Southeastern Russia Research Articles

Mechanism of Coupled Upper Troposphere and Boundary Layer Induces Two Types of Short‐Term Heavy Rainfall Along the Eastern Foothills of the Taihang Mountains

AbstractUsing 11 years of hourly merged rainfall records and ERA reanalysis data, this paper reveals two major circulation modes leading to two types of short‐term heavy rainfall (STHR) along the Taihang Mountains' eastern foothills, and further explains their mechanisms. One circulation mode has a distinct warm anomaly at 300 hPa covering most areas of North China, together with the boundary‐layer westerly anomaly occurring in North China and its southern region (UTWA‐BLWA). UTWA‐BLWA effectively contributes to the reinforcement of the upper‐level divergence and the low‐level moisture convergence by promoting the strengthening of upper anticyclonic and low‐level southwesterly anomalies. The combined effects of low‐level jet (LLJ) and topographic uplift form the central‐northern STHR pattern. The other circulation structure has a 300‐hPa warm anomaly located to the southeastern Russia and a prominent 300‐hPa cold anomaly covering the south, together with the boundary‐layer easterly anomaly occurring over the whole region of eastern China (UTCA‐BLEA). The southern STHR pattern is attributed to the exit of the boundary‐layer jet (BLJ) over lower elevations due to moist transport and dynamic uplift associated with the easterly anomaly. The results indicate that the locations of STHR are related to the direction, intensity, and height of the LLJ. The findings highlight that the upper‐tropospheric temperature anomalies (UTTA) and boundary‐layer easterly flow jointly modulate heavy rainfall. Analysis of the coupled upper troposphere and boundary layer could help understand and forecast heavy rainfall.

Current and future patterns of vascular plant species richness across a forest–grassland–desert transect in East Asia

AbstractQuestionsRapid climate change has profoundly altered the spatial distribution of terrestrial plants especially in arid and semi‐arid biomes. However, it remains poorly documented how climate shapes the current and future patterns of plant diversity within and across these vulnerable vegetation types.LocationParts of Mongolia, southeastern Russia, and northern China (94.78°–126.78°E, 34.60°–54.27°N).MethodsUsing a random forest model trained by a comprehensively compiled database on vascular plant species richness (i.e., the number of species within a defined plot area) and corresponding climate variables, soil conditions and vegetation types (forest, grassland, desert), we assessed the current pattern of vascular plant species richness across a typical forest–grassland–desert transect in East Asia. We further predicted future changes in vascular plant species richness under three climate scenarios (SSP1‐2.6, SSP3‐7.0, and SSP5‐8.5).ResultsVascular plant species richness generally showed a decrease from northeast to southwest across the transect, mainly explained by spatial variations in growing‐season precipitation and the minimum temperature of the coldest month. More than half of the transect area will likely experience a loss in vascular plant species richness in 2041–2070 under all three scenarios. The decrease in vascular plant species richness will likely occur in a smaller area under the low‐emission scenario (SSP1‐2.6). We also predict distinct changes in vascular plant species richness for different vegetation types, including a slight increase in forests but an overall decrease in both grasslands and deserts.ConclusionsOur findings suggest a dominant role of growing‐season precipitation in shaping the spatiotemporal patterns of vascular plant species richness across the forest–grassland–desert transect and highlight a risk of plant diversity loss in the regional dryland ecosystems in response to future climate change.

A G6P1E isomerase of sugar metabolism is involved in the flower colors of Dianthus chinensis

