Northeastern Side Research Articles

Planktonic Foraminifera of the Middle and Upper Eocene Successions at the Northwestern and Northeastern Sides of the Nile Valley, Egypt: Stratigraphic and Paleoenvironmental Implications

This study deals with the biostratigraphic determination and paleoenvironmental reconstruction of the middle–upper Eocene sediments along the northwestern and northeastern banks of the Nile Valley, Egypt. The studied successions are classified into four rock units as follow: The Qarara (Lutetian–Bartonian), the El Fashn (Bartonian), the Gehannam, and the Beni Suef (Bartonian–Priabonian) formations. A total of eighty planktonic foraminifera species belonging to twenty-two genera and eight families are identified, and their vertical distribution enabled us to recognize four planktonic biozones, namely the Morozovelloides lehneri Zone (late Lutetian–early Bartonian), Orbulinoides beckmanni Zone (early Bartonian), Morozovelloides crassatus Zone (late Bartonian), and Globigerinatheka semiinvoluta Zone (late Bartonian–early Priabonian). The faunal assemblages characterizing these zones showed a great similarity with those recorded in the lower latitudes (tropical and sub-tropical) regions and correlated with the planktonic zones in the northern and southern Tethyan provinces. The appearance of Orbulinoides beckmanni distinguishes the early Bartonian period, its lowest occurrence defines the upper boundary of the Morozovelloides lehneri Zone, and its highest occurrence marks the lower boundary of the Morozovelloides crassatus Zone. The disappearance of the spinose forms of morozovellids and the large acarininids, besides the highest occurrence of Morozovelloides crassatus, defines the lower boundary of the Globigerinatheka semiinvoluta Zone. The middle/upper Eocene boundary is traced based on the last and first appearance of the marker planktonic species and located herein within the Globigerinatheka semiinvoluta Zone. The paleontological data, including the planktonic to benthic foraminiferal ratio (P/B), statistical analyses of different foraminiferal groups, and ternary plot diagrams in conjunction with the sedimentological features, indicate changes in the depositional settings, fluctuating between the inner to middle and outer neritic environment and the uppermost bathyal environment at some levels.

Summertime secondary convection and interaction with sea‐breeze circulations

AbstractSummertime convection in the arid United Arab Emirates (UAE) is mostly confined to the eastern and northeastern sides of the country, known as primary convection. Convection can also occur in the drier central and western parts of the country; this is called secondary convection. However, the mechanisms behind the latter are still not fully understood, even though it represents a crucial water source in the hotter months. To this end, a series of real‐case and semi‐idealized numerical simulations are performed to explore the role of sea breezes emanating from the nearby water bodies in triggering convection. We found the primary convection is mostly driven by convergence of the sea breezes from the Sea of Oman and Arabian Gulf with the topography‐driven circulations at the Al Hajar mountains. When the Arabian Gulf sea breeze is removed, which is achieved by replacing the water body with flat desert land, the convection is weaker. Secondary convection is triggered by the convergence of the sea breeze from the Arabian Gulf with the circulation associated with the Arabian heat low (AHL). In the absence of the Arabian Gulf sea breeze, it develops in response to low‐level convergence within the southerly monsoon flow reinforced by the AHL's circulation. It is fed by moisture from the Arabian Sea advected by the southerly flow into the UAE enhanced by surface evaporation. The sea breeze from the Sea of Oman plays a minor role in the secondary convection. Sensitivity experiments confirmed these findings. The results presented here stress that any variation in the characteristics of the sea breezes, such as through changes in surface properties (e.g., land‐use land cover), will impact the nature and intensity of the primary and secondary convection in the UAE. However, summertime convection will continue to occur, owing to favourable dynamic and thermodynamic conditions at regional scale.

