The paper presents the results of paleomagnetic and rock magnetic studies of rocks from the mafic dikes of the Sergeevka terrane that intruded the basement rocks. Currently, they are widespread in coastal outcrops of the eastern part of the Peter the Great Bay of the Sea of Japan between Anna and Priboinaya bays in the south of Primorsky Krai. Structural information allows us to conclude that dikes of both the eastern (Srednyaya Bay-Priboinaya Bay) and the western (Anna Bay-Cape De Livron) clusters intruded from the igneous centers of the same strike. Rocks of the dikes have undergone significant secondary alterations. Inverse magnetic fabric in the dikes is the result of high-temperature decomposition and granulation of primary titanomagnetites during postmagmatic deformations and metamorphism, traces of which are clearly visible in the microscopic and microprobe study of secondary alteration products. All this testifies to a significant secondary change in the rocks of the dikes after their intrusion. This is the secondary heating of the dikes above a temperature of 600 °C, that is, above the Curie point of magnetite (578 °C). The nature of the isolated high-temperature NRM component of the dikes is not primary, but secondary, that is, metachronous. The paleomagnetic data constrained the time of the metamorphic event leading to the remagnetization of mafic dikes of the Sergeevka terrane to ca. 250 Ma. The calculated paleolatitude of the Sergeevka terrane at the time of acquisition of the metachronous NRM component by mafic dikes (21.8 ± 4.2° N) is consistent with the paleolatitudes of the northeastern edge of the North China Craton at the Late Permian/Early Triassic boundary.

Dike

Sill

10.30911/0207-4028-2022-41-3-92-115

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Gold in Mineralized Volcanic Systems from the Lesser Khingan Range (Russian Far East): Textural Types, Composition and Possible Origins

Geosciences (2021)

Н. В. Бердников В. Г. Невструев Pavel Kepezhinskas И. А. Астапов N. S. Konovalova

While gold partitioning into hydrothermal fluids responsible for the formation of porphyry and epithermal deposits is currently well understood, its behavior during the differentiation of metal-rich silicate melts is still subject of an intense scientific debate. Typically, gold is scavenged into sulfides during crustal fractionation of sulfur-rich mafic to intermediate magmas and development of native forms and alloys of this important precious metal in igneous rocks and associated ores are still poorly documented. We present new data on gold (Cu-Ag-Au, Ni-Cu-Zn-Ag-Au, Ti-Cu-Ag-Au, Ag-Au) alloys from iron oxide deposits in the Lesser Khingan Range (LKR) of the Russian Far East. Gold alloy particles are from 10 to 100 µm in size and irregular to spherical in shape. Gold spherules were formed through silicate-metal liquid immiscibility and then injected into fissures surrounding the ascending melt column, or emplaced through a volcanic eruption. Presence of globular (occasionally with meniscus-like textures) Cu-O micro-inclusions in Cu-Ag-Au spherules confirms their crystallization from a metal melt via extremely fast cooling. Irregularly shaped Cu-Ag-Au particles were formed through hydrothermal alteration of gold-bearing volcanic rocks and ores. Association of primarily liquid Cu-Ag-Au spherules with iron-oxide mineralization in the LKR indicates possible involvement of silicate-metallic immiscibility and explosive volcanism in the formation of the Andean-type iron oxide gold-copper (IOCG) and related copper-gold porphyry deposits in the deeper parts of sub-volcanic epithermal systems. Thus, formation of gold alloys in deep roots of arc volcanoes may serve as a precursor and an exploration guide for high-grade epithermal gold mineralization at shallow structural levels of hydrothermal-volcanic environments in subduction zones.

Melt inclusions

10.3390/geosciences11020103

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Citations (22)

Differentiation of layered silicates and biogenic silica in meadow podbel soils of the Central Amur Lowland

Eurasian Soil Science (2013)

Н. П. Чижикова G. V. Kharitonova L. A. Matyushkina N. S. Konovalova А. С. Стенина

Eluvium

Illite

Soil horizon

10.1134/s1064229313080024

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Organic matter of the liquid phase of peat and its hydrolyzates from the deposits of the Middle Amur basin

Russian Journal of Pacific Geology (2008)

В. В. Чаков Н. В. Бердников N. S. Konovalova

Carbon fibers

Liquid phase

10.1134/s1819714008060109

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Explosive ultramafic volcanism in phanerozoic accreted terranes: A case study of the Taragai peridotite complex (Russian Far East)

Journal of Asian Earth Sciences (2025)

Н. В. Бердников Pavel Kepezhinskas В. Г. Невструев В. О. Крутикова N. S. Konovalova

Peridotite

Ultramafic rock

10.1016/j.jseaes.2025.106503

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Nature of Paleozoic Basement of the Catalan Coastal Ranges (Spain) and Tectonic Setting of the Priorat DOQ Wine Terroir: Evidence from Volcanic and Sedimentary Rocks

Geosciences (2023)

Pavel Kepezhinskas Н. В. Бердников Nikita Kepezhinskas N. S. Konovalova В. О. Крутикова

The Paleozoic volcano-sedimentary rocks within the structural basement of the horst-and-graben system of the Catalan Coastal Ranges (CCR) are composed of black shale, volcaniclastic sediments, lava flows, sills and lithocrystalloclastic tuffs. Paleozoic sediments are depleted in high-field strength elements (HFSE) such as Nb, Ta, Zr, Hf and Ti, suggesting their accumulation within the Andean-type active continental margin environment. Volcanic rocks within the Paleozoic CCR sequence belong to shoshonitic and high-K volcanic series and are enriched in Cs, Rb and Ba and depleted in HFSE, which is consistent with their derivation from metasomatized (possibly through deep recycling of pelagic sediments) subduction-related mantle source. The presence of sills (sill-sediment complex) suggests that Paleozoic basement of the CCR was formed within the rifted active continental margin or an arc-back-arc basin system akin to the modern Western Pacific subduction configuration. This complex volcanic terroir hosts world-class wines of the Priorat DOQ region. The presence of framboidal pyrite and magnetite, siderite, sphalerite xenotime, (La–Ce–Nd)-monazite, zircon and baddeleyite, as well as cuprite, tenorite and cupriferous and native silver in volcanic-derived black shale (and consequently in the world-famous “llicorella” soil overlying it) may have had dramatic effects on wine quality and sensory characteristics. These mineral features, together with strong enrichment of Priorat shale in Au, Ag and, to a lesser extent, Pt could have pronounced effects on (1) rates and specific types of chemical reactions; (2) plant metabolism; (3) response to nutrient components and (4) determination of grape flavor. Volcanic wine terroirs, such as the Priorat DOQ region, are special geologic environments for wine growth, capable of producing unique wine aromatic and gustatory characteristics.

10.3390/geosciences13020031

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Citations (3)