Acanthodiaptomus tibetanus (Daday, 1908) (Calanoida, Diaptomidae) – a biogeographic relict in the water bodies of Baikal Rift Zone

A detailed morphological description of the copepod Acanthodiaptomus tibetanus and its geographic distribution on the territory of Irkutsk Region, Buryat Republic, Zabaikalsky Region and Republic of Sakha (Yakutia) within the limits of Baikal Rift Zone is presented for the first time. The authors provided information on the paleogeographic conditions of the territory these crustaceans inhabited and characterized their habitats in brief. An overview of the personal data and available literature on the geographic distribution of A. tibetanus is given. One of the major results obtained under this study was elucidation of the distribution patterns of A. tibetanus. In order to understand current distribution patterns of organisms, A. tibetanus in particular, in different basins, we carried out a historical analysis of the relief formation taking into account climatic aspects involved in these transformations.

Accumulative landforms in valleys with gas-hydrothermal manifestations of the Kuril-Kamchatka region

Within the watercourse valleys of geothermal zones, where manifestations of gas-hydrothermal activity are noted, the processes of relief formation are accompanied by chemical and thermal effects. Thermal waters contribute to the formation of specific accumulative landforms both directly in the channel and in the bottom and on the sides of river valleys. Similar phenomena have been studied in river valleys draining the slopes of the Mendeleev volcano (Kunashir Island), Baransky volcano (Iturup Island), Mutnovsky volcano and Uzon-Geyzernaya caldera (Kamchatka). The typification of accumulative relief forms is carried out, the influence of gas-hydrothermal manifestations on fluvial and slope processes is determined.

Features of aeolian relief formation of the sandy massif Suvinskii Kuitun in the Barguzin Depression

The principal objective of the article is the determination of the main features of the aeolian relief formation of the Suvinskii Kuitun sand massif, one of the regions of active modern aeolian morphogenesis in the Barguzinskaya Depression. A brief description of the morphology of the aeolian relief, characterized by the predominance of deflationary forms over accumulative ones, is given. Among the forms of active deflation, deflation basins dominate here, separated by elongated deflation inselbergs, composed of sands of lacustrine, alluvial, deluvial-proluvial, and aeolian genesis. The mineralogical and granulometric composition of sandy deposits in the southern part of the Suvinskii Kuitun, characterized by poor roundness of sandy grains, has been analysed. A distinct northeastward eolomotion was revealed towards the foothills of the Ikat Range and its accumulation there. The age of the aeolian sands, mainly related to the formation of the Tagar culture (the end of the Bronze Age) was determined. The phytomelioration carried out in the second half of the 20th century led only to a partial fixation of sands, without affecting their overall deflation in most areas of the Suvinskii Kuitun.

MODERN UKRAINIAN GEOMORPHOLOGY: ACHIEVEMENTS, PROBLEMS, PROSPECTS (ON THE OCCASION OF THE 70TH ANNIVERSARY OF THE DEPARTMENT OF GEOMORPHOLOGY AND PALEOGEOGRAPHY OF IVAN FRANKO NATIONAL UNIVERSITY OF LVIV)

Representatives of the specialty, science or scientific field periodically discuss their condition, problems, prospects for development. This applies to a large extent to geomorphology as geological and geographical science. The analysis of its status, problematic issues, state and prospects of development was highlighted during the 70th anniversary of the Department of Geomorphology and Paleogeography of Ivan Franko National University of Lviv, which was celebrated by the geomorphological community of Ukraine and neighboring countries in 2020. The All-Ukrainian scientific-practical conference "Current state and prospects of development of geomorphology and paleogeography in Ukraine" was dedicated to this matter. It featured reports by Lydia Dubis, Jaroslav Kravchuk, Ivan Kovalchuk, Volodymyr Stetsiuk, Andriy Bogutsky, Roman Spitsa, Natalia Gerasimenko, Galyna Bayrak, Petro Voloshin, Oleksandr Mkrtchyan, Andriy Yatsyshyn and other researchers, which reflected modern trends in geomorphological and paleogeographical research. Given this fact, we will try to answer a range of questions that are raised by both the geomorphologists themselves and in specialists in related fields of geographical and geological science. These include, in particular: can we consider the attention, paid to the analysis of the current state of the science of relief and the processes of relief formation in Ukraine sufficient? What are the achievements of geomorphology of the 20s of the XXI century? How does Ukrainian geomorphology relate to foreign geomorphology in research methods, results obtained, and public recognition? What problems does geomorphological and paleogeographic science have to solve in order to remain modern and socially important? What obstacles does it have to overcome? What prospects await her? The highlighted research results are based on the analysis of publications, reports at conferences of various ranks, creative work of the founders of Ukrainian geomorphology, its protagonists who worked in the XIX - XXI centuries or continue to work today, summarizing the results of own research on geomorphological science. Key words: modern Ukrainian geomorphology, problems of geomorphology, prospects of geomorphological researches.

