Eastern Kamchatka Research Articles

Iceberg-rafted debris events from the glacial Kamchatka in the southwestern Okhotsk Sea over the past 110 kyrs

High-resolution analyses of ice-rafted debris (IRD) and its light and heavy minerals in a sediment core sample from the SW Okhotsk Sea reveal the varying sources of terrigenous material and iceberg discharge events from the Kamchatka Peninsula into the SW Okhotsk Sea since the last interglacial period (Marine Isotope Stage (MIS) 5). Our results suggest the dominance of seasonal and mobile sea ice since 110 ka BP, with occasional perennial sea ice in the SW Okhotsk Sea, which is the most important agent for the basin-wide dispersal of land-sourced terrigenous material. Between 33 ka BP and 14 ka BP (MIS 2), prevalent sea ice formed on the northern shelves. Since 14 ka BP, instead, the IRD originated mainly from the Sakhalin Gulf, with a substantial increase in near-source material input. Thirteen events of IRDKamchatka were identified between 87 and 27 ka BP (mainly in MIS 4–3), with debris definitely originating from the Kamchatka Peninsula. Among these events, the four most prominent types of iceberg/ice sheet rafting occurred at ∼63 ka, ∼53 ka, ∼40 ka, and ∼33 ka BP. Simultaneously, they are consistent with the IRDiceberg events that occurred in the core of western Kamchatka and are also close to the age of H6, H5, H4 and H3 in the Heinrich Events. The initial source areas and transportation pathways of these iceberg armadas varied considerably over time. During ∼87–53 ka BP, icebergs originated from the western Kamchatka Peninsula and migrated southward. During ∼53–27 ka BP, IRDKamchatka inputs likely originated from the eastern Kamchatka Peninsula. This suggests that during MIS 4/3, the mountain glaciers of the Kamchatka Peninsula experienced a reduction in scale and retreated from the western to the eastern part of the peninsula. The event at 27 ka BP marks the last major IRDKamchatka contribution to the Okhotsk Sea from the Kamchatka Peninsula. Since 14 ka BP, the input of IRDKamchatka into the SW Okhotsk Sea has become very weak.

Cycles in adult steelhead length suggest interspecific competition in the North Pacific Ocean

Anadromous fishes rely on abundant prey in the ocean to grow large quickly, but prey limitation leads to interspecific competition. When species interactions are difficult to observe, growth can be studied to detect otherwise cryptic signals of competition. We describe a previously undocumented 2-year cycle in the lengths of adult natural-origin steelhead ( Oncorhynchus mykiss) returning to spawn in the Snake River Basin. Returning steelhead were 38 mm shorter on odd return years, not accounting for sex, stock, and years of ocean residence. The well-known cycle in abundance of pink salmon ( Oncorhynchus gorbuscha) from eastern Kamchatka and North America had statistically significant negative effects on returning steelhead lengths that depended on sex and the number of years of ocean residence. These results suggest that competition for limited resources occurs well after initial ocean entry and that interactions during later stages of ocean residence can be influential. Interspecific competition has implications for future returns of steelhead from the ocean, especially as metabolic demands for steelhead increase as the ocean warms.

Tyushevskaya Marine Paleobasin (Eastern Kamchatka): Composition and Development Features

Tyushevskaya Marine Paleobasin (Eastern Kamchatka): Composition and Development Features

Paleoaltimetry and paleotectonic reconstruction using triple oxygen and hydrogen isotopes: Depleted δ18O and δD values in ignimbrites of Verkhneavachinskaya caldera record collisional uplift during Miocene arc accretion to Kamchatka

