Petrogenetic conditions at 18°–20° N MAR: Interaction between hydrothermal and magmatic systems     

S. A. Silantyev  N. S. Bortnikov  K. N. Shatagin  V. E. Bel’tenev  N. N. Kononkova  Ya. V. Bychkova  E. A. Krasnova 《Petrology》2016,24(4):336-366

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.  相似文献   

Isotopic Indications of Meromixis in Separated Lakes on the White Sea Coast     

Vasil’chuk  Yu. K.  Lisitzin  A. P.  Krasnova  E. D.  Budantseva  N. A.  Voronov  D. A.  Pantyulin  A. N.  Chizhova  Ju. N.  Shevchenko  V. P. 《Doklady Earth Sciences》2018,480(1):646-651

Studies of lakes at different stages of separation from the sea have been carried out on the northwestern coast of Kandalaksha Gulf of the White Sea. At the end of the winter period, from March 16 to 29, 2013, the lakes Kislo–Sladkoe, Trekhtzvetnoe, Nizhnee Ershovskoe, Ermolinskaya Bay and snow near the pier of Pertsov White Sea Biological Station of Moscow State University (WSBS MSU) were studied. The isotope characteristics of the water of lakes, ice and snow, the distribution of salinity, temperature, and hydrogen sulfide content were studied.

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Occurrence and Distribution of Cetaceans in the Northeastern Part of the Black Sea     

Chernetsky  A. D.  Krasnova  V. V.  Boltunov  A. N.  Panova  E. M.  Agafonov  A. V.  Belikov  R. A.  Belikova  E. A. 《Oceanology》2021,61(4):488-498

Oceanology - Studies of Black Sea cetaceans were carried out in September 2018 (11 days, 799 km of the survey route) and June 2019 (12 days, 1174 km of the survey route). The research vessel...  相似文献   

Isotope composition and magma sources of the Kresty volcanopluton in Polar Siberia     

I. F. Gertner  V. V. Vrublevskii  A. M. Sazonov  T. S. Krasnova  Yu. V. Kolmakov  E. A. Zvyagina  P. A. Tishin  D. N. Voitenko 《Doklady Earth Sciences》2009,427(2):961-967

The first data are presented on the distribution of rare elements and isotope composition of neodymium and strontium in the rocks of the alkaline-ultramafitic association of the Kresty volcanoplutonic structure (one of the probable satellites of the Gulinian massif being the largest in the Maimecha-Kotui alkaline province in Polar Siberia). On the basis of the results of geochemical studies performed and formerly obtained geophysical and isotope data, a new model is proposed for the plume nature of magmatism in the region, based on the action of a single mantle source of the PREMA type and its active interaction with the matter of the Earth’s crust.  相似文献   

Karchevskyite, [Mg18Al9(OH)54][Sr2(CO3,PO4)9(H2O,H3O)11], a new mineral species of the layered double hydroxide family     

S. N. Britvin  N. V. Chukanov  G. K. Bekenova  M. A. Yagovkina  A. V. Antonov  A. N. Bogdanova  N. I. Krasnova 《Geology of Ore Deposits》2008,50(7):556-564

