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This article presents the results of a detailed paleomagnetic study of five sections of the Permian-Triassic sedimentary rocks from the southeastern part of the Volga-Ural anteclise in the East European Platform (Orenburg region, Russia): Boevaya Gora, Vyazovka, Sambulak, Krasnogor, and Vozdvizhenka. The magnetic fabric determined by magnetic susceptibility anisotropy indicates that the rocks accumulated under the conditions of intense hydrodynamic activity. This makes it possible to reconstruct a predominantly submeridional transport of detrital material. The rocks of the Boevaya Gora section have a bipolar distribution of the characteristic component of their remanent magnetization, while other sections show a reversed polarity. In the Vyazovka section, the E/I method was used to calculate the inclination shallowing coefficient of the rocks (f = 0.79). The regional fold test yielded positive results, suggesting that the rocks of the studied sections were displaced after the deposition. For each section, paleomagnetic poles were calculated, with the poles of the Boevaya Gora and Vyazovka sections being the most reliable. The mean paleomagnetic pole coordinates of the studied sections, except the Sambulak section, are as follows: slat = 51.7°, slong = 55.8°, n = 4, plat = 48.5°, plong = 173.4°, α95 = 3.4°, paleolat = 23.4°.

Giant mafic dykes are the key markers of the Earth’s evolution in the Precambrian and have been the subject of extensive research. This article presents the results of the paleomagnetic, rock-magnetic, and paleointensity Banc studies of the Great Dyke of the Kola Peninsula (2.68 Ga). The mean paleomagnetic direction of the characteristic magnetization component and the paleomagnetic pole of the Murmansk craton were calculated using the data from 5 sites (n = 41 samples): D = 117.6°, I = 77.1°, K = 40.9, α95 = 12.1°, slat = 69.265°, slong = 34.35447°, plat = 51.5°, plong = 70.7°, dp/dm = 21.1°/22.6°, and paleolat = 65°. The rocks under study were thoroughly examined for their thermomagnetic properties, revealing that the main carriers of remanent magnetization are single-domain or small pseudo–single-domain (group A) or multidomain (group B) magnetite. The paleointensity values Banc = (6.16 ± 0.92) μT were obtained for 12 samples from group A by the Thellier–Coe method. The corresponding mean virtual dipole moment VDM2.68Ga = (0.85 ± 0.13)×1022 Am2 was determined. These new findings align with previous results on the Archean and Proterozoic objects, indicating that the Earth’s magnetic field was remarkably weak in the Late Archean.

We present the first systematic results of U-Pb LA-ICP-MS dating of detrital zircons from 12 samples representing different stratigraphic levels of 5 sections of the Permian-Triassic rocks, located within the eastern part of the Moscow basin (syneclise) – Zhukov ravine, Astashikha, Nedubrovo, Balebikha and Klykovo. It is shown that the accumulation of the Upper Permian and Lower Triassic terrigenous complexes occurred under the influence of competing sources with two contrasting provenance signals with Neoproterozoic (Vendian)-Paleozoic and Paleo-Mesoproterozoic ages. The identified provenance signal patterns were used to detail the correlation and stratigraphic subdivision of the Permian-Triassic terrigenous complex of the Moscow basin. Raman spectroscopy of detrital zircon, first applied to the Permian-Triassic rocks of the East European platform, made it possible to identify sedimentary complexes of a relatively older terrigenous basin as a separate source of zircons, which experienced superimposed thermal impact in the VendianCambrian time (~500–600 Ma).

In this paper we present the results on apatite fission-track dating, which was first performed at the Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, using the laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS, Dobretsov Geological Institute, Siberian Branch of the Russian Academy of Sciences) for two intrusions of the Siberian Permian-Triassic large igneous province: Magan alkaline-ultramafic pluton (two samples) and Kontay intrusion (one sample). The obtained AFT ages are 217.6±18.6 and 238.8±35.8 Ma (95% confidence) for the Magan intrusion and 150.0±23.0 Ma for the Kontay intrusion and mark the time since they have been cooled below 120 °C. The distributions of track lengths in apatite grains from the studied samples indicate their rapid cooling to near-surface temperatures. We provide a detailed description of the method used, and also demonstrate that the results of fissiontrack analysis performed on the "sample-to-sample" principle by the classical external detector method (EDM) and the LA-ICP-MS method in the modification of the zeta calibration coincide within the age uncertainty.

