HR: 0800h
AN: V31B-1428    [Abstracts]
TI: Ridge-Hotspot Interactions and Submarine Hydrothermal Activity: Do Seafloor Vent-Sites Even Care?
AU: Connelly, D P
EM: dpc@soc.soton.ac.uk
AF: Southampton Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AU: * German, C R
EM: cge@soc.soton.ac.uk
AF: Southampton Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AU: Evans, A J
EM: alje@soc.soton.ac.uk
AF: Southampton Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AU: Parson, L M
EM: lmp@soc.soton.ac.uk
AF: Southampton Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AB: One of the most intriguing aspects of modern hydrothermal exploration has been the divergence from the predicted abundance of hydrothermal activity along the Mid-Atlantic Ridge close to both the Iceland (anomalously low hydrothermal activity) and Azores (anomalously high hydothermal activity) hot-spots. One recent hypothesis has been that the increase in activity SW of the Azores and almost complete absence of activity along the Reykjanes Ridge may result from waxing and waning of hot-spot activity and concomitant swelling and/or fracturing of ocean crust at the ridge-axis which may perturb the abundance of deep-penetrating faults required to sustain high-temperature hydrothermal circulation. A complication of both the Iceland and Azores ridge-hotspot systems, however, is that in each case the ridge-axis shallows close to the hotspot, to depths shallower than those at which phase separation of hydrothermal vent-fluids would be expected. Consequently, variations in vent-discharge along-axis may have aliased earier plume-based studies. To remove that potential problem, new studies have been conducted along the Central Indian Ridge and on the southern Mid-Atlantic Ridge, close to and away from the Rodrigues and Ascension hotspots. In those locations, ridge morphology indicates a thermal influence from hotspot-ridge interactions without any major perturbation of ridge-axis bathymetry itself. Here, we will present an update of our understanding of hydrothermal activity along these systems, based on geochemical analysis of the overlying water column coupled with seafloor imaging, to deduce what the significance (or otherwise) of ridge-hotspot interactions upn seafloor venting may be.
DE: 8424 Hydrothermal systems (8135)
DE: 4832 Hydrothermal systems
DE: 4835 Inorganic marine chemistry
DE: 4875 Trace elements
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting