO2 sequestration site. At the same time, I will address theoretical aspects, extending static models to dynamic cases and eventually developing a comprehensive picture of the multi faceted interaction between external stress field, magma and rock properties, crustal deformation and seismicity. I also plan, besides presenting my team’s work in the major national and international geophysical conferences, to produce, with technical support from the media services of DKRZ (Deutsches Klimarechenzentrum), an audiovisual teaching DVD illustrating scientific advances and unresolved issues in magma dynamics, in the prediction of eruptive activity and in the physics of reservoirs.

1 507 679 €

Start date: 2010-07-01, End date: 2015-06-30

Crustal magmatism is periodic on a very wide range of timescales from pulses of continental crustal growth, through formation of granite batholiths, to eruptions from individual volcanic centres. The cause of this periodicity is not understood. I aim to address this long-standing geological problem through a combination of experiments, petrological methods and numerical models via a novel proposal that periodicity arises because of the highly non-linear ( critical ) behaviour of magma crystallinity with temperature in a series of linked crustal magma reservoirs. The ultimate objective is to answer five fundamental questions: " Why is crustal magmatism episodic? " How are large batholiths formed of rather similar magmas over long periods of time? " How do large bodies of eruptible magma develop that can lead to huge, caldera-forming eruptions? " What controls the chemistry of crustal magmas? Why are some compositions over-represented relative to others? " What is the thermal structure beneath volcanic arcs and how does it evolve with time? The project will address these questions through case studies of three contrasted active volcanoes: Nevado de Toluca, Mexico; Soufriere St Vincent, Lesser Antilles; and Mount Pinatubo, Philippines. For each volcano I will use experimental petrology to constrain the phase relations of the most recently erupted magma as a function of pressure, temperature, volatile content and oxygen fugacity in the shallow, sub-volcanic storage region. I will also carry out high-pressure phase equilibria on coeval Mg-rich basaltic rocks from each area with the aim of constraining the lower crustal conditions under which the shallow magmas were generated and use diffusion chronometry to constrain the frequency of magmatic pulses in the sub-volcanic reservoirs. The project will result in a quantum leap forwards in how experimental and observational petrology can be used to understand magmatic behaviour beneath hazardous volcanoes

2 959 518 €

Start date: 2010-04-01, End date: 2015-03-31

Volcanism, is a vital factor in the Earth system. Molten silicates are a major transport agent in the differentiation and interaction of lithosphere, hydrosphere, atmosphere, and biosphere. Further, the immediate consequences of volcanic eruptions on all scales - local, regional and global - are issues of direct practical relevance to mankind as they are measured in lives, infrastructure and the environment. Volcanism is the result of a complex interplay of physico-chemical processes operating at varying efficiencies during ascent, differentiation and eruption of magma. As a result, volcanic phenomena span a range from effusive to explosive. The largest explosive events are repeatedly responsible for global impact on the Earth System, yet it is precisely these events that, due to their explosive character, are relatively inaccessible for direct scientific investigation. A major opportunity in accessing such systems has been provided by recent technological advances permitting the experimental investigation of volcanism. Experimental volcanology operates directly under volcanic conditions of time, pressure, temperature, and state; a near-unique opportunity in the solid earth sciences. Based on experimental volcanology, this project aims to provide mechanistic models of magmatic/volcanic processes and their impact on the Earth System. Four priority areas are selected as those needing most urgent attention. These are: 1) Quantification of the rheology of magma/lava for parameterisation of stress-strain relationships in numerical simulations of eruptive events. 2) Mechanistic understanding explosive failure of magma for the interpretation of volcanic hazard monitoring. 3) Development of quantitative methods for inferring eruptive physics from the physico-chemical fossil records (thermal, magnetic, chemical) preserved in volcanic lavas. 4) Experimental characterisation of the physical, chemical and biological properties and impact of volcanic ash on the earth system.

2 991 058 €

Start date: 2010-04-01, End date: 2017-07-31