Here we use δ18O and δD values as tools to investigate the paleo-altitude and the origin of large-volume (120 km3, 10 × 12 km) ignimbrites of Verkhneavachinskaya caldera (cf. Verkhne-Avachinskaya) (VC) in eastern Kamchatka, formed the in Late Miocene 5.8 Ma. The basaltic-andesitic intracaldera ignimbrite deposit exhibits low δ18O values, reaching −5.03‰, and δD values of −182‰ across a 1.2 km depth range in several sampled sections. The results support a massive meteoric-hydrothermal system throughout the cooling history of the thick intracaldera ignimbrite deposit. Using triple oxygen isotope data we estimate that the δ18O values of altering meteoric water are as low as −19‰ to −23‰, much lower than modern precipitation of −14‰, or − 16‰ estimated for the 2–3 °C warmer Kamchatka climate of the late Miocene. Therefore, the VC meteoric-hydrothermal system depended on high-altitude precipitation and glaciers, and altitudinal isotopic lapse rates suggest a paleo-altitude of 3.5 km at 5.8 Ma during caldera formation. These elevations exceed the modern by 1.5 km and provide a unique snapshot into an evolving landscape and paleo-environment of eastern Kamchatka at 6–5 Ma as the dynamic outcomes of accretion of the Kronotski arc. In particular, the existence of such a high plateau is in line with contemporary accretionary tectonics: accretion of the Shipunsky peninsula of this accreting arc terrain, ∼120 km to the east of the VC, and evidence of contemporaneous exhumation of high-grade Ganal amphibolites to the west. We conclude that the eruption of large-volume mafic ignimbrites that formed VC caldera was syncollisional or intracollisional in nature, likely requiring delamination of thickened crust to account for both uplift and magmatism.

Biological characteristics of the Pacific halibut in the Bering Sea and off the eastern coast of Kamchatka in spring 2022

The purpose of the work: to give a biological characteristic of the Pacific halibut in different areas of the Bering Sea and off the eastern coast of Kamchatka and to analyze its size age composition in catches of trawl fishing. Methods used: the material was collected during the expedition research, a complete biological analysis of the Pacific halibut was carried out, the otoliths were selected to determine the age. The age was determined in accordance with the guidelines developed specifically for the Pacific halibut in the International Commission on Pacific Halibut (International Pacific Halibut Commission, IPHC).Novelty: the elements of novelty are generalized and analyzed data on Pacific halibut. The material collected in the waters of Eastern Kamchatka and the Bering Sea in 2022. Pacific halibut from trawl catches have been studied, its biological characteristics have been considered, the size-age composition and growth rate have been analyzed.Practical significance: the results of these studies can be used in forecasting the stocks of Pacific halibut in this area.Result: data on catches of Pacific halibut in different regions of the North West Pacific Ocean, the size and age composition, a comparative characteristic of males and females by growth rate, the age composition of fish by maturity stages.

Rare metal concentration features at a caldera type deposit in the Miocene-Quaternary boron-lithium province of North America. Search for analogues

The fact that lithium has a wide range of applications in many fields including the production of lithium-ion batteries determines an increased interest in lithium mining. The most common types of lithium raw material sources are underground brines, saline lakes (“salars”), and ore minerals. In 2021, the first and unique deposit of lithium clays was discovered in the McDermitt caldera (Nevada, USA). Its resources are estimated at 13.7 million tons of lithium carbonate with the lithium concentration of 2231 mg/l. The uniqueness of this deposit raises the interest in the formation of model ideas about lithiumclay genesis to search for analogous deposits and explore them. The purpose of the article is to provide an overview of the geological structure and describe the main development periods of the McDermitt caldera. The authors also characterize the potential sources of lithium (felsic igneous rocks and hydrothermal fluids), migration paths of lithium-bearing brines as well as the formation mechanism of clays with a high lithium content (hectorite, illite and smectite). A generalized formation model of this type of deposits is proposed. Particular attention is paid to the role of hydrothermal fluids as a potential additional source of lithium “supply” to the caldera basin. Key criteria characteristic of industrial accumulations of lithium of this type have been formed in order to explore and identify analogous deposits. In conclusion, the authors put forward a hypothesis about the presence of deposits that are analogous to the Thacker Pass in the McDermitt caldera in the lithium province on the Altiplano-Puna plateau in one of the calderas of the Altiplano-Puna volcanic complex, and in Eastern Kamchatka.

