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In soils of the temperate zone, there is an increase in the magnetic susceptibility χ of an upper layer compared to χ C of parent rocks. The difference between χ and χ C characterizes the magnetic "enhancement" Δχ, which is usually considered as associated with mean annual precipitation (MAP), allowing the reconstruction of MAP of the past from Δχ values of paleosols. which is widely enough used. However, in regions with a wide MAP range, non-monotonic dependence of Δχ on MAP is observed, making this reconstruction ambiguous. To construct climatic functions for reconstructing the past climate, we subdivided the south of European Russia into three regions, where climatic functions such as MAP(Δχ) of modern soils are monotonic and close to linear. These regions are relatively dry, humid, and semi-humid cold. We considered an extended set of climatic features including potential evapotranspiration (PET), actual evapotranspiration (AET), water deficit (WD = PET–AET), moisture index (MI = MAP/PET), an index of De Martonne (IDM = MAP/(MAT+10), where MAT is the mean annual temperature). The links of Δχ with MAP were positive in dry and negative in humid and semi-humid cold where they are weaker, but there were closer links with temperature-dependent WD and PET. Reliable (with R 2 > 0.7) climatic functions were constructed for dry and semi-humid cold, but such reliable functions were absent in humid part. Since the differences in soil - forming material, it is necessary to identify some parameter to characterize lithological factors. For this reason, we include in consideration median grain sizes (lgSz) in soil profiles and total iron (Fet) to obtain some explanations for the results. Although the use of Δχ, lgSz and Fe t together made the climatic functions more reliable (R 2 ∼ 0.8), but Δχ played the main role, while lgSz and Fe t were not always significant. Based on the obtained data, it appears possible to provide a more detailed subdivision of paleoecological periods in the Late Holocene for the steppe and forest-steppe zones of the Eastern Europe. Taking into account the diversity of soil conditions in different regions, equations using soil profile MS enhancement to reconstruct rainfall should be used locally and regionally, taking into account the identified limitations and eliminating the possible ambiguity of reconstructions. [ABSTRACT FROM AUTHOR]

The results of study of lacustrine sediments of Northeastern Russia are presented. The reasons for the extremely high values of magnetic susceptibility are considered for the transitional Late Pleistocene to Holocene beds. The magnetic fraction of sediments of Grand Lake includes detrital titanomagnetite and magnetite. The high values of magnetic susceptibility of sediments of Gryazevoe, Sosednee, Vodorazdel'noe, and Sapog lakes are caused by the presence of authigenic Fe sulfides, mostly, greigite. Our data contradict the well-known suggestion on the presence of an impact event at the Pleistocene–Holocene boundary. [ABSTRACT FROM AUTHOR]

The installation and development of a magnetic observatory can require additional studies of the magnetic properties of construction materials for pavilions and measurement pillars, as well as of the environmental conditions, including, first of all, the magnetic properties of the surrounding rocks. In some cases, detailed studies of magnetic susceptibility can be necessary. To date, these procedures have only briefly been described in the existing manuals and guides. With the development of new construction materials, as well as with the increase in the number of magnetic observatories, the need for such studies has risen even more. This article is focused on studies of the magnetic properties of construction materials for magnetic observatories, and the results are presented based on our experience in the deployment of magnetic observatories and stations in Russia and abroad. An overview of the magnetic susceptibility of different materials is presented. A kappametry method and its application to studies of construction materials are described, and the results of magnetic susceptibility tests performed on the construction materials and the surrounding rocks in the vicinity of an observatory are provided. Finally, some recommendations for studies of materials for observatory construction are given. [ABSTRACT FROM AUTHOR]

The Ulban terrane composed of a thick sedimentary series of Jurassic clastic deposits is located at the junction of the Mongol-Okhotsk and Sikhote-Alin orogenic belts. The results of studying the deposits assigned to the Middle Jurassic Elgon Formation are presented. The structure of the sedimentary succession and sedimentological features, which indicate sand-rich turbidite sedimentation in a setting of sandy lobe of turbidite fans or ramps, are considered and illustrated. The paleocurrent directions measured in outcrops and calculated using the anisotropy of the initial magnetic susceptibility suggest the transport of clastic material from western or southwestern sources. [ABSTRACT FROM AUTHOR]

