Lowermost Part Research Articles

Spores constraining age of the Middle Devonian paleosol from Voronezh, Russia and their paleopedological and evolutionary significances

As a tangible record that formed on ancient landscape, paleosols provide unique evidence for the evolutionary, paleoecological, and paleoenvironmental understandings to land organisms. However, not all paleosols have a good potential for fossil preservation. Plant preservation of paleosols is highly dependent on Eh-Ph conditions of the past and usually favor reducing paleosols. In this study, we carry on palynological analysis for an acid sulfate paleosol from Voronezh, Russia. Abundant and well-preserved spores are recognized from the middle part of this paleosol and its overlying shale. The Ancyrospora tichonovitschi–Retispora archaeolepidophyta–Rhabdosporites langii (TAL) assemblage from the paleosol, including spores of 45 genera and 101 species, indicates a late Eifelian?–early Givetian age. This new age constraint on the paleosol is entrenched by another spore assemblage from the lowermost part of the overlying shale, namely Cristatisporites conannulatus–Geminospora decora–Membrabaculisporis comans (CDC) assemblage. This assemblage includes spores of 38 genera and 89 species, and can be well correlated with the early Givetian Cymbosporites magnificus–Hymenozonotriletes tichonovitschi (MT) Subzone in eastern Europe. Both the assemblages are characteristic for the humid subtropical flora. Assessments of sporopollenin degradation within the paleosol lead to the suggestion that low pH value probably plays a significant role in spore preservation and can explain the surprising diversity and abundance of spores. New palynological results indicate a flourishing land flora in the Kačák interval of Voronezh High, where terrestrial vegetation might have suffered from a collapse coincident with the Taghanic event.

Insights into the K–Pg extinction aftermath: The Danish Cerithium Limestone Member

The Cretaceous–Palaeogene (K–Pg) mass extinction about 66 Ma ago was one of Earth's largest mass extinction events. The demise of calcifiers, among others, influenced biogeochemical cycles and changed the conditions for carbonate deposition in the global ocean. This study addresses the sedimentology and carbonate microfacies of the Cerithium Limestone Member of the Rødvig Formation within the renowned Stevns Klint succession in Denmark. The limestone was deposited in the earliest Danian Stage, immediately after the K–Pg mass extinction. It is a pale yellow, partly cemented unit with a dense network of Thalassinoides burrows and numerous flint nodules. Studies of the thin sections revealed that the Cerithium Limestone Member is more variable than expected from its overall homogeneous appearance at the macroscopic scale. The thin sections and scanning electron microscope (SEM) images showed that the highly bioturbated limestone consists of four principal microfacies: a mudstone, a wackestone and two different packstones. The 30 to 120-cm thick Cerithium Limestone Member fills depressions between low-amplitude mounds in the Maastrichtian chalk. The lowermost part constitutes a thin layer of a bryozoan-rich packstone, probably reworked from the crests of the Maastrichtian mounds. The successive part of the member is dominated by wacke stone with mainly foraminifera (planktic and benthic), molluscs and echinoderm debris, and in some areas an abundance of peloids. The foraminifera- and mollusc rich packstone appears in lenses. The mudstone contains few foraminifera and is linked to burrows and syn-sedimentary fractures. SEM observations revealed that the Cerithium Limestone Member corresponds to a dispersed micrite, with small calcite crystals ~1–4 µm in size. The general shape of these calcite crystals suggests precipitation from cyanobacterial activity and, thus, a microbial genesis for the micrite of the Cerithium Limestone Member.

