Southern Sikhote-Alin Research Articles

The Development of the Natural Environment in the Valley of the Knevichanka River in the Middle and Late Holocene (Southern Sikhote-Alin)

The Development of the Natural Environment in the Valley of the Knevichanka River in the Middle and Late Holocene (Southern Sikhote-Alin)

Биотопическое распределение пауков-кругопрядов (Aranei: Araneidae) в привершинной зоне гор Южного Сихотэ-Алиня

Until recently, the study of spiders in the mountainous conditions of the Primorsky Region of Russian Far East was carried out only with the example of ground dwelling spiders. The purpose of this work is to reveal the species composition and features of the biotopic distribution of orb-weaver spiders (Aranei: Araneidae) in the ridge-top zone of the Southern Sikhote-Alin mountains (Primorsky Region). The field material was collected from may to october in 2016 and 2017 at key sites located on different mountain ranges and their spurs in the altitude range from 1000 to 1560 m above sea level. Within each key sites, transect-sites with a size of 3 x 25 m were laid. The spider's collections were by the hands collecting and sweeping method. A total of 305 specimens of spiders belonging to 10 species from 7 genera were caught. Comparison of species lists of spiders was carried out by cluster analysis methods (unweighted pair group method with arithmetic mean, UPGMA) using the Jacquard coefficient. For automatic calculations data processing program Past v. 2.17 is used. The maximum diversity of spiders is observed among the herbage-reed meadows, which do not form a continuous belt of vegetation at altitudes of 1000–1400 m above sea level. seas. Seven species belonging to 6 genera were caught here. The minimal diversity is noted among the continuous open stony debris, devoid of vegetation. Here is the only species caught – Aculepeira matsudae. The species Plebs sachalinensis and Araniella yaginumai are most numerous and widespread in the ridge-top zone of the Southern Sikhote-Alin. The high abundance of Araniella yaginumai is achieved due to favorable conditions for this species in the herbage-reed grass lands. In all the studied biotopes in the ridge-top zone of the mountains the density of the orbweaver spiders is low and does not exceed 2.04 specimens per 10 m2.

The Crust and Upper Mantle Structure of the Southern Sikhote Alin from Magnetotelluric Sounding and Density Modeling

Based on the results of correlation of the geoelectric and density sections constructed using three-dimensional inversion of three profiles located in the southern Sikhote Alin, the distribution regularities were revealed in the electric and density parameters, the relationships between them were established, and new data on the crust and upper mantle structure of the region were obtained. A relationship between certain density and electric inhomogeneities within the upper mantle and the Late Cretaceous subduction processes was proposed.

The Fractal Geometry of the River Network and Neotectonics of South Sikhote-Alin

The proposed complex Parameter of River Network Self-similarity (PRNS), which is a combination of the exponents in the equations for distribution of channel lengths, the fractal dimension of channels, and the fractal dimension of points of change of the order of the channel, matches neotectonic movements more accurately. A comprehensive analysis of the self-similarity of the southern Sikhote-Alin River network model derived from the Digital Elevation Model (DEM) based on the Shuttle Radar Topography Mission image (SRTM) has been performed. Comparison of the results of morphostructural and fractal analyses showed the good consistency of these two methods. The relative PRNS maxima coincide with areas with the largest amplitude of ascending neotectonic movements (increment of relief), while the minima coincide with the areas either with the lowest increment of relief or with greatest erosion rates. Most of the crustal earthquakes are confined to the boundaries between PRNS relative maxima and minima, that is, uplifts are surrounded by seismic areas, which is due to the block nature of neotectonic vertical movements.

The Crust and Upper Mantle Structure of the Southern Sikhote Alin from Magnetotelluric Sounding Data along the Abrazheevka–Valentin Profile

Based on the results of magnetotelluric soundings carried out in the southern part of the Sikhote Alin Fold System in the frequency range from 10 kHz to 0.001 Hz, the geoelectric section was constructed down to a depth of 150 km. The electrical parameters have been obtained and the crust and upper mantle structure has been studied. The crust has a high resistivity ranging from 1000 to 20 000 Ohm m and is divided into fault-bordered blocks according to low resistivity zones. Two zones with abnormally low resistivities of 100–200 Ohm m and lower have been distinguished in the crust and upper mantle. The structure of the geoelectric section is related to the subduction of an ancient plate and the formation of a slab window.