This paper presents the results of geochemical research on the Kamyshovoe Lake sediments (Kaliningrad oblast, Russian Federation). The study of Pb, Ni, Zn, As, Co and Cu concentration and enrichment factors (EF) combined with the results of the lithological, geochronological, magnetic susceptibility and microcharcoal studies revealed possible anthropogenic sources of metals in southeastern Baltic lake sediments from the Neolithic to the Medieval period. Increasing Co EF value and peaks of the Pb EF in Kamyshovoe Lake sediments, starting from ~6000 cal yr BP in the Neolithic, probably show the growing role and usage of metals as dyes and fixatives. Since ~3100 cal yr BP, in the end of the Bronze Age, a simultaneous increase in the content of indicators of metallurgical production Pb, Ni, Zn and As, coinciding with growth of the microcharcoal curve, can show a growing demand for metal objects in the southeastern Baltic region and the input of the local or regional ancient metallurgy into the metal pollution of the lake sediments. [ABSTRACT FROM AUTHOR]

The chronosequence of paleosols buried under structures of different ages in kurgan 1 of the Boldyrevo IV burial site in Orenburg oblast of Russia has been studied. The kurgan was built by representatives of the early (Repino) stage of the Yamnaya culture (about 5500 years ago) and included four successively made structures. According to archaeological data, the kurgan was built during decades, and 300-year-long interval was determined by radiocarbon dating. During that period, the morphological and physicochemical properties of buried soils changed: the lower boundary of the humus horizon became more tonguing; the degree of zooturbation of the profiles by burrowing animals increased; the organic carbon content dropped; and the contents of carbonate carbon, gypsum, and exchangeable sodium in the composition of exchangeable bases and magnetic susceptibility increased. The trend of changes in morphological properties, in the content of organic carbon and carbonates, and in magnetic susceptibility in the materials from the early to late kurgan structures correlated with that for the soils buried under them. Our study enables us to suggest that the climate during the analyzed period (the early stage of the Yamnaya culture) was more arid than the modern climate. The technological approaches used by the ancient builders for kurgan construction were revealed on the basis of data on the micromorphology and physicochemical properties of the materials of kurgan structures. [ABSTRACT FROM AUTHOR]

Dansgaard–Oeschger events of the last glacial cycle are widely observed in the North Atlantic sector. In far northeast Asia, however, a lack of data means the presence or absence of these events is uncertain and, if present, the mechanisms that connect this region with the North Atlantic remain unresolved. A sediment record from Grand Lake, North‐East Russia (latitude 60°44′N, longitude 151°53′E), spans much of the last glacial cycle and shows strong variations in magnetic parameters. These variations are related to sedimentation changes that were likely influenced by the palaeoclimate. Rock magnetic properties of a 1020‐cm‐long sediment core were determined for four lithological units. Additionally, samples taken from across the modern catchment aided the interpretation of the magnetic properties of the down‐core sediments. Magnetic minerals in all sediment units consist of detrital, oxidized Ti‐poor titanomagnetites. Sediments of Holocene age (Unit 1) display the lowest values of magnetic susceptibility (MS), saturation magnetization (Js) and saturation remanence (Jrs), and reflect dilution by biogenic silica and organic matter. Variations of magnetic properties in Units 2, 3 and 4, which correspond to Marine Isotope Stages (MIS) 2, 3 and 4, respectively, parallel granulometric changes. Massive sediment structure, which characterizes Unit 3, has a coarser grain size and higher MS, Jrs and Js as compared with the laminated sediments of Unit 2 and Unit 4, suggesting higher‐energy catchment processes. Nine distinct peaks in MS, Js and Jrs within MIS 3 coincide with TiO2 minima and with high pollen percentages of trees and shrubs, supporting the conclusion that lake and catchment sediment processes are associated with fluctuating regional climate. While the dating is not resolved enough to be certain, the data are suggestive that these cycles correlate with Dansgaard–Oeschger events. [ABSTRACT FROM AUTHOR]