Miocene bioerosion in a Cretaceous metamorphic basement from the Arzew Mountains (Oran, northwestern Algeria): First evidence of a Tortonian rocky shore in the southwestern Mediterranean area

Bioerosive trace fossils at the Guessiba Valley (Arzew Mountains) document an ancient Tortonian shoreline cut into Barremian calcschists at the lowermost part of the Tortonian Balanid Marl Formation. Four ichnogenera produced by endolithic bivalves (Gastrochaenolites) and polychaete annelids (Caulostrepsis, Maeandropolydora, Trypanites) have been identified. The four traces consist of dwelling structures (domichnia). The encrusting epifauna on the rockground include acorn barnacles of the genus Balanus and scarce, poorly preserved bivalves. These epibionts exhibit Trypanites and Entobia, respectively. This ichnoassociation identifies the Entobia ichnosubfacies as part of the Trypanites ichnofacies. The fossil rocky shore described in this paper is related to a transgression that occurred during the Tortonian, characterising a stratigraphic surface corresponding to a sequence boundary. The Guessiba Valley succession marks the first Mediterranean marine transgression affecting the southern flank of the Arzew Mountains, characterised by three distinct phases. The calcschists reported here are among the rare examples of non-carbonate rocky substrates colonised by endolithic boring organisms.

Spread and frequency of explosive silicic volcanism of the Carpathian-Pannonian Region during Early Miocene: Clues from the SW Pannonian Basin and the Dinarides

Explosive silicic volcanism of the Carpathian-Pannonian Region (CPR) is increasingly recognized as the primary source of tephra across the Alpine-Mediterranean region during the Early and Middle Miocene. However, the tephrostratigraphic framework for this period of volcanic activity is still incomplete. We present new multi-proxy data from Lower Miocene ignimbrites and tephra fallout deposits from the southwestern CPR and the Dinaride Lake System and integrate them into existing datasets to better resolve the regional extent and scale of these eruptions of the CPR. Volcanic glass geochemistry indicates distal fallout tuffs deposited in the Sinj Basin are correlative with the proximal Ostoros ignimbrites from the Bükkalja Volcanic Field, indicative of regionally extensive volcanism at 17.295 ± 0.028 Ma, based on CA-ID-TIMS UPb zircon geochronology. Based on integrated tephrostratigraphic data, newly identified 17.064 ± 0.010 Ma massive rhyolitic ignimbrite deposits from the Kalnik Volcaniclastic Complex located in the southwestern CPR are correlative with the 17.062 ± 0.010 Ma Mangó massive ignimbrite found in the Bükkalja Volcanic Field located in the northern CPR. Based on these new observations of its potential areal distribution and estimated thicknesses, these two widespread ∼17.1 Ma ignimbrites represent intermediate to large caldera-forming ignimbrites, larger than previously suggested. Finally, volcanic glass geochemistry of fallout deposits from the Dinaridic Sinj and Livno-Tomislavgrad Basins have similar volcanic glass geochemistry as the rhyolitic pumices from the lowermost part of the Bogács ignimbrite unit of the Bükkalja Volcanic Field. However, high-precision geochronology indicates that these distal ashfalls were deposited at 16.9567 ± 0.0074 Ma, significantly predating the 16.824 ± 0.028 Ma emplacement of the fiamme-bearing part of the Bogács ignimbrite. These distinct ages suggest that the Bogács unit represents multiple eruptive events and indicating that further work is required to deconvolve this portion of the CPR volcanic record. Together, these data suggest that large volume CPR ignimbrite volcanism was more frequent and widespread than previously understood, enhancing the existing volcanic framework and history of the source region for this time period.

Calcareous nannoplankton fluctuation within the Albian-Cenomanian Boundary Event of the Tethyan Himalaya

A hemipelagic succession 29m thick, situated in South Tibet within the Tethyan Himalaya tectonic unit, has been investigated for its calcareous nannofossil content. A total of 17 samples were subject to qualitative and semi-quantitative analysis. The studied interval belongs to the upper Albian-lowermost Cenomanian and extends into the UC0 nannofossil zone; based on the last occurrence of Hayesites albiensis, the UC0a and UC0b-c subzones were recognized. The most abundant nannofossil of the Youxia section is Watznaueria barnesiae. Other common taxa are Eiffellithus turriseiffelii, Eprolithus floralis, Rhagodiscus spp., and Zeugrhabdotus spp. In the lowermost part of the studied section, below the beginning of the Albian-Cenomanian Boundary Event (ACBE), i.e., prior to the δ13C positive excursion related to OAE1d, the nannofossils confined to high paleolatitudes, namely Repagulum parvidentatum, Seribiscutum primitivum, and Sollasites horticus, are present with a low abundance. This occurrence is believed to be evidence of a short episode of cooler surface waters linked to a transgressive event. The nannofossil abundance and diversity, along with the fluctuation patterns of the nutrient and temperature indices throughout the section, reflects a primary signal of mesotrophic to eutrophic conditions from the base of the succession up to the two oldest δ13C peaks of ACBE, both late Albian in age and within the OAE1d. By contrast, the dominance of Watznaueria barnesiae, representing more than 80% of the total assemblages, along with the significant drop in abundance and diversity shown by nannofossils within late phases of ACBE, are interpreted as a diagenetic signal. Mesotrophic to eutrophic conditions returned towards the top of the studied succession, where Biscutum constans and Zeugrhabdotus erectus again show a higher abundance.