Dianthus chinensis L. is indigenous to northern China, Korea, Mongolia, Kazakhstan, and southeastern Russia. It is widely cultivated in urban landscapes. Its flower has a great variety of colors and color schemes. Sugars control and induce anthocyanin synthesis and accumulation in plants. In sugar metabolism, many enzymes are specific for their substrate’s α or β anomer. Gaining and characterizing genes involved in sugar metabolism and flower color will be beneficial in clarifying the role of sugar in the flower colors of D. chinensis. Glucose-6-phosphate-1-epimerase (G6P1E, EC 5.1.3.15) catalyzes the α or β change of glucose-6-phosphate at the branch point of glucose metabolism. DchG6P1E1 (MZ292712) was isolated in D. chinensis and characterized using the tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) system. Its cDNA full length is 1401 bp, including an open reading frame of 918 bp. In the DchG6P1E1-silenced flowers, the reducing purple was observed, as well as the anthocyanin content, reducing sugar content, G6P1E activity, and DchG6P1E1 expression were significantly decreased. During the development of floral buds and among the three flower colors, the anthocyanin content, reduced sugar content, G6P1E activity, and DchG6P1E1 expression rose dramatically, with pigments increasing in the petals. Among the organs, the flowers had the highest anthocyanin contents and reducing sugar. The highest levels of G6P1E activity and DchG6P1E1 expression were in the roots. The anthocyanin content was positively related to the reducing sugar content at 0.05 levels by correlation analysis. In conclusion, DchG6P1E1 is a root-enriched gene associated with flower colors in D. chinensis.

Range-wide trends in tiger conservation landscapes, 2001 - 2020

Of all the ways human beings have modified the planet over the last 10,000 years, habitat loss is the most important for other species. To address this most critical threat to biodiversity, governments, non-governmental actors, and the public need to know, in near real-time, where and when habitat loss is occurring. Here we present an integrated habitat modelling system at the range-wide scale for the tiger (Panthera tigris) to measure and monitor changes in tiger habitat at range-wide, national, biome, and landscape scales, as often as the underlying inputs change. We find that after nearly 150 years of decline, effective potential habitat for the tiger seems to have stabilized at around 16% of its indigenous extent (1.817 million km2). As of the 1st of January 2020, there were 63 Tiger Conservation Landscapes in the world, covering 911,920 km2 shared across ten of the 30 modern countries which once harbored tiger populations. Over the last 20 years, the total area of Tiger Conservation Landscapes (TCLs) declined from 1.025 million km2 in 2001, a range-wide loss of 11%, with the greatest losses in Southeast Asia and southern China. Meanwhile, we documented expansions of modelled TCL area in India, Nepal, Bhutan, northern China, and southeastern Russia. We find significant potential for restoring tigers to existing habitats, identified here in 226 Restoration Landscapes. If these habitats had sufficient prey and were tigers able to find them, the occupied land base for tigers might increase by 50%. Our analytical system, incorporating Earth observations, in situ biological data, and a conservation-oriented modelling framework, provides the information the countries need to protect tigers and enhance habitat, including dynamic, spatially explicit maps and results, updated as often as the underlying data change. Our work builds on nearly 30 years of tiger conservation research and provides an accessible way for countries to measure progress and report outcomes. This work serves as a model for objective, range-wide, habitat monitoring as countries work to achieve the goals laid out in the Sustainable Development Goals, the 30×30 Agenda, and the Kunming-Montreal Global Biodiversity Framework.

Religious nationalism and the dynamics of religious diversity governance in post-communist Eastern Europe

The analysis of the dynamics of the governance of religious diversity in Southeastern and Central Eastern Europe and Russia provided in country studies in this special issue reveals that the countries of the region share several common tendencies but also exhibit significant divergences. This contribution compares the experiences of post-communist transition in religious diversity governance in the countries covered in the special issue. I assess the degree to which liberal regimes of religious diversity governance have been achieved or abandoned. I explore the explanatory factors behind the diversity of regimes in the region and the internal dynamics that these regimes have undergone throughout the post-communist period. I also compare policy issues related to the governance of religious diversity and the subsequent policy approaches adopted to tackle those challenges. The papers in this collection seek to explain a recent turn away from pro-diversity policy orientations by examining the influence of religious nationalism and the securitization of religion. In the conclusion, I argue for the need to consider additional factors related to post-communist transition in analyzing outcomes related to religious diversity governance.