Boreal Molluscan Records Around the Jurassic–Cretaceous Boundary in East Asia Provide Clues for the Paleobiogeographical Reconstruction in the Mid-Latitudes of the Northwest Pacific

Studying marine paleobiogeographical conditions in the mid-latitudes of the Northwest Pacific around the Jurassic–Cretaceous boundary would be expected to contribute to a better understanding of the paleoclimatic and/or paleoenvironmental background of the evolution of the Late Mesozoic terrestrial ecosystem in East Asia. However, uncertainty about the paleogeography of the eastern margin of the Asian Continent has meant difficulties for paleobiogeographical discussion. In this paper, the strata containing Boreal faunal elements, Buchia, and cylindroteuthidid belemnites in East Asia (Far East Russia, Heilongjiang in northeastern China, and Japan) and their tectonic settings are reviewed. The Uda and Torom (northern Sikhote-Alin), Suibin (Heilongjiang), and Tetori (northern Central Japan) regions were located from north to south in the eastern margin of the already amalgamated Asian Continent around the Jurassic–Cretaceous boundary and can be considered the “fixed points for paleobiogeographical reconstruction.” On the other hand, Buchia-bearing strata in the Komsomolsk (northern Sikhote-Alin) and Dong'an (Heilongjiang) regions can be considered to have been deposited in the fore-arc basin or trench slope basin on the accretionary complex along the East Asian continental margin. The strata around the Jurassic–Cretaceous boundary in the Partizansk Basin (southern Sikhote-Alin) contain both Buchia and Tethyan ammonoids and were deposited on the Paleozoic continental basement or block (Sergeevka Belt). The paleo-position of these three regions around the Jurassic–Cretaceous boundary is highly debated.The Tethyan–Pacific ammonoids, Boreal belemnites, and Tetori bivalve fauna, showing some similarities with those in the Boreal Realm and Early Cretaceous strata in Heilongjiang, are present in the late Tithonian–Berriasian Mitarai Formation of the Tetori Group in the Tetori Region. This unit, deposited in the eastern margin of the North China Block, provides evidence that Boreal faunal elements reached the mid-latitudes of the Northwest Pacific. The position of the ecotone of the Boreal and Tethys realms in the Northwest Pacific can be discussed based on the comparison of the faunal elements among almost coeval strata in the Tetori Region (fixed point), the Sergeevka Belt, and the South Kitakami Belt (Pacific side of Northeast Japan), which is usually correlated with the Sergeevka Belt but contains only Tethyan faunal elements. Further studies of the records of Tethyan and Boreal taxa in the “fixed points” and other localities could provide clues to reveal the paleoclimatic and/or paleoenvironmental background of the evolution of the terrestrial and marine ecosystems in East Asia around the Jurassic–Cretaceous boundary.

Late Pleistocene and Holocene small mammal (Lipotyphla, Rodentia, Lagomorpha) remains from Medvezhyi Klyk Cave in the Southern Russian Far East

Late Pleistocene-Holocene faunal complexes of small mammals (Lipotyphla, Rodentia, and Lagomorpha) from the Russian Far East are described for the first time. We used material from the Medvezhyi Klyk Cave, located in Southern Sikhote-Alin. The numerous fossil findings from the cave display a remarkable taxonomic diversity and high degree of preservation. AMS 14C dating used for determination of deposits age. The Holocene sediments were divided into three periods: Early, Middle, and Late. The Pleistocene deposits age was not exactly determined, but under approximately estimation it can reach 50–60 ka. Thirty-nine species were found, including one member of the extinct genus of arvicolins. There are six faunal complexes identified from the studied Late Pleistocene and Holocene deposits. In general, the faunal complexes characterized by the dominance of Craseomys rufocanus within rodents, Sorex caecutiens within lipotyphlans; and relatively stability composition of most number of the dominant, codominant and subdominant species. Accordingly, the faunal complexes were described by means of two determining criteria only: relative number of species; and presence or absence of certain species. The dominant species are eurytopic and so they cannot use for reconstruction of the paleoenvironment.

