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Chronology of seafloor massive sulfides formation within the Pobeda hydrothermal cluster (Mid-Atlantic Ridge)

Kuznetsov V., Cherkashov G., Kuksa K., Firstova A., Maksimov F., Bel’Tenev V., Lazareva L., Levchenko S., Baranova N.

Geochronometria

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2020

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Vol. 47, no.1

63--70

EN

A geochronological and mineralogical study on the seafloor massive sulfides from the Pobeda hydrothermal cluster at the Mid-Atlantic Ridge was carried out. To improve the reliability of geochronological data, the 230Th/U ages were measured for both the bulk samples and monomineral separates. The oldest age ca. 52 kyr within Pobeda-1 and ca. 107 kyr within Pobeda–2 fields have been obtained. Then, several episodes of hydrothermal activity were identified within both fields up to ca. 0.3 kyr ago and up to ca. 4.3 kyr ago, respectively.

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The oldest seafloor massive sulfide deposits at the Mid - Atlantic Ridge: 230th/u chronology and composition

Kuznetsov V., Tabuns E., Kuksa K., Cherkashov G., Maksimov F., Bel’Tenev V., Lazareva L., Zherebtsov I., Grigoriev V., Baranova N.

Geochronometria

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2015

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Vol. 42, no.1

100--106

EN

A geochronological and geochemical study on 10 samples of seafloor massive sulfides (SMS) from the inactive Peterburgskoye hydrothermal field at the Mid-Atlantic Ridge (MAR) was carried out. The 230Th/U ages of the SMS are the oldest for the Quaternary hydrothermal ores ever found at the ocean floor. According to them the hydrothermal activity at Peterburgskoye field started at least 170 ka and continued down to 63 ka. The oldest hydrothermal ores from this field consist mainly of pyrite and chalcopyrite and have geochemical properties typical for SMS associated with basalts.

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Geochronology and Palaeomagnetic Records of the Snaigupėlė Section in South Lithuania

Baltrūnas V., Maksimov F. E., Kuznetsov F. Y., Karmaza B., Katinas V.

Geochronometria

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2015

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Vol. 42, no.1

172--181

EN

The interglacial deposits in the South Lithuanian Snaigupėlė outcrop and borehole Snaigupėlė-705 are marked for different bedding conditions though the sections are in proximity of each other. In the borehole section, the interglacial deposits are thicker and bedding at a greater depth than the analogous deposits of the outcrop. In the Snaigupėlė outcrop, the highest compatibility of isochronic-correction dates, calculated using L/L (method of leaching) and TSD (method of total sample dissolution) models, was determined for combination of three samples. With the help of the f value (section of isochrones in the axis of ordinates), the contribution of the primary pollution with thorium was determined where, as based on corrected analytical data, isochronic-correction dating was performed: 18 14 127+ − ka years for the L/L model and 22 16 132+ − ka for the TSD model. Palaeomagnetic investigations showed that the section of lacustrine sediments in the lower part of Snaigupėlė outcrop were orientated by reversed magnetic excursion and in the upper part by normal magnetic polarity. Collation of the obtained data with the global geomagnetic scale showed that the palaeomagnetic inversion observed in the Snaigupėlė section was related with the Blake Event in the Eemian Interglacial.

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First 230Th/U date of middle Pleistocene peat bog in Siberia (key section Krivosheino, Western Siberia)

Maksimov F. E. F. E., Laukhin S. A., Arslanov K. A., Kuznetsov V. Y., Shilova G. N.

Geochronometria

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2012

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Vol. 39, no. 4

241-251

EN

A ¹⁴C date older than 53900 yrs BP was obtained for the uppermost part of the buried peat bog in Krivosheino section (Middle Pleistocene of Western Siberia). These sediments also yielded ²³⁰Th/U dates of 195 _-9.1 ka using the leachate alone (L/L) and 204 ⁺¹⁷ _-13 ka using total sample dissolution (TSD) models. Peculiarities of 230Th/U dating are discussed. Palynological investigation of the buried peat bog together with underlying and overlaying sediments, and comparison with palynologi-cal data from Baikal and Elgygytgyn lakes revealed that the peat layer in Krivosheino section was formed at the end of Shirta Interglacial (Marine Isotopic-Oxygenous stages MIS-7), when climate conditions at all studied sites were more severe compared to the modern ones.

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230Th/U chronology of ore formation within the Semyenov hydrothermal district (13°31' n) at the Mid-Atlantic Ridge

Kuznetsov V., Maksimov F., Zheleznov A., Cherkashov G., Bel’tenev V., Lazareva L.

Geochronometria

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2011

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Vol. 38, no. 1

72-76

EN

A radiochemical study was carried out on massive sulfides from Semyenov hydrothermal district at the Mid-Atlantic Ridge. New and published results provide evidence that 230Th/U ages obtained for massive sulfides are reliable. The sulfide deposits from the West, North-West, North-East, and East hydrothermal sites at the Semyenov hydrothermal district were formed between ~124 ka and ~37 ka ago. The hydrothermal activity might have started in the eastern part of the district and moved to the west by episodic ore formation.

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230TH/U dating of massive sulfides from the logatchev and rainbow hydrothermal fields (Mid-Atlantic Ridge)

Kuznetsov V., Cherkashev G., Lein A., Shilov V., Maksimov F., Arslanov K., Stepanova T., Baranova N., Chernov S., Tarasenko D.

Geochronometria

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2006

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Vol. 25

51-55

EN

A radiochemical study was carried out on massive sulfides from three hydrothermal fields in the Mid-Atlantic Ridge. The main objective was to check whether 230Th/U dating yields reliable results. The absolute 230Th/U ages of massive sulfide samples of three hydrothermal fields at the Mid Atlantic Ridge were determined 58.2±4.2 ka and 16.8±1.0 ka for the "Logatchev-1" site, 3.9±0.4 ka for the "Logatchev-2" site and 23.0±1.5 ka, 3.9±0.6 ka and 2.2±0.3 ka for the "Rainbow" site. The dates correspond to the activation periods of hydrothermal ore formation systems.