Part Of Margin Research Articles

On the Rhodopean protoliths and their Middle Jurassic to Early Cretaceous evolution. A review

The Rhodope Massif represents a large high-grade metamorphic complex situated in the Balkan Peninsula, straddling the border between Bulgaria and Greece. Geological studies carried out during the last thirty years clearly established that the complex is composed of three major lithotectonic units characterized by differing protolith ages and Alpine thermotectonic evolution. The Rhodope Massif consists of Upper and Lower terranes representing continental fragments composed mainly of pre-Mesozoic magmatic rocks and covered by Early Mesozoic sedimentary sequences. These two entities are separated by an Intermediate Terrane comprising a Jurassic magmatic arc and its host rocks tectonically intercalated with Jurassic ophiolitic fragments together with the Early Mesozoic sediments. Detailed analyses of the previously published geochronological data revealed that the three main tectonic terranes were juxtaposed in the Late Jurassic–Early Cretaceous during the continental collision and northward subduction of the Lower and Intermediate terranes. These rocks experienced Middle Jurassic to Early Cretaceous high-pressure metamorphism, followed by high-temperature one accompanied by anatexis. At that time, the Upper Terrane was metamorphosed and deformed only partially. Being part of the European margin, this terrane represented an upper continental plate during the subduction, and therefore is not considered as a part of the Alpine Rhodope metamorphic complex. It is important to note that, although most of the present-day fabric and major tectonic zones in the Rhodope metamorphic complex are younger than Early Cretaceous, and therefore they postdate the geological evolution discussed in this study, they often reactivate the old boundaries between the main terranes and units.

Cylindrical Models Motivated through Extended Sine-Skewed Circular Distributions

Cylindrical Models Motivated through Extended Sine-Skewed Circular Distributions

Modelling diagenetic reactions and secondary porosity generation in sandstones controlled by the advection of low‐molecular‐weight organic acids

AbstractHigher secondary porosity was observed in the centre of a sandstone unit in the Eocene Shahejie Formation fan delta front sandstones from the Bozhong Depression, Bohai Bay Basin. This differs from past studies showing secondary porosity mainly in the marginal parts of sandstones adjacent to shales. This study utilized reactive transport models involving low‐molecular‐weight organic acids (LMWOA) to discuss potential processes resulting in the contrary distribution of secondary porosity. An interface model simulating LMWOA diffusion from adjacent shales to the sandstone resulted in secondary porosity in sandstones adjacent to shales. In contrast, an advection model simulating advective transport of LMWOA parallel to the sandstone bedding successfully generated higher secondary porosity in the central part. The central part of the sandstone exhibited better grain sorting (greater depositional porosity) and significantly less early carbonate cements compared to the marginal sandstone parts. Consequently, the central part had greater porosity prior to the dissolution through LMWOA. The initially higher porosity in the central part allowed for a higher advective flux of LMWOA‐rich water and associated lower pH, resulting in decreased oligoclase saturation, higher oligoclase dissolution rates and ultimately higher secondary porosity. This study indicates that grain sorting during sediment deposition, early carbonate cementation, LMWOA production in adjacent shales, and advection processes collectively control the diagenetic reactions and the distribution of secondary porosity in sandstones.

Формации каменноугольно-нижнепермских карбонатных отложений бассейна верхней Печоры (Северный Урал)

The Upper Pechora basin is part of the northeastrn margin of the European Platform. In the Paleozoic, it was located within the carbonate shelf of the passive continental margin. According to A. I. Eliseev, Visean terrrigenous-carbonate (platamovy type) and Upper Visean-Lower Artinskian carbonate (kaleydovy type) formations occupy the upper part of the final sedimentation cycle of the formations row. According to new data, the history of the geological development of the Upper Pechora basin of the Late Visean-Asselian period has significant differences. Four types can be distinguished in the structure of sediments according to the composition of rocks: siliceous-clay-limestone, limestone, dolomite-limestone, siliceous-limestone. They were formed during three stages respective to the time of formation of three transgressive-regressive cyclites: the Visean-Serpukhovian, Bashkirian-Moscovian, Upper Carboniferous-Lower Permian. The studied deposits are divided into lithological complexes: siliceous-clay-carbonate of open sea (Tulian), siliceous-carbonate of open sea (Aleksinian-Early Mikhailovian, Bashkirian-Early Moscovian, Kasimovian-Midle Gzhelian), carbonate of shallow-shallow (Late Mikhailovian-Protvinian, Moscovian), and also the Late Gzhelian-Asselian shallow-depression (siliceous-limestone, limestone, clay-limestone). Lithological complexes, formed in open-sea conditions, belong to formations from the platamovy type and in shallow-shallow conditions — to formations from the kaleidovy type (by Eliseev, 2008).

