Abstract—The collection of paleomagnetic samples of the Lower Devonian Frænkelryggen Formation from the northwest of Spitsbergen is studied. The main carrier of the natural remanent magnetization of the studied rocks is hematite. Based on the component analysis results, the prefolding, bipolar components of the natural remanent magnetization with a positive reversal test are identified. The sequence of the magnetozones of the studied section is compared with the existing world data for Lower Devonian.

New paleomagnetic determinations are presented for a collection of rocks of the Middle-Upper Devonian (Givetian and Frasnian stages), sampled from an outcrop on the southwestern slope of the Pavlov granite quarry. Three characteristic components of natural remanent magnetization have been identified. The bipolar component C corresponds to the Late Paleozoic remagnetization in the Carboniferous and two components of Givetian - Frasnian age. The bipolar component of D2NR passes the geomagnetic field polarity reversal test. The obtained position of the paleomagnetic pole in terms of the bipolar component of the natural remanent magnetization is consistent with the available data on the Middle Devonian strata of the Main Devonian Field (Russian platform).

To evaluate the effect of undersaturation of magnetic hysteresis loops measured in moderate (<2 T) fields in magnetically hard minerals such as goethite or hematite, we measured room temperature hysteresis loops in a 7 T field and DC backfield demagnetization curves in fields up to 3 T using an MPMS 3 instrument. Sediments from different regions of the East European platform, mostly of Carboniferous age were used for this study. Similar experiments were also carried out for a small collection of archaeological ceramics (bricks) apparently containing a High Coercivity Low unblocking Temperature (HCLT) magnetic phase (ε-Fe2O3?). Hysteresis measurements were complemented by thermomagnetic analysis at low and high temperatures, microscopic observations, and X-ray diffraction studies. High-field magnetic hysteresis loops alone appear insufficient to definitively discriminate goethite from hematite, though there is, expectedly, a tendency that increasing goethite content leads to magnetic hardening, with coercive force reaching 1 T and coercivity of remanence 1.7 T. At the same time, ε-Fe2O3 can seemingly be distinguished from either hematite or goethite due to its high saturation magnetization. However, combining hysteresis measurements with low- and high-temperature thermomagnetic analysis provides a much better insight into the magnetic mineralogy of samples. Still, acquiring the reference data on well characterized hematite, goethite, and ε-Fe2O3 samples is highly desirable.

Проведены палеомагнитные исследования микулино-ранневалдайских (МИС 5) почв и отложений Среднерусской возвышенности. Отбор образцов для измерения магнитной восприимчивости К и определения естественной остаточной намагниченности Jn выполнялись в непрерывной колонке палеопочв и лессов мощностью 4,5 м, формировавшихся в первую половину позднего плейстоцена (128–65 тысяч лет назад). В верхней части ранневалдайских отложений с возрастом по ОСЛ – 115±7 ka BP (МИС 5d), установлен эпизод обратной намагниченности, вероятно, связанный с концом экскурса Блейк. Завершение экскурса Блейк совпало с похолоданием, наступившим после завершения микулинского межледниковья. Величина магнитной восприимчивости К максимальна для гумусового горизонта межледниковой рышковской палеопочвы (МИС 5e) и его педоседимента, имеющего следы сильного пожара. Распределение К по профилю палеопочв аналогично с распределением для сходных по генезису современных почв. Paleomagnetic studies of the Mikulino-Early Valdai (MIS 5) soils and sediments of the Central Russian upland were carried out. Sampling for measuring the magnetic susceptibility to and determining the natural residual magnetization of Jn was performed in a continuous column of paleosols and loess with a thickness of 4.5 m, formed in the first half of the Late Pleistocene (128–65 thousand years ago). In the upper part of the Early Valdai sediments with an age of OSL – 115±7 ka BP (MIS 5d), an episode of reverse magnetization was established, probably associated with the end of the Blake excursion. The end of the Blake excursion coincided with a cold snap that occurred after the end of the Mikulino interglacial. The magnitude of the magnetic susceptibility to is maximal for the humus horizon of the interglacial Ryshkovo paleosol (MIS 5e) and its pedosediment, which has traces of a strong fire. The distribution of K in the paleosol profile is similar to the distribution for modern soils with similar genesis.

