High-energy Environment Research Articles

Damage triggered by bioerosion and surface residence time in Holocene shell beds from Brazil

Holocene shell beds along the Brazilian coast provide critical records of sea level variations influenced by climatic changes. This study examines the taphonomic implications of bioerosional traces in bioclastic accumulations from coastal sites in Rio de Janeiro State, Brazil. By integrating sedimentological, taphonomic, and taxonomic data, the relationship between bioerosion and shell damage signatures was explored, focusing on three Quaternary localities rich in mollusk shell remains. Detailed analyses using thin sections, X-ray microtomography, and compaction tests identified four distinct bioerosion incipient- traces: Entobia, Caulostrepsis, Meandropolydora, and Oichnus. The results show that the one active depositional site has a higher proportion of bioclasts with bioerosion but fewer shells with taphonomic damage compared to two Holocene sites. The higher fragmentation rates at Holocene sites are linked to longer exposure times of bioeroded shells before final burial. These differences suggest that shorter exposure times lead to lower fragmentation rates despite higher bioerosion levels. Mechanical tests confirmed that bioeroded shells are more fragile, breaking into angular fragments, thereby contributing significantly to shell damage. Thus, bioerosion coupled with moderate surface residence times, plays a crucial role in shell fragmentation, with hydrodynamic conditions being a secondary agent of shell damage in high-energy environments.

Growth of Microbial Mats on Hard Nuclei in Shallow Sandy Environments.

The growth of most stromatolites is a result of interactions among the growth of microbial mats, mineral precipitation, water flow, and sediment movement. Here, we ask how oxygenic photosynthetic microbes colonize surfaces and interact with sediments in high-energy environments that contain constantly moving sand. For this, we investigate cyanobacterial growth on centimeter-scale concrete spheres in a continuously agitated wave tank. Cyanobacteria are unable to colonize moving sand, but establish biofilms on spheres within 5-6 weeks. These biofilms trap up to 0.5 g/cm2 of sand on the top and 0.3 g/cm2 on the sides within 25 weeks. The colonization does not depend on the size of the spheres, but instead depends on their surface roughness. Cyanobacteria easily colonize spheres with a surface roughness that matches the bed grain size (0.3 mm), but cannot colonize the initial topographic highs with a roughness of ~0.001 mm. In both cases, recesses on the surfaces of the spheres protect cyanobacteria from sandblasting. Thus, microbial biofilms can become established even in high-energy environments, if topographic highs are large enough not to be rolled around by the flow and rough enough to provide attachment loci. If cementation occurs within biofilms, the interplay among biofilm growth, sediment trapping, and cementation can lead to the upward as well as lateral growth of stromatolites. These experimental observations can explain the preferential upward growth of stromatolites on topographic highs in areas with frequently mobilized sediment grains, including modern stromatolites in the intertidal zone in Shark Bay and the subtidal zone in The Bahamas.

Occupational Injuries and Fatalities in Norwegian Fish Farming

ABSTRACT Objective People working in the Norwegian fish farming industry work in a high energy environment, where there are many hazards in the daily work. An important part of mitigating hazardous situations is to keep track of the characteristics of the accidents that have already happened and to learn from these, when planning future work. The objective of this study was to strengthen the knowledge of factors and conditions influencing personnel safety in Norwegian fish farming, based on analyses of registered occupational fatalities and injuries. Methods We gathered reported injuries and fatalities from vessels and fish farms from three different registries. Two of these are based on mandatory reporting to authorities, and one is a privately maintained registry. The accidents from the three registries are analyzed separately, and different types of characteristics are presented. Results The results demonstrate that fall and crush/impact are the most common types of accidents both on vessels and fish farms. Other characteristics described are the type of vessels involved and during which type of operations injuries happened. During the last 10 years, fatalities have happened mainly in relation to lifting and maintenance operations. The reported accidents are discussed in relation to the quality of accident reports, the development in the industry towards more specialized and outsourced operations, and it points to some of the major challenges that the industry faces when planning for safe working places and operations. Conclusion This overview can be used in the fish farming industry as a basis for going into further details about how accident prevention should be planned.