The Alpine Geological History of the Hellenides from the Triassic to the Present—Compression vs. Extension, a Dynamic Pair for Orogen Structural Configuration: A Synthesis

In this paper, the Hellenic orogenic belt’s main geological structure and architecture of deformation are presented in an attempt to achive a better interpretation of its geotectonic evolution during Alpine orogeny. This study was based not only on recent research that I and my collaborators conducted on the deformational history of the Hellenides but also on more modern views published by other colleagues concerning the Alpine geotectonic reconstruction of the Hellenides. The structural evolution started during the Permo–Triassic time with the continental breaking of the supercontinent Pangea and the birth of the Neotethyan ocean realm. Bimodal magmatism and A-type granitoid intrusions accompanied the initial stages of continental rifting, followed by Triassic–Jurassic multiphase shallow- and deep-water sediment deposition on both formed continental margins. These margins were the Apulian margin, containing Pelagonia in the western part of the Neotethyan Ocean, and the European margin, containing continental parts of the Serbo-Macedonian and Rhodope massifs in the eastern part of the Neotethyan ocean. Deformation and metamorphism are recorded in six main deformational stages from the Early–Middle Jurassic to the present day, beginning with Early–Middle Jurassic Neotethyan intra-oceanic subduction and ensimatic island arc magmatism, as well as the formation of a suprasubduction oceanic lithosphere. Compression, nappe stacking, calc-alkaline magmatism, and high-pressure metamorphic events related to subduction processes alternated successively over time with extension, orogenic collapse, medium- to high-temperature metamorphism, adakitic and calc-alkaline magmatism, and partial migmatization related to the uplift and exhumation of deep crustal levels as tectonic windows or metamorphic core complexes. A S- to SW-ward migration of dynamic peer compression vs. extension is recognized during the Tertiary Alpine orogenic stages in the Hellenides. It is suggested that all ophiolite belts in the Hellenides originated from a single source, and this was the Neotethyan Meliata/Maliac-Axios/Vardar ocean basin, parts of which obducted during the Mid–Late Jurassic on both continental margins, Apulian (containing Pelagonia) and European (containing units of the Serbo-Macedonian/Rhodope nappe stack), W-SW-ward and E-NE-ward, respectively. In this case, the ophiolite nappes should be considered far-traveled nappes on the continental parts of the Hellenides associated with the deposition of Middle–Late Jurassic ophiolitic mélanges in basins at the front of the adjacent ophiolite thrust sheets. The upper limit of the ophiolite emplacement are the Mid–Upper Jurassic time(Callovian–Oxfordian), as shown by the deposition of the Kimmeridgian–Tithonian Upper Jurassic sedimentary carbonate series on the top of the obducted ophiolite nappes. The lowermost Rhodope Pangaion unit is regarded as a continuation of the marginal part of the Apulian Plate (External Hellenides) which was underthrust during the Paleocene–Eocene time below the unified Sidironero–Kerdylia unit and the Pelagonian nappe, following the Paleocene–Eocene subduction and closure of a small ocean basin in the west of Pelagonia (the Pindos–Cyclades ocean basin). It preceded the Late Cretaceous subduction of the Axios/Vardar ocean remnants below the European continental margin and the final closure of the Axios/Vardar ocean during the Paleocene–Eocene time, which was associated with the overthrusting of the European origins Vertiskos–Kimi nappe on the Sidironero–Kerdylia nappe and, subsequently, the final collision of the European margin and the Pelagonian fragment. Subsequently, during a synorogenic Oligocene–Miocene extension associated with compression and new subduction processes at the more external orogenic parts, the Olympos–Ossa widow and the Cyclades, together with the lower-most Rhodope Pangaion unit, were exhumed as metamorphic core complexes.