The objective of this study is to provide a well-dated point for a future palaeosecular variation (PSV) reference curve for western Russia. For this purpose archaeomagnetic and magnetic property analyses were carried out on a pottery kiln unearthed at the UNESCO World Heritage site of ancient Bolgar, having a rather precise age dating. The archaeological context provided an age between 1340 and 1360 C.E. The characteristic remanence vector was determined through alternating field demagnetisation and Thellier-Thellier palaeointensity experiments. Some innovations were introduced regarding palaeointensity. The check testing the equality of blocking and unblocking temperature was redefined. This allowed waiving the commonly used additional zero-field cooling steps during the Thellier-Thellier experiment. Another innovation concerns the calculation of archaeointensity at structure level. A Bayesian approach was introduced for averaging individual specimen archaeointensities using a prior probability distribution of unknown uncertainties. Next, an additional prior probability distribution was used to correct for cooling rate effects. This resulted in a lower uncertainty compared to common practice and in eluding time consuming cooling rate experiments. The complex magnetic mineralogy consists of maghaemite, multi-domain haematite and Al-substituted haematite. Some samples contained also some non-stoichiometric magnetite. The magnetic mineralogy was determined through hysteresis loops, backfield and remanence decay curves, measurements of the frequency dependence of magnetic susceptibility and through low temperature magnetisation curves. Accompanying high-temperature thermomagnetic analyses revealed an excellent thermo-chemical stability of the studied specimens. Directions obtained from alternating field demagnetisation and those extracted from archaeointensity experiments are congruent and have low uncertainties. The obtained archaeomagnetic results are fairly in agreement with global geomagnetic field models and contemporary PSV data of the wider area. The geomagnetic field vector obtained for ancient Bolgar is of high quality, deserving thus its inclusion in a future PSV reference curve for European Russia. [ABSTRACT FROM AUTHOR]

The Palaeoproterozoic Onega Basin in northwestern Russia is an important geological archive for global events during oxygenation of Earth at 2.5-2.0 Ga. In this study, we make use of recent drilling results from the Fennoscandian Arctic Russia - Drilling Early Earth Project and the Onega Parametric Hole in combination with available gravity and magnetic data to illuminate the structure of the basin and its internal build-up. These drilling campaigns have provided new information on petrophysical properties (density, magnetic susceptibility) and stratigraphic thickness of the main horizons in the basin. We use this information in combination with gravity and magnetic data to construct a 3D crustal model of the basin with emphasis on its near-surface structure. Our near-surface structure is in agreement with previous findings and most of the gravity and magnetic anomalies are associated with known geological bodies. Modelling also suggests a lateral lithological subdivision of the upper Archaean crust into three parts. The central crust has a higher magnetic susceptibility of 0.12 (SI) and lower density of 2.7 g/cm3, while the surrounding upper crust in the western and eastern edge regions has a lower magnetic susceptibility of 0.075-0.1 (SI), but a slightly higher density of 2.75-2.8 g/cm3. One possible explanation for the differences is the presence of highly magnetised magmatic rocks in the centre of the Onega region caused by magmatic activity resulting in lava flows and comagmatic shallow intrusions during the early Palaeoproterozoic. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of meteorite impacts on magnetic properties including magnetic susceptibility and the Verwey transition of Ti-poor titanomagnetite of volcanic rocks from the 3.6 Ma old El'gygytgyn impact structure located in the Okhotsk-Chukotka volcanic belt in north-eastern Russia. The target rocks consist mainly of rhyolite with some andesites, and is a rare example of impact structures within volcanic target rocks on Earth. 27 samples from outside the crater, the crater rim and from the depth interval 316 to 517 m below lake bottom (mblb) of the El'gygytgyn ICDP drilling were studied. A significant decrease of the average specific magnetic susceptibility by around 90% was observed between felsic volcanic rocks from the surface (18.1 × 10 m/kg) and the drill cores from near the crater central uplift (1.9 × 10 m/kg). Ferrimagnetic Fe-Ti oxide assemblages (Verwey transition temperature, T: -161 to -150°C, Curie temperature, T: 451 to 581°C), occurring in all studied samples, differ significantly. At the surface titanomaghemite is ubiquitously associated with titanomagnetite. The drill cores lack titanomaghemite, but either show a transformation into titanomagnetite and ilmenite or a strong fragmentation associated with a second T between -172 and -188°C. Reversible curves of temperature dependence of magnetic susceptibility in the suevite indicate high depositional temperatures of at least 500°C. In the polymict and monomict impact breccia mechanical deformation of titanomagnetite and temperatures of at least 200-350°C related to the shock are suggested from temperature dependent magnetic susceptibility cycling. Lowtemperature oxidation along strongly brecciated grain surfaces in titanomagnetite is suggested to cause the lower TV and we suggest that this phenomenon is related to postimpact hydrothermal activity. The strong magnetic susceptibility decrease at El'gygytgyn is mainly influenced by shock, and post-impact hydrothermalism causes a significant additional depletion. These observations explain why magnetic lows are a ubiquitous phenomenon over impact structures. [ABSTRACT FROM AUTHOR]