Ecosystem Service Value Estimation and Ecological Security Pattern in Heilongjiang Province

To maintain ecosystem functions and ensure ecological security, estimating the value of ecosystem services and constructing an ecological security pattern are necessary. Considering the lack of systematic research on the estimation of ecosystem service value and the construction of ecological security pattern, this study extracted the ecological source based on the analysis of ecosystem service value and morphological spatial pattern. According to the natural conditions such as geographical location and altitude, land use type, landscape pattern type, elevation, slope, and normalized difference vegetation index were selected to establish the resistance surface. The minimum cumulative resistance model was used to identify potential ecological corridors, so as to construct the ecological security pattern of Heilongjiang Province, and longitudinal analysis was conducted from 2000 to 2020. The results showed that： ① The overall value of ecosystem services in Heilongjiang Province showed an upward trend （with an amplitude of 42%）, the value of hydrological regulation services accounted for the largest proportion among different service types （approximately 30%）, and the value of forest land services accounted for the largest proportion among different land use types （up to 70%）. ② Eight ecological source areas were extracted, mainly distributed around Greater Khingan Mountains, Lesser Khingan Mountains, Changbai Mountain, and Wanda Mountain, with the largest area of ecological source in Greater Khingan Mountains. ③ Twenty-eight potential ecological corridors were identified, mainly distributed in the northeastern side of the line from Heihe City to Mudanjiang City, forming densely populated areas in Qitaihe City, northern Mudanjiang City, and southern Jixi City. ④ An ecological security network pattern in Heilongjiang Province was constructed with Greater Khingan Mountains Region, Mudanjiang City, and Shuangyashan City as endpoints and Yichun City as the center, finding that the main problem faced at that time was uneven spatial distribution. The research results are helpful to formulate and establish more reasonable ecological environment protection measures and policies and can provide reference value and scientific basis for provincial ecosystem protection and optimization.

Crustal 3‐D S‐Wave Velocity and Azimuthal Anisotropy in the Sanjiang Lateral Collision Zone in the SE Margin of the Tibetan Plateau

AbstractThe eastward extrusion of the Tibetan Plateau materials has caused intricate tectonic deformations and frequent seismic activities in the Sanjiang lateral collision zone (SLCZ). To reveal crust structures and deformation mechanisms, we investigate high‐resolution structural features of crustal depth (≤40 km). A 3‐D S‐wave velocity and azimuthal anisotropy model is constructed by the direct tomography method with Rayleigh phase velocity at periods of 2–40 s from multiple temporary seismic arrays and regional permanent network. In the middle‐to‐lower crust, an obvious low‐velocity zone is confined by the large‐scale fault systems of Jinhe‐Qinghe fault and Chenhai fault (CHF) to the northeast and east, Lancangjiang fault (LCJF) and Red River fault (RRF) to the west, with strong N‐S‐oriented anisotropy, which evident differs from the ENE‐WSW‐oriented weak anisotropy in the high‐velocity zone on the northeastern side. We consider that the weak material may be obstructed by large faults and the high‐velocity zone, resulting in complex crustal deformation and tectonic boundary. The crustal low‐velocity materials beneath the Tengchong volcano (TCV) are probably separated with those from the Tibetan Plateau. The low‐velocity beneath the Chuxiong basin (CXB) may be combinations of partial melts and fluid derived from shear deformation and deep material upwelling. The segmented anisotropy at the NW end of the RRF suggests complex deformation by crustal flow, emphasizing the important influence of faults on anisotropic pattern. The complex anisotropy in the fault intersection of the Lijiang‐Xiaojinhe fault and RRF also highlights the important role of these faults in shaping crustal deformation.

Swinepox virus: an unusual outbreak in free-range pig farms in Sicily (Italy)

BackgroundTwo outbreaks of swinepox were investigated in free-range domestic pig farms located in the northeastern side of Sicily, Italy. The disease is generally self-limiting with a low mortality rate, but morbidity can reach high rates in case of poor sanitary conditions, improper husbandry practices and ectoparasitic infestation. The presented cases are the first ever reported on the island and part of the few cases reported in domestic pigs.Case presentationCarcasses condemned at the slaughterhouse and deceased pigs from Farm A and Farm B respectively, were referred for post-mortem examination and further investigations, with a strong suspect of SwinePox virus (SWPV) infection. Twelve deceased pigs were examined in total, showing poor body condition and pustular lesions scattered all over the cutaneous surfaces. Moreover, pigs from Farm B showed ocular lesions classified from Grade I to IV (from mild conjunctivitis to severe keratoconjunctivitis with corneal oedema, opacity, and ulcers). Final diagnosis was pursued by the microscopic assessment of skin lesions in both farms, which revealed the typical SWPV-lesion appearance, such as severe and disseminated ulcerative dermatitis and suspected inclusion bodies multifocally observed in the epidermis. Moreover, negative staining Electron Microscopy (nsEM) was performed on skin lesions and ocular swabs from Farm B, revealing in two samples the presence of brick-shaped viral particles, 220 nm long and 160 nm wide, with irregularly arranged surface tubules, identified as SWPV. The gene encoding the 482-bp fragment of the virus late transcription factor–3 was detected by PCR and sequencing revealed 99.79% identity and 100% query-cover with a strain previously isolated in Germany. Field clinical assessment was then performed in Farm B, revealing high overcrowding, poor sanitary conditions and improper husbandry practices, which are relevant risk factors for SWPV transmission.ConclusionsThe present is the first case report of SWPV in free-range pigs raised in Sicily, an island of the Southern coast of Italy, and wants to raise awareness on a neglected disease, and cause of animal health and welfare issues.