Porosity and mineralogy in the Lajas tight gas sandstone reservoir, Neuquén Basin, Argentina

ABSTRACT In specific subsurface conditions, the sandstones of the Lajas Formation represent a tight gas reservoir in a deltaic mouth-bar system. Therefore, understanding the diagenetic processes that affected these sandstones is a first step towards reservoir quality prediction and production optimization.14C-PMMA autoradiography can be used to characterize the porosity distribution at centimeter-to-micrometer scales. The mineral phases can be associated with specific porosities using scanning electron microscopy (SEM) in the backscattered-electron imaging mode (BSEi) and can be combined with elemental mapping using energy-dispersive X-ray spectroscopic (EDS) analysis. For bulk analysis, porosity mapping is useful for characterizing the constrictivity and the tortuosity of the porous network created by the geological processes related to the basin’s evolution (e.g., compaction, dissolution, fracturing, cataclasis). 14C-PMMA autoradiography offers a reliable porosimetry method which is adaptable to most rocks. In our study, the superimposition of porosity maps and mineral maps revealed that: 1) secondary porosity, deriving from feldspar dissolution in medium- to coarse-grained sandstone, and the varying degree of dissolution are both influenced by grain size and degree of cementation, 2) mudstone rip-up clasts have homogeneous porosities (3–4%), 3) the host rock’s porosity varies widely (1–8%), 4) bioturbated siltstone and sandstone present higher porosities within the trace fossils, mainly associated with organo-pores (primary porosity in the organic matter), mineral formation (pyrite precipitation), and clay development (microporosity). Integrating these petrophysical and mineralogical observations with the interpretation of the sedimentary and structural processes that affected the lithologies analyzed allows the following generalizations: 1) the highest porosity and permeability occur in samples representing high-energy environments of deposition (deltaic channel infills and mouth bars), 2) deformation bands cannot be considered fairways for fluid migration, as they have a lower porosity than the sandstone matrix, mainly because dilational shear bands underwent cementation and compactional shear bands underwent cataclasis.

Palaeoenvironmental interpretation and isotope stratigraphy of the Campanian–Danian successions in the Zagros Foreland Basin (Kabir Kuh, Lurestan, Iran)

The successions of the Gurpi Formation and the lower Pabdeh Formation were examined through analyses of lithology, sequence stratigraphy, stable isotope stratigraphy, and ichnofossils in the Jahangir Abad and Abhar sections of the Kabir Kuh anticline within the Lurestan Zone. Stratigraphic correlation with the well-dated Gandab section, located within the same anticline, indicates a late Campanian to early Danian age for these successions. This correlation further confirms the presence of notable carbon isotope excursions associated with the Campanian-Maastrichtian Boundary Event (CMBE) and Mid-Maastrichtian Event (MME). Field observations, along with sedimentological and paleontological analyses, suggest that the Kabir Kuh area was situated within the fore-bulge of the Zagros foreland basin during the Late Cretaceous. Changes in lithology, fossil content, and ichnofacies indicate a significant decrease in water depth at the end of the Campanian and the beginning of the Maastrichtian. This interval contains shallow marine macrofossils, including oysters (mainly Lopha), benthic foraminifers, and fossil debris traces, indicative of a high-energy environment. In contrast, shallow-water facies are not recorded within the middle and late Maastrichtian sequences. These sequences are composed of pelagic mud-dominated facies containing deep-sea ichnofossils, indicating a rapid increase in water-depth during the middle–late Maastrichtian. The observed late Campanian to early Maastrichtian shallowing is associated with the development of the Zagros fore-bulge, while the subsequent deepening and significant sediment deposition during the mid to late Maastrichtian are attributed to the subsidence of the basin. This research re-evaluates and refines the existing sequence stratigraphic and sedimentary models of the Zagros foreland basin, offering new perspectives on its geological evolution.