Clarifying the taxonomic status and exploring hidden diversity in Graphomya minor Robineau-Desvoidy, 1830 (Diptera: Muscidae: Mydaeinae) using molecular and morphological evidence

Summary A first report on the phylogeography and phylogeny of the widespread Holarctic species, Graphomya minor Robineau-Desvoidy, 1830, within its continuous range throughout northern Eurasia and North America, is presented. The geographic patterns of genetic and morphological variability in G. minor were examined. The phylogenetic structure was assessed using the barcode fragment of the mitochondrial COI gene. We detected 35 unique COI haplotypes in in G. minor, with only two common haplotypes for both the Palaearctic and Nearctic regions. A higher number of COI haplotypes was detected in the Eurasian populations (27 haplotypes) than in the North American samples (eight haplotypes). The diversity of mitochondrial DNA haplotypes and the degree of genetic differences between five geographic populations of G. minor varies. Morphological analysis did not reveal correlations between haplotypes and morphological characters. A genetic comparison of G. minor with morphologically close Palaearctic (G. maculata, G. rufitibia) and Nearctic species (G. ungava, G. minuta, G. americana, G. transitionis) was made. The newly obtained COI sequences of Graphomya species (155) were combined with those published in the GenBank and BOLD databases (76) and were analysed using the species delimitation software ASAP. The results of these species delimitation analyses validated the morphological species in Graphomya and revealed two new species lineages of Graphomya located in north-eastern and south-eastern Russia. Based on the results of our analyses, we concluded that G. minor is a valid widespread polymorphic Holarctic species and is not a junior synonym of G. maculata; and assign 30 unidentified sequences from BOLD and GenBank to named morphospecies.

Intersections between Italian and Slavic cinemas

The purpose of this issue is to explore the encounter between Italy and Central, Eastern and Southeastern Europe and Russia during and after the Soviet period, as well as the fervid cooperation and fruitful co-productions between the film industries in this vast geographic region. More specifically, this Special Issue covers the following topics: the reception of neorealist films in Slavic countries and the influence of neorealism in Slavic cinema, the links between Italian political cinema and Slavic media, the presence of popular Italian genres of television shows and series in these geographical areas, transnational stardom in cinema and television, co-productions and their adaptation to the needs of national film and television markets, Soviet–Italian film institutional exchanges and co-productions and Italian film festivals in Russia and Italy.

Процесс чистки студенческого состава высшей школы Юга России в 1924 году: приоритеты и итоги

The article studies the process of extensive academic and qualitative inspection of the student body of the higher school of Southern Russia (South-Eastern Russia at that time) made in 1924. The study is based on archival documents of territorial and local inspection commissions, as well as students’ appeals deposited in the funds of the State Archive of the Rostov Region. The official goal of the inspection was to ease the overcrowding of universities and to get rid of the «dead weight» meaning students who did not fit the criteria of a «red» specialist capable of benefiting the state. The authors attempted to determine whether the local commissions properly understood their tasks and the conditional boundary between academic and qualitative approaches, which led to the conclusion of a significant dependence of the inspection process on the mood of the local inspection commissions, often too keen on the class- based approach in their work. Another conclusion is the poor effectiveness of the inspection process itself, which did not lead to solving the overcrowding of the higher school problem, but once again alarmed the students. An analysis of the appeals of expelled students led to the conclusion of a high level of antagonism not only among the student body, but also in Soviet society in general, which was expressed, first of all, in searching for internal enemies. A student who had joined the White Army during the Civil War and failed to conceal it was often condemned to be expelled or to be denounced. Moreover, as an analysis of the reactions of the students has revealed, the purge also negatively affected the proletarian student body, which was forced to work every day and actually struggle for its survival under conditions of extreme material insecurity, leading to poor academic performance.

Study of the Crustal Displacement Fields by Space Geodesy Method at the Primorie

This work presents the results of GPS observations (2003–2020) carried out in Primorsky Krai (aka the Primorie) and Khabarovsk Krai in southeastern Russia. The objectives of our study were to obtain displacement velocities, to test the relation of current velocities with seismicity, with the specific features of the geological structure of the Primorie, and to study the rheological parameters of the crust and asthenosphere at the continental margin. This paper analyzes the results of measurements made in the Primorie at the Central Sikhote-Alin fault. The study includes the effects of the Tohoku-Oki earthquake in Japan with magnitude M = 9, which occurred on March 11, 2011. The zone of coseismic and postseismic displacements extends to a distance of over 1,000 km from the epicenter. The postseismic attenuations of the multi-year horizontal and vertical displacements allow us to estimate the relaxation time for the elastic-viscous model. With attenuation times of 4 to 8 years, the following viscosity values were obtained for the lower layer according to the two-layer rheological model: 8 × 1018–3 × 1019 Pa s. Using the bending model of the Earth’s surface and the bottom of the Sea of Japan, we estimated the thickness (20–25 km) of the elastic upper part of the Earth's crust in the continent–ocean contact zone.