Karchevskyite, a new mineral related to the family of layered double hydroxides (LDHs), has been found in the Iron open pit at the Kovdor carbonatite massif, Kola Peninsula, Russia. The mineral occurs as spherulites of up to 1.5 mm in diameter composed of thin, curved lamellae. Dolomite, magnetite, quintinite-3T, strontium carbonate, and fluorapatite are associated minerals. Karchevskyite is white in aggregates and colorless in separate platelets. Its luster is vitreous with a pearly shine on the cleavage surface. The new mineral is nonfluorescent. The Mohs hardness is 2. The cleavage is eminent (micalike), parallel to {001}. The measured density is 2.21(2) g/cm³, and the calculated value is 2.18(1) g/cm³. Karchevskyite is colorless and nonpleochroic in immersion liquids. It is uniaxial, negative, ω = 1.542(2), and ? = 1.534(2). The chemical composition (electron microprobe, average of ten point analyses, standard deviation in parentheses, wt %) is as follows: 29.7(1.1) MgO, 18.3(0.7) Al₂O₃, 7.4(0.4) SrO, 0.2(0.1) CaO, 1.3(0.2) P₂O₅, 14.5(0.4) CO₂, and 28.6 H₂O (estimated by difference); the total is 100. The empirical formula calculated on the basis of nine Al atoms is Mg_18.00Al_9.00(OH)_54.00(Sr_1.79Mg_0.48Ca_0.09)_2.36 (Ca₃)_8.26(PO₄)_0.46(H₂O)_6.54(H₃O)_4.18. The idealized formula is [Mg₁₈Al₉(OH)₅₄][Sr₂(CO₃, PO₄)₉(H₂O, H₃O)₁₁]. The new mineral slowly dissolves in 10% HCl with weak effervescence. Karchevskyite is trigonal; possible space groups are P3, P3, P $ \overline 3 Karchevskyite, a new mineral related to the family of layered double hydroxides (LDHs), has been found in the Iron open pit at the Kovdor carbonatite massif, Kola Peninsula, Russia. The mineral occurs as spherulites of up to 1.5 mm in diameter composed of thin, curved lamellae. Dolomite, magnetite, quintinite-3T, strontium carbonate, and fluorapatite are associated minerals. Karchevskyite is white in aggregates and colorless in separate platelets. Its luster is vitreous with a pearly shine on the cleavage surface. The new mineral is nonfluorescent. The Mohs hardness is 2. The cleavage is eminent (micalike), parallel to {001}. The measured density is 2.21(2) g/cm³, and the calculated value is 2.18(1) g/cm³. Karchevskyite is colorless and nonpleochroic in immersion liquids. It is uniaxial, negative, ω = 1.542(2), and ɛ = 1.534(2). The chemical composition (electron microprobe, average of ten point analyses, standard deviation in parentheses, wt %) is as follows: 29.7(1.1) MgO, 18.3(0.7) Al₂O₃, 7.4(0.4) SrO, 0.2(0.1) CaO, 1.3(0.2) P₂O₅, 14.5(0.4) CO₂, and 28.6 H₂O (estimated by difference); the total is 100. The empirical formula calculated on the basis of nine Al atoms is Mg_18.00Al_9.00(OH)_54.00(Sr_1.79Mg_0.48Ca_0.09)_2.36 (Ca₃)_8.26(PO₄)_0.46(H₂O)_6.54(H₃O)_4.18. The idealized formula is [Mg₁₈Al₉(OH)₅₄][Sr₂(CO₃, PO₄)₉(H₂O, H₃O)₁₁]. The new mineral slowly dissolves in 10% HCl with weak effervescence. Karchevskyite is trigonal; possible space groups are P3, P3, P 1m, P31m, P312, P312, P3m1, or P3m1; unit-cell dimensions are a = 16.055(6), c = 25.66(1) ?, V = 5728(7) ?³, Z = 3. The strongest reflections in the X-ray powder diffraction pattern [d, (I, %)(hkl)] are: 8.52(10)(003), 6.41(4)(004), 5.13(3)(005), 4.27(6)(006), 3.665(9)(007), 3.547(9)(107), 3.081(6)(315). Wavenumbers of absorption bands in the infrared spectrum of the new mineral are (cm⁻¹; s is shoulder): 3470, 3420s, 3035, 2960s, 1650, 1426, 1366, 1024, 937, 860, 779, 678, 615s, 553, 449, 386. Results of thermogravimetric analysis: total weight loss is 42.0 wt %, with three stages of loss: 12.2%, maximum rate at 230°C; 6.1%, maximum rate at 320°C; and 23.7%, maximum rate at 440°C. Karchevskyite is a late-stage hydrothermal mineral. The mineral is named in memory of Russian mineralogist Pavel Karchevsky (1976–2002), who made a significant contribution to the study of carbonatites. The type material of karchevskyite is deposited at the Mineralogical Museum, Division of Mineralogy, St. Petersburg State University, and the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow. Original Russian Text ? S.N. Britvin, N.V. Chukanov, G.K. Bekenova, M.A. Yagovkina, A.V. Antonov, A.N. Bogdanova, N.I. Krasnova, 2007, published in Zapiski Rossiiskogo Mineralogicheskogo Obshchestva, 2007, No. 5, pp. 44–56. The new mineral karchevskyite and its name accepted by the Commission on New Minerals and Mineral Names, Russian Mineralogical Society, March 21, 2005. Approved by the Commission on New Minerals and Mineral Names, International Mineralogical Association, June 30, 2005.  相似文献