Moytirra: Discovery of the first known deep‐sea hydrothermal vent field on the slow‐spreading Mid‐Atlantic Ridge north of the Azores. (16th October 2013)

• Record Type: Journal Article
• Authors: Wheeler, A. J.; Murton, B.; Copley, J.; Lim, A.; Carlsson, J.; Collins, P.; Dorschel, B.; Green, D.; Judge, M.; Nye, V.; Benzie, J.; Antoniacomi, A.; Coughlan, M.; Morris, K.
• Is Part Of: Geochemistry, geophysics, geosystems. Volume 14:Number 10(2013)
• Page Start: 4170
• Page End: 4184
• Publication Date: 2013-10-16
• Subjects: Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 550.5
• DOI: 10.1002/ggge.20243
• Languages: English
• ISSNs: 1525-2027

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>[1] Geological, biological, morphological, and hydrochemical data are presented for the newly discovered Moytirra vent field at 45<sup>o</sup>N. 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 (<italic>Peltospira</italic> sp.) and populations of alvinocaridid shrimp (<italic>Mirocaris</italic> sp. with <italic>Rimicaris</italic> sp. also present). Other fauna present include bythograeid crabs (<italic>Segonzacia</italic> sp.) and zoarcid fish (<italic>Pachycara</italic> 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.</p> </abstract>