Phosphatized discontinuity surfaces are widely distributed in Lower – Middle Ordovician
condensed carbonate sections of Baltoscandia. However, it is difficult to diagnose them and therefore
they are poorly studied as compared to other impregnated surfaces. Morphological typification
and genetic interpretation of the phosphatized discontinuities are given using material from the
Endoceras limestone of the Kunda Regional Stage. The distribution of the discontinuity surfaces on
the paleofacies profile is shown. The discontinuity surfaces with fine, usually eroded impregnation
and phosphate-filled shells which are relics of full-eroded surfaces are common in the most shallowwater
and high-energy lithofacies (bioclastic grain- and packstones, proximal wackestones). In the
deeper-water wackestones, the discontinuity surfaces with deeper phosphate impregnation, varying
from hardground (strongly phosphatized, not bioturbated) to softground (weakly phosphatized,
bioturbated) are common.

Lower Jurassic ammonites Dactylioceras (Orthodactylites) semicelatum (Simpson), Dactylioceras (Dactylioceras) ex gr. commune (Sowerby), Arnioceras ex gr. ceratitoides (Quenstedt), Angulaticeras (Boucaulticeras) dumortieri (Fucini), Angulaticeras sp. and Eleganticeras (?) sp. from the zone of tectonic melange (“Eskiordinsky series”) and flysch of the Tauriс series of the Bodrak River Basin were described. The first three species have been identified in this area for the first time. Representatives of the Angulaticeras and Arnioceras genera are typical of the Sinemurian stage, the Dactylioceras and Eleganticeras (?) genera for the lower substage of the Toarcian stage. Some of the described ammonite species correspond to the zones established in Western Europe: A. (B.) dumortieri to the Lower Sinemurian Oxynotum zone, D. (O.) semicelatum to the Lower Toarcian Tenuicostatum zone. In addition, the D. (D.) ex gr. commune suggests the correlation with the Lower Toarcian of the Northeast of Russia, Northern Alaska, Arctic Canada, Spitsbergen
archipelago and South America.

Silurian brachiopods collected over the years from 10 outcrops of the Sette-Daban were first analyzed. The monotonous assemblage of the Tayakhsky Formation (Lower Silurian) represented by pentamerids, atrypids, rhynchonellids is characterized by mixed systematic composition similar to assemblages studied from sediments of the same age in the Siberian platform, Taimyr and North-East of Russia that confirms  paleogeographic relations of the Silurian basins in the Early Silurian.

Paleoarchean (3.4 Ga) anatectic tonalite-granodiorite plagiogneiss hosts xenoliths of mafic (metagabbro) and plagioclase (metamonzodiorite) rocks. Xenoliths are characterized by T_Nd(DM) = = 3.65 to 3.67 Ga and contain Eoarchean zircon: in mafic schist, zircon discordant analyses give upper intersections of 3987 ± 71 to 3599 ± 33 Ma; in plagioclase schist, the age of zircon is 3631 ± 5 Ma. Xenoliths are considered as remnants of the Eoarchean mafic crust.

The Norsko-Sukhotinsky Trough, also known as the Selemdzhinsky Fold System or the Nora-Sukhotinsky Terrane, is a structural element of the Bureya Massif sedimentary cover superimposed on the Oktyabrsky (Mamynsky) and Turansky blocks. It is a northeast segment of the Dasinanling-Selemdzhinsky Fold System, which is outcropped on the continental crust of the massif. The trough occurs as small discrete roof pendants of granitoid plutons with xenoliths in them, and as small
basement fragments of the Amur-Zeya Plate in the south. The trough is composed of Middle Riphean (?) through Lower Triassic stratified shallow marine, coastal, lagoonal, and continental terrigenous, carbonate and volcanic deposits, as well as intrusive rocks dated as Ordovician (and, possibly, Late Cambrian) and Mid – Late  Carboniferous (Kiviliysky, Oktyabrsky, and Tyrma-
Bureinsky complexes). The platform-type folding consists of simple folds replaced by multiple folds in fault zones.

In the area of Sheet Q-1-XXI, XXII of the Geological Map, the Late Cretaceous age of the Amgenʾ strata and Leurvaam Formation have been confirmed based on foraminifers’ findings. For the first time, Paleogene deposits with the remains of planktonic foraminifers were found on the Chukotka Peninsula. The discovery of this marine fauna helps our better understanding of the geological history of the region and allows amendments in paleogeographic reconstructions.

Oceanic carbonaceous deposits adsorb gold from seawater during sedimentation and diagenesis, and Au has formed part of sedimentary pyrite starting from 3.5 Ga. Water of the Meso- and Neoarchean oceans contained several times more Au than modern oceans. Au grade in the water of the oceans decreased, particularly after a global oxidative event in the Paleoproterozoic, and then slowly increased again in the Neoproterozoic (from 800 to 520 Ma). In the Archean  and Proterozoic, the Au grade in the seawater is correlated with the time of the distribution of high-Mg
basalts, komatiites and black shales in greenstone belts. Oxygen increase in the Earth’s atmosphere is combined with a low Au background in komatiites and Mg basalts, which previously enriched the seawater with gold. This is also indicated by the absence or insignificant amount of gold deposits in the period of 1600–800 Ma, which can be explained by low Au grade in the water of the oceans
during this age period.

Main stages of technology of processing and analysis of hyperspectral data for mineral exploration are described. Examples of hyperspectral data (airborne and satellite) application to identify zones of hydrothermal-metasomatic alterations of rocks, perspective for gold mineralization in the Suetkinskaya area (Altai Republic) and Mnogovershinnaya area (Amur region) are given.

The paper deals with petrographic and mineralogical features of gold-bearing changed country rocks and ores of the Albazinskoe deposit and Ulbansky volcanogen ore occurrences (Khabarovsk Territory, P. Osipenko and Tuguro-Chumikansky districts). Ore targets of the studied areas are located in different geological settings: in volcanic rocks (Trudnoe ore occurrence), in roots of paleovolcanoes (Albazino deposit), in intrusive rocks (Yagodnoe ore  occurrence). Main ore minerals of the deposit and occurrences, the ontogenetic succession of their formation and the elemental composition are given. The formation affinity of near-ore metasomatites and ores is  determined, the typification of gold ores is given.

Chromite ores from Bassit Peninsula deposits in the northwestern Syrian Arab Republic are described. Petrological, mineralogical, structural, and textural features of their evolution, resource potential have been identified based on the analysis of published data and own studies carried out by VSEGEI in the past century.

Paper describes the history of the All-Union Geological Research Institute (VSEGEI) and its personnel during the Siege of Leningrad. Some institute employees fought on the fronts, others were evacuated from Leningrad and carried out geological surveys in all parts of the country. Those who remained in the besieged city experienced all the horrors of the Siege of Leningrad and participated
in the restoration of the institute and geological activity after lifting the siege.