The petromagnetic properties of rocks from the Verkhnii Omolon, Magnetitovyi, Innyaga, and Alekseeskii areas of the Southern Omolon iron-ore district located in the southern part of the Omolon Massif (Northeast Russia) are investigated. The maximum values of natural remanent magnetization (NRM) and magnetic susceptibility ( k) of 22.8-1196 A/m and 1046 × 10 SI on average, respectively, are typical of ferruginous quartzite from the Innyaga site. The amphibolites exhibit high values of these magnetic parameters: J is approximately 28.6 A/m and k is 45 × 10 SI. The magnetic properties ( J and k) of the plagiogneisses and granite gneisses are highly heterogeneous and variable. The migmatites, rhyolites, and dacites are submagnetic. Magnetic minerals are largely represented by multidomain and pseudosingle-domain magnetites and their oxidation products such as maghemite, hematite, and iron hydroxides. It is revealed that the amphibolites are characterized by normal polarity of the remanent magnetization, while the ferruginous quartzites demonstrate normal and reverse polarities. These rocks may serve as sources of magnetic bipolar anomalies. [ABSTRACT FROM AUTHOR]

This paper presents the results of geological and petrophysical research carried out on Popov Island by the Pacific Oceanological Institute of the Far East Branch of the Russian academy of Sciences during 2003-2009. As a result, 7 types of rocks were identified. Their density and magnetic susceptibility have been determined. It was established that the rock types are clearly differentiated with respect to their physical parameters. The identified relationship allows one to use these physical properties, first of all, for the geological interpretation of the gravity and hydromagnetic survey carried out in the surrounding water area of Peter the Great Bay and, secondly, as an additional indicator for igneous rock typification on other islands of the region. Such comprehensive and integrated research was carried out for the first time in this area. The results obtained are important for solving the problem of the structural, compositional, and genetic relationships between the terrestrial and marine structures at the junction zone between the Japanese Basin and the adjacent continent. [ABSTRACT FROM AUTHOR]