Paleomagnetic determinations for the Devonian strata of the Main Devonian Field, available in the international paleomagnetic data base, do not make it possible to construct both detailed magnetostratigraphic scales and reliable trajectories of the apparent polar wander path of the paleomagnetic pole. This is primarily due to the insufficient amount of data that determine modern reliability criteria. Obtaining more complete series of reliable paleomagnetic determinations is one of the important tasks of paleomagnetic studies. The paper presents new paleomagnetic determinations from a collection of rocks of the Frasnian stage of the Upper Devonian (Ilmen and Bureg Beds of the Semiluky Formation), sampled on the southern shore of Lake Ilmen, east of the village. Korostyn in 2009. Magnetomineralogical studies were carried out to determine the magnetic minerals of carriers of natural remanent magnetization. Three characteristic components of natural remanent magnetization have been identified. Two components correspond to the Late Paleozoic magnetization reversal (in the Carboniferous and Permian times). The third, bipolar component of the Frasnian age passes the reverse polarity test of the geomagnetic field.. The obtained position of the paleomagnetic pole by the bipolar component of the natural remanent magnetization is consistent with the available data on the section of the Late Upper Devonian of the Main Devonian Field.

New data for the Early and Late Carboniferous sections of the Russian platform (Moscow syneclise and Donbass) are presented. Magneto-mineralogical studies are carried out to identify the magnetic minerals—carriers of natural remanent magnetization. Extensive Late Paleozoic remagnetization of Carboniferous rocks is revealed. The obtained paleomagnetic data allowed us to determine the average paleomagnetic poles for the Gzhelian, Serpukhovian, and Visean stages of Carboniferous deposits of the Moscow syneclise.

The collections of Carboniferous rocks from sections of the Russian Platform (Gzhelian, Moscovian, Bashkirian, and Visean stages) are studied. The new mean paleomagnetic poles are obtained from the Gzhelian, Moscovian, and Visean layers of the Carboniferous of the Russian Platform. In the redbed Gzhelian and Moscovian rocks, the natural remanent magnetization (NRM) components with the inclination shallowing are revealed, which is due to the presence of the large hematite particles or particle aggregates associated with the interaction between the magnetic and clay particles. Based on the obtained determinations and the results contained in the World paleomagnetic database, the trajectory of the apparent polar wander path (APWP) for the East European Platform is constructed in the interval from the Devonian to Early Permian. The Carboniferous kinematics of the East European Platform is estimated.

The collections of Permian rocks from sections of the Kozhim River (Asselian, Kungurian, and Ufimian stages) and the Kama River (Ufimian and Kazanian stages) are studied. The paleomagnetic directions determined on the studied structures closely agree with the existing data for the Subpolar Urals and Russian Platform (RP). In the Middle Permian red clays of the Kama River region, the paleomagnetic pole N/n = 28/51, Φ = 47° N, Λ = 168° E, dp = 3°, and dm = 5° is obtained. The analysis of the existing paleomagnetic determinations for the Early and Middle Permian of the Russian and Siberian platforms and Kazakhstan blocks (KBs) is carried out. For the Subpolar Ural sections, the estimates are obtained for the local rotations during the collision of the Uralian structures with the Russian and Siberian platforms and KBs. The amplitudes of the horizontal displacements of the studied structures are, on average, 170 ± 15 km per Middle Permian. The scenario describing the evolution of the horizontal rotations of the structures of Subpolar Urals is suggested.

Paleomagnetic studying of Cambrian-Ordovician-Devonian collection of Paleozoic deposits of the Paga River valley has been carried out.The results of paleomagnetic research show a twocomponent structure of natural residual magnetization (NRM).The identified typical components are postfolded.The estimates of horizontal turns of structures are executed.The possible model of magnetic reversal of the studied deposits has been realized.

The collections of the Silurian, Devonian, Carboniferous, and Early Permian rocks from the Kozhim River section in the Subpolar Urals are studied. It is established that the pre-Permian Paleozoic deposits from the Kozhim River were remagnetized during the Kiama hyperchron (C-2-P-2) probably due to magnetoviscous processes that were blocked as these sediments were leaving the zone of increased temperature during the collision between the East European Platform and the Urals. The thrusts that took place at the last stage of this collision rendered the paleomagnetic directions of the studied structures different from those extrapolated from the East European Platform. The estimates of local rotations and displacements are obtained and applied in the combined analysis with the paleomagnetic determinations for the Pai-Khoi Ridge and Subpolar Urals. The amplitudes of the thrusts average 260 km and 180 km for the structures of Pai-Khoi and Subpolar Urals, respectively. The reconstruction of the prethrusting layout of the studied structures is presented.

We present the results of studying the paleomagnetic samples of Carboniferous and Devonian rocks collected in 1986–1987 from the Island of Spitsbergen. The paleomagnetic poles determined from these collections are compared to the poles from the coeval rocks of the Russian Platform. On the basis of these results and the available data of the World paleomagnetic database, the paleogeographic layout of Spitsbergen and the Russian Platform in Early Devonian and Early Triassic are reconstructed. The reconstructions demonstrate a common north-northwestern drift of these units from the southern equatorial latitudes in the Early Devonian to the middle northern latitudes with a small (800 km) convergence, compared to this drift, of Spitsbergen with the Russian Platform by the Early Triassic, which is followed by the subsequent retrograde motion.