Changes in physicochemical parameters of the alpine/mountain stream influenced by summer flash flood in Tatra Mountains (Western Carpathians)

taChanges to the physicochemical parameters of water in alpine/mountain streams can provide evidence of ongoing natural and anthropogenic processes in their catchment. In this study, we analysed a mountain stream (Javorinka) on the north-eastern side of the Tatra Mountains (Western Carpathians), which is minimally influenced by human activity. The stream was monitored weekly for 5 years (2017–2021) and evaluated for its seasonal variations in physicochemical parameters. These seasonal variations were influenced by the large summer flash flood in July 2018. We hypothesise that floods are essential for the oligotrophic profile of alpine/mountain streams. To support this idea, our main objective was to compare the seasonal trends of the main physicochemical parameters in the stream before and after floods or periods of high flow. We found evidence to support our hypothesis. For example, there was a significant decrease in the chemical consumption of oxygen and ammonia, and, conversely, an increase in the ratio of saturated oxygen and nitrate concentrations. Stream bed erosion also resulted in increased phosphates (over the next 2 years) and high enrichment of the water by dissolved solids in the spring. Interestingly outside of the main objectives, we observed a significant decrease in sulphates, especially in the summer and autumn of 2020 and 2021, which may be related to suppressed emissions due to the restriction of the COVID-19 lockdown. The observed trends and their changes therefore support the idea that alpine/mountain streams are excellent indicators of ongoing environmental processes, and that occasional summer flash floods support the oligotrophic profile of the stream system.

Reconstruction of the Subsurface of Al-Hassa Oasis Using Gravity Geophysical Data

Al-Hassa city, located in Eastern Saudi Arabia, boasts the world’s largest oasis and the most expansive naturally irrigated lands. Historically, a total of 280 natural springs facilitated significant groundwater discharge and irrigation of agricultural land. Furthermore, the water in certain springs formerly had a high temperature. The spatial variability of the water quality was evident. At the same time, Al-Hassa Oasis is situated on the northeastern side of the Ghawar field, which is the largest conventional onshore oil field in the world in terms of both reserves and daily output (approximately 3.8 mmb/d). The aforementioned traits suggest an intricate subsurface that has not yet been publicly and thoroughly characterized. Due to the presence of significant cultural noise caused by agricultural and nearby industrial activities, a robust, easy-to-use, and accurate geophysical method (gravity) was used to cover an area of 350 km2, producing the 3D subsurface model of the study area. A total of 571 gravity stations were collected, covering the whole Al-Hassa Oasis and parts of the nearby semi-urban areas. The gravity data were corrected and processed, and a 3D inversion was applied. The resulting 3D geophysical subsurface modeling unveiled an intricate subterranean configuration and revealed lateral variations in density, indicating the presence of a potential salt dome structure, as well as fracture zones that serve as conduits or obstacles to the flow of the subsurface fluids. This comprehensive modeling approach offers valuable insights into the subsurface dynamics of the broader study area, enhancing our understanding of its qualitative tectonic and hydraulic features and their impacts on the area’s natural resources, such as groundwater and hydrocarbons.