The results of U-Pb LA-ICP-MS dating of 150 detrital zircon grains from the Precambrian (Riphean?) sandstones of the Kildin group on the coast of the Ivanovka Bay (northeastern Kola Peninsula) are presented. A group of three youngest grains yielded constraint on the sandstone maximum depositional age of 1179±45 Ma. Detrital zircon age distribution is dominated by three maximums of 1.9, 2.4 and 2.7 Ga. The authors consider two complementary scenarios of interpretation of the data obtained. The first scenario involves the contribution of distant provenance out of granitoids in the Lapland-Kola orogen (~1.9 Ga) and adjacent areas of the Kola-Karelia region (~2.7 Ga), Imandra-Varzuga structure (~2.4 Ga), and Sveconorwegian belt (~1.2 Ga); the off-Baltic (Greenland?) sources of the detrital zircon also cannot be excluded. According to the second scenario, the Ivanovsky graben received zircons also from the proximal sources – sialic complexes formed upon melting of granite-gneiss substratum of the upper crust of the Murmansk craton during largescale episodic mafic magmatism 1.86, 2.50 and 2.68 Ga. The Raman spectroscopy showed that about 25 % of the analyzed detrital zircon grains experienced a 1.4-Ga-old thermal effect which did not lead to Pb losses but partially restored the crystalline structure of zircon. This result can be used as an additional constraint in the detailed provenance analysis of the northeastern East European Platform sedimentary basins and is indicative of 1.4-Ga-old large-scale magmatic events related to the breakup of the supercontinent Nuna.

Shared Research Facilities "Petrophysics, Geomechanics and Paleomagnetism", created based on actively developing divisions of the Schmidt Institute of Physics of the Earth RAS, has advanced research equipment and unique methods, which determines the possibility of solving a wide range of applied and fundamental problems in Earth sciences. The main activities of the Shared Research Facilities "Petrophysics, Geomechanics and Paleomagnetism" are in the field of geomechanical modelling and petrophysics, paleomagnetism, rock magnetism and applied analytical studies of the composition and structure of minerals, rocks and materials. The research results carried out at the Center are used to solve actual problems of prospecting and exploration of oil and gas basins, mineral deposits, tectonics, global geodynamics and tectonophysics. The article presents the scientific equipment of the Center and its key characteristics, describes the methodological and analytical capabilities, and the most significant results of research groups.

The first results of U-Pb LA-ICP-MS dating of 150 detrital zircon grains from the Upper Permian sandstone of the Boyevaya Gora section (Orenburg region, the Southern Cis-Urals) are presented. 95 conditional zircon U-Pb isotopic dates form two age peaks – 381 and 529 Ma. It is assumed that clastic material entered the sedimentation basin mainly due to erosion of the Early Hercynian Ural complexes and relics of the Protouralian-Timanian orogen.

The study of the geomagnetic field evolution on minor timescales, in particular of such significant events as geomagnetic reversals and excursions, has acquired particular relevance nowadays due to the increased attention of mankind to the environment. The question of how exactly abrupt changes in the characteristics of the geomagnetic field affect the climate and biosphere remains largely debatable; the idea of the speed and dynamics of these changes is also very vague. "Classical" geological objects and existing methods provide limited opportunities for highly detailed reconstructions of geomagnetic field variations; therefore, paleomagnetologists are looking for new objects and approaches to solve this problem. The research that we have begun involves the use – for the first time in Russia – of speleothems to study secular variations of the geomagnetic field.This brief communication presents paleomagnetic records of two drill-cores from the flowstone from Vorontsovskaya cave, located on the western flank of the Caucasus Mountains in the valley of the river Kudepsta. Preliminary results indicate the presence of a geomagnetic excursion record in both drill-cores. Further study of the samples from Vorontsovskaya cave will make it possible to compare the discovered event with known excursions, as well as to clarify its age, duration, and dynamics.