At the core of the ABYSS research programme are cross-disciplinary research projects to address specific scientific challenges by combining: case studies of well-chosen target areas; specifically designed laboratory experiments and measurements; and numerical modelling, with a special focus on the multi-scalar integration of the results. Each project involves at least two different disciplinary approaches and will be co-supervised by senior scientists from different institutions via secondments. These research projects form two research-based work packages, which are centered on better understanding of the linkages between the magmatic, hydrothermal and biotic processes that control the formation and alteration of oceanic lithosphere. Each Work Package is structured as a suite of Individual Research Project; each project provides a training position for either an ESR who will pursue a PhD, or an ER following a postdoctoral research programme.
- Dynamic melt-rock interactions: building the oceanic lithosphere (WP3)
The formation of the oceanic lithosphere is controlled by melt transport from the mantle to the surface, which in turn, controls the structure of the lithosphere by two competitive processes: the conduction and advection of heat from depth, and cooling by conduction and hydrothermal circulation.
Three research projects are dedicated to better constrain melt focusing toward the spreading ridges and melt accumulation processes at and across the mantle-crust boundary, and more particularly, to determine the role of fractional crystallization and reactive porous melt flow in the formation of lower oceanic crust, and the control such processes exert on melt evolution in the oceanic crust using laboratory experiments (ESR1) and field-based studies (ESR2 and ESR3). Two projects aim to develop new criteria to better constrain the cooling of the newly-formed lithosphere and hydrothermal – magmatic interactions, by combining geochemical tools and experimental and field approaches (ESR4 and ESR5). The extent and efficiency of heat transport by hydrothermal circulation during the cooling and crystallization of magma within the lower oceanic crust remains one of the greatest unknowns in our understanding of mid-ocean ridge formation processes, and must control the size and distribution of magma chambers, as well as the magnitude of chemical exchange fluxes. ER1 builds on the expertise, methods and approaches developed in the ITN to improve exploration models and methods for future discovery of unexposed onshore and offshore ore-deposits.
- Cracks, fluxes & fluid-rock interactions: alteration of the oceanic lithosphere (WP4)
Circulation of seawater within the cooling oceanic lithosphere is of critical importance in elemental and heat exchange budgets on Earth. A large set of complex and interrelated physical and chemical processes govern how much and where in the system reaction between fluid and rock takes place. The types of reaction include carbonation (CO2 sequestration), hydrogen production (energy generation), and various reactions in the source-to-trap processes that lead to the formation of ore-deposits. Understanding the fluid-rock interactions more comprehensively is crucial in assessing the potential use of the ocean floor as a resource and in appreciating the role life sustained by these interactions in Earth’s geochemical cycles. ESR6, ESR7 and ESR8 explore the couplings between chemical, mechanical and hydrodynamic processes as well as the effect of transport, and fluid and rock compositions on rates and products of reactions in hydrothermal open systems. Using experimental and observational approaches, ESR8, ESR9 and ESR10 examine carbonation processes, and ESR10 and ESR11 investigate abiotic and biotic forms of carbon and carbon mineralization in hydrothermally altered mantle rocks. Mapping serpentinization reactions and developing geophysical tools needed in prospecting deposits tied to ultramafic rocks is the goal of ESR12. The last two projects require synthesis skills and numerical modelling, and these are consequently best carried out by Experienced Researchers with advanced specialist knowledge. ER2 will combine 3D microanalyses of reacted samples (in collaboration with WP4 participants) and numerical approaches to develop pore-scale models allowing to predict the linkages between chemical and transport processes during open system reactions. ER3 will combine reactive flow experiment and advanced isotope geochemistry to test and calibrate the isotopic tools commonly used today to determine the extent of fluid flow during the hydration of the oceanic lithosphere.