Monitoring the response of Saudi Arabia's largest fossil aquifer system to climate variability

The study utilizes an integrated approach that involves GRACE and Global Precipitation Climatology Project (GPCP) data to analyze temporal water mass variations in Saudi Arabia (KSA). Recently, KSA has witnessed a historic wet period between 2018 and 2020 (i.e., 120–150 mm/year) following a prolonged dry period between 2002 and 2017 (i.e., 80–100 mm/year). Inspection of GRACE data showed a decline in groundwater recharge of −4 to −6 mm during the dry period. The depletion was reduced by 1 to 6.8 mm in the Northeastern side of KSA (e.g. Hail, Al-Jouf, Al-Hudud Ash-Shamaliyah areas) during the wet period. This impressive recovery has led to a groundwater recharge increase of 360 km3 in Hail, 174 km3 in Al-Jouf and 97 km3 in Al-Hudud Ash-Shamaliyah. The findings emphasize the notion that climate change will bring more frequent extreme climatic events to the Kingdom of Saudi Arabia and call for continuous monitoring of aquifers every year.

Comparative analysis of two strengthening solutions for the structural rehabilitation of a historical masonry building

The paper presents a comparative analysis based on the Finite Element Method (FEM) for a masonry building located in Iasi, the North-Eastern side of Romania. This specific region is known to be found in a seismic area having a design peak ground acceleration of 0.25g. The building was assessed as being in the 1st seismic risk class, according to the Romanian norms, with a high probability of collapse in case of future earthquakes. Being a historical monument, the structural strengthening solutions are very limited. The study consists of modal and seismic analyses for the masonry structure. A comparison of the advantages and disadvantages of two approaches of structural rehabilitation solutions is done. The structural strengthening solution “A” consists of the addition of reinforced concrete thin wall elements, while the other - called solution “B” - consists of an interior steel profile skeleton mechanically and chemically connected to the adjacent masonry walls.

GENETIC APPROACH OF THE COIBA ISLAND HOWLER MONKEY Alouatta coibensis coibensis FROM PANAMA, AND ITS CONSERVATION IMPLICATIONS

Studies on genetic diversity are key to conservation management because they may determine the resilience of primate populations under environmental and anthropogenic changes. Herein, we studied genetic diversity and connectivity in a population sample of the Coiba island howler monkey Alouatta coibensis coibensis from Coiba island in Panama. We collected 14 faecal samples from individuals at two sites on the northern and north-eastern sides of the island at the Gambute and Los Pozos trails, respectively. DNA was extracted from these samples, and partial sequences of cytochrome oxidase I (COI) were obtained and used as molecular markers to determine genetic diversity. Haplotypic diversity estimates ranged from 0.68 to 0.80 and from 0.0026 to 0.0041 for nucleotide diversity. Genetic connectivity based on reduced genetic distances and nonsignificant Hudson Snn test values suggests elevated connectivity between sites and the existence of a single population with good variability. Demographic history data identified positive Tajimas D as an indication of population contraction and reduced population size in this species. These results will be the baseline for establishing a better understanding of population structure, genetic health, connectivity patterns and reproductive behaviour along the largest island of the Central American Pacific. This information will allow scientists to understand and better evaluate the conservation status of this primate, confirming good availability of genetic flow even for this population living in isolation.

Minerageny of Jurassic deposits of the northeastern side of the Ulyanovsk-Saratov depression

The Jurassic terrigenous-clayey complex on the territory of the northeastern side of the Ulyanovsk-Saratov depression contains numerous groups of solid minerals. Some of them are at the stages of industrial development, some have not found application due to local distribution. Analysis of the composition and conditions of formation of solid mineral raw materials showed that the main factor influencing the formation of minerals was the marginal position of the territory in the Middle-Upper Jurassic time. The relatively high bioproductivity of the epicontinental Central Russian paleosea contributed to the accumulation of layers of calcareous marls, oil shale and phosphate raw materials. All these rocks were formed in the Mesozoic basin of sedimentation with the active participation of organic matter, the producers of which were zoo- and phytoplankton. The accumulation of coccolithophora in clayey silts led to the formation of calcareous marls, the accumulation of dying algae in bottom sediments led to the formation of oil shale. Nodular phosphorites are also biochemogenic raw materials. During periods of regressive development of the Central Russian paleosea along the coast, conditions were created for the accumulation of oolitic siderites together with leguminous goethite-hydrogethite aggregates of iron ores. Periodically, regional faults were activated on the northeastern edge of the Ulnovsko-Saratov depression. At this time, there was an upward migration of deep mineralized fluids through weakened zones. Unloading in the bottom part of the Central Russian paleosea, they contributed to the formation of fields of pyrite and barite mineralization in sedimentary rocks.