Political and Military Implications of Private Military Contractors in Russia

The topic, which is of personal interest, makes an impression that contractors are only a marginal part of the modern security studies, the academic community of international relations and the public interest. The world is in constant evolution, dominated by more urgent topics and the previous ones are pushed into the background, which specifically in this case poses a great threat. Article focuses on the issue of private military contractors as an alternative to modern privatisation of military and overview of their main differences to the known mercenaries, ethics, and their restrictions with the aim to showcase timelessness and adequate usability of these contractors with the focus on characterising the Russian Private Military Companies and their recent operations. We intend to look at the role of Russian Private Military Contractors and analyse the possible impact that these companies may have and continuously still have in the sphere of international relations and security studies. We offer an updated viewpoint on their place in the current global governance order, and we showcase why and how have they achieved their status. Such findings are crucial for understanding the role of non-state actors in the current security environment.

EVIDENCES OF MINERAL MELTING IN THE ORES OF THE SVETLINSK GOLD DEPOSIT, SOUTH URALS, RUSSIA

For the large Svetlinsk gold deposit (South Urals) evidences of partial melting of minerals and possible participation of polymetallic melts in the concentration and redistribution of gold and other metals are given. Finding of bismuth and antimony minerals in ores, among which there are gold minerals new to the deposit (pampaloite, montbrayite and aurostibite), specific mineral intergrowths (polymineral Sb–Bi–Pb–Te–Ag–Au drop inclusions), enrichment of early sulphides with Low-Melting-point Chalcophile Elements (LMCE), high formation temperatures for ore assemblages (up to 400°C), as well as the occurring metamorphism of amphibolite facies indicate the possibility of the formation of such melts. Polymetallic melts at the deposit could be formed both by partial melting of early sulphides and directly from hydrothermal fluids. The signs of melting also include simplectites of calaverite and native gold in the marginal parts of the large montbrayite grain.

Структура и эволюция углеводородных систем окраинных морей Северного Ледовитого океана (Восточная Арктика)

The article presents the results of studying the structure and evolution of hydrocarbon systems in the marginal seas of the Eastern Arctic — the Chukchi, East Siberian and Laptev Seas. The authors assess the hydrocarbon potential of the studied water areas basing on the results of the basin analysis and numerical modeling. Three promising sedimentary complexes Aptian–Upper Cretaceous, Paleocene–Eocene, and Oligocene–Lower Miocene are predicted in the composition of the sedimentary cover. It is shown that the development of hydrocarbon systems is determined mainly by the rate of sinking of the basins and the thickness of the formed overburden complexes. The main centers of hydrocarbon generation of the Aptian–Upper Cretaceous perspective complex are located in the North Chukchi trough, while those of the Paleocene–Eocene and Oligocene–Lower Miocene complex are located in the Laptev Sea basin. The most likely areas of hydrocarbon accumulation in the reservoirs of the Aptian–Upper Cretaceous complex are the marginal parts of the North Chukchi and East Siberian basins, where deposits are expected at a depth of ~5 km. In the Laptev Sea basin, in addition to the marginal zones, there is a large accumulation area in its central part with deposits predicted at a depth of ≥5 km. In the Paleogene (Paleocene–Eocene) complex, hydrocarbon accumulations are predicted mainly in the central parts of the studied basins and, to a lesser extent, in the near-side parts. The occurrence depths of promising objects vary from 5–6 km in the central parts to 2–3 km in the near-side ones. In the Oligocene-Lower Miocene complex, hydrocarbon accumulations are expected mainly within the Laptev Sea basin at depths of 3–5 km. Significant hydrocarbon potential may be associated with Paleogene clinoform deposits.

Petrography and geochemistry of sandstones of the Ash Shumaysi Formation in the Jeddah-Makkah region, Saudi Arabia: Implications for provenance, tectonic setting, paleoweathering, paleoclimate and paleogeography

This study aims to evaluate the provenance of sandstones of the Ash Shumaysi Formation (Early Eocene to Oligo-Miocene) exposed in the Jeddah-Makkah region (an intra-continental cratonic region in the west of the central part of the Arabian Shield), in addition to re-establish the tectonic setting, paleoclimate and paleo-weathering of their source rocks. This aim has been achieved by petrographic investigation and geochemical (major, trace and rare earth elements) analysis of the sandstones. Integration of both petrographic and geochemical data reflects a derivation of the sandstones from intensively-weathered and multi-recycled felsic igneous (granites) rocks, with a minor contribution of intermediate (granodiorite), mafic igneous (andesite), metamorphic (mainly gneisses) and recycled sedimentary rocks, which correspond to the Precambrian rock units of the west of the central part of the Arabian Shield. The latter was developed under semi-humid climatic conditions in the source area. Tectonically, the source rocks are of a cratonic interior in a passive continental margin of the Upper Continental Crust. This passive continental margin was later affected by rifting as revealed from the discrimination function diagrams of high-silica samples of sandstones. In general, the Ash Shumaysi sandstones may represent erosional products of the nearby high-topographic crystalline rocks of the Western Arabian Shield that were located in a tectonically stable passive margin subjected to a subsequent continental rift. Results of this study could add to the knowledge about paleoweathering, paleoclimate and tectonic setting in the Arabian Shield which is a part of the southern margin of the broad stable continental shelf of the northern margin of the Gondwana supercontinent.