Ordovician and Devonian microfacies of Sierra Agua Verde, central Sonora, Mexico: A new locality of the Nuia Province from Western Laurentia

The Lower Ordovician carbonate rocks exposed in the Tuntunudé hill north of the Sierra Agua Verde, northeast of the town of Mátape, in central Sonora, consists of intraformational breccia, conglomeratic limestone, sandy limestone and limestone, which are overlain by a mixed succession of quartz sandstone and dolomitic sandstone. This succession is in turn unconformably overlain by an Upper Devonian sequence of dolomitic limestone, marl, conglomeratic limestone and sandy dolomite. The Lower Ordovician rocks contain abundant bioclasts of gastropods, brachiopods, trilobites, echinoderms, and sponges. Their microfacies show a marine medium to low energy environment, with sedimentation dominated by distal tempestites in laminar stages and intraclast debris formation during deposition. The depositional paleoenvironment corresponds to a marine middle-to-outer ramp. These strata are characterized by conodonts belonging to the Oepikodus communis and Reutterodus andinus biozones, as well as cyanobacteria incertae sedis Nuia sibirica. Devonian rocks overlying the Ordovician strata contain bioturbation and abundant bioclasts of echinoderms, brachiopods, bryozoans, gastropods, chaetetiform sponges, stromatoporoids; and also, colonial corals like Hexagonaria attenuata, Phillipsastrea hennahii and Phillipsastrea jachowiczi, monothalamous foraminifera like Vicinesphaera sp., monoserials such as Tikhinella measpis and planispiral such as Nanicella gallowayi. The microfacies show a high-energy environment in marine tropical shallow open-sea lagoonal waters, with ooids and reef building organisms.

Integrated geological study for reservoir modeling and characterization of the Shurijeh gas bearing sandstones in one of the Northeast Iran gas fields

The sandstones deposited in the sequence of Shurijeh Formation comprise a giant gas reservoir in the Northeast of Iran. Five primary facies (petrofacies) were identified in the deposits of Shurijeh Formation such that the entire sedimentary sequence was divided into eight zones. Diagenetic processes have affected the pore properties of sandstone (zone D2). In this research, the petrophysical parameters (porosity and water saturation) and lithology were gamma-ray in the correlation with the petrofacies and core data. The areas with good reservoir properties for each zone and the total reservoir volume were simulated by exerting an appropriate threshold cutoff limit for the reservoir parameter (porosity and water saturation) and shale volume. For determine the economic hydrocarbon volume of the field, the uncertainty analysis in volumetric calculations was carried out utilizing the Monte Carlo method, with the production of Case50, gas-in-place was calculated as 28 × 106 cubic meters. The sensitivity analysis was conducted to determine the impact of each parameter on gas-in-place. Based on the results of this study, the sedimentary facies and diagenesis processes directly affect the in gas-in-place the reservoir. According to the sensitivity analysis, the map of underground lines (UGC) and fluid contact were the most sensitive compared to porosity and water saturation. That the fluid contact is related to the sedimentary facies and diagenetic processes. In fine-grained sedimentary facies, due to the transition zone increase, it is difficult to accurately determine the fluid boundary of the reservoir, while in coarse-grained sediments, which have high permeability, due to the transition zone reduction, the fluid boundary is more accurately determined. Also, diagenetic processes such as cementation, dissolution, and dolomitic processes cause great complexity in determining fluid boundaries. Therefore, comprehensive geological and reservoir studies must be done before any field development work. In this study, the spread of the reservoir zones B and D1, which have the highest volume of in-situ hydrocarbons, with lithofacies that are associated with high-energy environments (mostly sandstone) and have excellent petrophysical parameters in terms of reservoir quality was demonstrated. In accordance with these results, initial depositional processes control the distribution of porosity, water saturation, thickness and extension of prolific areas at the field scale.

Differential controlling on the deep tight sandstone reservoirs: Insight from the second member of lower Triassic Xujiahe Formation in Xinchang area, western Sichuan basin, China

