BIBLIOS

Tipo
Artigos em Conferência

Tipo de Documento
Resumo

Título
Sediment geochemistry reveals abundant off-axis hydrothermal fields on the ultraslow-spreading Southwest Indian Ridge

Participantes na publicação
Liao, Shili (Author)
Tao, C (Author)
Dias, Ágata Alveirinho (Author)
Dep. Geologia
IDL
Jamieson, John W (Author)

Resumo
Inactive hydrothermal fields on mid ocean ridges prefers accumulate large sulfide deposits and are important potential habitant for reduced iron and sulfur sourced ecosystem. However, their abundance remains poorly constrained, largely because current estimates were mostly based on known and active fields associated with buoyant plumes. In this study, we present the first reported abundance of off-axis inactive fields along four segments of the ultraslow-spreading Southwest Indian Ridge, based on systematic sediment geochemistry survey. We found distinct disperse pattens of hydrothermal Cu and Zn between magmatic- and detachment fault- controlled, that likely attributed to multiple factors, including variable physicochemical conditions of the hydrothermal plume, seafloor topography and bottom current direction. Up to 15 potential fields and their approximate locations were identified by the dispersion distance of hydrothermal Zn, Cu, and Fe. Among these fields, 8-14 are located off-axis, and 3-7 of the off-axis fields are likely newly identified inactive fields. After this study, two of the newly identifide fields were confirmed by TV-grab sampling. These identified fields were likely still active within the last 10ka, and more than 60% of them were controlled by detachment faults. Consequently, our results suggested the occurrence frequency of inactive fields is at least 2 times higher than previously reported active ones within 40km axial zone of the studied segments, thus largely increases estimates of sulfide resources on ultraslow spreading ridges. As the studied sediments represent only the last 10 ka, significantly more buried inactive hydrothermal fields would be expected to be identified over longer time intervals. Our study establishes a robust method for identifying the possible number and approximate location of inactive hydrothermal fields through the systematic survey of sediment geochemistry, and benefits sulfide resource estimations on ancient seafloor in the ocean.


Evento
Goldschmidt

Identificadores da Publicação