Effects of axial launch spacing on cavitation interference and load characteristics during underwater salvo

This paper analyzes the effect of launch interval on cavitation flow interference and load characteristics during underwater salvo. The study employs the Improved Delayed Detached Eddy Simulation and the Schnerr-Sauer cavitation model, Volume of Fluid (VOF) multiphase flow model, and overlapping grid. Additionally, decompression experiment systems are designed, and numerical simulations are found to be in good agreement with experimental results, thus verifying the effectiveness of the simulation. Detailed discussions are provided on multiphase flow field and load distribution. The results reveal a top-down collapse process of the cavity, with collapse shrinking to an isolated bubble at the end. Synchronized collapse pressure is characterized by short pulse widths at the peaks, all located at the lowermost part of the cavity. During the underwater stage, when the axial launch spacing ranges between 0.5 times and 1.0 times the length of the projectile, the head of the second projectile acts on the area below the center of mass of the first. This leads to gradual stabilization of the initial cavity and a decrease in deviation of the center of mass toward the inside. Despite experiencing large-scale fracture and detachment due to interference from the wake of the first engine, the motion stability of the inside cavity of the second projectile remains intact. In the water exit stage, when the axial launch spacing ranges between 0.75 times and 1 time the length of the projectile, it causes expansion and contraction of the inside cavity of the second projectile. However, asymmetric synchronous collapse loads may occur, leading to unstable motion posture.

Post-cranial remains of Rhinocerotidae from the Neogene of central Myanmar: morphological descriptions and comparisons with ratios

ABSTRACT New post-cranial remains from the early Late Miocene have been discovered in the lowermost part of the Irrawaddy Formation, Tebingan area, central Myanmar. Three genera and one indeterminate taxon were identified: Rhinoceros sp. Rhinoceros cf. R. sondaicus, Dicerorhinus sp., Brachypotherium perimense, and Rhinocerotidae indet. The evolutionary history of the Rhinocerotidae is still poorly known in Southeast Asia. Few Rhinoceros species, Rhinoceros sp. ‘B’. fatehjangense, and B. perimense, has already been identified in the Tebingan area by dental remains. The present discovery of the post-cranial remains of Rhinoceros cf. R. sondaicus and Dicerorhinus sp. that complements previous studies based on dental remains. The early Late Miocene Tebingan record is the oldest fossil record of Dicerorhinus in Southeast Asia, indicating a continental origin of the genus. Furthermore, the possible presence of R. sondaicus in the Tebingan area suggests that it may have appeared in Southeast Asia as early as the early Late Miocene.

The subaqueous felsic volcanism from the Upper Member of the Cordón de Lila Complex, Antofagasta region, northern Chile