With advancements in deep exploration, the deep tight sandstone gas reservoir has become a significant exploration field. However, it remains challenging to develop on a large scale due to the unclear distribution of relatively high-quality reservoirs. In this paper, the petrology, reservoir properties, diagenesis, and structural fracturing of deep tight sandstone reservoirs are systematically studied, focusing on the second member of the Upper Triassic Xujiahe Formation (T3x2) in the Xinchang area, and the types of relatively high-quality reservoirs and their differential controlling are further clarified. According to the matching relationship between pores and fractures, tight sandstone reservoirs can be classified into four types: extremely tight, fractured, porous, and pore-fractured types. Among these, the porous and pore-fractured types are considered effective reservoirs. The formation of tight sandstone reservoirs is closely related to sedimentary microfacies, grain size, diagenesis and tectonic fracturing, with distinct controlling differences across reservoir types. Overall, sedimentary microfacies provide the foundation, while differential diagenesis and tectonic fracturing are the key factors influencing reservoir quality. Among them, the extremely tight sandstone reservoirs can form in various sedimentary microfacies, particularly in medium to fine, lithic-rich sandstones, where strong compaction and cementation are the main factors for the underdevelopment of reservoir space. In contrast, fractured reservoirs mainly form based on porous reservoirs through the superimposition of tectonic fracturing. The porous reservoirs are typically found in relatively high-energy environments such as distributary channels and mouth bars, with medium to coarse feldspar-rich sandstone. Dissolution and chlorite-liner cementation are the key factors for their pore formation. Similarly, pore-fractured reservoirs originate from porous reservoirs that have been further altered by superimposing tectonic fracturing.

Local Strain Effects on Lattice Defect Dynamics and Interstitial Dislocation Loop Formation in Irradiated Tungsten-Molybdenum Alloys: A Molecular Dynamics Study.

In this study, molecular dynamics (MD) simulations were used to investigate how alloying tungsten (W) with molybdenum (Mo) and local strain affect the primary defect formation and interstitial dislocation loops (IDLs) in W-Mo alloys. While the number of Frenkel pairs (FPs) in the W-Mo alloy is similar to pure W, it is half that of pure Mo. The W-20% Mo alloy, chosen for further analysis, showed minimal FP variance after collision cascades induced by primary knock-on atoms (PKAs) at 10 to 80 keV. The research examined hydrostatic strains from -1.4% to 1.6%, finding that higher strains correlated with increased FP counts and cluster formation, including IDLs. The following two types of IDLs were identified: majority ½ <111> loops as well as <100> IDLs that formed within the initial picoseconds of the simulations under higher tensile strain (1.6%) and larger PKA energies (80 keV). The strain effects also correlated with changes in threshold displacement energy (TDE), with higher FP formation under tensile strain. This study highlights the impact of strain and alloying on radiation damage, particularly in low-temperature, high-energy environments.

Early Life History Divergence Mediates Elevational Adaptation in a Perennial Alpine Plant.

Spatially divergent natural selection can drive adaptation to contrasting environments and thus the evolution of ecotypes. In perennial plants, selection shapes life history traits by acting on subsequent life stages, each contributing to fitness. While evidence of adaptation in perennial plants is common, the expression of life history traits is rarely characterized, limiting our understanding of their role in adaptive evolution. We conducted a multi-year reciprocal transplant experiment with seedlings from low and high elevation populations of the alpine carnation Dianthus carthusianorum to test for adaptation linked to contrasting climates and inferred specific contributions of early life stages to fitness. We assessed genotype by environment interactions in single fitness components, applied matrix population models to achieve an integrated estimate of fitness through population growth rates, and performed trade-off analyses to investigate the advantage of alternate life history traits across environments. We found evidence of genotype by environment interactions consistent with elevational adaptation at multiple stages of the early life cycle. Estimates of population growth rates corroborated a strong advantage of the local genotype. Early reproduction and survival are alternate major contributors to adaptation at low and high elevation, respectively, and are linked by trade-offs that underlie the evolution of divergent life history traits across environments. While these traits have a strong genetic basis, foreign populations express co-gradient plasticity, reflecting the adaptive strategy of the local populations. Our study reveals that selection associated to climate has driven the evolution of divergent life histories and the formation of elevational ecotypes. While the high energy environment and strong competition favor investment in early reproduction at low elevation, limiting resources favor a more conservative strategy relying on self-maintenance at high elevation. The co-gradient plasticity expressed by high-elevation populations may facilitate their persistence under warming climatic conditions.

