eastern kamchatka
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Author(s):  
N. P. Sergeeva

Longterm data on the liver weight, hepatosomatic (HSI) and gonadosomatic (GSI) indices of walleye pollock, Pacific cod and saffron cod are analyzed on Eastern Kamchatka in seasonal aspect and in the course of gonad maturation. Individual values of the indices extensively vary and depend on the fish body length, season and stage of gonad maturity. The dynamics of the HSI is agree to the dynamics of the GSI during the year and depending on gonad maturity. The maximum values of the HSI are typical for walleye pollock and Pacific cod individuals with the gonads of the III stage of maturity. The maximum values of the index in saffron cod are found in mature individuals with immature gonads. The minimum values are demonstrated by the fish with the gonads at the stage of final spawning or of post-spawning recovery. During the annual reproduction cycle males and females of walleye pollock and cod realize different scenarios of spending and accumulating liver fat. Whereas the maximum HSI is observed in the fish with the gonads at the III maturity stage, the minimum values in males are typical for individuals with smelting gonads, and in females – on finishing the spawn. That can be connected to possible feeding for the individual. Liver weight and liver index can increase in males just shortly after finishing spawning, in females that is found only at the stage of post-spawning recovery.


2021 ◽  
pp. 103703
Author(s):  
Anton V. Kutyrev ◽  
Vadim S. Kamenetsky ◽  
Jung-Woo Park ◽  
Roland Maas ◽  
Elena I. Demonterova ◽  
...  
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2021 ◽  
Vol 40 (5) ◽  
pp. 3-15
Author(s):  
A.I. Khanchuk ◽  
◽  
A.V. Grebennikov ◽  

Testing of the geochemical compositions of the Late Cenozoic volcanites of Kamchatka on new discriminant diagrams confirmed the idea of the existence of different geodynamic regimes at this time. It is shown that the Late Miocene (~6 Ma)-Pliocene volcanites of Eastern Kamchatka and the Central Kamchatka Depression, as well as the Late Pliocene (~3.5 Ma)-Holocene alkaline, calcareous-alkaline, and adakite volcanites of the central part of the Middle Ridge are similar to the volcanites of the transform margins of the Pacific type. At the same time, the Miocene–Holocene volcanites of Southern Kamchatka, the Miocene-Early Pliocene volcanites of the Middle Ridge, and the Pleistocene–Holocene volcanites of Eastern Kamchatka are similar to the volcanites of the convergent margins. In the central part of Kamchatka (from the coast to the Middle Ridge), at the end of the Miocene-Pliocene, during the collision of the Kronotsky terrane of the island arc and the slip of the Pacific plate, magmatic complexes typical of the transform margin were formed in this area. The geochemistry of the transform margin volcanites is due to the upwelling of the subslab asthenosphere both into the collision zone and into the zone of the volcanic arc of the Middle Ridge, after the rupture and subsequent separation of the Komandor-Kronotsky microplate slab.


Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1124
Author(s):  
Galina Palyanova ◽  
Evgeny Sidorov ◽  
Andrey Borovikov ◽  
Yurii Seryotkin

The copper-containing agates of the Avacha Bay (Eastern Kamchatka, Russia) have been investigated in this study. Optical microscopy, scanning electron microscopy, electron microprobe analysis, X-ray powder diffraction, Raman spectroscopy, and fluid inclusions were used to investigate the samples. It was found that copper mineralization in agates is represented by native copper, copper sulphides (chalcocite, djurleite, digenite, anilite, yarrowite, rarely chalcopyrite) and cuprite. In addition to copper minerals, sphalerite and native silver were also found in the agates. Native copper is localized in a siliceous matrix in the form of inclusions usually less than 100 microns in size—rarely up to 1 mm—forming dendrites and crystals of a cubic system. Copper sulphides are found in the interstices of chalcedony often cementing the marginal parts of spherule aggregates of silica. In addition, they fill the micro veins, which occupy a cross-cutting position with respect to the concentric bands of chalcedony. The idiomorphic appearance of native copper crystals and clear boundaries with the silica matrix suggest their simultaneous crystallization. Copper sulphides, cuprite, and barite micro veins indicate a later deposition. Raman spectroscopy and X-ray powder diffraction results demonstrated that the Avacha Bay agates contained cristobalite in addition to quartz and moganite. The fluid inclusions study shows that the crystalline quartz in the center of the nodule in agates was formed with the participation of solutions containing a very low salt concentration (<0.3 wt.% NaCl equivalent) at the temperature range 110–50 °C and below. The main salt components were CaCl2 and NaCl, with a probable admixture of MgCl2. The copper mineralization in the agates of the Avacha Bay established in the volcanic strata can serve as a direct sign of their metallogenic specialization.


2020 ◽  
Vol 15 (4) ◽  
Author(s):  
N.V. Bol'shakova ◽  
◽  
S.M. Danil'ev ◽  
N.A. Danil'eva ◽  
◽  
...  

The article highlights the main results of regional geological exploration carried out in the last decade in the Pre-Pacific petroleum province - offshore Behring Sea and the Pacific Ocean joining the Eastern Kamchatka onshore area . Comparative assessment of hydrocarbons resources potential of this region is made based on the results of the research, that allowed to justify further directions of exploration.


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