This contribution presents the study of an Ordovician subaqueous felsic succession, formed by the ~400 m-thick Upper Member of the Cordón de Lila Complex (CISL), northern Chile. From bottom to top, the succession starts with two dacitic sills that intruded into the sediments of the lowermost part of the Upper Member. Then, it is followed by a thick sedimentary deposit, two rhyolitic lavas, a volcanoclastic felsic breccia with pyroclastic clasts, and ends with a red rhyolitic lava. The first rhyolitic lava shows centimetric to metric folds with a north-northwestern vergence, evidence of flow in that direction. In the volcanoclastic breccia, an abundant pumice-and-fiamme-rich green matrix wraps around lithic clasts, giving the rock an eutaxitic texture at the outcrop scale. This matrix and texture evidence is characteristic of hot pyroclastic flows deposited under subaqueous conditions. The described section of the breccia is formed by four coarsening-up sequences, reflecting respectively four pulses of building up energy. The lack of internal erosional features points to a single and continuous explosive eruption. An accidental granite clast in the upper part of the breccia suggests a connection with a granitic body, possibly the Pingo-Pingo monzogranite. The geochemical character of the felsic succession is calc-alkaline. The tectonic setting diagram shows a within-plate setting for the succession. This suggests a shift from the arc position inferred for the Lower Member of the CISL to a forearc continental setting for the Upper Member of the CISL.

In situ observations of supercooled liquid water clouds over Dome C, Antarctica, by balloon-borne sondes

Abstract. Clouds in Antarctica are key elements that affect radiative forcing and thus Antarctic climate evolution. Although the vast majority of clouds are composed of ice crystals, a non-negligible fraction constitutes supercooled liquid water (SLW; water held in liquid form below 0 °C). Numerical weather prediction models have great difficulty in forecasting SLW clouds over Antarctica, favouring ice at the expense of liquid water and therefore incorrectly estimating the cloud radiative forcing. Remote-sensing observations of SLW clouds have been carried out for several years at Concordia Station (75° S, 123° E; 3233 m above mean sea level), combining active lidar measurements (SLW cloud detection) and passive HAMSTRAD microwave measurements (liquid water path, LWP). The present project aimed at in situ observations of SLW clouds using sondes developed by the company Anasphere, specifically designed for SLW content (SLWC) measurements. These SLWC sondes were coupled to standard meteorological pressure–temperature–humidity sondes from Vaisala and released under meteorological balloons. During the 2021–2022 summer campaign, 15 launches were made, of which 7 were scientifically exploitable above a height of 400 m above ground level, a threshold height imposed by the time the SLWC sonde takes to stabilize after launch. The three main outcomes from our analyses are as follows: (a) the first in situ observations so far of SLW clouds in Antarctica with SLWC sondes; (b) on average, the consistency of SLW cloud heights as observed by in situ sondes and remote-sensing lidar; and (c) the liquid water path (vertically integrated SLWC) deduced by the sondes being generally equal to or greater than the LWP remotely sensed by HAMSTRAD. In general, the SLW clouds were observed in a layer close to saturation (U > 80 %) or saturated (U ∼ 100 %–105 %) just below or at the lowermost part of the entrainment zone, or capping inversion zone, which exists at the top of the planetary boundary layer and is characterized by an inflection point in the potential temperature vertical profile. Our results are consistent with the theoretical view that SLW clouds form and remain at the top of the planetary boundary layer.

The Campanian-Maastrichtian benthic foraminiferal assemblages at the Elles section (Tunisia): A perspective for paleoenvironmental, paleobathymetric and sea-level fluctuation reconstruction

The Late Cretaceous Period experienced prevailing hothouse conditions that were characterized by relatively elevated atmospheric pCO2 concentrations, high global mean sea level and mostly lacking ice sheets. These conditions were interrupted by an overall global decreasing trend in temperature during the Campanian-Maastrichtian interval (83.65 to 66.04 Ma). The Upper Cretaceous sedimentary successions in Tunisia (southwestern Tethyan Ocean) like at the Elles section are regarded as unique archives for investigating paleoenvironmental and paleoclimatic changes, as well as constrain oscillations of sea-level. Here, we perform high resolution quantitative analysis of the benthic foraminiferal assemblages in the Campanian-Maastrichtian interval at the Elles section in order to infer palaeoenvironmental and paleobathymetric changes in relative sea-level. The Campanian succession (Abiod Fm.) is inferred to be deposited at upper to middle bathyal (i.e., 540–675 m) and is characterized by prevailing well‑oxygenated conditions and low organic matter flux to the seafloor. The Campanian/Maastrichtian transition-coincides with the lowermost part of the El Haria Fm. deposited in outer neritic to upper bathyal settings under oligotrophic, well‑oxygenated and reduced productivity conditions. Shallower depositional setting (i.e., 436–515 m) is inferred for the Maastrichtian succession (El Haria Fm.) that is also characterized by a lowering in oxygen availability at the seafloor associated with an increase of organic matter. Eight main sea-level regressions (four in the Campanian, one at the Campanian-Maastrichtian transition and three in the Maastrichtian) have been identified and biostratigraphically constrained. These sea-level regression events are mostly accompanied by a negative excursion carbon isotope (δ13C) and their stratigraphical positions appear to be quite consistent with those previously recognized at the nearby El Kef section.