ФРАКТАЛЬНАЯ ГЕОМЕТРИЯ РЕЧНОЙ СЕТИ И НЕОТЕКТОНИКА ЮЖНОГО СИХОТЭ-АЛИНЯ

A new complex parameter is proposed to characterize the self-similarity of a river network, that is, the parameter of river networks self-similarity (PRNS), which is a combination of the exponent in the distribution of channels along the lengths, fractal dimension of channels, and fractal dimension of points of channel order change, which is more correct when compared with neotectonic movements. A comprehensive analysis of the self-similarity of the river network model for the southern Sikhote-Alin derived from the Digital Elevation Model (DEM) based on the Shuttle Radar Topography Mission (SRTM) image was performed. Comparison of the results of morphostructural and fractal analyses showed a good correlation of these two methods. PRNS relative maxima coincide with areas where ascending neotectonic movements are of the largest amplitude (increment of relief), while minima coincide with areas either of the least increment of relief or where erosion rates are the greatest. At the same time, most epicenters of crustal earthquakes are confined to the boundary zones between PRNS relative maxima and minima, that is, uplifts are flanked by elongated seismic areas, which is related to the block nature of neotectonic vertical movements.

The Crust and Upper Mantle Structure of the Southern Sikhote Alin along the Profile Dal’nerechensk–Roshchino–Plastun from Magnetotelluric Sounding Data

Magnetotelluric soundings (MTS) are carried out in a broad frequency range from 104 to 10–3 Hz at a total of fifty-five sounding sites spaced about 5 km apart along the profile Dal’nerechensk–Roshchino–Plastun across the strike of the Sikhote Alin Orogenic Belt (SAOB). Based on the results of data interpretation, the crust and upper mantle geoelectric section is constructed down to a depth of 150 km. The section shows the crust of variable thickness between 20 and 40 km with a resistivity higher than 1000 Ohm m, which consists of different-resistivity blocks bordered by subvertical and inclined low-resistivity zones, from tens to a few hundreds of Ohm m. Three abnormal-resistivity zones are revealed in the crust and upper mantle. The upper mantle structure is nonuniform. Beneath the western and eastern parts of the SAOB, the lowest resistivity values are observed at 40–80 km depths. A high-resistivity zone of 300–500 Ohm m, stretching in the westerly direction from the coast beneath the Khanka superterrane, is identified in the 80–150 km depth range. This area is treated as remnants of the plate of an ancient subduction zone; two low-resistivity canals are distinguished here, which are associated with a slab-window. The results obtained for the northern and southern parts of the SAOB are compared and their similarities and dissimilarities are ascertained.

Climate And Human Impact On Vegetation In The Upper Part Of The Ussuri River Basin In Late Holocene, Russian Far East

Changes in vegetation in the southern Sikhote-Alin Mountains, which are in the upper reaches of the Ussuri R., are shown respond to minor climatic fluctuations over the past 5.4 ka. The largest mountain, Muta mire, chosen for paleoenvironmental reconstructions, is located within the main regional watershed. The studies include diatoms and pollen analyses. Chronology is based on radiocarbon dating and position of B-Tm tephra of the Millennium eruption of Baitoushan volcano. The cooling and warming reconstructed from the regional data correlate with global paleoclimatic events. The regional humidity changes notably along with the temperature fluctuations. Fire chronology was established and its significance for vegetation was estimated. Periods of frequent forest fires coincided with reduced moisture supply during cooling events. The analysis per formed revealed a considerable human impact on the vegetation in the 20th century.

The Late Cretaceous East Sikhote-Alin Volcanic Belt: Transition from Subduction to Sliding of Lithospheric Plates (Structure-Geological, Petrological, and Isotope-Geochemical Aspects)