Minerals of the Au-Cu-Ag System in Grains from the Placers of the Olkhovaya-1 River (Eastern Kamchatka, Russia)

Heterogeneous grains in the heavy fractions of the placers of the Olkhovaya-1 river (Kamchatka Cape Peninsula, Eastern Kamchatka, Russia) containing Au-Ag, Au-Cu, and Au-Ag-Cu particles were analyzed using scanning electron microscopy, electron-probe microanalysis, and X-ray powder diffractometry. The analyses showed that auricupride dominates in some grains, whereas in others, the main phases are tetra-auricupride or Ag-rich and (or) Au-rich alloys. It was revealed that in the central parts of some grains of exsolution structures, auricupride Cu3.04–2.74Au0.96–1.26 (Ag < 1 wt.%) occurs in intergrowths with low-fineness Ag0.86–0.67Au0.09–0.33Cu<0.05 solid solutions (160‰–480‰), and tetra-auricupride Cu1.12–0.87Au0.88–1.11Ag<0.02 (Ag < 2 wt.%) occurs with higher-fineness Au0.73–0.62Ag0.2–0.38Cu<0.07 solid solutions (520‰–850‰). We also observed, mainly in the peripheral parts of the grains, insignificant amounts of secondary phases that were compositionally similar to Cu2Au, Cu3Au2, Au3Cu2, Au2Cu, Au3Cu, high-fineness gold with impurities of Cu and occasionally Ag (>850‰), and pure gold. In intergrowths with auricupride and tetra-auricupride, we also observed earlier-formed silicates (garnet, pyroxene, chlorite, epidote, titanite), syngenetic sulfides (pyrrhotite, bornite, galena), and later minerals (chalcocite, covellite, anilite, cuprite, goethite, etc.). The XRD analysis of the peripheral parts of some grains showed the presence of auricupride (Cu3Au), tetra-auricupride CuAu (I) and Cu(Au0.92Ag0.08) (II), and gold. The profiles show the absence of peaks of the Au3Cu phase and other Au-Ag-Cu phases identified by the EMPA, which is likely due to their low concentrations in the samples or their structural similarity to gold. It is assumed that the probable source of Au-Ag-Cu mineralization in the Olkhovaya-1 river placers is located in the upper reaches of watercourses that erode the ultrabasic massif of Mounts Soldatskaya and Golaya (Kamchatka Cape Peninsula).

Variability of stock status walleye pollock fishery

The analysis of the variability of walleye pollock stocks assessment and fisheries showed that in most areas the degree of exploitation is at a low level (4,7–13,5%), with the exception of the Navarinsky region of the Bering Sea, the coast of eastern Kamchatka, the northern Kuril Islands and western Sakhalin (16,7–18,9%). Climate change has a significant impact on the of walleye pollock stocks assessment. Positive anomalies of the PDO climate index (Pacific Decadal Oscillation) create favorable conditions for northern populations, whereas for southern populations living on the southern border of the area, on the contrary, those periods when negative anomalies are noted are more comfortable. Subject to the implementation of the cooling scenario in the North Pacific Ocean, walleye pollock biomass centers may shift to the southern regions (the economic zone of the DPRK), which will lead to a significant reduction in catches in the economic zones of the Russian Federation and the United States, which are currently the main players in the walleye pollock market.

The Age and Exhumation Time of the Eastern Kamchatka Sedimentary Complexes Based on Apatite Track Dating

The Age and Exhumation Time of the Eastern Kamchatka Sedimentary Complexes Based on Apatite Track Dating

Subduction and Oceanic Magmatism Records in Plutonic Rocks of the Kamchatsky Mys Ophiolite, Eastern Kamchatka

Subduction and Oceanic Magmatism Records in Plutonic Rocks of the Kamchatsky Mys Ophiolite, Eastern Kamchatka

MORPHOLOGY OF THE DECAPODITE STAGES OF <i>ARGIS</i> <i>LAR</i> (OWEN 1839) (CARIDEA, CRANGONIDAE) FROM THE KRONOTSKY BAY, EASTERN KAMCHATKA

Two decapodite stages of the shrimp, Argis lar, family Crangonidae, from the plankton off the Kronotsky Bay, northwestern Pacific, eastern Kamchatka, are described. Сomparison of The available larvae were morphologically compared with decapodites of other species of this family with a shortened development. The first and second decapodite stages were similar in size and structural features of the pleon, carapace, antennae, mandibles, maxillae, pereiopods, and pleopods. Significant differences were found in the morphology of the telson, maxilliped, and antennules in the first and second decapodite stages of A. lar. In the second decapodite stage, the posterior median spine shifted to the middle of the carapace, the number of antennular and maxilliped endopod segments were increased, the epipodite appeared in the third maxilliped, the shape of the telson changed, the terminal spines in the telson disappeared, and the relative length of the angular setae were decreased. Kuro shrimps are thought to have three to five larval stages.