Outburst flood events since the Last Glacial Maximum in the Hutiao Gorge of Jinsha River: Geomorphological evidence from eddy gravel bars

Breaching of natural dams in the Hutiao Gorge of the Jinsha River across the Yulong-Haba Mountains is one of the major geomorphological events in the largest river of Asia. Catastrophic flood events have an important influence on the geomorphological evolution of the First Bend of the Yangtze River since the Last Glacial Maximum (LGM). However, detailed geomorphological evidence, ages, and depositional phases of outburst flooding remain unclear. In this paper, large-scale gravel bars overlying the river terraces and dammed lakes are analyzed within the Daju Basin. The macroscopic geomorphological characteristics of megaflood landforms with large thickness and uniform gravel bars are similar to those of Missoula and Altai megafloods. Morphological analysis shows that eddy gravel bars (EGBs) with rhythmic structure are characterized by a dome-shaped protrusion in the cross section and a gravel mound in the longitudinal section. Each bar with oblique, parallel and massive bedding was analyzed from the horizontal and vertical directions. Three dome-shaped bars clearly show at least three palaeoflood phases. Quartz grain surface macrotextures are mainly V-shaped pits and conchoidal fractures, which exhibits a high-energy environment during the flood. The stratigraphic sequence model of EGBs is dominated by coarse sand and fine gravel rhythmic bedding in high-energy eddy environments and suspended sand deposits in low-energy backwater environments. Such phenomenon reveals megaflood fluctuates, which is also confirmed by geochemical difference. The episode of natural dam break floods triggered by tectonic activity and glacier fluctuation was dated to 20–17 ka during the LGM. Sedimentary pattern of EGBs offers fresh insights into understanding the megaflood geomorphological characteristics of the upper Yangtze River and better identification similar high-energy palaeoflood landforms in the southeast Tibetan Plateau.

The high-energy environment of the heavy sub-Earth GJ 367 b indicates likely complete evaporation of its atmosphere

The planet GJ 367 b is a recently discovered high-density sub-Earth orbiting an M dwarf star. Its composition was modelled to be predominantly iron with a potential remainder of a hydrogen-helium envelope. Here we report an X-ray detection of this planet’s host star for the first time, using data from the spectro-imaging X-ray telescope eROSITA onboard the Spectrum-Roentgen-Gamma mission. We characterise the magnetic activity of the host star from the X-ray data and estimate its effects on a potential atmosphere of the planet. We find that despite the very low activity level of the host star the expected mass loss rates, both under core-powered and photoevaporative mass loss regimes, are so high that a potential primordial or outgassed atmosphere would evaporate very quickly. Since the activity level of the host star indicates that the system is several Gigayears old, it is very unlikely that the planet currently still hosts any atmosphere.

In Situ transmission Electron Microscope Observation of Biased-Induced Dynamic Evolution of Two-Dimensional CrS2

Two-Dimensional transition-metal dichalcogenides (2D-TMDs) have attracted great attention recently owing to their potential to become the important material for next generation semiconductor devices. While using the device, it needs to ensure high density current and biased voltage for a long time. However, the study on TMDs in high-energy environment is insufficient. In this work, the phase evolution of CrS2 are revealed via in-situ biasing experiments and recorded by transmission electron microscope (TEM) at atomic scale. The ultra-thin layered (~1.6nm) CrS2 was synthesized through atmospheric pressure chemical vapor deposition (APCVD), followed by transferring the as-grown samples onto specialized TEM electrical chips. The TEM characterization of CrS2 initial sample provided the basic understanding of this Cr-based TMD, identified as pure 1T phase with single crystal structure as shown in Figure 1. The advanced in situ technique was employed to record the structural evolution and was tested the endurance of CrS2 during biasing. Moreover, the results can make significant contributions to future semiconductor device designs and demonstrate CrS2 has great potential as a semiconductor device with its outstanding characteristic of biased-endurance. Figure1. (a) Low-magnification TEM image of 1T-CrS2. (b) High-resolution TEM image of 1T-CrS2, corresponding with FFT along [001] zone axis. (c) AFM image of the as-grown CrS2 sample, blue bar in the image is X axis of (d). (d) AFM height profile of as-grown 1T-CrS2 with average thickness of~1.6nm. (e) STEM image of 1T-CrS2 and shows d-spacing~0.336 nm. (f) Low-magnification TEM image of the device, showing that the transferred CrS2 layer was suspended on the membrane with Au electrodes on both sides. (g,h) In-situ TEM observation of the biasing experiment after 5V biasing for 5 min of 1T-CrS2. Time-sequencing TEM images showing the structural evolution of biasing. The inset shows the corresponding FFT-DP to reveal the variation of crystallinity of the sample. (g) Initial structure of 1T-CrS2. (h) 1T-CrS2 under in-situ biasing experiment after 10 minutes. Figure 1