Abstract: Dependences of magnetic susceptibility (MS) on the temperature of natural iron sulfide samples (pyrite, marcasite, greigite, chalcopyrite, arsenopyrite, pyrrhotite) from the deposits of northeastern Russia were studied. The thermal MS curves for pyrite and marcasite are the same: On heating, MS increases at 420–450 °C, and unstable magnetite (maghemite) and monoclinic pyrrhotite with a well-defined Hopkinson peak are produced. In oxygen-free media with carbon or nitrogen, magnetite formation is weak, whereas pyrrhotite generation is more significant. The heating curves for chalcopyrite are similar to those for pyrite. They show an increase in MS at the same temperatures (420–450 °C). However, stable magnetite is produced, whereas monoclinic pyrrhotite is absent. In contrast to that in pyrite, marcasite, and chalcopyrite, magnetite formation in arsenopyrite begins at >500 °C. Arsenopyrite cooling is accompanied by the formation of magnetite (S-rich arsenopyrite) or maghemite (As-rich arsenopyrite) with a dramatic increase in MS. Arsenopyrite with an increased S content is characterized by insignificant pyrrhotite formation. Greigite is marked by a decrease in MS on the heating curves at 360–420 °C with the formation of unstable cation-deficient magnetite. Monoclinic pyrrhotite is characterized by a decrease in MS at ∼320 °C, and hexagonal pyrrhotite, by a transition to a ferrimagnetic state at 210–260 °C. The addition of organic matter to monoclinic pyrrhotite stimulates the formation of hexagonal pyrrhotite, which transforms back into monoclinic pyrrhotite on repeated heating. The oxidation products of sulfides (greigite, chalcopyrite) show an increase in MS at 240–250 °C owing to lepidocrocite. [Copyright &y& Elsevier]

Vivianite, a hydrated iron phosphate, is abundant in sediments of Lake El'gygytgyn, located in the Anadyr Mountains of central Chukotka, northeastern Russia (67°30' N, 172°05' E). Magnetic measurements, including mass-specific low-field AC magnetic susceptibility, fielddependent magnetic susceptibility, hysteresis parameters, temperature dependence of the induced magnetization, as well as susceptibility in different heating media, provide ample information on vivianite nodules. Electron microprobe analyses, electron microscopy and energy dispersive spectroscopy were used to identify diagnostic minerals. Vivianite nodules are abundant in both sediments of cold (anoxic) and warm (oxic) stages. Magnetic susceptibility of the nodules varies from 0.78×10-6 m³ kg-1 to 1.72×10-6 m³ kg-1 (average =1.05×10-6 m³ kg-1) and is higher than the susceptibility of sediments from the cold intervals. Magnetic properties of vivianite are due to the respective product of oxidation as well as sediment and mineral inclusions. Three types of curves for high-temperature dependent susceptibility of vivianite indicate different degrees of oxidation and inclusions in the nodules. Vivianite acts as a reductant and reduces hematite to magnetite and masks the goethite-hematite transition during heating. Heating vivianite and sulfur mixtures stimulates the formation of monoclinic pyrrhotite. An additive of arsenic inhibits the formation of magnetite prior to its Curie temperature. Heating selective vivianite and pyrite mixtures leads to formation of several different minerals - magnetite, monoclinic pyrrhotite, and hexagonal pyrrhotite, and makes it difficult to interpret the thermomagnetic curves. [ABSTRACT FROM AUTHOR]

Abstract: Large earthquakes took place in southern Cisbaikalia in the first half of 1912. They might have caused a mass release of gas (methane?) into the water column of Lake Baikal and the atmosphere near Sharyzhalgai station of the Circum-Baikal Railroad. This phenomenon was observed in August 1912 by the residents as rising water columns several meters high and reported in the regional press. To find traces of this event, core was recovered from bottom sediments at a depth of 1300 m in winter 2010. The depth interval 1–8.7 cm is a homogeneous layer, no more than 100 years old (210Pb dating). The sediments here are poor in SiO2biog but richer in Corg than the underlying sediments. Also, they are marked by a considerable content of terrestrial plant remains, a lower content of planktonic diatoms, and higher contents of benthic and ancient diatoms. These data indicate that the layer under study formed as a result of the 1912 earthquake, with a considerable contribution from the littoral and shallow-water zones of Lake Baikal. [Copyright &y& Elsevier]

