Correlation of continental genesis strata: the case of the Pokur formation of the Beregovoye field

The paper analyzes one of the most important and difficult stages of constructing a geological model of the Beregovoye field when calculating hydrocarbon reserves – the correlation of the productive strata. It considers the productive strata of the Pokur formation of continental origin, analyzes the conditions of sedimentation, recommends the main correlation benchmarks and examines their characteristic features and inherent patterns.

Features of biodiversity of the Uchursky landscape nature reserve (Ayano-Maiskoye district of Khabarovsk Territory)

It was revealed that the botanical and geographical feature of the vegetation cover of the Uchursky complex nature reserve is its position in the zone of convergence of the continental and monsoon climates, claimed by sharply contrasting phlorogenetic elements of the vegetation cover. The gradient of continentality - oceanicity in the vegetation cover is quite clearly traced between the eastern and western macroslopes of the mountain systems of the Uchur River basin. A complex history of the formation of the territory, the height difference from 1,000 to 2,000 meters, the variety of rocks created the conditions for the existence of floristic complexes of different ecology and origin. In this regard, on the territory of the nature reserve, an overlap of the marginal zones of plants ranges of oceanic and continental origin was found, which defines the richness of the region’s biodiversity, but makes both species and communities unstable. The uniqueness of the flora of the Geran Ridge was revealed, with the main core formed by species of non-Angarid origin, concentrated on the weathering crust of the basic rocks. The participation of alpinogenic, arctic and arctic-alpine species is noted. The pine-larch forests, which are unique in their species composition, are found on the outcrops of carbonate rocks on the right bank of the Uchur River, opposite the mouth of the Lyalmi River and in the Uchur-Ulkan interfluve. In this area, there are 79 species of endemic highland species of North Asia. The Red Book of Khabarovsk Territory includes 37 species of vascular plants, 4 species of lichens and 1 representative of the kingdom of mushrooms.

Biogeochemical processes in the Barents sea

Biogeochemical processes involving microorganisms play an important role in marine sedimentogenesis. The study of biogeochemical processes in the Barents Sea was carried out from 1997 with interruptions until 2019. Using a complex of geological-geochemical, microbiological, radioisotope and stable isotope methods, it was possible to obtain a quantitative estimate of the total abundance and biomass of microorganisms, rates of biogeochemical processes, methane content and organic matter suspended. In the course of work in four expeditions, it was found that in the surface (0–10 m) water column south of 74° N the magnitude of the total abundance and the biomass of microorganisms increased by 2019 by about 5 times compared to 1998. To the north, in colder waters, the total abundance and the biomass of organisms were lower than in the southern region of the sea. The methane concentration in the surface layer of the water column at the border with the atmosphere did not change much for 20 years (1976–1997) and increased noticeably from 1997 to 2017, from 3.3 to 15.8 nM. The increase in FFM, the biomass of organisms and the concentration of methane in the water column is associated with the melting of glaciers, with the release of organic matter of continental origin released from ice into the water. The results of the work indicate changes in the ecosystem of the Barents Sea.

Features of the glacial formations structure and bottom relief forms related to them according to seismoacoustic profiling data and their role in the decision of discussion issues of the quarterly cover formation of the Barents Sea

Hot questions in the modern Quaternary geology of the Arctic seas associated with their glaciation are discussed in this article. The questions of the history of the occurrence of the problem of shelf glaciation or “drift” accumulation of boulder-bearing sediments are considered in detail. The results of seismic-acoustic studies and their interpretation with the aim of seismic stratigraphic and genetic partition of the cover of loose sediments of Quaternary age are considered in detail. Arguments are presented in favor of the continental origin of glaciers (Novaya Zemlya, Ostrovnoy and Scandinavian), which in the late Neopleistocene spread to the shelf of the Barents Sea and occupied its surface to depths of 120−150 m. Further development of glaciation was already due to the expansion of the area of shelves glaciers. The facies zoning of glacial-marine deposits is estimated, which is related to the distance from the front of the glaciers. It is concluded that already at the end of the Late Pleistocene, most of the modern Barents Sea was free from glaciers and from the annual cover of pack ice. Data on the absence of the area distribution of frozen sediment strata within the modern Barents Sea shelf are presented.

Features of the geological structure of an oil and gas condensate field in Tomsk region

The X oil and gas condensate field is located in Parabel district of Tomsk region; the field is large in terms of recoverable reserves. Oil and gas content is confined to Jurassic sediments of Tyumen suite and Vasyugan suite. The reservoirs of the Vasyugan suite are marine and coastal-marine sediments, characterized by alternating sandstones, mudstones, siltstones, clays and exhibit complex internal aging. The productive deposits of the Tyumen suite are of continental origin and are distinguished by significant lithological variability. One oil deposit (J11 stratum), one gas and oil deposit (J12 stratum) and three gas condensate deposits (J13-4, J3, J4-5 strata) were identified in the productive formations. The article analyzes the features of the geological structure and conditions of sedimentation of productive strata. In terms of its phase state and physicochemical proper-ties, the fluid of the J11 deposit is a "volatile oil", phase state of which is close to the near-critical. Reservoirs of productive formations are of terrigenous type, porous, low-permeability, while the oil productivity of the formations is high due to the ultra-low oil viscosity.