When an explosion of life leads to death – hypoxic zones in the Menilite Shales from the Silesian Unit (Polish Outer Carpathians)

Oligocene siliciclastics belonging to the Silesian Unit in the Outer Carpathians were sampled from five locations (Iwonicz Zdrój, Krosno, Równe, Rymanów Zdrój, Zmysłówka) with the first four locations connected to Menilite Shales. The sample from Zmysłówka is an example of the lowermost part of the Krosno Beds. Preliminary geochemical results obtained from the Rock-Eval analysis suggested the presence of immature mixed II/III Type kerogen. Detailed geochemical (GC-MS) and petrological analyses show evidence of extensive phytoplankton blooms, causing the occurrence of episodic ferruginous hypoxic zones. Hypoxic zones were present in the photic zone, where molecular evidence of green and/or brown pigmented sulfur reducing bacteria were marked. The size and character of the blooms were controlled by the palaeoenvironmental conditions. In cases of intense nutrient-rich freshwater loading by a palaeoestuary and/or rainfall, extensive algal blooms were reported. With the increasing aridity and/or decrease of the palaeoestuary impact, the phytoplankton blooms gradually acquired a mostly bacterial character and were reduced in size. The most hypoxic conditions were noted in causes linked with the most intense algal blooms. In most of the cases, algal blooms were dominated by diatoms, suggested by the extensive presence of C25 Highly Branched Isoprenoid, a specific biomarker linked with these organisms. The dinoflagellates only recorded a dominant role in blooms in the Krosno location. A comparison of diterpenoids and triterpenoids revealed that terrestrial organic matter was mostly dominated by gymnosperms like conifers from the Cupressaceae, Pinaceae and Podocarpaceae families. Beside these, the molecular evidence of the angiosperms, bryophytes, and fungi was marked. Both geochemical and petrological analyses confirm the minor role of palaeo-wildfires in the land areas near the deposition place of the analysed samples.

Application of integrated GNSS tomography in observation study over the area of southern Poland

Despite the growing number of GNSS sites, GNSS meteorology still suffers from insufficient observational data. This deficiency is particularly evident in GNSS tomography processing in the lowermost part of the troposphere, where the highest variability of weather conditions is observed. To address this challenge, we propose an integrated tomography solution that uses both ground-based GNSS observations and radio occultation (RO) excess phase in the same tomography model. Our integrated approach benefits from improved geometry and increased number of observations. In order to verify presented methodology, we use 41 GNSS stations and 78 RO profiles gathered during four different high precipitation events over the region of southern Poland. The results are validated against radiosonde observations and WRF reanalysis. Our study indicates an enhancement in the representation of wet refractivity on the order of 20 to 30% RMSE decrease when RO are integrated into the tomography solution with the mean error of final integrated product equal 3.5 ppm.

Ordovician-Silurian trace fossils from the Takche Formation, Parahio Valley, Spiti Himalaya, India: biostratigraphic and paleoenvironmental significance