Abstract: We carried out a multiparameter investigation for non-magnetic proxies of the intensity of pedogenesis in loess/paleosol sections from two different climate settings, Dolní Věstonice, central Europe, and Krasnogorskoye, southern Siberia. The work was performed in order to clarify the problem of two opposite scenarios of magnetic susceptibility (MS) patterns in these two profiles, the “Chinese” model with magnetically enhanced paleosols and the “Siberian/Alaskan” model with magnetically depleted paleosols. The age constraints on the Krasnogorskoye section were inferred from an independent correlation with the well-dated Dolní Věstonice section, based on MS and sediment color (CIE L∗ ), and with the MS log from Lake Baikal. The pedologic description of the loess/paleosol sections and their correlation was considerably improved by the use of Vis spectral proxies (CIE L∗ , reflectance in the red band); their weathering intensity can be effectively characterized by diffuse reflectance spectroscopy (DRS) and geochemical (CEC and Rb/Sr) proxies. Whereas the MS is strongly dependent on the type of soil (chernozems vs. brown soils), the geochemical proxies, in particular CEC, proved to be relatively independent of the soil type. These parameters are less affected by region-specific conditions than the MS signal. The non-magnetic proxies indicate relatively dissimilar climatic trends at the two sites during the last glacial–interglacial cycle. A long-distance correlation, based solely on the MS signal, can be adversely affected by switching between the Chinese and the Siberian/Alaskan magnetic modes, this having been observed at the Krasnogorskoye section. In general, no single universal proxy of weathering or pedogenesis intensity would be applicable across broad regions or considerable climatic gradients. Paleoclimatologic interpretations of large regions should always be based on a carefully designed, multi-proxy approach. [Copyright &y& Elsevier]

Abstract: The paper presents the results of a comprehensive investigation into the recent sediments of Proval Bay. This bay formed during catastrophicflooding of a big block of land as a result of an earthquake in 1862. Comparison of the sketch map of the bay for 1862 with its modern mapshows that the boundary of the Selenga River delta has shifted considerably eastward. The sediments of Proval Bay are sands, silty pelite,and pelitic silt. Terrigenous material is predominant and consists of mineral grains and land plant remains, admixed with diatom frustules andsponge spicules. In the southwestern part of the bay, turbidites and a soil layer have been found. The latter was buried when the water levelin Lake Baikal rose after the construction of the Irkutsk dam in 1959–1964. In the northeastern part of the bay, a peatlike layer has beenfound in the bottom sediment core. It formed in Lake Beloe, which existed in the Tsagan steppe before the 1862 earthquake. According todiatom analysis, this lake was shallow and eutrophic. The sedimentation rates in different parts of Proval Bay differ greatly and directly dependon proximity to the Selenga River. Variations in the geochemical indicators which reflect the ratio of organic to clastic components in thebottom sediments of the bay are controlled by temperature and water level variations in Lake Baikal. [ABSTRACT FROM AUTHOR]