Subduction and Oceanic Magmatism Records in Plutonic Rocks of the Kamchatsky Mys Ophiolite, Eastern Kamchatka

The paper presents petrographic, mineralogical, and geochemical data on dunites, pyroxenites, peridotites, and gabbroids of the Kamchatsky Mys ophiolite. These data were acquired to distinguish cogenetic assemblages of igneous rocks, gain an insight into their geodynamic settings, and test various criteria of genetic links between the different magmatic rocks of ophiolites. The ultramafic and mafic rocks are shown to belong to two series, which differ in the compositions of the primary minerals, bulk rocks, and estimated trapped melts. The rocks of these series are found out to have been produced by geochemically different melts in different geodynamic settings, and during different episodes of mantle magmatism. The rocks of the high-Ti series (gabbro of the Olenegorsk massif, dunite and melanogabbro xenoliths in them, and vein gabbro in these xenoliths) crystallized from N-MORB melts in an oceanic spreading center. The rocks of the low-Ti series (dunite, pyroxenite, and gabbro veins in the residual spinel peridotites of the Mount Soldatskaya massif, as well as pyroxenite, peridotite, and gabbro alluvium and diluvium in the central and western parts of the peninsula) crystallized from water-rich boninite melts in relation to initial subduction magmatism. Taken into account the absence of boninite lavas from the Kamchatsky Mys ophiolite, the plutonic ultramafic rocks (including the rocks of the veins) might be the only evidence of subduction boninitic magmatism in the ophiolites. It was demonstrated that conclusions about the geodynamic settings of plutonic ultramafic and mafic rocks and recognition of cogenetic relations of these rocks with spatially associated basalts are more reliable when derived from the compositions of the trapped melts, which are estimated from their bulk geochemistry and primary mineral compositions, than when they are based on the mineral compositions only.

An intraoceanic juvenile arc of shoshonite and adakitic andesite in the Nemuro Belt, the Lesser Kuril Arc, across the K/Pg boundary

In situ eruptions and accreted blocks of Mesozoic basalts exhumed in present-day forearc settings, around the Pacific Rim record paleovolcanic events in intraplate oceanic settings since the closure of the Panthalassa Ocean. Basaltic and andesitic volcanic and intrusive rocks occur in the present-day forearc area of the Late Cretaceous Nemuro Belt in northeastern Japan. Most basalts in this area are K-rich (i.e. shoshonites), similar to rocks erupted in oceanic back arc or petit-spot settings. In this study, we investigated the occurrence, geochemistry, and age of these shoshonitic rocks (ca. 70 Ma), along with associated adakitic andesites (ca. 62 Ma). The petrogenesis of these igneous rocks and petrography of the associated Nemuro sandstones were used to constrain the nature of the Nemuro paleo-arc during the Late Cretaceous to early Paleogene. The shoshonitic, adakitic, and basaltic rocks in the Nemuro sandstones formed in an intraoceanic juvenile arc setting. Previous paleomagnetic studies have suggested that the Nemuro and Lesser Kuril paleo-arcs were approximately ENE–WSW-trending, located in the central paleo-Pacific, and extensions of the Olyutorsky (eastern Kamchatka) and Terpenia (eastern Sakhalin) paleo-arcs near the mid-ocean ridges of the Kula/Izanagi and Pacific plates in the central Pacific. Our findings are consistent with these previous results, although the shoshonites in the lower part of the Nemuro Group indicate that the Nemuro paleo-arc drifted rapidly northward or northwestward after ca. 65 Ma.