ABSTRACT The Ordovician-Silurian trace fossils from the Takche Formation exposed near the Gechang locality, Parahio Valley, Spiti region, Himalaya are described. Following trace fossils were found in the Takche Formation: Arenicolites isp. Aulichnites parkerensis, Archaeonassa fossulata, Catenichnus isp. Cochlichnus isp. Cruziana furcifera, Cruziana goldfussi, Cruziana semiplicata, Chondrites targoni, Chondrites isp. A, Chondrites isp B, Helminthodoichnites isp. Lockeia siliquaria, Laevicyclus mongraensis, Planolites isp. Phycodes circinatus, Phycodes rarus, Phycodes isp. Treptichnus pedum, Thalassinoides isp. and Zoophycos isp. The lowermost part of the Takche Formation yielded significant traces of Cruziana affinity i.e. Cruziana furcifera, Cruziana goldfussi, and Cruziana semiplicata suggesting Tremadocian-Darriwilian age (Lower to Middle Ordovician). The middle part of the Takche Formation is dominated by Zoophycos isp. Chondrites targoni, Chondrites isp. A, and Chondrites isp. B suggests a deeper water offshore setting. The uppermost part yielded Archaeonassa fossulata, Aulichnites parkerensis, Laevicyclus mongraensis, Planolites isp. Helminthoidichnites isp. Phycodes rarus, Phycodes isp. and scratch marks. Overall, the trace fossil assemblages indicate a shallow marine shoreface to offshore depositional setting.

LicenseMiddle Triassic deeper-marine volcano-sedimentary successions in western Slovenia

A Ladinian – Carnian volcano-sedimentary succession from western Slovenia, paleogeographically belonging to the western Slovenian Basin, is presented in 17 sections. Except for the lowermost part, which is dominated by volcanics and volcaniclastics, most of the succession is dominated by shale, sandstone, and micritic limestone. Various authors use the name Pseudozilja and/or Amphiclina formation for this part, which is dominated by clastics, but they disagree on the differences between the formations. The lower Pseudozilja formation, represented by the Malenski Vrh section, comprises diabase, tuf and shale. No substantial differences in lithological composition have been observed between the upper Pseudozilja formation and the Amphiclina formation, which are predominantly composed of shale, sandstone, and limestone. The shale and sandstone are largely composed of quartz, feldspar, and lithic grains (especially volcanics), which vary in proportions. Limestone varieties comprise hemipelagic limestones and resedimented carbonates deposited by gravity-flows. Deposition of the Ladinian – Carnian volcano-sedimentary succession took place on or near the continental slope that was generally inclined to the S, with the direction of transport mainly from N to S.

Sound velocities in lunar mantle aggregates at simultaneous high pressures and temperatures: Implications for the presence of garnet in the deep lunar interior

Recent experimental and theoretical studies on lunar magma ocean crystallisation have suggested the presence of significant proportions of garnet in the deep lunar interior. While phase relation studies indicate a deep lunar mantle consisting of olivine, pyroxene, and garnet, the compatibility of such an assemblage with seismic models of the lunar interior is yet untested. In this study we report compressional and shear wave velocities in an iron-rich assemblage consisting of olivine, orthopyroxene, clinopyroxene, and garnet up to ∼8 GPa and 1300 K, by means of ultrasonic interferometry measurements combined with synchrotron techniques using the multi-anvil press apparatus. Sound velocity and density models of lunar mantle rocks along a selenotherm based on our experimental results find good agreement with the seismic and density profiles at lunar interior depths of 740–1260 km. Further models are constructed, allowing for the variation of chemical composition, phase proportion, and temperature; these suggest that a garnet-rich deep lunar mantle is compatible with present-day lower lunar mantle temperatures of between 1400–1800 K. Our results show that lunar mantle rocks with up to 33 wt.% garnet may provide an explanation for the observed high velocities of the lower lunar mantle. The presence of garnet in the lowermost part of the Moon's mantle has significant implications for the depth and temperature of the Moon's magma ocean as well as the composition, structure and internal dynamics of the solid Moon.

Response of the calcareous nannofossils to the Cretaceous-Paleogene boundary event: A case study from Sinai, Egypt

