New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR)
The internal structure of Seafloor Massive Sulfides (SMS) deposits is one of the most important and complex issues facing the study of modern hydrothermal ore systems. The Semenov-5 hydrothermal field is a unique area where mass wasting on the slope of the oceanic core complex (OCC) structure expose...
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MDPI AG
2022-12-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/12/1593 |
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| author | Anna Firstova Georgy Cherkashov Tamara Stepanova Anna Sukhanova Irina Poroshina Victor Bel’tenev |
| author_facet | Anna Firstova Georgy Cherkashov Tamara Stepanova Anna Sukhanova Irina Poroshina Victor Bel’tenev |
| author_sort | Anna Firstova |
| collection | DOAJ |
| description | The internal structure of Seafloor Massive Sulfides (SMS) deposits is one of the most important and complex issues facing the study of modern hydrothermal ore systems. The Semenov-5 hydrothermal field is a unique area where mass wasting on the slope of the oceanic core complex (OCC) structure exposes the subsurface portion of the deposit and offers an exceptional opportunity to observe massive sulfides that have formed not only on the seafloor but in sub-seafloor zones as well. This paper examines the internal structure of the OCC-related Semenov-5 hydrothermal field along with analysis of the mineralogy and chemistry of different parts of sulfide deposit. The seafloor deposit is comprised of pyrite, marcasite, hematite, goethite, lepidocrocite, rare pyrrhotite, isocubanite and Co-rich pyrite. Sulfide chemistry indicates the prevailing influence of ultramafics on their composition irrespective of the spatial relation with basalt lavas. Sub-seafloor mineralization is associated with ultramafic rocks and is represented by massive and disseminated sulfides. Pyrrhotite, isocubanite, pyrite, chalcopyrite, Co-rich pyrite, quartz with rutile, quarts with hematite and Cr-spinels are fixed in massive subseafloor mineralization. The presence of Cr-spinels as well as a very high Cr content are regarded as indicators of the metasomatic nature of this part of the deposit that had formed as a result of ultramafic replacement. As a result, three zones of a hydrothermal ore-forming system have been described: massive sulfides precipitated from hot vents on the surface of the seafloor, massive sulfides formed due to replacement of ultramafics below the seafloor and disseminated sulfide mineralization-filled cracks in hosted rocks which have formed stockwork around metasomatic massive sulfides. Despite differences in the mineral and geochemical composition of sub-seafloor and seafloor mineralization, all minerals subject to the sample formed as a consequence of fluid circulation in ultramafic rocks and were linked by a common ore-forming process. |
| first_indexed | 2024-03-09T16:04:37Z |
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| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T16:04:37Z |
| publishDate | 2022-12-01 |
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| series | Minerals |
| spelling | doaj.art-d3ca47701cc3463185de89cb50f530e02023-11-24T16:52:25ZengMDPI AGMinerals2075-163X2022-12-011212159310.3390/min12121593New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR)Anna Firstova0Georgy Cherkashov1Tamara Stepanova2Anna Sukhanova3Irina Poroshina4Victor Bel’tenev5Institute for Geology and Mineral Resources of the Ocean (FSBI “VNIIOkeangeologia”), 1 Angliisky Ave., 190121 St. Petersburg, RussiaInstitute for Geology and Mineral Resources of the Ocean (FSBI “VNIIOkeangeologia”), 1 Angliisky Ave., 190121 St. Petersburg, RussiaInstitute for Geology and Mineral Resources of the Ocean (FSBI “VNIIOkeangeologia”), 1 Angliisky Ave., 190121 St. Petersburg, RussiaInstitute for Geology and Mineral Resources of the Ocean (FSBI “VNIIOkeangeologia”), 1 Angliisky Ave., 190121 St. Petersburg, RussiaInstitute for Geology and Mineral Resources of the Ocean (FSBI “VNIIOkeangeologia”), 1 Angliisky Ave., 190121 St. Petersburg, RussiaInstitute for Geology and Mineral Resources of the Ocean (FSBI “VNIIOkeangeologia”), 1 Angliisky Ave., 190121 St. Petersburg, RussiaThe internal structure of Seafloor Massive Sulfides (SMS) deposits is one of the most important and complex issues facing the study of modern hydrothermal ore systems. The Semenov-5 hydrothermal field is a unique area where mass wasting on the slope of the oceanic core complex (OCC) structure exposes the subsurface portion of the deposit and offers an exceptional opportunity to observe massive sulfides that have formed not only on the seafloor but in sub-seafloor zones as well. This paper examines the internal structure of the OCC-related Semenov-5 hydrothermal field along with analysis of the mineralogy and chemistry of different parts of sulfide deposit. The seafloor deposit is comprised of pyrite, marcasite, hematite, goethite, lepidocrocite, rare pyrrhotite, isocubanite and Co-rich pyrite. Sulfide chemistry indicates the prevailing influence of ultramafics on their composition irrespective of the spatial relation with basalt lavas. Sub-seafloor mineralization is associated with ultramafic rocks and is represented by massive and disseminated sulfides. Pyrrhotite, isocubanite, pyrite, chalcopyrite, Co-rich pyrite, quartz with rutile, quarts with hematite and Cr-spinels are fixed in massive subseafloor mineralization. The presence of Cr-spinels as well as a very high Cr content are regarded as indicators of the metasomatic nature of this part of the deposit that had formed as a result of ultramafic replacement. As a result, three zones of a hydrothermal ore-forming system have been described: massive sulfides precipitated from hot vents on the surface of the seafloor, massive sulfides formed due to replacement of ultramafics below the seafloor and disseminated sulfide mineralization-filled cracks in hosted rocks which have formed stockwork around metasomatic massive sulfides. Despite differences in the mineral and geochemical composition of sub-seafloor and seafloor mineralization, all minerals subject to the sample formed as a consequence of fluid circulation in ultramafic rocks and were linked by a common ore-forming process.https://www.mdpi.com/2075-163X/12/12/1593seafloor massive sulfidesMid-Atlantic Ridgehydrothermal processesmass wasting landslide processesreconstruction model |
| spellingShingle | Anna Firstova Georgy Cherkashov Tamara Stepanova Anna Sukhanova Irina Poroshina Victor Bel’tenev New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR) Minerals seafloor massive sulfides Mid-Atlantic Ridge hydrothermal processes mass wasting landslide processes reconstruction model |
| title | New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR) |
| title_full | New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR) |
| title_fullStr | New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR) |
| title_full_unstemmed | New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR) |
| title_short | New Data for the Internal Structure of Ultramafic Hosted Seafloor Massive Sulfides (SMS) Deposits: Case Study of the Semenov-5 Hydrothermal Field (13°31′ N, MAR) |
| title_sort | new data for the internal structure of ultramafic hosted seafloor massive sulfides sms deposits case study of the semenov 5 hydrothermal field 13°31 n mar |
| topic | seafloor massive sulfides Mid-Atlantic Ridge hydrothermal processes mass wasting landslide processes reconstruction model |
| url | https://www.mdpi.com/2075-163X/12/12/1593 |
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