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GEOREF RECORD

Mineralogy of massive sulfides from the Ashadze hydrothermal field, 13 degrees N, Mid-Atlantic Ridge

Nadezhda N. Mozgova, Nikolay V. Trubkin, Yuri S. Borodaev, Georgy A. Cherkashev, Tamara V. Stepanova, Tatiana A. Semkova and Tatiana Yu. Uspenskaya
Mineralogy of massive sulfides from the Ashadze hydrothermal field, 13 degrees N, Mid-Atlantic Ridge
The Canadian Mineralogist (June 2008) 46 (3): 545-567

Abstract

The ultramafic-rock-hosted and active Ashadze submarine hydrothermal field, located at a depth of 4100-4200 m at 13 degrees N along the Mid-Atlantic Ridge, was discovered and sampled by dredge and grab sampler at four stations in 2003, on the 22 (super nd) cruise of RV "Professor Logatchev". Recovered material included fragments of sulfide chimneys, massive and veinlet-disseminated ore assemblages, sulfide breccia and mineralized peridotite. Preliminary investigations of the field suggested a zonal structure, which was confirmed by further laboratory investigations. A mineralogical study was carried out, using EMPA and SEM/EMD (280 analyses). Data on the morphology and composition of the principal sulfides indicate non-equilibrium conditions of submarine formation of the minerals. The following main characteristics of the massive sulfides in the Ashadze field were established: 1) varied morphologies of the main sulfide minerals (pyrrhotite, sphalerite, chalcopyrite, isocubanite, pyrite and chalcocite). 2) Variations occur in the composition of the main sulfide minerals. Concentrations of minor elements are much higher than the amounts estimated experimentally in corresponding systems under equilibrium conditions, but may also depend on mineral associations. 3) Temporal and spatial transformations of minerals were observed and are reflected by pseudomorphs (most commonly after pyrrhotite grains) and exsolution phenomena in various solid-solutions. For the first time, an exsolution texture was found in phase Y (Cu (sub 2) FeS (sub 5) ) along with that in isocubanite and bornite. The latter transformations occur as a result of microfacies zoning of chimney walls.


ISSN: 0008-4476
EISSN: 1499-1276
Coden: CAMIA6
Serial Title: The Canadian Mineralogist
Serial Volume: 46
Serial Issue: 3
Title: Mineralogy of massive sulfides from the Ashadze hydrothermal field, 13 degrees N, Mid-Atlantic Ridge
Affiliation: Russian Academy of Sciences, IGEM, Moscow, Russian Federation
Pages: 545-567
Published: 200806
Text Language: English
Publisher: Mineralogical Association of Canada, Ottawa, ON, Canada
References: 35
Accession Number: 2008-116912
Categories: Mineralogy of non-silicatesOceanography
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 12 tables, sketch map
N12°58'15" - N12°58'30", W44°51'54" - W44°51'30"
Secondary Affiliation: Moscow State University, RUS, Russian FederationInstitute of Geology and Mineral Resources of the World Ocean, RUS, Russian FederationShirshov Institute of Oceanology, RUS, Russian Federation
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Mineralogical Association of Canada. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200844
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