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SEAHMA - Seafloor and Sub-seafloor Hydrothermal Modelling in the Azores Sea

Coordenador Científico


 

Investigador Responsável/CVARG


Resumo


​SEAHMA is a large and diverse proposal, involving many research teams. This follows the PDCTM guideline of trying to optimise heavy deep-sea cruises and equipment and concurs to the development and strengthening of a true deep-sea scientific community in Portugal. Other reasons for the scope of SEAHMA include (1) global biogeochemical cycles, a classic, extremely difficult objective and (2) attention to the deep biosphere, a novel, immensely promising field of multidisciplinary research. The teams involved in SEAHMA derive largely from the European research contracts MARFLUX/ ATJ and AMORES.

SEAHMA will focus on the most intriguing recent discoveries on the MAR near the Azores: the Rainbow and Saldanha hydrothermal fields. It will also tests models of the occurrence of this type of ultramafic-associated hydrothermal activity north of the Azores, in an attempt to widen our understanding of hydrothermalism in the whole region. Understanding sub-surface phenomena will be a major concern. Some material will be collected at the Lucky Strike site as well, for comparative purposes. The approach is a natural evolution from European projects MARFLUX-ATJ and AMORES, and relates with the InterRidge MOMAR initiative (Long Term Monitoring of the Mid-Atlantic Ridge), which selected the region of study as a target for multidisciplinary international studies for years to come.

Three main cruises and two additional cruises will take place, for extensive observations and sampling (rocks, sediments, fluids, fauna and micro fauna); geophysical surveys including sophisticated controlled source electromagnetic sounding and magnetic surveys over Mount Saldanha. This is a recently discovered hydrothermal site, partly as a result of the Portuguese/French Saldanha cruise in 1998.

Detailed study of the diffuse hydrothermal discharge at Mount Saldanha will have important bearing to the exploration of the vast, off-axis regions that host most of the hydrothermal processes in the oceanic crust, relating to international efforts such as the novel HOC project (Hydrogeology of the Oceanic Crust).

A vast array of laboratory studies will be performed on the SEAHMA samples, from macro and micro observations to comprehensive chemical and isotopic analyses, on rocks, sediments, fluids and fauna.

Among others, the SEAHMA objectives are: understanding the regional setting; monitoring an incipient hydrothermal site and understanding serpentinisation-related hydrothermal activity and mineralization, rich in Cu, Zn, Co and Ni; insight into sub-surface processes, including hydrothermal circulation, mineralization and the sub-surface biosphere; knowledge of sediment-covered diffuse discharge and its application to the exploration of off-axis areas; hydrothermal exploration of the MAR north of the Azores with emphasis on serpentinite-related hydrothermalism.


Equipa Científica/CVARG


Outros Investigadores


​F.J.A.S. Barriga, J. Relvas, I. A. Costa, I.R. Costa, M. Miranda, F. Santos, R. Nolasco (FCUL); J. Alveirinho Dias, T. Boski, J. Luís (U. Algarve).

Outras Instituições


Ficha de Projecto


SEAHMA
Seafloor and Sub-seafloor Hydrothermal Modelling in the Azores Sea
Entidade financiadora: FCT
Referência do Projecto: PDCTM1999MAR15281
Programa: Programa Dinamizador das Ciências e Tecnologias do Mar
Gestão: ICTE
Investigador Responsável: F.J.A.S. Barriga (FCUL) / Gabriela Queiroz
Duração: 2001 - 2004
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