The first documentation of the Nearctic-Paleotropical migratory route of the Arctic Warbler.

The Arctic Warbler (Phylloscopus borealis) is a cryptically plumed songbird with an uncommon Nearctic–Paleotropical migratory strategy. Using light‐level geolocators, we provide the first documentation of the migratory routes and wintering locations of two territorial adult male Arctic Warblers from Denali National Park and Preserve, Alaska. After accounting for position estimation uncertainties and biases, we found that both individuals departed their breeding grounds in early September, stopped over in southeastern Russia and China during autumn migration, then wintered in the Philippines and the island of Palau. Our documentation of Arctic Warbler wintering on Palau suggests that additional study is needed to document their wintering range. Our study provides hitherto unknown information on stopover and wintering locations for Arctic Warblers and indicates that this species may migrate further overwater than previously thought.

Murray Bookchin; Dari Bolshevik ke Marxis Otonomis

This study discusses a brief biography of Murray Bookchin's revolutionary journey by tracing his activism and intellectual movements. This study uses a literary or library research approach, namely a comparative study to explore and trace the life journey of Bookchin. Boochin's long history of involvement in the revolutionary movement was inherited directly by his grandmother Zeitel Carlat who was a combatant in the war against the dictatorship of the Tsarist Empire. Zeitel who grew up with a liberal and secular education from the Haskalah tradition then passed his ideas on to his children, one of whom was Bookchin's mother, Rose. Rose is very different from her mother Zeitel. The difference was clearly illustrated when Rose chose to join the Russian Anarchist Workers' Union rather than join the American Communist Party. Over time Rose later married Nathan, a fellow Jewish immigrant. However, because Zeitel's hatred for Nathan was so strong, Rose and Nathan's relationship had to end. It was at this moment that Bookchin was first educated directly by his grandmother. From a young age, Bookchin was introduced to Russian revolutionary traditions, such as Stenka Razin, the leader of the Cossack rebellion and the large-scale peasantry in southeastern Russia. This search process is an attempt to elaborate and trace the background of Murray Bookchin's life so that he can find his own concept of thinking, namely dialectical naturalism and the concept of social ecology which has an important contribution to the dimensions of social science, especially sociology.

Climatology of Northeast China cold vortices during the warm season: A comparison of ERA5 and MERRA‐2 reanalyses

AbstractThe Northeast China cold vortex (NCCV) is an important type of synoptic scale system, which often induces local torrential rainfall events, strong winds, and lightning during warm seasons (May–September). By using an automatic identification method that involves a three‐step algorithm, NCCVs during warm seasons of 1980–2018 were identified based on ERA5 and MERRA‐2, the latest generation of reanalysis. Employing this recognition result and intensive surface observations, climatology of the NCCV was analysed. With respect to average climatic characteristics, the results indicate that the NCCV is most frequently located from the east of the Yablonov Mountains to the west of the Xiao Hinggan Mountains. The average rain belt and cold tongues resulting from NCCVs both mainly fall within Northeast China, Japan, Southeast Russia, and the Korean Peninsula, causing precipitation and temperature anomalies there, especially in Northeast China. Regarding interannual variation, the number of NCCV‐occurrence hours varies at a cycle of about 3 years, and has increased in the last 10 years compared to 1999–2008. The intensity of the NCCV also fluctuates in a cycle of approximately 3 years and shows a weakening trend, particularly from July to September. As for life characteristics, NCCVs usually form at the border area between China, Mongolia, and Russia, then develop and move eastwards, and finally disappear in areas of Heilongjiang in China, southeastern Russia, and the Okhotsk Sea. The NCCV moves in complex paths; among all 55 types of routes that occurred in warm seasons of 1980–2018, the most favoured paths are east, southeast, northeast, southeast‐to‐northeast, and circular. The above results based on the up‐to‐date reanalysis datasets with high resolutions are updates and supplements to previous studies, further improving our understanding of the NCCV in aspects of its cooling effects, weakening trends, and crucially, paths of movement and their occurrence frequency.