Calcareous Nannoplankton from the Upper Cretaceous and Paleogene Deposits of the Kamchatsky Mys Peninsula (Eastern Kamchatka)

Calcareous Nannoplankton from the Upper Cretaceous and Paleogene Deposits of the Kamchatsky Mys Peninsula (Eastern Kamchatka)

Volcano–Plutonic Complex of the Tumrok Range (Eastern Kamchatka): An Example of the Ural-Alaskan Type Intrusion and Related Volcanic Series

Zoned plutons, composed of dunites, pyroxenites, and gabbroic rocks, have been referred to as the Ural-Alaskan type complexes (UA-complexes) and occur in numerous paleo-arc settings worldwide. Many of these complexes are source rocks for economic placers of platinum-group metals. Thus, it is important to understand how UA-complexes form and the origin and behavior of platinum-group elements (PGEs). It is widely assumed that the UA-complexes result from differentiation of supra-subduction high-Ca high-Mg sub-alkaline magmas. However, there is a lack of direct evidence for the existence and differentiation of such magmas, mainly because cases of UA-complexes being spatially and temporally linked to co-genetic volcanics are unknown. We studied an UA-complex from the Tumrok range (Eastern Kamchatka) where a dunite-clinopyroxenite-gabbro assemblage is spatially and temporary related to high-Ca volcanics (i.e., picrites and basalts). Based on the mineral and chemical composition of the rocks, mineral chemistry, and composition of melt inclusions hosted within rock-forming minerals, we conclude that the intrusive assemblage and the volcanics are co-genetic and share the same parental magma of ankaramitic composition. Furthermore, the compositions of the plutonic rocks are typical of UA-complexes worldwide. Finally, the rocks studied exhibit a full differentiation sequence from olivine-only liquidus in picrites and dunites to eutectic crystallization of diopside or hornblende, plagioclase, and K-Na feldspar in plagio-wehrlites and gabbroic rocks. All these results make the considered volcano–plutonic complex a promising case for petrological studies and modelling of UA-complex formation.

ПОЛОВЫЕ РАЗЛИЧИЯ В СОДЕРЖАНИИ МИКРОЭЛЕМЕНТОВ В ОРГАНАХ  И ТКАНЯХ НЕРКИ ИЗ ВОСТОЧНЫХ ЗАЛИВОВ ПОЛУОСТРОВА КАМЧАТКА

The content of essential (Cu, Zn, Fe) and non-essential (Cd, Pb, Ni) elements, which are trace and heavy metals, in the organs and tissues of one of the most popular and consumer-preferred species of Pacific salmon – sockeye salmon, one of the three most significant objects in the salmon fishery in the Far East of Russia, caught in the waters of two gulfs from the eastern Kamchatka – Avacha Gulf and Kamchatka Gulf. Emphasis is made on reproductive products – caviar and testes of fish. Element concentrations were determined by the atomic absorption method on a Shimadzu AA-7000 spectrophotometer on flame and flameless atomizers from sample mineralizates obtained by their decomposition with concentrated HNO3 grade extra pure in a MARS 6 microwave complex, using standard samples with known concentrations. Statistical data processing was performed in MS Excel. It was found that the concentration of copper in eggs was 10 times higher than in the testes, the levels of Zn in the gonads of fish differed by a factor of 2, and the differences in the amount of Fe were less pronounced. No patterns were observed in the distribution of Cd, Ni, and Pb in the gametes of fish. The content of microelements, except for Pb, as a rule prevailed in the liver.

НАХОДКИ ИЗВЕСТКОВОГО НАННОПЛАНКТОНА В ВЕРХНЕМЕЛОВЫХ И ПАЛЕОГЕНОВЫХ ОТЛОЖЕНИЯХ ПОЛУОСТРОВА КАМЧАТСКИЙ МЫС (ВОСТОЧНАЯ КАМЧАТКА)

Results of the study on calcareous nannofossils found for the first time in the lower part of the Stolbovaya Group of the Kamchatsky Mys Peninsula, eastern Kamchatka, are presented. Two assemblages of different age are identified, with one assigned to the Upper Cretaceous and the other to the Paleogene (not younger than the Lutetian Stage of the Middle Eocene). The obtained data help to refine the age of terrigenous-tuffaceous sequences in the lower part of the Stolbovaya Group, which are poor in organic remains.

Some issues of walleye pollock reproduction in the pacific waters adjacent to the Kamchatka peninsula and the northern Kuril Islands in 2013–2022.