Lacustrine and palustrine carbonates in a Brigantian (late Dinantian) intrashelf basin in the Derbyshire carbonate platform

The Brigantian (late Dinantian) Headstone Laminite provides a record of freshwater carbonate deposition in an intrashelf basin when the surrounding Derbyshire carbonate platform was emergent. The laminated grainstone/carbonate mudstone facies contains calcified plant material, peloids, ostracods and lenses of calcite tufa deposited in a lake margin and sublittoral part of a freshwater lake in a humid palaeoclimate. Precipitation of tufa may have taken place along water courses or resurgences fed by meteoric run‐off and seepage from the karsted carbonate platform. The fenestral carbonate mudstone with calcrete and fenestrae represent deposition in well‐drained parts of the lake margin. A shift to more arid conditions is represented by the laminated dolomudstone facies with an allochem assemblage of calcified plants and micropeloidal dolomicrospar grains and occasional alginite in restricted a lake basin setting. Gypsum crystals and desiccation curls are also present in evaporitic lake margin settings. A return to more humid conditions is indicated by deposition of the laminated grainstone/carbonate mudstone facies with organic‐rich mudstone with thin coal seams and carbonized roots deposited in a poorly drained lake margin setting. This may be a reflection of a gradual transgression after emergence. The eastern margin of the intrashelf basin may have been formed by the Edensor Anticline; however, it is not known if a further complex of lacustrine, palustrine and lagoonal facies was present to the east. Deposition of graded beds containing lithoclasts derived from lacustrine facies were associated with slumping generated by reactivation of structures controlling the intrashelf basin margins.

BIOS-02. RECAPITULATE TUMOR DIVERSION AND SPATIAL PATTERNING IN GLIOBLASTOMA BACKGROUND

Abstract BACKGROUND Intra-tumoral heterogeneity of glioblastoma multiforme (GBM) drives aggressive behavior and intrinsic therapeutic resistance. To investigate heterogeneity, high-resolution sequencing techniques provided us to feature tumor molecular subtyping and simulate differentiation. In our study, we proposed to dissect tumor heterogeneity in different anatomical regions by single cell transcriptome analysis. Material and Method We performed single-cell RNA sequencing on 10675 adult IDH-wild type GBM cells from six pairs of tumor core (central necrotic part of tumor) and tumor margin (junction between tumor and brain). Subtyping following RNA velocity was performed to investigate tumor diversity. Result Four subgroups of tumor cells (OPC-like (oligoprogenitor cell), NPC-like (neuroprogenitor cell), AC-like (astrocyte), and MES-like (mesenchymal) )were identified. The higher cell population of OPC/NPC at tumor margin and AC/MES at tumor core was found. The RNA velocity analysis showed the major diversity order was OPC at margin, OPC at core, NPC at margin, and AC with MES at core. CONCLUSION We explore the spatial pattern of tumorigenesis of GBM that OPC at margin part could be the tumor initiating cell. Further investigation of biological characteristics of OPC could be the strategies to block tumor differentiation and progression.

Zircon U-Pb-Hf isotope evidence for juvenile Penokean sources (ca. 1.9 Ga) in the SW Grenville Province