Abstract —The East Sikhote-Alin volcanic belt extending for ~1500 km is commonly considered a single tectonomagmatic structure formed during the Late Cretaceous subduction and the Cenozoic oceanic-slab breakup and active asthenospheric diapirism under transform plate sliding. Based on analysis of the published geological information and the new data on the age and trace-element and isotope compositions of the igneous rocks of the Late Cretaceous Bol’ba Formation, it is shown that the initial stages of volcanism in the southern and northern Sikhote-Alin took place in different geodynamic settings. In contrast to the coeval suprasubductional volcanics of the southern sector (Primorye), the volcanic section of the Bol’ba Formation is dominated by magnesian (Mg# = 26–40) adakites (La/Yb = 19–34) and high-Nb basalts. This igneous rock association and the lead (Δ8/4Рb = 30–46) and neodymium (0.51279–0.51281) isotope ratios of the studied rocks suggest the influence of the “hot” oceanic asthenosphere on magma genesis. The earlier slab breakup north of 48–49 °N was due to the oblique convergence of oceanic and continental lithospheric plates in the Late Cretaceous, accompanied by sinistral shears. The results obtained indicate that the lateral zonation of the eastern Sikhote-Alin is due to different geodynamic settings of formation of its northern and southern sectors rather than variations in its basement composition. In theoretical aspect, the performed research is important for the correct reconstruction of the geologic events in zones of convergence of oceanic and continental plates. It is necessary to take into account not only the general direction of the convergence but also the configuration of the plate boundary.

Development of the Natural Environment of Midlands of the Southern Sikhote-Alin Recorded in the Sergeev Plateau Peat Bogs

The evolution of the natural environment of the middle mountains of the Southern Sikhote-Alin is reconstructed for the last 4.9 ka by data of the comprehensive study (botanic, diatom, and pollen analysis) of two peat swamps on the Sergeev Plateau. Radiocarbon dates and the position of the B-Tm marker ash layer of the Baitoushan Volcano, which erupted in the tenth century, are used to determine the chronology of events. An age model is constructed and peat accumulation rates and ash content in the peat are analyzed. It is revealed that the belt of dark coniferous forests at altitudes of about 900 m is relatively stable, while multidirectional climatic variations caused sharp changes in the predominating peat-forming plants. Unstable climatic conditions determined most of the features of the hydrological regime of the swamps. Reduced groundwater level and a greater role of atmospheric precipitation were usually related to cold events. Fires were one of the factors determining the landscape development; their frequency and intensity are determined. The longest period of intensive fires occurred in the last millennium. It is proposed that they may be of anthropogenic origin and related to the development of the area in the Middle Ages.

Crust and Upper Mantle Structure of the Southern Sikhote-Alin Along the Profile Spassk-Dalnyi–Zerkal’naya Bay from Magnetotelluric Sounding Data

Magnetotelluric soundings (MTS) were conducted in a broad frequency range of 103 kHz to 10–3 Hz at a total of fifty sounding sites spaced 5 km apart along the profile Spassk-Dalnyi – Zerkal’naya Bay across the strike of the Sikhote-Alin Orogenic Belt (SAOB). As a result of data interpretation, the geoelectric section of the crust and upper mantle has been constructed down to 150 km depth. The section distinguishes the crust with a resistivity higher than 1000 Ohm m and variable thickness between 20 and 50 km that is composed of different resistivity blocks bordered by low resistivity (a few tens to a few hundreds of Ohm m) subvertical and inclined zones. The abnormal low-resistivity zones associated with ore deposits are revealed in the upper crust. The upper mantle structure is nonuniform. The lowest resistivity values are noted in the depth range of 40–80 km beneath the central SAOB. It is underlain by a high-resistivity (350–450 Ohm m) layer stretching westwards from the coast and confined by a high-resistivity (about 500 Ohm m) area beneath the Khanka superterrane in the depth range of 80–120 km. The distinguished structure is associated with the ancient subduction zone. We considered the relationship between the deep structure and the resistivity values of the upper mantle and seismicity. The temperature regime in the upper mantle is evaluated. The geodynamic model of evolution of the area is proposed.

Carbon Emission from the Surface of Coarse Woody Debris in Korean Pine Forests of Southern Primorye

Carbon dioxide fluxes from the surface of coarse woody debris (CWD) have been measured in Korean pine forests of the southern Sikhote-Alin mountain range. The seasonal dynamics of oxidative conversion of CWD carbon have been evaluated, and average values of the CO2 emission rate have been determined for CWD fragments of three tree species at different stages of decomposition. The degree of decomposition is an important factor of spatial variation in CO2 emission rate, and temporal variation in this parameter is adequately described by an exponential function of both CWD temperature and air temperature (R2 = 0.65–0.75).