A new species of Sun Skink (Reptilia: Scincidae: Eutropis) from the Zamboanga Peninsula, southwestern Mindanao Island, Philippines

We describe a new species of lizard in the genus Eutropis Fitzinger 1843 from the southwestern tip of the Zamboanga Peninsula on the western part of Mindanao Island, Philippines. The new species is related to Eutropis rugifera, which is a secretive, forest-adapted skink that ranges widely outside the Philippines from the western extent of its distribution on Nicobar Island (the type locality) through southern Peninsular Malaysia, Sumatra, and the Mentawai islands, Borneo, Java, and as far east as Bali Island. The discovery of a new, morphologically distinct, and genetically highly divergent Sun Skink lineage in the low elevation forests of the Zamboanga Peninsula creates a puzzling disjunct geographic distribution (E. rugifera has not been reported from the Sulu Archipelago). The new species is estimated to have diverged ~10–16 mya from E. rugifera, from which it appears to have an extralimital and isolated distribution. Considering the dynamic geological history and ancient continental origin of the Zamboanga Peninsula, colonization by the new species may have been facilitated by pre-Pleistocene overseas long-distance dispersal, saltatory range expansion, and subsequent contraction/extinction in the Sulu Archipelago, and/or possibly paleotransport on the ancient crustal fragment of Zamboanga. The new species is known only from Zamboanga City’s primary surface water supply catchment at the lowest elevations inside the boundaries of Pasonanca Natural Park, despite the fact that there have been historical surveys of herpetological diversity at multiple sites to the northeast (Zamboanga, western Mindanao) and to the southwest (Sulu Archipelago). The new species, thus, may be limited to just the tip of the Zamboanga Peninsula, possibly rendering KEYWORDS: IUCN Red List, Palawan microcontinent block, Pasonanca Natural Park, Sulu Archipelago, Surface catchment watershed biodiversity

Molecular data suggest multiple origins and diversification times of freshwater gammarids on the Aegean archipelago

Our main aim was to investigate the diversity, origin and biogeographical affiliations of freshwater gammarids inhabiting the Aegean Islands by analysing their mtDNA and nDNA polymorphism, thereby providing the first insight into the phylogeography of the Aegean freshwater gammarid fauna. The study material was collected from Samothraki, Lesbos, Skyros, Evia, Andros, Tinos and Serifos islands as well as from mainland Greece. The DNA extracted was used for amplification of two mitochondrial (COI and 16S) and two nuclear markers (28S and EF1-alpha). The multimarker time-calibrated phylogeny supports multiple origins and different diversification times for the studied taxa. Three of the sampled insular populations most probably represent new, distinct species as supported by all the delimitation methods used in our study. Our results show that the evolution of freshwater taxa is associated with the geological history of the Aegean Basin. The biogeographic affiliations of the studied insular taxa indicate its continental origin, as well as the importance of the land fragmentation and the historical land connections of the islands. Based on the findings, we highlight the importance of studying insular freshwater biota to better understand diversification mechanisms in fresh waters as well as the origin of studied Aegean freshwater taxa.

Freemasonry in Colombia (18th-19th centuries): French or continental origin, leading Freemasons, the Catholic Church, political parties and revolutionary elements in South America

The history of Colombian Freemasonry can be divided into three clearly identifiable stages, this work focused on the first historical stage characterized by the influence of continental European Freemasonry. This article analyzed the essence of French freemasonry on the origin of the Colombian nation-state. The impact of operative or patriotic lodges in South America was reviewed in general, as well as the relations between the Catholic Church and the 19th-century leading freemasons. The methodology used is documentary review, bibliographic and critical analysis when consulting, reviewing and analyzing reference sources. The article attempts to gauge the scope of the masonic influence on the process of independence from Spain, and it arrives at the conclusion that without the intervention of masonic elements the revolutionary goals would not have materialized in the way they did.

Source–Receptor Relationships and Cluster Analysis of CO2, CH4, and CO Concentrations in West Africa: The Case of Lamto in Côte d’Ivoire

The contribution in terms of long-range transport of CO2, CH4, and CO concentrations to measurements at Lamto (5°02′ W–6°13′ N) was analyzed for the 2014–2017 period using the FLEXPART model that calculates the retro-plumes of air masses arriving at the station. The identification of the source-receptor relationships was also studied with a clustering technique applied on those retro-plumes. This clustering technique enabled us to distinguish four categories of air mass transports arriving at Lamto site described as follows: oceanic and maritime origin (≈37% of the retro-plumes), continental origin (≈21%), and two hybrid clusters (≈42%). The results show that continental emission sources contribute significantly to the increases in concentrations of CO2, CH4, and CO and explain ≈40% of their variance. These emission sources are predominantly from north and north-east directions of the measurement point, and where densely populated and economically developed areas are located. In addition, the transport of air masses from these directions lead to the accumulation of CO2, CH4, and CO. Furthermore, the ratios ΔCO/ΔCH4 and ΔCO/ΔCO2 observed in the groups associated with Harmattan flows clearly show an influence of combustion processes on the continent. Thus, the grouping based on FLEXPART footprints shows an advantage compared to the use of simple trajectories for analyzing source–receptor relationships.