The Proterozoic evolution of Laurentia involved intermittent orogens and arc-related crustal growth along a modern-style convergent margin, termed the Great Proterozoic Accretionary Orogen (GPAO). The major lithotectonic provinces of the GPAO in the United States are exposed as telescoped equivalents within the thrust stack of the Grenville Province in Canada. We report zircon UPb and LuHf isotope analyses for two orthogneisses and one quartzite from Archean and Paleoproterozoic domains in the gneiss belt of the SW Grenville Province, Canada. The data constrains Paleoproterozoic crustal growth and sedimentation for this part of the Laurentian margin. The orthogneisses have similar zircon UPb and LuHf isotope systematics that reflect igneous reworking (ca. 1700–1660 Ma) of a Penokean aged (ca. 1.9 Ga) depleted mantle derived source, along with metamorphic reactivation at both ca. 1.45 Ga and during the Grenville Orogeny (1.2–1.0 Ga). The quartzite has a bimodal Paleoproterozoic (2.1–1.8 Ga) and Archean (> 2.5 Ga) detrital zircon age spectrum. The Paleoproterozoic detrital zircon grains have a wide range of Hf(t) compositions (εHf(t) = −12.5 to 10) reflecting co-eval interaction of Archean and depleted Paleoproterozoic sources, contrasted by a more restricted range for the Archean population (εHf(t) = −7 to 4). The new data support the presence of reworked ca. 1.9 Ga depleted mantle sources in the Paleoproterozoic Parautochthon, which extend further east than previously thought. They also identify correlations amongst detrital zircon age spectra and Hf isotope compositions in quartzites from different locations of the Archean Parautochthon.

Cretaceous-Paleogene rifting on the NW margin of the Australian continent, SE Banda Arc region

The Banda Terrane successions of Timor Island and correlative units in Sumba are widely considered allochthonous with respect to the Australian continental margin successions that form the main part of the Banda arc-continent collision complex. A new interpretation is proposed for the Banda Terrane, which suggests that these units originated on the outermost (northern) edge of the Australian continent. Volcanic successions in the Banda Terrane, which date to the Cretaceous and Paleogene (Aptian/Albian to Eocene), are interpreted as originating in a backarc/marginal basin setting behind a northward-facing arc that rifted away from the NW margin of Australia through this period. The Banda terrane successions are interpreted as representing the southern, continent-attached portion of the marginal basin, and occupied a position on the distal edge of Australia up to the onset of Banda arc-continent collision in the Miocene.Supporting evidence for an Australian margin origin of the Banda Terrane includes very similar age ranges for zircons dated to the Cretaceous in Sumba and Timor (Banda Terrane) and in sandstones of the Ungar Formation in Tanimbar, the latter forming an element of the Australian margin succession. In Timor there is also previously reported evidence for continental margin rifting during the Late Cretaceous, while contemporaneous Late Cretaceous-Paleogene volcanism is also recognised in the Bird’s Head-Misool region of eastern Indonesia, which forms part of the Australian continental margin. In addition, a number of stratigraphic links between the Banda Terrane and the Australian continental margin successions in Timor are summarised in this study.The effects of the Cretaceous-Paleogene rifting event are also apparent in subsidence curves derived from petroleum exploration wells drilled on the northern ‘passive’ continental margin of Australia from SW of Timor to the Bird’s Head-Misool region of eastern Indonesia. Inferred rift-related subsidence commenced in the Aptian-Albian on the Australian palaeo-margin immediately east of Timor and developed sporadically but in regionally consistent groupings throughout the Late Cretaceous and Paleogene.

The First Detrital Zircon Data on the Northwestern Precambrian Yenisei Ridge: Identification of the Continental–Arc Kiselikha Terrane

Northwestern segment of the Precambrian Yenisei Ridge contains ophiolite and is known in the literature as the Isakovka terrane or Isakovka domain. We suggest dividing it into two belts: the Kiselikha one (western) and Torzhikha (eastern), which differed in geodynamic regime during the late Neoproterozoic (~750–600 Ma). It is believed that the Kiselikha belt is composed mostly of volcanic rocks erupted at island arc setting in the second half of the Neoproterozoic, and that collision of this arc with Siberian continent formed the Yenisei Ridge orogen. This idea has not been sufficiently confirmed by geological and geochronological data. Dating of four detrital zircon samples extracted from sedimentary and volcanic-sedimentary rocks in the southern part of the belt revealed that the sampled strata belong to three different Precambrian levels: the Mesoproterozoic, the mid Neoproterozoic (800–750 Ma), and the end of the Neoproterozoic (620–600 Ma). Thus the authorized stratigraphic layout of the belt as well as its proposed island-arc origin require revision. By this paper we announce the identification of the Kiselikha terrane, which was a part of active margin of the Siberia paleocontinent at the beginning of the Neoproterozoic. Approximately in the middle of the Neoproterozoic, this block was rifted off Siberia and further evolved as a microcontinent bounded by an active margin from the outer side.