Biostratigraphy and sequence stratigraphy of the Toarcian Ludwigskanal section (Franconian Alb, Southern Germany)

Extensive construction work at the canal cutting of the Ludwigskanal near Dörlbach, Franconian Alb, provided the opportunity to re-investigate a scientific-historical and biostratigraphically important reference section of the South-German Toarcian. The 16 m thick section, described bed by bed with respect to lithology and macrofossils, starts within the Upper Pliensbachian Amaltheenton Formation, covers the Toarcian Posidonienschiefer and Jurensismergel Formation, and ends in basal parts of the Opalinuston Formation. Carbonate contents are high in the Posidonienschiefer and successively decline within the Jurensismergel to basal parts of the Opalinuston. The high carbonate contents in the Posidonienschiefer are associated with comparatively low organic carbon contents. However, organic carbon contents normalized to the silicate fraction are similarily high if compared to other regions in Germany. Only the persistence of high organic carbon levels into middle parts of the Upper Toarcian differs from those of most regions in central Europe. Ammonite biostratigraphy indicates a thickness of >9 m for the Upper Pliensbachian, 1.15–1.20 m for the Lower Toarcian, 5.04 m for the Upper Toarcian, and >0.5 m for the Lower Aalenian. Despite the low sediment thickness, all Toarcian ammonite zones and almost all subzones are present, except for major parts of the Tenuicostatum Zone and the Fallaciosum Subzone. On the basis of discontinuities, condensed beds, and correlations with neighbouring sections in Southern Germany, a sequence stratigraphic interpretation is proposed for the Toarcian of this region: (i) The Posidonienschiefer Formation corresponds to one 3rd order T-R sequence, from the top of the Hawskerense Subzone to a fucoid bed at the top of the Variabilis Subzone, with a maximum flooding surface at the top of the Falciferum Zone. (ii) The Jurensismergel Formation exhibits two 3rd order T-R sequences: The first ranges from the basis of the Illustris Subzone (i.e., the Intra-Variabilis-Discontinuity) to the top of the Thouarsense Zone, with a maximum flooding surface within the Thouarsense Zone. The “belemnite battlefield” reflects a transgressive “ravinement surface” within the first Jurensismergel Sequence, not a maximum regression surface at its basis. The second sequence extents from the erosive basis of the Dispansum Zone to the top of the Aalensis Subzone, with a maximum flooding surface at the Pseudoradiosa-Aalensis Zone boundary. Finally, the Opalinuston starts with a new sequence at the basis of the Torulosum Subzone. Transgressive system tracts of these 3rd order T-R sequences are commonly phosphoritic, while some regressive system tracts show pyrite preservation of ammonites. The maximum regression surfaces at the basis of the Toarcian and within the Variabilis Zone reflect a significant submarine erosion and relief formation by seawater currents, while this effect is less pronounced at the basis of the Dispansum Zone and basis of the Torulosum Subzone (i.e., the boundary Jurensismergel-Opalinuston Formation).