Diagenesis of Cenomanian–Early Turonian and the Control of Carbonate Reservoirs in the Northern Central Arabian Basin

The carbonate reservoirs of Cenomanian–Early Turonian in the northeastern Central Arabian Basin hold considerable oil reserves and are great contributors to oil production. Diagenesis have a great impact on carbonate reservoir petrophysical properties, microstructure, and heterogeneity. By integrating cores, cast thin sections, regular core analysis, CT, and isotopes, this study provides an improved understanding of diagenesis in the Cenomanian–Early Turonian and its effect on carbonate reservoirs. The results showed that three diagenetic environments were identified in the Cenomanian–Early Turonian based on texture, structure, cement, crystal form, and crystal size, which were marine environment, meteoric environment, and burial environment. Six diageneses were identified based on residual bioclastic, secondary pores, calcite quantity, dolomite size, and stylolite, namely dissolution, cementation, micritization, dolomitization, compaction, and pressure solution. A micritization model in high energy sediment, a dolomitization model in burrows, and a comprehensive diagenetic model were established. It concluded that dissolution during meteoric environment is most favorable to reservoir physical properties, while cementation is least favorable. The cement content controls the microstructure and petrophysical property. Micritization is detrimental to the petrophysical properties, and the micrite it forms are distributed in the interparticle pores, reducing the reservoir property deposited in high energy environment. Dolomitization is less developed in substrate but widely developed in burrows, which result in the physical properties of the burrows being higher than those of substrate. Compaction and pressure solution have a negative impact on reservoir physical properties.

Palynofacies analysis of a lacustrine succession: The Maracangalha Formation (Lower Cretaceous), Recôncavo Basin, Brazil

A palynofacies analysis was carried out using samples collected from the Manguinhos, Gameleira, Praia da Falha and Penha outcrops of the Lower Cretaceous Maracangalha Formation, Recôncavo Basin, NE Brazil. Qualitative and quantitative analysis of the organic particles, as well as grouping analysis based on the characteristics of the particles found, were conducted to establish the present database. The organic particles were grouped into amorphous organic matter (AOM); opaque phytoclasts; non-opaque phytoclasts and palynomorphs and four distinct palynofacies were recognized. The palynofacies I (P I), present in the Praia da Falha outcrop, is composed of a high abundance of non-opaque phytoclasts (51.22%), followed by palynomorphs (23.61%). The palynofacies II (P II), occurring in the Penha outcrop, shows a high abundance of non-opaque phytoclasts (71.67%), followed by opaque phytoclasts (12%). The palynofacies III (P III), occurring in the Manguinhos outcrop, consists of a high abundance of AOM (48.07%), followed by opaque phytoclasts (32,6%). The palynofacies IV (P IV), occurring in the Gameleira outcrop, also has a high abundance of AOM (47.05%), followed by non-opaque phytoclasts (28.76%). According to the associations of sedimentary organic matter, essentially represented by particles of continental origin, a lacustrine setting is well characterized, corroborating what has been previously suggested in the literature. The palynofacies interpretation also indicates deposition strongly controlled by fluvio-deltaic input. Overall, the Praia da Falha and Penha outcrops suggest proximity to the depositional source in a high-energy environment. In these localities, the predominance of non-opaque phytoclasts indicates deposition under oxic conditions probably near the lake shore. On the other hand, in the Gameleira and Manguinhos outcrops, the predominance of AOM suggests deposition away from the sediment source in a more distal, low-energy environment, with prevalence of suboxic-to-anoxic conditions.