Diversity of horsefly fauna (Diptera: Tabanidae) of Bansko Hill

From 2018 to 2022, at 10 localities on Bansko Hill, 3,639 horseflies were sampled. Most specimens (3,404) were sampled in 2022 in the period from mid-May to mid-September. The horseflies sampled are classified into two subfamilies, six genera and 19 species. The species Hybomitra ukrainica (Olsufjev, 1952), Tabanus miki Brauer in Brauer and Bergenstamm, 1880, Haematopota grandis Meigen, 1820 and Haematopota pandazisi (Kröber, 1936) are new finds of horsefly species for the studied area. The species Tabanus tergestinus Egger, 1859 is the most abundant species and makes up 71.11% of the horseflies sampled. The species Tabanus bromius L., 1758 followed with 10.16% of the abundance, Tabanus sudeticus Zeller, 1842 with 8.82% and Atylotus loewianus (Villeneuve, 1920) with 5.74% of the horseflies sampled, while 15 other species of horseflies were represented by the remaining 4.17%. In the collected sample, male horseflies accounted for 51.71% of the sample; all of them were sampled with an oil liquid trap. The largest number of horseflies (84.14%) were sampled in localities on the northeastern side of Bansko Hill, covered with forest vegetation of secondary origin. Three species, T. bromius, T. tergestinus and Heptatoma pellucens, (Fabricius, 1776) have the longest flight period, from mid-May to mid-September. The highest peaks of abundance for T. tergestinus, T. bromius, and T. sudeticus were recorded in July, for H. pellucens in June and for A. loewianus in August. The greatest similarity in horsefly fauna (85.71%) was recorded in the localities Popovac and Karanac. 90.98% of horseflies were collected by liquid oil traps, followed by sticky traps (5.22%) and canopy traps (3.79%). Data from earlier studies from 2011 and data from the current studies in the area of Bansko Hill have yielded records of 22 species of horsefly.

Ground penetrating radar (GPR) analysis of the deformation in the submerged drainage route at Ashour Bridge, El Bahira governorate, Egypt

ABSTRACT An underground structure called a siphon allows irrigation of water canals and channels to pass underneath water drains. Three groups of loads that may have an impact on the siphon’s Geotechnical stability are: (1) loads brought about by traffic and truck duties on bridges; (2) loads brought about by drain water on the siphon’s body; and (3) loads brought about by irrigation channels and the dynamic movement of sandals and bots. To address the problem, surveying was done to see if the body of the submerged Syphon had any deformations. A ground penetrating radar study of the research area will be used to pinpoint the exact location of the damaged parts and the areas of deformation in the body of the submerged Syphon. On the southwesterly side (the exit), three GPR profiles were made, and on the northeastern side (the mouth), five. To display the covered drainage body’s infrastructure, the measured GPR data were processed differently. Deformities and distortion areas in the body of the submerged siphon were discovered at various places and depths on the two sides of the siphon after the processed data were analyzed.

Three-dimensional characteristics of mesoscale eddies in the western boundary current region of the Bay of Bengal using ROMS-NPZD

Eddies play an important role in transporting and redistributing the heat, salt, and biological parameters in the global ocean. In this study, three-dimensional physio-biochemical characteristics of an anticyclonic (AE) and a cyclonic eddy (CE) associated with the poleward western boundary current (WBC) in the Bay of Bengal (BoB) are analyzed using a coupled bio-physical ocean model (ROMS-NPZD). Due to eddy-induced upwelling (downwelling) associated with the CE (AE), monopole patterns of temperature and salinity anomaly around the eddy center are occurred with extremum values at 100 – 150 m and 50 – 100 m depth, respectively. The upward (downward) curvature with a tip at eddy centers is observed in the isothermal layer depth, 20℃ isotherm (D20) nutricline, and oxycline. The depth of D20 deepens and shallows at the center from the edge by ∼60 m and ∼40 m for AE and CE, respectively. A relatively thick barrier layer around the center of AE is noted as compared to the CE. Within eddy interior, temperature and salinity tendencies of horizontal advection show a strong dipole pattern with extremum at eddy edges. The AE currents show positive tendencies in horizontal advection of temperature (salinity) at its northeastern (southwestern) side, which is totally opposite to that of CE. Intense horizontal advections in the adjacent flanks of eddies to the eastward jet of the WBC are due to their strong interactions. Vertical advection shows a quadrupole structure with alternating positive and negative cells within the eddies following the distorted vertical velocity field. Diffusion terms within eddies are quite small compared to the advection. Abundances of chlorophyll-a (∼1.2 mg/m3) at the base of the mixed layer around the CE center are absent for the AE.