В работе представлены результаты изучения коллекций палеомагнитных образцов горных пород каменноугольного и девонского возраста, собранных в 1986–1987 гг. на о. Западный Шпицберген. Проведено сравнение полученных по этим коллекциям палеомагнитных полюсов с полюсами по одновозрастным породам Русской плиты. На основе полученных определений и имеющихся в Мировой палеомагнитной базе данных проведена реконструкция палеогеографического положения Шпицбергена и Русской плиты в раннем девоне и раннем триасе. Реконструкции демонстрируют их совместный северо-северовосточный дрейф из южных приэкваториальных широт в раннем девоне в умеренные северные широты при малом, в сравнение с этим дрейфом сближении Шпицбергена с Восточно-Европейской платформой на 800 км к раннему триасу с его последующим возвратным движением.

Изучены коллекции горных пород ордовикского, силурийского, девонского каменноугольного и раннепермского возрастов из разрезов на р. Кожим, Приполярный Урал. Установлено, что допермские палеозойские отложения р. Кожим перемагничены во время гиперхрона Киама (С2 – Р2) вероятно за счет магнитовязких процессов блокированных в процессе выхода этих отложений из зоны повышенных температур при коллизии Восточно-Европейской платформы с Уралом. Надвиги, имевшие место на последнем этапе этой коллизии обусловили отличия палеомагнитных направлений по изученным структурам от экстраполированных с Восточно-Европейской платформы. Получены оценки локальных поворотов и смещений, что позволило использовать эти оценки при совместном анализе с имеющимися палеомагнитными определениями по Пай-Хою и Приполярному Уралу. Амплитуды надвигов составили в среднем 260 и 180 км для структур Пай-Хоя и Приполярного Урала, соответственно. Дана реконструкция донадвигового положения структур.

Проведено палеомагнитное исследование отложений археологических стоянок Баранова Гора и Подол III/1, расположенных вблизи оз. Волго в северо-западной части Средне-Русской равнины (56.9° N, 33.2° E). Палеомагнитные исследования для обеих стоянок впервые выявили в этом регионе развитие геомагнитного экскурса Гётенбург, который датируется 13000–12350 ВР. Выявление экскурса Гeтенбург позволило уточнить временные рамки начала развития климатической фазы Аллерeд на Средне-Русской равнине.

A paleomagnetic study of sediments at the Baranova Gora and Podol III/1 archaeological sites, located near Lake Volgo on the northwestern Central Russian Upland (56.9°N, 33.2°E), was performed. The paleomagnetic studies at both sites for the first time revealed the development of the Gothenburg geomagnetic excursion (dated 13000-12350 BP) in this region. This made it possible to specify the time interval when the Alleroed climatic phase started developing on the Central Russian Upland.

Palaeomagnetic investigations of deposits at the Baranova Gora archaeological site located near Volgo Lake (56.9°N, 33.2°E) in the Central Russian Upland have been carried out. The palaeomagnetic studies have revealed the development of the Gothenburg geomagnetic excursion dated at 13000–12350 BP. Revealing the Gothenburg excursion allowed us to use the findings of the palaeomagnetic investigations as a chronological benchmark, in addition to the results of palynological and archaeological (comparative analysis of archaeological artifacts) methods of dating the cultural layers of this archaeological monument, as well as to refine the time frame of the climatic Allerød interstadial in the Central Russian Upland. The data obtained in our study indicate that the Allerød interstadial in the Central Russian Upland began several hundred years before 12000 BP, the date commonly believed to be the beginning of the Allerød interstadial.

The paper presents the results of analyzing the set of dual-polarity paleomagnetic results the Global Paleomagnetic Database (GPMDB). The dataset was expanded by the results from the Paleomagnetic Data Catalogue for the USSR and with new data published after 2005. Some results were rejected to avoid the influence of overprints of ancient and recent magnetization. Overall, 59 dual-polarity results for the lithospheric plates of Baltica, Laurentia, and Siberia with their immediate framing were selected for the analysis in the interval of ages 207–359 Ma. The new data confirmed the model of the paleomagnetic field, according to which the field contains a long-lived component corresponding to the equatorial dipole which is responsible for the non-antipodal paleomagnetic directions in the zones of normal and reverse polarity in sedimentary and volcanic rock sequences. Retaining its value of 5–8% of the central axial dipole, the equatorial dipole changed its polarity a few times during the interval 359–207 Ma. The northern poles of the dipole formed two antipodal groups on the Earth’s surface, which lie within or near the subduction zones on the periphery of the Pangaea Supercontinent. Such localization of the equatorial dipole is suggested to be related to the ascending branches of the mantle convection and to the topography of both boundaries of the outer Earth’s core.