Late Cretaceous granitoids of the Sikhote–Alin orogenic belt, southeastern Russia: implications for the Mesozoic geodynamic history of the eastern Asian continental margin

We present new U–Pb age data for granitoids in the Central Sikhote–Alin orogenic belt in SE Russia, which refute the established opinion about the absence of the Late Cretaceous magmatism at the eastern margin of the Palaeo-Asian continent. It was previously thought that a period of magmatic quiescence occurred from 88 to 50 Ma, related to subduction of the Palaeo-Pacific plate under the eastern margin of the Palaeo-Asian continent, although this is inconsistent with evidence from the Sikhote–Alin, Sakhalin and Japan regions. Three suites of plutonic rocks with different ages were identified in this study. The first suite has ages of 105–92 Ma and formed in a syn-orogenic setting. The second (86–83 Ma) and third ( c. 73 Ma) suites formed during the post-orogenic stage of the Sikhote–Alin orogenic belt. The second and third suites were coeval with Late Cretaceous granitoids that formed in a supra-subduction continental arc known as the Eastern Sikhote–Alin volcanic–plutonic belt. However, the studied rocks are located far inland from the Eastern Sikhote–Alin volcanic–plutonic belt. The ages of the studied granitoids coincide with the timing of a change in the angle of convergence between the Palaeo-Pacific plate and eastern margin of the Palaeo-Asian continent. This change in motion of the oceanic plate with respect to the continental plate was probably caused by a rupture in the subducted slab (i.e. a slab tear), followed by asthenospheric upwelling and partial melting of the overlying crust, which ultimately generated post-orogenic intrusive magmatism. Supplementary material: Laser ablation–inductively coupled plasma–mass spectrometry zircon U–Pb data of the Bikin–Bol. Ussurka granitoid suites are available at https://doi.org/10.6084/m9.figshare.c.5738616

«Осмотреть весь полуденный Восток России»: кавказские травелоги Степана Нечаева

Stepan D. Nechaev is a poet and prose writer of the first quarter of the 19th century, who is known not so much for his literary works as for his literary connections. He was friends with A. Bestuzhev (Marlinsky), was familiar with K. Ryleev, V. Kyuchelbeker, D. Davydov, N. Polevoy, published in almanacs “Polar Star”, “Mnemosyne”, “Urania”, in the journals “Herald of Europe”, “Moscow Telegraph”, “Well-intentioned”, “Ladies’ Magazine”. Nechaev undertook a long trip around the Caucasus for ethnographic study and literary description of an unfamiliar region in 1823. The result of this trip was two literary travelogues – a large poem “Memories” and prose “Excerpts from travel notes about South-Eastern Russia”. Most of the time the author-traveler spent on the Caucasian Mineral Waters – in Goryachevodsk (future Pyatigorsk) and Kislovodsk. However, the entire Caucasian route turned out to be much longer: through Starocherkassk, Stavropol and Georgievsk to the Caucasian waters and back – through Georgievsk, Mozdok and Kizlyar to Astrakhan and further up the Volga. During this voyage, Nechaev had a number of important meetings. The official and writer V. Timkovsky, who was under General A. Yermolov, may have revealed to Nechaev the secret plans of the environment of the “proconsul of the Caucasus”. The Kabardian educator Sh. Nogmov introduced him to the culture and way of life of his people. A disgraced officer and future participant in the uprising on Senate Square A. Yakubovich became a friend of Nechaev and the hero of one of his poems. Nechaev’s Caucasian travelogues were published in 1825–1826, being one of the last lifetime publications of this author. After the defeat of the Decembrist uprising, among whom were friends and acquaintances of Nechaev (K. Ryleev, A. Bestuzhev, V. Kyuchelbeker, A. Yakubovich), he also came under suspicion. No great fault was found for Nechaev, but he preferred to give up his dream of literary glory

