Moytirra: discovery of the first known deep-sea hydrothermal vent field on the slow-spreading Mid-Atlantic Ridge north of the Azores


Wheeler, A.J., Murton, B.J., Copley, J., Lim, A., Carlsson, J., Collins, P., Dorschel, B., Green, D., Judge, M., Nye, V., Benzie, J., Antoniacomi, A., Coughlan, M. and Morris, K. (2013) Moytirra: discovery of the first known deep-sea hydrothermal vent field on the slow-spreading Mid-Atlantic Ridge north of the Azores Geochemistry Geophysics Geosystems, 14, (10), pp. 4170-4184. (doi:10.1002/ggge.20243).

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Description/Abstract

Geological, biological, morphological, and hydrochemical data are presented for the newly discovered Moytirra vent field at 45oN. This is the only high temperature hydrothermal vent known between the Azores and Iceland, in the North Atlantic and is located on a slow to ultraslow-spreading mid-ocean ridge uniquely situated on the 300 m high fault scarp of the eastern axial wall, 3.5 km from the axial volcanic ridge crest. Furthermore, the Moytirra vent field is, unusually for tectonically controlled hydrothermal vents systems, basalt hosted and perched midway up on the median valley wall and presumably heated by an off-axis magma chamber. The Moytirra vent field consists of an alignment of four sites of venting, three actively emitting “black smoke,” producing a complex of chimneys and beehive diffusers. The largest chimney is 18 m tall and vigorously venting. The vent fauna described here are the only ones documented for the North Atlantic (Azores to Reykjanes Ridge) and significantly expands our knowledge of North Atlantic biodiversity. The surfaces of the vent chimneys are occupied by aggregations of gastropods (Peltospira sp.) and populations of alvinocaridid shrimp (Mirocaris sp. with Rimicaris sp. also present). Other fauna present include bythograeid crabs (Segonzacia sp.) and zoarcid fish (Pachycara sp.), but bathymodiolin mussels and actinostolid anemones were not observed in the vent field. The discovery of the Moytirra vent field therefore expands the known latitudinal distributions of several vent-endemic genera in the north Atlantic, and reveals faunal affinities with vents south of the Azores rather than north of Iceland.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1002/ggge.20243
ISSNs: 1525-2027 (print)
Keywords: Mid-Atlantic Ridge, hydrothermal vent, massive sulfides, vent biota, median valley fault
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Q Science > QE Geology
Q Science > QH Natural history > QH301 Biology
Organisations: Ocean and Earth Science, Marine Geoscience
ePrint ID: 359132
Date :
Date Event
16 October 2013e-pub ahead of print
October 2013Published
Date Deposited: 24 Oct 2013 08:21
Last Modified: 17 Apr 2017 14:44
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/359132

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