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A. V. Dubinin T. Yu. Uspenskaya M. N. Rimskaya-Korsakova T. P. Demidova 《Lithology and Mineral Resources》2017,52(2):81-101
The Sr isotope stratigraphy of the biogenic apatite was used to determine the age of pelagic sediments in the Brazil Basin (Station 1541) that contain ferromanganese micronodules, nodules, and coatings on the weathered volcanic rocks. The age of sediments at horizons 0–5 and 86–90 cm was estimated at 24.1 ± 0.2 Ma and 24.8 ± 0.2 Ma, respectively. The average sedimentation rate in the Late Oligocene was about 13 mm/ka. The hydrogenous Fe–Mn nodule on the sediment surface with the Mn/Fe value of 1.05–1.95 was formed at a rate of 1.2–2.4 mm/Ma, which is 1000 times lower than the growth rate of buried nodule (Mn/Fe 0.4) at depth of 83 cm. Diagenesis provoked changes in the mineral composition of the buried nodule (asbolane-buserite partially replaced by goethite), leading to the loss of a part of Mn, Ni, Li, and Tl but accumulation of trace elements linked with iron oxyhydroxides (Ce, Th, Be, As, and V) were retained. The composition of manganese micronodules at two studied depths in sediments evolved in the course of two stages of ore formation: related to the oxic and suboxic diagenesis. The Sr isotopic composition in manganese micronodules from both horizons do not differ from that of dissolved Sr in the ocean water. The 143Nd/144Nd ratio, which reflects the Nd isotopic composition in the paleocean during the micronodule formation, varies in manganese micronodules from different horizons and is constant in different size fractions. 相似文献
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An analytical technique is proposed to determine ultratrace concentrations of Mo, V, and W found in seawater using mass spectrometry with inductively coupled plasma (ICP MS) after preliminary concentration by solid-phase extraction of metal complexes with 8-hydroxyquinoline (8-HQ) on C18 octadecyl silica. The technique utilizes 150 mL of a water sample. A preconcentration factor 50 is obtained. The detection limits are 0.25 nmol/kg, 0.041 nmol/kg, and 5 pmol/kg for Mo, V, and W, respectively. Dissolved Mo, V, and Wconcentrations in surface seawater from Atlantic Ocean transect were determined. The concentrations ranges along the transect were: 91–108 nmol/kg for Mo, 28–35 nmol/kg for V, and 55–75 pmol/kg for W. The Mo/W ratio varied from 1300 to 1800. 相似文献
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A. V. Dubinin V. N. Sval’nov E. D. Berezhnaya M. N. Rimskaya-Korsakova T. P. Demidova 《Lithology and Mineral Resources》2013,48(3):175-197
Indicator role of trace elements in sedimentation and ore formation is considered for sediments from Station 2182 in the Angola Basin. It is shown that pelagic sediments were formed from two main sources: biogenic calcium carbonate and lithogenic sediment component compositionally similar to the miopelagic clay. Increase of the Mn/Al ratio, Ce anomaly in the REE composition, Co/Ni and Mo/W ratios, and anomalous accumulation of Tl, Pb, Bi and other microelements indicate that sediments from horizons 15–20 and 30–35 cm contain significant amounts of hydrogenic material as Fe-Mn oxyhydroxides. Manganese micronodules (MN) were extracted from different horizons (10–15, 15–20, and 30–35 cm) and analyzed to study the hydrogenic component. Their development is related to retardation of biogenic and lithogenic sedimentation. The studied manganese micronodules are represented by the hydrogenic-diagenetic formations >100 μm in size with Mn/Fe = 2.0–2.8, Co/Ni = 0.2–0.4, Ce an = 4.2–5.7, and Mo/W = 5.2–7.9. The MN content is too low to affect the major and trace element composition of sediments. The main part of Fe and Mn is confined to fraction <10 μm. 相似文献
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Dubinin A. V. Kuznetsov E. V. Rimskaya-Korsakova M. N. Berezhnaya E. D. Dara O. M. Veldemar A. A. Rashidov V. A. Skolotnev S. G. 《Oceanology》2022,62(2):231-246
Oceanology - Ferromanganese (Fe-Mn) crusts in the ocean accumulate significant amounts of strategically important elements necessary for the development of high technologies. The recent study of... 相似文献
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The sedimentation and ore formation were studied in sediments from nine stations located in the 24°W profile in the Brazil
Basin of the Atlantic Ocean. The sediments are represented by mio- and hemipelagic muds, which are variably enriched in hydrothermal
iron and manganese oxyhydroxides. As compared to the sediments from other basins of the Atlantic Ocean, these rocks are marked
by extremely high manganese contents (up to 1.33%) and maximal enrichment in Ce. It was shown that the positive Ce anomaly
is related to the REE accumulation on iron oxyhydroxides. Influence of hydrothermal source leads to the decrease of Ce anomaly
and LREE/HREE ratio. In the reduced sediments, preservation of positive Ce anomaly and/or its disappearance was observed after
iron and manganese reduction. The REE contents were determined for the first time in the Ethmodiscus oozes of the Brazil Basin. Ore deposits of the Brazil Basin are represented by ferromanganese crust and ferromanganese nodules.
Judging from the contents of iron, manganese, rare, and trace elements, these formations are ascribed to the sedimentation
(hydrogenic) deposits. They are characterized by a notable positive Ce anomaly in the REE pattern. The extremely high Ce content
(up to 96% of total REE) was discovered for the first time in the buried nodules (Mn/Fe = 0.88). 相似文献
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A. V. Dubinin T. P. Demidova V. V. Kremenetskii N. M. Kokryatskaya M. N. Rimskaya-Korsakova E. V. Yakushev 《Oceanology》2012,52(2):181-190
The report presents the results of the studies of the reduced sulfur species in the water of the anoxic zone of the Black
Sea. The content of hydrogen sulfide was determined by means of spectrophotometry using dilution with oxygen-free distilled
water. The detection limit of the H2S amounted to 0.3 μM with the method’s precision below 3%. The accuracy of the spectrophotometric determination was verified
by iodometry after the fixation of the hydrogen sulfide in zinc acetate under the distillation with argon from the acidified
seawater sample. 相似文献
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