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Project Acronym: GEMMA

Project Name: GEMMA - GEMMA - improving GEodynamic Models in MAcaronesia by reconciling geodetic, geophysical and geological data

Activity years: 2022 - 2024

Funding: Fundação para a Ciência e a Tecnologia, I.P

Topic: Earth and Related Environmental Sciences - Geophysics

Budget: 249.999,99 €

Reference: PTDC/CTA-GEO/2083/2021

Host Institution: Universidade da Beira Interior (UBI)

Partners: Associação Raege Açores - Rede Atlântica De Estações Geodinâmicas E Espaciais (A-Raege-Az); FCiências.ID - Associação para a Investigação e Desenvolvimento de Ciências (Fciências.ID); Instituto Dom Luíz (IDL/FC/ULisboa)

Researchers (ISEL):
Professor Maria da Graça M. Silveira
Ciência ID: 1116-1080-16F3
Professor Pedro Manuel Fernandes Carvalho da Silva
Ciência ID: C314-1157-FD0C
Professor Mário Augusto de Andrade Moreira
Ciência ID: A214-9FF2-5978


GEMMA is a multidisciplinary research project that will produce the next generation of geodynamic models for the Macaronesian region, establishing a fundamental framework toassess and evaluate natural resources and geological hazards in the NE Atlantic. Macaronesia – which includes the mid-plate archipelagos of Madeira, the Canaries and Cape Verde,but also the Azores which is located at an active triple junction – is simultaneously the source of multiple high-impact geohazards and the ultimate expression of the enigmaticmantle-surface interactions acting in the North Atlantic, making it an excellent natural laboratory to investigate many of the processes that govern the Earth’s internal dynamics.Critically, current geodynamic models are only partially satisfactory to answer the wide diversity of geological and geophysical features observed in Macaronesia, posing realchallenges to scientists that investigate the generation mechanisms of geohazards and of the seafloor mineral and energy resources of the region. The refinement of existinggeodynamic models for this area of the North Atlantic is thus strategic for countries such as Portugal, Spain, and Cape Verde, which hold sovereignty over these volcanicarchipelagos, but are also of global interest given that the processes behind ocean island volcanism constitute one of the last frontiers in the comprehension of our Planet's internaldynamics. In this project, we plan to use the latest and improved precision of geodetic observations to monitor slow but relentless geophysical processes due to Earth dynamics.Geodetic methods can simultaneously quantify millimetre-scale horizontal and vertical changes of the Earth’s surface (GNSS) and the detection of small variations on the density ofit's interior (Gravity). When combined with other deep-earth geophysical and geological tools, geodetic observations may provide particularly powerful constraints on some of themost enigmatic aspects of the geodynamic processes that act within the crust and upper mantle, and which result in measurable topographical changes. The overarching goal ofGEMMA is thus to reconcile modern, robust geodetic observations with the latest seismic tomography & anisotropy, magnetic, geological, and structural studies, in order to test andrefine existing models for the processes acting in the region, and which include mechanisms such as plate strain, thermal subsidence, flexural loading, rifting, magmaticunderplating, volcanic uplift, and dynamic topography. In particular we plan to explore the following aspects: a. compare measured vs modeled rates of vertical motions for eachisland, at both human and geological timescales, and in response to mechanisms such as thermal, flexural (as a result of volcanic loading), tectonic subsidence (for islands on activerifts), uplift in response to magmatic underplating, rift shoulder elevation (near the Terceira Rift), volcanic inflation (if local), and dynamic topography (if regional and linked to large-scale mantle upwelling). b. refine plate strain rate maps using the horizontal component to quantify the amount of internal deformation in the oceanic domain of the Nubian plate,and in particular in the vicinities of the Azores Triple Junction; c. integrate island vertical and horizontal deformation with the latest structural seafloor mapping, to realisticallyconstrain deformation patterns and kinematic forces; d. develop new, more robust dynamic numerical models that account for topographical deformation in response to riftingand/or mantle upwelling, particularly suitable for the Azores; To address these challenges, we will capitalize and work in synergy with other ongoing projects – such as the ERC-funded UPFLOW and the FCT-funded SIGHT – in a novel onshore-offshore approach that will be the basis for a more holistic and integrative view of the mechanisms acting to shapethe topography of Macaronesia. In particular, we propose to integrate observations and analytical modeling with the latest advances in numerical modeling of geodynamic processesin order to test particular conceptual models and hypotheses that may explain the observed signals. This will allow us to simultaneously produce robust solutions to explain theobserved deformation patterns – on both the horizontal and vertical components – and gain insights on the dynamic mantle/surface processes, as well as their frontier conditions,going beyond previous studies. It is anticipated that GEMMA will thus result in novel geodynamic solutions to explain the forces and processes acting in the Macaronesian region,more robust than any before. The knowledge arising from this research will also have indirect implications to other disciplines – such as in geohazards and resources – also beingupstream of several applications in fields as diverse as navigation, engineering, and relative sea-level studies.