Oceanic and Continental Mantle Fragments in Ophiolites of the Northwestern Pacific Margins: Composition, Age, and Genesis of Sakhalin Peridotites

The paper presents the results from a study of original and published data on the chemical composition and age of mantle peridotites from Sakhalin Island ophiolites. The material and genetic proximity of peridotites from the Berezovsky and Shelting plutons, on the one hand, and melange zone serpentinites, on the other, have been established. In composition and Fe2O3 and MgO variations, Sakhalin peridotites differ radically from those of the Northeast Asia ophiolite complexes (Krasnogorsky Massif, Karaginsky Island Massif, etc.), which are fragments of Pacific Plate mantle. Conversely, Sakhalin peridotites have a subcontinental genesis and are compositionally close to xenoliths of lherzolites from Hankai Microcontinent mantle (southern Sikhote-Alin). The rythmics of alternation in compression and expansion at the margin of the Asian continent in the last 180 million years, caused by cyclical changes in the Pacific spreading rate, have been considered. According to data obtained by U-Pb dating of zircons, the formation of the Berezovsky Massif took place 169–154 Ma ago during Jurassic expansion of the continental margin. Matching age and composition data demonstrate that the Sakhalin ophiolites formed within the marginal sea basin during riftinduced destruction of the periphery of the Hankai Craton. The assumed tectonic setting was close to that reconstructed for the Jurassic Josephine ophiolites of the California margin of the North American continent. The continental genesis of the studied ophiolites agrees with the age and tectonic mode of ophiolite formation for Sakhalin Island.

Autumn–winter minimum temperature changes in the southern Sikhote-Alin mountain range of northeastern Asia since 1529 AD

Abstract. The aim of our research was to reconstruct climatic parameters (for the first time for the Sikhote-Alin mountain range) and to compare them with global climate fluctuations. As a result, we have found that one of the most important limiting factors for the study area is the minimum temperatures of the previous autumn–winter season (August–December), and this finding perfectly conforms to that in other territories. We reconstructed the previous August–December minimum temperature for 485 years, from 1529 to 2014. We found 12 cold periods (1535–1540, 1550–1555, 1643–1649, 1659–1667, 1675–1689, 1722–1735, 1791–1803, 1807–1818, 1822–1827, 1836–1852, 1868–1887, 1911–1925) and seven warm periods (1560–1585, 1600–1610, 1614–1618, 1738–1743, 1756–1759, 1776–1781, 1944–2014). These periods correlate well with reconstructed data for the Northern Hemisphere and the neighboring territories of China and Japan. Our reconstruction has 3-, 9-, 20-, and 200-year periods, which may be in line with high-frequency fluctuations in El Niño–Southern Oscillation (ENSO), the short-term solar cycle, Pacific Decadal Oscillation (PDO) fluctuations, and the 200-year solar activity cycle, respectively. We suppose that the temperature of the North Pacific, expressed by the PDO may make a major contribution to regional climate variations. We also assume that the regional climatic response to solar activity becomes apparent in the temperature changes in the northern part of Pacific Ocean and corresponds to cold periods during the solar minimum. These comparisons show that our climatic reconstruction based on tree ring chronology for this area may potentially provide a proxy record for long-term, large-scale past temperature patterns for northeastern Asia. The reconstruction reflects the global traits and local variations in the climatic processes of the southern territory of the Russian Far East for more than the past 450 years.

Elemental and Sr-Nd isotopic geochemistry of Cretaceous to Early Paleogene granites and volcanic rocks in the Sikhote-Alin Orogenic Belt (Russian Far East): implications for the regional tectonic evolution