Record-high Antarctic Peninsula temperatures and surface melt in February 2022: a compound event with an intense atmospheric river

The Antarctic Peninsula (AP) experienced a new extreme warm event and record-high surface melt in February 2022, rivaling the recent temperature records from 2015 and 2020, and contributing to the alarming series of extreme warm events over this region showing stronger warming compared to the rest of Antarctica. Here, the drivers and impacts of the event are analyzed in detail using a range of observational and modeling data. The northern/northwestern AP was directly impacted by an intense atmospheric river (AR) attaining category 3 on the AR scale, which brought anomalous heat and rainfall, while the AR-enhanced foehn effect further warmed its northeastern side. The event was triggered by multiple large-scale atmospheric circulation patterns linking the AR formation to tropical convection anomalies and stationary Rossby waves, with an anomalous Amundsen Sea Low and a record-breaking high-pressure system east of the AP. This multivariate and spatial compound event culminated in widespread and intense surface melt across the AP. Circulation analog analysis shows that global warming played a role in the amplification and increased probability of the event. Increasing frequency of such events can undermine the stability of the AP ice shelves, with multiple local to global impacts, including acceleration of the AP ice mass loss and changes in sensitive ecosystems.

Seismic velocity structure and seismicity at the Kairei hydrothermal vent field near the Rodriguez Triple Junction in the Indian Ocean

The Kairei hydrothermal vent field (KHF) is on the northeastern side of the first segment of the Central Indian Ridge and discharges H2-rich hydrothermal fluids. To identify the source of these fluids based on the crustal and upper mantle structures and tectonic stress fields, we conducted a seismic refraction survey and observed natural seismicity in and around the KHF. We estimated 3D P-wave and S-wave velocity (VP and VS, respectively) structure models from airgun and natural seismic sources and determined 1861 hypocenters during a period of about two months. Beneath Yokoniwa Rise, VP in a convex zone exceeded 6.0 km/s at ~2 km depth below the seafloor and exceeded 7.0 km/s at 3–4 km depth; we thus interpret the rise to be a non-transform offset massif formed by the uplift of deep rocks. We detected a seismic cluster in a normal fault zone 3–5 km northwest of the KHF. Many events in this cluster occurred at 2–5 km depth below the seafloor in an area of high VP/VS ratios (~2.0) that are consistent with serpentinized peridotite, suggesting that seawater seeping downward through the fault zone has serpentinized peridotite at depth, thus becoming H2-rich hydrothermal fluid. This high-VP/VS area extends laterally at depth, and other such areas are observed at <1 km below the seafloor near the KHF. This structural configuration suggests that the high-VP/VS areas might provide conduits for the hydrothermal fluids that issue from the vents of the KHF. At the first segment of the ridge, we detected distinct shallow and deep seismic clusters. Seismicity in the shallow cluster was intermittent whereas deeper seismicity was nearly continuous, possibly indicating distinct magmatic activities at each depth.

A tsunami deposit in the Stonewall Formation (Upper Ordovician), northeastern margin of the Williston Basin, Canada, and its tectonic and stratigraphic implications