Magnetic remanence vectors for 1737 samples from two ∼100 m cores of Lake Baikal sediments are reported along with complete magnetic susceptibility profiles obtained from a pass-through system. Chronological control is established by means of two independent correlations; first, by matching susceptibility variations to the oceanic oxygen isotope record and second, by matching the relative palaeointensity variations to the SINT-800 global reference curve. These both imply an average deposition rate of 15 cm kyr–1 and a basal age of ∼640 ka. Spectral analysis reveals the presence of Milankovitch signals at ∼100 kyr (eccentricity), ∼41 kyr (obliquity) and ∼23 and ∼19 kyr (precession). Stable remanence vectors are almost all of normal polarity. The few exceptions comprise brief intervals of low and/or negative inclinations which probably represent geomagnetic excursions. However, these are far less numerous than the high sedimentation rate would lead one to expect. Furthermore, only four of them can be readily matched to the—still poorly understood—global pattern. These are the Laschamp, the Albuquerque, the Iceland Basin and perhaps the West Eifel excursions which occurred at ∼38 000, ∼146 000, at 180 000–190 000 and at 480 000–495 000 yr ago, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A 28-m-long section situated on the coast of the Arctic Ocean, Russia (74°N, 113°E) was extensively sampled primarily for the purpose of magnetostratigraphic investigations across the Jurassic/Cretaceous boundary. The section consists predominantly of marine black shales with abundant siderite concretions and several distinct siderite cemented layers. Low-field magnetic susceptibility (k) ranges from 8×10−5 to 2×10−3 SI and is predominantly controlled by the paramagnetic minerals, i.e. iron-bearing chlorites, micas, and siderite. The siderite-bearing samples possess the highest magnetic susceptibility, usually one order of magnitude higher than the neighboring rock. The intensity of the natural remanent magnetization (M 0) varies between 1×10−5 and 6×10−3 A/m. Several samples possessing extremely high values of M 0 were found. There is no apparent correlation between the high k and high M 0 values; on the contrary, the samples with relatively high M 0 values possess average magnetic susceptibility and vice versa. According to the low-field anisotropy of magnetic susceptibility (AMS), three different groups of samples can be distinguished. In the siderite-bearing samples (i), an inverse magnetic fabric is observed, i.e., the maximum and minimum principal susceptibility directions are interchanged and the magnetic fabric has a distinctly prolate shape. Triaxial-fabric samples (ii), showing an intermediate magnetic fabric, are always characterized by high M 0 values. It seems probable that the magnetic fabric is controlled by the preferred orientation of paramagnetic phyllosilicates, e.g., chlorite and mica, and by some ferromagnetic mineral with anomalous orientation in relation to the bedding plane. Oblate-fabric samples (iii) are characterized by a bedding-controlled magnetic fabric, and by moderate magnetic susceptibility and M 0 values. The magnetic fabric is controlled by the preferred orientation of phyllosilicate minerals and, to a minor extent, by a ferrimagnetic fraction, most probably detrital magnetite. Considering the magnetic fabric together with paleomagnetic component analyses, the siderite-bearing, and the high-NRM samples (about 15% of samples) were excluded from further magnetostratigraphic research. [Copyright &y& Elsevier]

The work is devoted to the study of pollution by technogenic magnetic particles and heavy metals of soils in the city of Gubakha, Middle Ural (Russia). The aim of the work is the ecological and geochemical assessment of the elemental chemical composition of the soils of the city of Gubakha, and the establishment of the geochemical role of technogenic magnetic particles (TMPs). For the first time, the regularities of the spatial distribution of magnetic susceptibility in the soils of the city of Gubakha were revealed, and the morphology, elemental and mineralogical compositions of magnetic particles in the soils of an industrial city in the Middle Urals were characterized using the methods of the chemical extraction of iron compounds, magnetic separation, ESEM/EDS, and Mössbauer spectroscopy. The magnetic phase of soils contains magnetite/maghemite, hematite, pyrrhotite, intermetallic alloys and chromite. Spherical magnetic particles are hollow, and have a magnetite shell and a varied surface texture. The crystal lattice of magnetite is characterized by low stoichiometry. The heavy metals Zn, Cu, Ni and Cr are concentrated in magnetic particles and have a high correlation coefficient with magnetic susceptibility. The level of contamination of Cu, Ni, Zn, Cr and Mn in the soils of a residential zone of Gubakha, estimated by the value of the pollution load index (PLI), was high. The Igeo index for Fe ranges from 6.2 to 12.2, for Cu–1.1 and Ni–1.1. The combination of methods for measuring magnetic susceptibility, determining the mineralogical composition of iron compounds, and determining the elemental chemical composition by X-ray fluorescence, has shown the effectiveness of an integrated approach for carrying out an ecological–geochemical assessment of the soil cover of Gubakha. [ABSTRACT FROM AUTHOR]