Geomorphic evolution of the craton-derived Sone megafan in the southern Ganga plain, India: A tectono-climatic interplay

The Ganga plain neotectonics has been studied from surface and sub-surface faults, frequent geomorphic readjustment, changing sedimentation pattern, piedmont progradation, pedological variation, and frequent earthquake occurrences. However, being neotectonically stable, the peninsular region’s geomorphic changes are governed by climatic fluctuations, contributing to the Ganga plain’s sedimentation. Therefore, peripheral craton sourced marginal alluvial deposits in the Ganga basin are appropriate features to study the control of both the Himalayan tectonics and climate of core peninsular region away from their respective source areas. This study uses a process-response approach model to describe the geomorphic development of the Sone megafan, located at the marginal part of the Ganga plain to the south of the Ganga River, bordering the Indian craton.Geomorphological mapping, field investigation of the depositional features, soil profiles, and Optical Stimulated Luminescence (OSL) chronology suggest four phases of geomorphic evolution, i.e., in 22–8 Ka, 8.0 Ka–7.3 Ka, 7.3 Ka–2.4 Ka, and 2.4 Ka–0.5 Ka on the Sone megafan. The different evolutionary phases are marked by channel and floodplain abandonment and soil profile development. The megafan surface is divided into four distinct geomorphic units (OdSP – Oldest Sone Plain, OSP – Old Sone Plain, YSP – Young Sone Plain, and AFP – Active Floodplain) based on OSL ages and soil properties. Geomorphology and soil suggest a mixed climate in the source and sink area. The arid climate in the catchment contributed to the sediment production, and the humid climate promoted its transport, which resulted in the largest depositional unit of the megafan, even during the arid period in the Ganga basin. Contrast to the north of the Ganga River, no surface faults are found on the Sone megafan. However, the tectonic activity of the bounded basement faults, i.e., the East and the West Patna faults, are well pronounced in the sediment distribution and fluvial response. Tilting and twisting the fault-bounded block controls the sediment remobilization in space and time. Thus, the climatic fluctuation in the source, the sink, and the activity of the basement faults, propelled by the Himalayan tectonics, contributed to the Sone megafan’s geomorphic evolution. Two events of the Ganga River’s encroachment at the distal part of the Sone megafan were recorded (2.4 ± 0.14 and 1.3 ± 0.16 ka). The correlation between OSL ages of megafan units, climatic fluctuations in the Sone River’s catchment, and established time windows of tectonic episodes in the Ganga basin has also been investigated. As the Sone and the Gandak megafans rest on the same tectonic blocks, their tectono-geomorphic responses to the Himalayan neotectonics are similar.

Petrological and geochemical evidence for a hot crystallization path and a recharge filtering bypass at Antimilos, Milos volcanic field, Greece

Antimilos volcano in the South Aegean Volcanic Arc, Greece, comprises an andesite–dacite suite that follows a distinct evolutionary path than the main edifice of the Milos volcanic field, despite their proximity. Petrographic and geochemical analyses reveal that basaltic andesite to low-Si dacite lavas have similar phenocryst assemblages that indicate crystallization from hot, relatively dry magmas in an upper crustal storage region. Rare antecrystic high-Mg# clinopyroxene cores with low Y, low Dy, and high Sr contents record the cryptic involvement of amphibole, a phase nominally absent from the erupted products, in the deeper parts of the plumbing system. Low temperature antecrysts with textures recording various degrees of disequilibrium suggest a protracted history of interaction between the upper crustal reservoir and deeper mafic melts, forming mobile hybrid magmas that consequently erupt as highly mingled, crystal-rich lava domes. Antimilos magmas seem to have escaped recharge filtering in the upper crust and prolonged stalling, which is the process that is probably responsible for the paucity of mafic eruptions in the rest of the Milos volcanic system. Large extensional structures offshore of Antimilos promote rapid ascent of mafic melts, inhibiting prolonged stalling and interaction with the arc crust. This model highlights the dominant role of the regional stress field in generating petrologically distinct suites in the marginal parts of some volcanic fields.

Favorite Parts of a Single Leaf for Giant Flying Squirrels to Eat in Three Species of Food Trees.