A detailed study of calcareous nannofossils was conducted on a well-exposed succession encompassing the Cretaceous-Paleogene (K-Pg) boundary interval at Wadi Nukhul, Sinai, Egypt, as a part of the southern Tethyan margin. The nannofossil biostratigraphic data show that the Nukhul succession sustains a complete K-Pg boundary interval. The nannofossil assemblage indicates a shift from cool/oligo-mesotrophic conditions in the late Maastrichtian Micula murus Zone to warm/oligotrophic in the latest Maastrichtian M. prinsii Zone prior to the K-Pg boundary. At the K-Pg boundary, diversity, and total abundance of the calcareous nannofossils remarkably decreased signifying unstable marine conditions. The post-impact assemblage (lowermost part of NP1 Zone) was marked by acme of Cervisiella operculata indicating oligotrophic conditions in the photic zone related to the diminished of the marine primary producers in the lowermost Danian. At the upper portion of the NP1 Zone, the assemblage is still dominated by C. operculata, besides the successive occurrence of the small-sized incoming Paleocene taxa Biantholithus sparsus and Neobiscutum romeinii. This pattern was accompanied by increased frequencies of Zeugrhabdotus sigmoides indicating stressful cool/meso-eutrophic surface water conditions signify the initial recovery interval. Upward in the early Danian NP2-NP3 zones, the nannofossil species diversity and total abundance progressively increased. Also, the nannofossil assemblage characterized by the existence of the new Paleocene oligotrophic indicators like Cruciplacolithus primus, Coccolithus pelagicus, and Ericsonia subpertusa. This probably indicates a tendency toward rebuilding of the biological pump efficiency and, therefore, a full recovery phase was resumed.

Study on the pullout bearing characteristics of root piles in coral sand foundations under different water content states

Offshore wind energy will become one of the important sources of energy in the future, and root piles with good pullout bearing characteristics can be used for the foundation of offshore wind power generation facilities. Through the model test, the pullout bearing characteristics of root piles with different water content states in coral sand foundation are comparatively analyzed, and the pullout bearing deformation law and pile body force transmission characteristic law of root piles is revealed. The results show that when the coral sand foundation is saturated and the water level rises and falls, compared with the dry sand foundation, the pullout bearing capacity of the root pile decreases, and the ability to control the displacement is sharply weakened. The axial force curve at the root is in the shape of a step; after the foundation is affected by water, the maximum value of lateral friction resistance first appears at the bottom root, and the lateral friction resistance at the lower root is always greater than that at the upper root; the water level rise and fall leads to a decrease in the lateral friction resistance in the area of the pile without a root, and the lateral friction resistance in the area of the root is increased. Under saturated and water level rise and fall condition, the total bearing ratio of the root pile section increases, and the bearing ratio of the lower root pile section is always larger than that of the upper root. After loading, the soil in the upper part of the pile is compacted, and the soil in the lower part is loosened; the maximum value of soil pressure in the compacted area of the dry sand condition gradually moves downward, and the maximum value of soil pressure in the saturated and water level rise and fall condition is always located in the lowermost part of the compacted area; the pore water pressure in the saturated and water level rise and fall condition is basically equal with the hydrostatic pressure, and there is no obvious super pore water pressure generated. The research results provide scientific basis for the application of root piles in coral sand foundation.

The Badenian/Sarmatian (Middle Miocene) boundary in the Central Paratethys (Kreminna, western Ukraine): Foraminiferal and palynological evidence

The Badenian/Sarmatian boundary in the Paratethys basin, that marks the transition from normal marine to restricted semi-marine conditions due to isolation of the basin from the world ocean at the onset of Sarmatian time, is still far from being fully understood. The Kreminna section is located at the northeastern margin of the Carpathian Foreland Basin (Central Paratethys) in the Medobory Hills region. The Miocene deposits that overlie here the Upper Cretaceous substratum comprise the >1 m thick upper Badenian marls and clays passing upwards into ~4 m thick Sarmatian marly limestones with intercalations of marls, clays and limestones, and >2 m thick limestones in the uppermost part of the exposure. Fifty-three species of benthic foraminifera and four species of planktonic foraminifera have been recorded. Six benthic foraminiferal assemblages are composed almost exclusively of calcareous forms; agglutinated taxa are practically lacking. Elphidium spp., miliolids, Lobatula lobatula and Ammonia spp. are the most common calcareous benthic foraminifera in the material studied. Planktonic foraminifera are represented only by species of Globigerina and occur rarely in the lowermost part of the section. A characteristic feature of palynofacies is the very low proportion of land-derived elements – sporomorphs and cuticles, which suggests a sedimentary setting without terrestrial influx, and taxonomical impoverishment of dinoflagellate cyst assemblages, which are either monospecific or consist mainly of two to three species: in a majority of samples, assemblages with Polysphaeridium zoharyi and P. subtile occur. Most δ18O values range from –1.5 to ~+0.5‰ VPDB and most δ13C values are between 0 and +2‰ VPDB. In general, the δ13C curve mirrors the δ18O changes in the section. The Badenian/Sarmatian boundary is placed at the level where the Cibicidoides ungerianus Assemblage is replaced by the Elphidium fichtelianum Assemblage. At the boundary, planktonic foraminifers and most abundant stenohaline benthic foraminifera disappeared. Bottom waters were well-oxygenated both in the latest Badenian and earliest Sarmatian in the Kreminna location.