Major Russian helium project comes on line

The era of vexing helium shortages is likely at an end. The Russian state-owned company Gazprom brought 20 million m 3 of new helium capacity on line earlier this month when it opened the first of three helium production lines at its Amur gas-processing plant in southeastern Russia. The firm also commissioned a related logistics center that will feed liquid helium into cryogenic containers for shipment around the world. Helium will also flow from Amur via pipeline to nearby buyers in China. The facility boosts the global supply of helium by about 11%, according to helium consultant Phil Kornbluth. When all three lines are up and running, Amur is expected to provide 60 million m 3 of helium per year alongside methane, ethane, and other less valuable products. Gazprom says Amur will reach full capacity in 2025. The opening of the first Amur plant should mark the end of more

New host and distributional records for Camarosporidiella in Italy, Russia, and Ukraine

Camarosporidiella specimens collected from woody plants in central Italy, eastern Ukraine, and southeastern Russia were identified based on morphology and multi-gene (LSU, SSU, ITS, and TEF) sequence analyses. Camarosporidiella caraganicola on Amorpha fruticosa, C. celtidis on Ulmus pumila, C. elaeagnicola on Cytisus ruthenicus are described with new host records and as new fungal records for Ukraine. Camarosporidiella moricola on Morus nigra is newly reported for Italy, and C. robiniicola on Robinia pseudoacacia is new for Ukraine. Camarosporidiella elaeagnicola on Elaeagnus angustifolia is re-described to facilitate identification. Notes on host distribution of Camarosporidiellaceae are also provided.

Paleofloristic and paleoenvironmental implications of a Late Jurassic palynoflora from the Tochikubo Formation, North-East Japan

The first Jurassic palynofloral assemblage from Japan is reported from the Oxfordian Tochikubo Formation of the Soma-Nakamura Group, Fukushima Prefecture. Palynomorphs are quite diversified, with 32 genera and 41 species of lycopod and fern spores, gymnosperm pollen and freshwater algae. The composition of the assemblage is consistent with the Oxfordian age of this nonmarine formation and confirms a fluvio-lacustrine paleoenvironment, further detailing the paleovegetation reconstructed from macrofloral remains. Previous palynofloral reports of eastern Asia are reviewed and indicate that northeast Japan shares most similarities with coeval paleofloras of southeastern Russia. Consequences for paleofloristic provincialism and climates of the region during the Late Jurassic are discussed.

Poor fruit set due to lack of pollinators in Aristolochia manshuriensis (Aristolochiaceae)

Background and aims – Interactions of insects with trap flowers of Aristolochia manshuriensis, a relic woody liana with fragmented natural populations from south-eastern Russia, were studied. Pollination experiments were conducted to identify the causes of the poor fruit set in this plant.Material and methods – The study was carried out at two ex situ sites within the natural range of A. manshuriensis in the suburban zone of the city of Vladivostok (Russia). The floral morphology was examined to verify how it may affect the process of pollination in this species. To test for a probability of self-pollination, randomly selected flowers at the female phase of anthesis (day 1 of limb opening) were hand-pollinated with pollen from the same plant. The daily insect visitation was studied. The pollen limitation coefficient and the number of visitors to the flowers were determined. To identify insects that lay eggs on the flowers, the insects were reared from eggs collected from fallen flowers. Both caught and reared insects were identified.Key results – The floral morphology and the colour pattern of A. manshuriensis are adapted to temporarily trap insects of a certain size. The hand-pollination experiment showed that flowers of this plant are capable of self-pollination by geitonogamy and require a pollinator for successful pollination. The positive value (2.64) for the pollen limitation coefficient indicates a higher fruit set after hand-pollination compared to the control without pollination. The number of visitors to the flowers was low (0.17 visitors per flower per day). Insects from three orders were observed on the flowers: Diptera (up to 90.9%), Coleoptera (8.3%), and Hymenoptera (0.8%). Four species of flies (Scaptomyza pallida, Drosophila transversa (Drosophilidae), Botanophila fugax, and Botanophila sp. 1 (Anthomyiidae)) are capable of transferring up to 2500–4000 pollen grains on their bodies and can be considered as pollinators of A. manshuriensis. Data of the rearing experiment indicate that flies of the families Drosophilidae (S. pallida, D. transversa), Chloropidae (Elachiptera tuberculifera, E. sibirica, and Conioscinella divitis), and Anthomyiidae (B. fugax, B. sp. 1) use A. manshuriensis flowers to lay eggs. Beetles were also collected from the flowers, but they were probably not involved in pollination, because no pollen grains were observed on them during our study.Conclusions – Pollinators of A. manshuriensis include mainly Diptera that lay eggs on the flowers. The poor fruit set (2%) in A. manshuriensis is associated with pollen limitation due to the lack of pollinators, as the number of visitors to flowers was extremely low. This may be due to the fact that the flowers of this species are highly specialized on insects of a certain size for pollination.

