FN Archimer Export Format PT J TI Recent volcanic events and the distribution of hydrothermal venting at the Lucky Strike hydrothermal field, Mid-Atlantic Ridge BT AF ONDREAS, Helene CANNAT, M. FOUQUET, Yves NORMAND, Alain SARRADIN, Pierre-Marie SARRAZIN, Jozee AS 1:1;2:2;3:1;4:1;5:1;6:1; FF 1:PDG-DOP-DCB-GM-LGM;2:;3:PDG-DOP-DCB-GM-LGM;4:PDG-DOP-DCB-GM-CTD;5:PDG-DOP-DCB-EEP-LEP;6:PDG-DOP-DCB-EEP-LEP; C1 Inst Francais Rech Exploitat Mer, Ctr Brest, F-29280 Plouzane, France. Inst Phys Globe, CNRS, UMR 7154, F-75252 Paris, France. C2 IFREMER, FRANCE IPGP, FRANCE SI BREST SE PDG-DOP-DCB-GM-LGM PDG-DOP-DCB-GM-CTD PDG-DOP-DCB-EEP-LEP IN WOS Ifremer jusqu'en 2018 copubli-france IF 2.626 TC 49 TU Centre national de la recherche scientifique Institut National de l'Information Géographique et Forestière Institut de physique du globe Université Paris Diderot Université Pierre et Marie Curie Université de La Réunion UR https://archimer.ifremer.fr/doc/2009/publication-6161.pdf LA English DT Article CR EXOMAR FLORES GRAVILUCK IRIS MOMARETO MOMARSAT : MONITORING THE MID ATLANTIC RIDGE BO Unknown L'Atalante DE ;Hydrothermalism;Lava lake;Lucky Strike;Mid Atlantic Ridge AB We present new high-resolution bathymetry and backscatter data acquired in 2006 with the ROV Victor 6000 over the Lucky Strike hydrothermal field, Mid-Atlantic Ridge. As long-term monitoring of the Lucky Strike area (MoMAR project) is being implemented, these new high-resolution data offer an unprecedented view of the distribution of hydrothermal edifices, eruptive facies, and small-scale tectonic features in the Lucky Strike vent field. We show that vents located in the NW and NE correspond with wide expanses of lumpy seafloor which we interpret as primarily made of broken chimneys and sulfide edifices. They are found above scarps with relief > 50 m or on associated mass wasting deposits. By contrast, the SE and SW vents correspond with small expanses of lumpy seafloor and are located near smaller scarps which we interpret as more recent faults. Hydrothermal edifices in the SW venting area appear very recent, postdating the emplacement and faulting of the most recent lava. We propose that this difference in the age of hydrothermal edifices does not mean that hydrothermal venting itself is more recent in the southern part of the Lucky Strike field because preexisting sulfide deposits there may have been buried by recent volcanic deposits. Instead, the older edifices in the northern part of the hydrothermal field may have been allowed more time to grow because they are set above the level of recent lava flows. The formation of a lava lake is the most recent eruptive event detected at Lucky Strike. Lava drainback is evidenced by benches and lava pillars, suggesting a close connection with an underlying magma reservoir, which probably corresponds to the melt body imaged by Singh et al. (2006). We have found no evidence that this lake was active for months to decades, as lava lakes at terrestrial volcanoes. It may instead have formed as a lava pond, with successive lava flows covering the eruptive vents, as proposed for similar features at the EPR. The horizontal surface of the lake is deformed only near its southwestern shore, along a NNE-trending set of faults and fissures, which appear to control the distribution of hydrothermal chimneys. PY 2009 PD FEB SO Geochemistry Geophysics Geosystems SN 1525-2027 PU American Geophysical Union VL 10 IS 2 UT 000263173600002 BP 1 EP 18 DI 10.1029/2008GC002171 ID 6161 ER EF