Knowledge of Pap smear test among reproductive age group women of Kathmandu, Nepal

Cervical cancer is a malignant tumor of the lowermost part of the uterus and a major cause of morbidity and mortality among women in the world. Globally, it is the fifth leading cause of cancer-related deaths among women after cancers of the breast, lungs, stomach and colorectal in developing countries. About 80% of new incidences of cervical cancer occur in developing countries, usually, with less comprehensive cervical cancer prevention programs. The objective of the study is to assess the level of knowledge on cervical cancer and Pap smear tests among Reproductive age group women. A descriptive study was conducted in Gokarneshwor-8, Kathmandu community on 105 respondents through non-probability purposive sampling techniques and data was collected using interviewers administered questionnaires. Out of 105 respondents, a majority (64%) respondents had adequate knowledge of cervical cancer and Pap smear tests, while 36% had inadequate knowledge. This study concluded that the majority of respondents had adequate knowledge of Pap smear tests while only thirty-six percent had inadequate knowledge. Though there is adequate knowledge, only a few respondents had ever done a Pap smear test. Still, there are existing gaps that need more education to connect knowledge with attitudes as well as to uplift the regular practice of cervical cancer screening for eligible women.

Sedimentary environment and benthic oxygenation history of the Upper Cretaceous Austin Chalk Group, south Texas: An integrated ichnological, sedimentological and geochemical approach

ABSTRACTOxygen concentration in the ocean is vital for sustaining marine ecosystems. While the potential impacts of deoxygenation on modern oceans are hard to predict, lessons can be learned from better characterizing past geological intervals formed under a greenhouse climate. The greenhouse Cretaceous containing several oceanic anoxic events characterized by widespread oxygen‐deficient water is ideal in this regard. The Austin Chalk Group in south Texas (USA) shows organic‐rich intervals that can be linked to oxygen depletion in the ocean, but the exact bottom water oxygenation conditions have not been estimated. This study aims to reconstruct both sediment interstitial and bottom water oxygenation history during Austin Chalk Group deposition by integrating detailed ichnological, sedimentological and geochemical (X‐ray fluorescence and X‐ray diffraction) analyses, thereby providing a consistent model that may be applicable across a range of marine shelf settings. The 141.12 m Gise #1 core contains a continuous record of the Austin Chalk Group, providing an opportunity for unravelling oxygenation and deoxygenation events. Whereas the anaerobic–exaerobic deposits are essentially nonbioturbated, four oxygen‐related ichnocoenoses are defined, further refining the transition of aerobic to dysaerobic conditions in the sediment interstitial water. Omission surfaces and glauconitic grains, products of current‐induced scouring and condensation, suggest sporadic high‐energy events in the Austin Chalk Group ramp that drove elevated terrestrial inputs. Geochemical data further help to identify anoxic bottom water conditions within the anaerobic facies. Additionally, the lowermost part of the Austin Chalk Group illustrates redox cycles, whereas dilution events characterized by elevated terrestrial input are identified throughout the rest of the Austin Chalk Group. The evolution of oxygenation levels in sediment interstitial water and bottom water disputes the existence of a long‐lasting oxygen‐deficient sea in south Texas. The refined depositional model may be applicable to coeval shelfal settings. Moreover, the results provide insights into variable, evolving palaeoclimatic and palaeoceanographic conditions of the greenhouse Late Cretaceous.