Paleocene–early Eocene post-subduction magmatism in Sikhote-Alin (Far East Russia): New constraints for the tectonic history of the Izanagi-Pacific ridge and the East Asian continental margin

New isotopic, geochemical and geochronological data justify the widespread occurrence of middle Paleocene to early Eocene (60–53 Ma) post-subduction felsic magmatism across the entire Sikhote-Alin territory (southeastern Russia), conform with previous observations in Northeast China, the southern Korean Peninsula, and the Inner Zone of Japan. This igneous activity in East Asia coincided with the reactivation (after tectonic quiescence between ~93–60 Ma) of left-lateral strike-slip displacements along the Tan-Lu and Central Sikhote-Alin faults and with the post-60 Ma cessation of subduction/accretion recorded in the Shimanto belt of SW Japan. The Sikhote-Alin post-subduction igneous A-type rocks present diverse mineralogical and geochemical features that suggest interactions of the subducting plate with anhydrous mantle upwelling through slab tears in the continental margin. The middle Paleocene–early Eocene magmatism is not related to subduction but is synchronous with strike-slip tectonics and the termination of accretionary prism development, suggesting a shift in tectonic regime from oceanic plate subduction at a convergent margin to parallel sliding and initiation of a transform continental margin. These new observations are inconsistent with the current tectonic model of 60–50 Ma Izanagi-Pacific ridge subduction beneath East Asian continental margin.

Seismotectonic Deformation of Active Segments of the Junction Zone of the Kolyma–Omolon Superterrane and South Anui Suture (Southeastern Russia)

Our seismotectonic studies focus on active segments of the junction zone of the Kolyma–Omolon superterrane and the South Anui suture. The aim of our research is to identify features that show activation of suture zones and to determine the parameters of the stress–strain state of the crust in the study area. The analysis was based on the average seismotectonic deformation tensors, which were estimated for the main epicentral fields of Russia’s northeastern regions. New data are now available on the focal characteristics of moderate earthquakes, which can improve determination of the kinematic types of junctions of suture zones of the tectonic taxa located along the Arctic and Pacific continental margins. Seismotectonic crustal destruction regimes are determined for the active segments of the junction zone of the Kolyma–Omolon superterrane and the South Anui suture. These regimes are influenced by global geodynamic processes taking place at lithospheric plate margins, as well as by the dominant deformation fields of adjacent tectonic taxa. The seismotectonic analysis results suggest activation of the suture zones of the northwestern flank of the Kolyma–Omolon superterrane under stable north-eastward compression. The suture zones may extend into the Laptev Sea area, where they are conjugate with the structural elements of the South Anui suture (Novosibirsk–Svyatoi Nos segment). In the Anui–Chukotka segment of the suture, seismotectonic crustal destruction changes from compression to extension. This is due to the effect of deformation fields of active megazones of conjugated tectonic taxa of the Novosibirsk–Chukotka fold-and-thrust and Okhotsk–Chukotka active margin zones. For the tectonic taxa of the Arctic sector of Russia’s northeastern regions, a database has been consolidated, including the of seismotectonic crustal deformation parameters, which may be useful for various geodynamic reconstructions.