Petrogenetic conditions at 18°-20°N MAR; interaction between hydrothermal and magmatic systems

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doi: 10.1134/S0869591116040044
Author(s): Silantyev, S. A.; Bortnikov, N. S.; Shatagin, K. N.; Bel'tenev, V. E.; Kononkova, N. N.; Bychkova, Ya. V.; Krasnova, E. A.
Author Affiliation(s): Primary:
Russian Academy of Sciences, Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russian Federation
Other:
Russian Academy of Sciences, Institute of the Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Federation
Polar Marine Geological Exploration Expedition, Russian Federation
Volume Title: Petrology
Volume Author(s): Kurdyukov, E.
Source: Petrology, 24(4), p.336-366. Publisher: Springer Science+Business Media for Russian Academy of Sciences, MAIK Nauka/Interperiodica, Moscow, International. ISSN: 0869-5911
Note: In English. 41 refs.; illus., incl. 9 tables, sketch map
Summary: The paper presents petrological and geochemical data on mantle peridotite, basalt, and metamorphic rocks sampled in Cruise 36 of the R/V Professor Logachev at the MAR axial zone between 17° and 20° N. These data are interesting not only as providing new information on the inner structure of the oceanic crust in the still-poorly known axial MAR segment but also in the context of the fundamental problem of interaction between magmatic and hydrothermal systems in slow-spreading mid-oceanic ridges. The MAR axial zone between 17° and 20°N was determined to host both weakly and strongly depleted residual peridodites, which suggests that the degree of mantle source melting significantly varied along the ridge axis in this segment. The MAR crest zone comprises slabs of serpentinized peridotite brought to the seafloor surface at various time. The most strongly depleted mantle peridotites likely uplifted later than the mildly and weakly depleted rocks in the same areas. A mantle reservoir beneath the MAR axial zone at 20°N is not isotopically related to the mantle source of the parental MORB melts, and high-Mg metabasites exposed at 17°56'N were derived from a crustal source that was modified near the root zone of a high-temperature hydrothermal system. The studied area seems to display traces of an extinct hydrothermal field and likely an ore occurrence related to it. Copyright 2016 Pleiades Publishing, Ltd.
Year of Publication: 2016
Research Program: ODP Ocean Drilling Program
Key Words: 05 Petrology, Igneous and Metamorphic; Alkaline earth metals; Aluminum oxides; Atlantic Ocean; Basalts; Chain silicates; Chemical analysis; Crust; Dredging; Geothermal systems; Harzburgite; Hydrothermal conditions; Igneous rocks; Iron oxides; Isotope ratios; Isotopes; Kane fracture zone; Leg 106; Leg 109; Leg 153; Magmatism; Magnesium oxides; Major elements; Mantle; Mass spectroscopy; Melting; Metabasite; Metaigneous rocks; Metals; Metamorphic rocks; Metasomatic rocks; Metasomatism; Mid-Atlantic Ridge; Mid-ocean ridge basalts; Mid-ocean ridges; Mineralization; Nd-144/Nd-143; Neodymium; Nesosilicates; North Atlantic; ODP Site 648; ODP Site 649; ODP Site 669; ODP Site 670; ODP Site 920; ODP Site 921; ODP Site 922; ODP Site 923; Ocean Drilling Program; Ocean floors; Oceanic crust; Olivine; Olivine group; Ore minerals; Orthosilicates; Oxides; Peridotites; Petrography; Plutonic rocks; Pyroxene group; R/V Akademik Fersman; Rare earths; Research vessels; Sea water; Sea-floor spreading; Serpentinite; Serpentinization; Silica; Silicates; Snakepit hydrothermal field; Spectroscopy; Spinel; Sr-87/Sr-86; Stable isotopes; Strontium; Sulfides; Textures; Thermal ionization mass spectroscopy; Thermal properties; Thermal waters; Trace elements; Ultramafics; Volcanic rocks
Coordinates: N170000 N200000 W0400000 W0490000
Record ID: 2018049965
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by Springer Verlag, Berlin, Federal Republic of Germany