The dolomudstone of the Stonewall Formation was deposited on the present-day northeastern side of the low-relief, relatively shallow, tropical Williston Basin of central Laurentia during the latest Ordovician. This unit hosts a geographically widespread carbonate conglomerate, up to 0.5 m thick and consisting of rudstone to floatstone, that thins and eventually disappears westward and southward. The bed contains dolomudstone intraclasts in a variably argillaceous dolomudstone matrix and varies in composition laterally and vertically. Intraclasts range from millimetres to centimetres in size, are spheroidal to tabular to irregular in shape, and are angular to rounded. They record incipient microcrystalline calcite precipitation in localised domains in lime mud that began just below the sediment–water interface, forming lightly cemented nodules in an unconsolidated matrix, and indicate exhumation and deposition by a single, short-duration, high-energy but variable event that fragmented and abraded many of the nodules and washed in clay and lime mud. The composite nature of the bed in terms of varying proportion of intraclasts versus mud, and range of intraclast size with variable rounding and sorting, suggest that the event fluctuated in intensity and current direction. We interpret this bed as having been formed by a succession of tsunami waves and backwash that scoured the sea bottom and reworked the nodules, and brought in suspended illite from shallow water and the adjacent land surface. Despite drainage from tsunami-inundated coastal areas, the absence of allochthonous quartz sand and silt suggests that there was no sediment of this size stored there. Backwash transport may also have played a role in the formation of argillaceous marker beds which have been attributed previously to sea level fall and subaerial exposure. Other anomalous beds that punctuate shallow epeiric sea successions may also be tsunami deposits, especially if the ambient paleoclimate and bathymetry were not conducive to generating or leaving a signal of major storms, and sea level fluctuation can be discounted.

Validation of the generic name Prescottiella gen. nov. (Desmidiales, Zygnematophyceae): a rare African desmid

Prescottiella sudanensis is a rare, asymmetrical desmid currently known from only a few countries in equatorial Africa. During the present study, P. sudanensis cells were found in water samples from Vogel Pan located in the far north-eastern side of Namibia, thereby expanding the known geographical distribution of the species. The location of the sampling site, which is situated in a direct line halfway between the Makgadikgadi pans and Okavango Delta towards the east (Botswana) and the Etosha pans towards the west (Namibia), suggests that migrating birds are likely vectors spreading desmids from one waterbody to another. In this paper a morphological description (including dimensions) and micrographs of P. sudanensis are presented, and the known geographical distribution of the species is discussed in relation to migration routes of birds. As the genus and species names are invalid according to ICN Art. 40.1, the names are also validated in this paper.

The Impact of Extreme Rainstorms on Escarpment Morphology in Arid Areas: Insights From the Central Negev Desert

AbstractThe impact of climate on topography, which is a theme in landscape evolution studies, has been demonstrated, mostly, at mountain range scales and across climate zones. However, in drylands, spatiotemporal discontinuities of rainfall and the crucial role of extreme rainstorms raise questions and challenges in identifying climate properties that govern surface processes. Here, we combine methods to examine hyperarid escarpment sensitivity to storm‐scale forcing. Using a high‐resolution DEM and field measurements, we analyzed the topography of a 40‐km‐long escarpment in the Negev desert (Israel). We also used rainfall intensity data from a convection‐permitting numerical weather model for storm‐scale statistical analysis. We conducted hydrological simulations of synthetic rainstorms, revealing the frequency of sediment mobilization along the sub‐cliff slopes. Results show that cliff gradients along the hyperarid escarpment increase systematically from the wetter (90 mm yr−1) southwestern to the drier (45 mm yr−1) northeastern sides. Also, sub‐cliff slopes at the southwestern study site are longer and associated with milder gradients and coarser sediments. Storm‐scale statistical analysis reveals a trend of increasing extreme (&gt;10 years return‐period) intensities toward the northeast site, opposite to the trend in mean annual rainfall. Hydrological simulations based on these statistics indicate a higher frequency of sediment mobilization in the northeast, which can explain the pronounced topographic differences between the sites. The variations in landscape and rainstorm properties across a relatively short distance highlight the sensitivity of arid landforms to extreme events.

Reconstruction of the structural setting of the north-eastern side of the high Agri Valley (Southern Apennines, Italy) based on detailed field mapping

ABSTRACT The Southern Apennines consist of a Cenozoic to Quaternary fold and thrust belt characterized by a complex structural architecture. In the axial portion of the chain, corresponding to the Agri Valley, folds and faults with multiple styles formed during the progressive emplacement of various tectonic units, derived from different paleodomains. In the available geological maps, the geometry of these tectonic structures is often hindered by scarce cartographic detail due to the use of basic stratigraphic subdivisions. Therefore, at the aim to better define these structures and contextually update the outcropping stratigraphic units, we realized a detailed geological map, which take into consideration not only the formation as basic stratigraphic units, but also finer subdivisions such as members or beds. Using this approach, we improved the stratigraphy of the area, we recognized new geological units and, eventually, we reconstructed the structural setting, and the tectonic evolution of the Agri Valley in detail.