The Sikhote-Alin Orogenic Belt in Russian Far East is an important Late Mesozoic to Early Cenozoic accretionary orogen related to the subduction of the Paleo-Pacific Plate. This belt was generated by successive accretion of terranes made of accretionary prisms, turbidite basins and island arcs to the continental margin of northeastern Asia (represented by the Bureya-Jiamusi-Khanka Block) from Jurassic to Late Cretaceous. In order to study the tectonic and crustal evolution of this orogenic belt, we carried out zircon U-Pb dating, and whole-rock elemental and Sr-Nd isotopic analyses on granites and volcanic rocks from the Primorye region of southern Sikhote-Alin. Zircon dating revealed three episodes of granitoid emplacement: Permian, Early Cretaceous and Late Cretaceous to Early Paleogene. Felsic volcanic rocks (mainly rhyolite, dacite and ignimbrite) that overlay all tectonostratigraphic terranes were erupted during 80–57Ma, postdating the accretionary process in the Sikhote-Alin belt. The Cretaceous-Paleogene magmatism represents the most intense tectonothermal event in the Sikhote-Alin belt. Whole-rock major and trace elemental data show arc-like affinity for granitoids and volcanic rocks, indicating that they were likely generated in a supra-subduction setting. Their initial 87Sr/86Sr ratios range from 0.7048 to 0.7114, and εNd(t) values vary from +1.7 to −3.8 (mostly<0). Thus, the elemental and Sr-Nd isotopic data suggest that the felsic magmas were generated by partial melting of source rocks comprising mantle-derived juvenile component and recycled crustal component. In addition to the occurrence in the Sikhote-Alin orogenic belt, Cretaceous to Early Paleogene magmatic rocks are also widespread in NE China, southern Korean peninsula, Japanese islands and other areas of Russian Far East, particularly along the coastal regions of the Okhotsk and Bering Seas. These rocks constitute an extended magmatic belt along the continental margin of NE Asia. The generation of this belt was ascribed to subduction of the Paleo-Pacific Plate.

Genetic structure of the Amur tiger (Panthera tigris altaica) population: Are tigers in Sikhote-Alin and southwest Primorye truly isolated?

We used molecular genetic analyses to noninvasively identify individual Amur tigers and define subpopulations of tigers in the Russian Far East. We identified 63 individuals after genotyping 256 feces, 7 hair and 11 blood samples collected within southern, central and northern Sikhote-Alin, as well as Southwest Primorye. Analysis of nuclear DNA at 9 microsatellite loci demonstrated greater genetic similarity between animals from southern and northern Sikhote-Alin (some 500 km apart) than between animals from Ussuriskii State Nature Reserve and Southwest Primorye (less than 10 km apart at their nearest point), suggesting that a true barrier exists preventing movements of tigers between Southwest Primorye and the southern Sikhote-Alin Mountains.

REE fractionation in the rivers of eastern and southern Sikhote Alin with natural and anthropogenic anomalies

The behavior of REE in the rivers of eastern and southern Sikhote Alin (Primorye) is discussed. The high-resolution ICP-MS (HR-ICP-MS) technique is used for determining the REE concentrations and degree of REE fractionation in the background unpolluted rivers and in the Rudnaya River, affected by mining industry waste products. In addition, water streams from tailing storages (Dal’negorsk) and from the rivers of Vladivostok are subjected to study. It is shown that the studied rivers differ from each other in the studied parameters and in migration forms. These differences are explained by the different degrees of chemical denudation of rocks in their drainage areas by and anthropogenic impacts on the surface water streams.

New K–Ar biotite and amphibole ages of granitoids of Sikhote-Alin (Russian Far East): Criteria of reliability and interpretation

Biotite and biotite–amphibole pairs from granitoids of the southern Sikhote-Alin–North Sakhalin orogenic belt are dated by the K–Ar method. The obtained ages are highly consistent with U–Pb zircon data (original and published data). In the zircon (U–Pb)–biotite (K–Ar)–amphibole (K–Ar) triad, the zircon and biotite define close, frequently identical, ages, whereas the amphiboles usually yield younger K–Ar ages, which is inconsistent with the idea of the relative stability of the K–Ar isotope system of amphibole to thermal impact. Our research confirms the existing opinion that the isotope system of biotite is more stable to hydrothermal–metasomatic alteration than that of amphibole. The younger age of amphibole in monzonitic associations is probably caused by the formation of amphibole after pyroxene at the late magmatic and early postmagmatic stages. The obtained results, with allowance for analysis of the reliability of the isotope K–Ar and U–Pb dates on different mineral phases, confirm the idea that the Albian stage played a special role in the geological evolution of the studied region and mark the peak of magmatic activity at 105–95 Ma. According to isotope dates, the Albian–Cenomanian time was a period of simultaneous formation of monzonites and granites in Sikhote-Alin, which is typical of the continent–ocean transform-plate-boundary setting. It is found that the distribution of granitoids of different age is determined by the boundaries of the terranes of orogenic belts.