Purpose: To characterize some issues of East Kamchatka pollock reproduction in the last 10 years.Methods: complex (ichthyoplankton and hydrological) surveys in the Pacific waters adjacent to the Kamchatka Peninsula and the northern Kuril Islands, surveys in the spawning center — the “North” canyon, located in Avacha Bay, layer-by-layer surveys in the canyons and on the shelf.Novelty: the currently available data on the main spawning areas of the Eastern Kamchatka pollock were supplemented, new data on the state of the spawning stock, vertical distribution of eggs at different stages of development were presented.Results: During the period under consideration, the main pollock spawning in Avacha and Kronotsky bays occurred above deep-water canyons, and on the shelf near southeastern Kamchatka and northern Kuril Islands — in the whole surveyed water area, in some years — to the south of the island Paramushir. According to the results of ichthyoplankton surveys, model calculations, the spawning stock of the Eastern Kamchatka pollock peaked in 2010, and then it gradually decreased. Currently, resources are at an average level. Horizons of the main pollock spawning in deep-water canyons change in an inter-a nnual aspect. In addition, as egg development, as a result of internal processes occurring in the canyons (internal waves), it, then rises, then falls in the underlying layers of water.Practical significance: The results of the work can be used to improve the method of assessment of the current and prospective state of stocks, justification of the TAC of the Eastern Kamchatka pollock.

Temporal trends of persistent organic pollutants biotransport by Pacific salmon in the Northwest Pacific (2008-2018).

The present study aimed to assess the biotransport of POPs, including OCPs and PCBs, by Pacific salmon (genus Oncorhynchus) on the northwestern Pacific Ocean. In 2008-2012, the Amur River basin, the eastern Kamchatka, and the mainland coast of the Sea of Okhotsk received the largest amounts of pesticides. In 2018, the transport of OCPs to the Russian northwestern Pacific reached only 1kg, and the total OCP levels in muscles of fish from this region were significantly lower than in previous years. The average concentration of PCBs for all species under study differed from that of OCPs, with the highest concentration recorded from sockeye salmon. In 2018, pink salmon brought the largest amount of PCBs to the Russian northwestern Pacific. Coastal water pollution has decreased significantly in recent years due to the ban on the use of POPs in the Northwest Pacific (according to the measurements in 2010 and 2018).

Water Circulation, Temperature, Salinity, and pCO2 Distribution in the Surface Layer of the East Kamchatka Current

The ship-borne observations of the temperature, salinity, pCO2 (1995–2020) and satellite geostrophic velocity fields, SST, and chlorophyll concentration are used to identify the factors that determine the spatio-temporal variability of seawater parameters on the western boundary of the subarctic North Pacific. In winter, the surface layer of the East Kamchatka Current (EKC) was characterized by two types of water: the waters with a negative temperature (−1.0–−0.5 °C) and salinity of 32.4–32.9 and waters with a positive temperature (0.4–1.7 °C) and salinity of 33.0–33.1. The source of water with negative (positive) temperature and decreased (increased) salinity for the EKC zone is the Bering Sea shelf (Aleutian Basin). The surface waters in the eastern Kamchatka area in winter were close to gas equilibrium with the atmosphere or supersaturated with carbon dioxide (pCO2 = 380–460 µatm). In summer, extremely low pCO2 values (140–220 µatm) in the surface layer of the eastern Kamchatka and the northern Kuril Islands regions have been associated with the decreased salinity (32.1–32.6) of the waters. The distributions of the temperature, salinity, and pCO2 in the surface layer of the central Kuril Islands are determined by the location and intensity of the Kuril eddies and the EKC stream jets. The water mixing in the central Kuril Straits and the Kruzenshterna Bank area leads to increased salinity (33.2–33.4) and high values of pCO2 (480–670 µatm) in the surface layer of the EKC. The comparison of the pCO2 data collected in winter demonstrates an increase in pCO2 between 1998/2001 and 2018/2020 at about 50 µatm in the surface waters with a salinity of 33.0–33.1, which is in agreement with an increase in pCO2 in the atmosphere at 46 µatm (from 368 to 414 µatm) during this period.