To examine the effect of leaf chemical composition on selective herbivory by the Japanese giant flying squirrels (Petaurista leucogenys), we measured and compared the total phenolic, glucose, and water contents of leaves among their main food tree species, deciduous Quercus acutissima, and evergreen Q. sessilifolia and Phonitia serratifolia. Leaves of these three tree species were available in the warm season (April to October), but the flying squirrels mostly preferred the leaves of Q. acutissima, having higher glucose and water contents than those of the other two tree species. In the cold season (November to the next March), the two evergreen tree species were available, and the flying squirrels used both leaves without any apparent influence of the chemical compositions. On the other hand, the favorite parts of a single leaf differed among the three tree species. Flying squirrels dropped the individual leaves after partial consumption. Their feeding marks on the dropped leaves were distinguished into four types: apical, basal, central, and marginal parts of consumption. The basal parts of consumption were most frequent in Q. acutissima leaves in which more water was contained at the basal part, and the central part consumption followed, which may be related to a lower phenolic content and more glucose and water at the leaf center than its margin. In contrast, the apically consumed leaves dominated in Q. sessilifolia, with relatively homogeneous leaf chemical distribution except for more water at the center. In P. serratifolia, leaves consumed at the center were frequent, but those with marginal consumption were also observed, which may be related to its specific chemical distribution with less phenolics and more glucose at the leaf margin. Thus, the chemical distributions within the single leaf differ among tree species, and the flying squirrel's selectivity of the tree species and the part of each leaf depends partly on the relative compositions of preferable glucose and water and unpreferable phenolics.

New dinoflagellate cyst species from the Middle Eocene of the Volgograd–Volga region, south-west Russia

The Keresta Formation, located in the Volgograd–Volga region (the Volga–Caspian subregion of south-west Russia) has been dated as Middle Eocene, Lutetian, based on dinoflagellate cysts of the Enneadocysta arcuata Zone and nannofossils from the Lutetian subzones CP13c–CP14a. Within this interval, four new species of dinoflagellate cysts are described: Spiniferella grigorovichiae sp. nov., Impagidinium tuberculatum sp. nov., Hystrichostrogylon crassitunicatum sp. nov. and Hystrichosphaeropsis tenerum sp. nov. The new species present a high correlation potential for Middle Eocene stratigraphy over the southern part of the Russian Platform. Also, the assemblage of organic-walled microphytoplankton from the Keresta Formation indicates warm-water marine environments within the marginal part of the Paratethys Basin.

Lattice preferred orientation of quartz in granitic gneisses from Tso Morari Crystalline Complex, Eastern Ladakh, trans-Himalaya: evaluating effect of Dauphiné twin in dynamic recrystallization during exhumation

Abstract The Tso Morari Crystalline complex (TMCC) of eastern Ladakh, India, is part of the north Indian continental margin and is characterized by eclogitic enclaves embedded within ortho- and paragneisses known as the Puga Gneiss. Two fault zones bound the TMCC: the Karzok fault to the southwest and the Zildat fault to the northeast. In the present study, we carried out Electron Backscatter Diffraction study of quartz of 10 samples collected from the Puga Gneiss. The relict and recrystallized quartz grains were treated separately to understand the deformation conditions of the Puga Gneiss during early and late deformation stages related to UHP metamorphism and final stage of exhumation during retrogression, respectively. Microstructural observations suggest dynamic recrystallization in quartz and plagioclase at different temperature ranges. Misorientation analysis of both relict and recrystallized quartz grains reveals presence of Dauphiné Twins. Lattice preferred Orientation (LPO) of <c> axis of relict quartz grains generally shows more than one point maxima indicating that the relict grains preserve LPO developed during different stages of metamorphism/deformation. On the other hand, LPO of <c> axis of recrystallized grains from Karzok and Zildat fault zones shows asymmetric single girdle either normal or at an angle to the foliation plane, which suggests simple shear. We conclude that grain size reduction and recrystallization of the Puga Gneiss was greatly influenced by Dauphiné Twin and the final exhumation of the TMCC took place in a simple shear environment aided by activity along its two binding fault zones.

The Slotting Fee

According to Article 15(1)(4) of the Act on Combating Unfair Competition, it is an act of unfair competition to obstruct other entrepreneurs’ access to the market, in particular by charging fees other than the trade margin for accepting goods for sale. The purpose of this article is to present concerns related to the aforementioned provision in the light of the jurisprudence of Polish courts and to assess whether the current legal framework provides uniform grounds for classifying slotting fees as part of the trade margin for accepting goods for sale.