Optimization of technogenic landscapes of the Crimea. Report 1. Quarries and pits

The main forms of anthropogenic relief formation (defensive ditches, mounds, canals, quarries, dumps, etc.) from the Neolithic to the present, which were marked by the presence of 152 abandoned and 137 active quarries on the territory of the peninsula, are considered. The basic principles and approaches to the reclamation of anthropogenic landforms are stated. Improvement options should be determined by the specific conditions of the technogenic landscape, as well as the suitability of the quarry for the intended use and the possibility of its transformation and, of course, the need of the ecosystem and society for an optimized object of the proposed type. The versions of optimization of open-pit workings during dry and wet rock excavation are considered. It is noted that in conditions of water shortage, preference should be given to the creation of reservoirs at the place of workings. The basic requirements for reclamation for agricultural and forest lands, the formation of sozological reserves by the formation of artificial reservoirs for various purposes: a reservoir to maintain ecological balance and preserve biological diversity (landscape-ecosystem function), a reservoir as a recreation area (recreational function), a reservoir as a source of drinking water (hydrological function), a reservoir for fish farming, including professional fishing (economic function). Possible approaches to optimization of quarries are discussed. An assortment of plant species suitable for creating coastal communities with a coastal protection function is presented.

Triassic evaporites: a vast reservoir of brines mobilised successively during rifting and thrusting in the Pyrenees

Triassic evaporites have a very particular location in the Pyrenees, close to detachment areas between the basement and the sedimentary cover, and constitute enormous chlorine and potentially brine reservoir. During the two successive deformation cycles related successively to the Cretaceous rifting and the convergence during early Cenozoic, brines were expulsed and implied in fault activity, breccia formation and fluid-rock interactions. Fluid inclusions from fault infillings and alpine-style fissures sampled all along the Pyrenean chain have a maximal chlorinity close to that of halite-water equilibrium at temperatures between 250 and 350°C. Mixing of brines with low chlorinity waters formed a series of fluids covering an extensive range of salinities. During syn-rift events, the hotter dilute end-member is likely derived from seawater infiltrated and heated near the exhumed mantle as no emerged areas were present at that time. During convergence and thrusting, brines again predominate and mixing occurred with a colder end-member, probably of meteoric origin, consistent with a significant period of relief formation. Brines played, therefore, an essential role in mass and heat transfer during the whole orogenic cycle in the Pyrenees.

New insights on the Vélodrome syncline in the western sub-alpine foreland basin of Haute Provence : 3-D geometrical modelling approach

<p>In the front of the Digne thrust, the deformed foreland basin, the well exposed tectonic window of Barles, is still not well understood. This region has undergone a complex tectonic history involving synsedimentary deformation, potential migration of alpine front, late exhumation related to surface processes and potential salt tectonics. Although the stratigraphy and the structural geology of the area is well known, the respective contributions of regional tectonics, salt tectonic and surface processes remain uncertain. The region displays still enigmatic objects emplaced at each step, from the rifting phase to the late exhumation, such as the overturned Liassic Barre de Chine or the overturned Miocene syncline of the Vélodrome. This study aims at understanding the evolution of the foreland Valensole basin from the deposition of first sediments 30Ma ago to late exhumation and relief formation. We focused our work on the emblematic Vélodrome syncline which is also the only place where a continuous sequence of the basin deposits is exposed. The molassic and conglomeratic layers of the Vélodrome form an overturned syncline with a curved axis of which direction changes from EW in the north to NS in the most south-eastern part. The Vélodrome has been studied for more than a century but its history is still debated. If the Vélodrome is often interpreted as a growth fold which explain the observation of progressive unconformities, microstructural analyses (Fournier et al., 2008) suggest that folding postdates sedimentation. Moreover, recent studies (Graham et al., 2012) propose that this spectacular fold formed as a result of salt tectonic. The obliquity of the regional shortening direction regarding the axis direction, the 3-D pattern of the overturned Miocene series and the origin of the progressive unconformities are issues still not resolved. Such a complex tectonic structure as the Vélodrome fold requires a thorough understanding of the 3-D geometries and their evolution through time. Based on field observations and 3-D geometrical modelling (GeoModeller - ©BRGM), we propose a preliminary model of the Vélodrome that brings new insights on this part of the Valensole basin. The implicit approach that offer the GeoModeller and the field structural data-based approach (here more than 2000 structural data) bring an objective and new vision of the geometries in 3-D of the Vélodrome basin and provide arguments to determine the contribution of each geological processes in the tectonostratigraphic evolution of the north margin of the Valensole basin and subsequent shortening at the western subalpine front.</p>