With the goal to provide the paleomagnetic and magnetostratigraphyc analyses twenty-one samples of Panagia Cape section (45°N, 37°E, Taman Peninsula, Russia) covering the Upper Sarmatian – Lower Maeotian were collected. The section is composed mainly of clays and has a total thickness about 29 m. The composition of the ferromagnetic fraction was examined using dependences of magnetic susceptibility on temperature. This thermomagnetic analysis showed that monoclinic pyrrhotite is the main carrier of the natural remanent magnetization NRM. Coercivity of remanence Bcr values, determined from backfield demagnetization measurements, range between ~20 and 63 mT. In order to determine true NRM directions, we studied the anisotropy of magnetic susceptibility. The part of the rock samples possesses planar anisotropy, which is characteristic of normal sedimentary rocks. Another part of the collection was isotropic. Alternating field AF-demagnetization of the samples (three duplicates from each level) was used for obtaining NRM vector angle elements. Demagnetization results were analyzed using orthogonal plots and stereographic projections. Polarity components were isolated in most samples between 15-25 mT. The values of the declination D and inclination I of the NRM satisfactory agree for all three duplicates from each level. This allows to average angle elements and construct curves of I and D variations over the thickness of the section. We recognized about four polarity intervals in the studied succession: reversed and normal polarities at the Upper Sarmatian part, reversed and normal polarities at the Lower Maeotian part. As a result of this research the studied interval of Upper Sarmatian can be interpreted as Chron C4r and C4n, and the interval of Lower Maeotian deposits corresponds to the Crons C3Br and C3Bn. New magnetostratigraphic data on the Sarmatian-Maeotian transition are used for dating the biotic event related to the marine transgression at the beginning of the early Maeotian. This work was supported by RFBR, project № 17-05-01085. [ABSTRACT FROM AUTHOR]

The origin of the Lake Bolshoe Miassovo, Chelyabinsk region, Russia (55°09.3'N, 060°17.1'E) is tectonic. Seismoacoustic investigations were carried out for choose the best places for coring with continuous sedimentation and avoid gas saturated sediments. 5 long cores of sediments (up to 5 meters) were collected with using special hydraulic corer. Sediments consist of small grained sands, silty sand and organic matter.To study the sediments, a set of methods was used, including petromagnetic studies, the study of mineralogical and elemental composition. According radiocarbon dating the maximum age of samples 13.5 thousand year. The age of samples increases with depth naturally, which means we have continuous sedimentation without hiatus. The average accumulation rate is 0.35 m / thousand years/Measurements of magnetic susceptibility (MS), hysteresis parameters and thermomagnetic analysis were carried out to determine changes in magnetic mineralogy and sedimentation conditions. Thermomagnetic curves measured on Curie express balance, coercitive parameters on J-coercivity spectrometer and magnetic susceptibility on multi-function kappabridge MFK1-FA (AGICO). Changes in magnetic susceptibility in first 4.5 meters are very low, but never the less could be used for cores correlation. Coercivity spectra decomposition has been demonstrated existing several magnetic components in the sediment, one of the components could be biogenic, produced by activity of magnetotactic bacteria. The elemental composition was studied on an S8 Tiger X-ray fluorescence wave dispersion spectrometer. X-ray diffraction was performed on a Bruker D2 Phaser for studying mineralogical composition. Elemental and mineralogical composition of sediments Obtained data from all methods (magnetic properties, minerology, elemental composition) used for preliminary paleoclimatic and paleoenvironmental reconstructions of South Ural region for last 13.5 kyr. All the data show a dramatic change in the properties of the sediment, this occurs around 4.2-4.5 meters. At this time, there is a sharp change in the conditions of sedimentation. The contribution of coarse material decreases, the level of the lake rises. On the basis of geochemical data, the lower part of the core, to a depth of 4.2 meters was deposited under colder and drier conditions, while middle and upper part in warmer conditions.This work was funded by the Russian Science Foundation under grant № 18-17-00251. [ABSTRACT FROM AUTHOR]