The Biological Crystals in Chamid Bivalve Shells: Diversity in Morphology and Crystal Arrangement Pattern

Chamid bivalves are marine organisms that live in high-energy environments and are cemented to hard substrates. To avoid shell damage, the organisms form thick, densely ornamented shells. Shell material consists of aragonite, and the ornamentation may be either aragonitic or calcitic. The latter can be developed as scaly spines, rows of blades, or comarginal, radial arched lamellae. We investigated biological crystal morphology and mode of assembly of Chama arcana and Chama gryphoides shells. Structural characteristics were obtained from electron backscatter diffraction (EBSD) measurements, complemented with laser confocal and BSE imaging. We found a wide range of crystal morphologies and sizes, ranging from irregularly shaped calcite and/or aragonite prisms to tiny and thin aragonite laths. We observed four different modes of crystal assembly patterns: 1. strongly interlocked dendritic calcite units forming the ornamentation blades; 2. aragonite laths arranged to lamellae forming the outer shell layer, the layer adjacent to the calcite; 3. aragonite laths arranged into blocks comprising inner shell layers or aragonitic ornamentations; and 4. shell portions consisting of aragonite prisms, structured in size and crystal orientation, at muscle attachment sites. These four different types of crystal arrangements were observed for the shells of the investigated chamid species; however, they had slightly different strengths of structuring and slight variations in crystal organisation. Additionally, we observed unique microstructural features in Chama shells: We report ornamentation crystals resembling idiomorphic calcite and novel, twinned entities found at the changeover between the aragonitic layers. We highlight and discuss these differences and anomalies in this contribution.

Fermionic signal of vacuum polarization in strong laser fields

Vacuum polarization (VP) is investigated for the interaction of a polarized γ-ray beam of GeV photons with a counterpropagating ultraintense laser pulse. In a conventional setup of a vacuum birefringence measurement, a VP signal is the emerging small circular (linear) polarization of the initially linearly (circularly) polarized probe photons. The pair production via the nonlinear Breit-Wheeler process in such a high-energy environment eliminates part of the γ photons in the outgoing γ beam, increasing the statistical error and decreasing the accuracy of this VP signal. In contrast, we investigate the conversion of the emerging circular polarization of γ photons into longitudinal polarization of the created positrons, considering the latter as the main VP signal. To study the VP effects in the highly nonlinear regime, where the Euler-Heisenberg effective Lagrangian method breaks down, we have developed a Monte Carlo simulation method, incorporating vacuum birefringence and dichroism via the one-loop QED probabilities in the locally constant field approximation. Our Monte Carlo method will enable the study of VP effects in strong fields of arbitrary configuration. With 10 PW laser systems, we demonstrate the feasibility of detecting the fermionic signal of the VP effect at the 5σ confidence level with a few hours of measurement time. Published by the American Physical Society 2024

Late Cretaceous marine flooding and installation of a mangrove swamp environment in the Prebetic (Betic External Zones, SE Spain)

The Cenomanian (Upper Cretaceous) sedimentary rocks of the External Prebetic (Betic Cordillera) in the Sierra de Montearagón-Carcelén (SE Spain) record the transgression and flooding of continental deposits and the subsequent development of an inner shallow carbonate platform. The transgressive surface is densely colonized by infaunal trace-makers of the Glossifungites ichnofacies (Gastrochaenolites and Glossifungites), which indicate sediment starvation and erosion as well as colonization of a firmground. The first deposits were a thick calcarenite bar (2 to 11 m) with large-scale cross-bedding pointing to a high-energy environment in a shallow carbonate platform. The record of the Rosselia ichnofacies (Rosselia and Ophiomorpha) confirms a loose sandy bottom under high-energy conditions. The overlaying stratigraphic succession is characterized by subtidal laminated marly limestones and intertidal limestones with rhizoliths interpreted as a mangrove swamp environment. These facies are organized in shallowing-upwards sedimentary sequences. An episodic high-energy event is represented by bivalve-rich limestones representing shell lags of disarticulated valves. This facies could be related to a climatic perturbation evidenced by a negative excursion of δ13C and δ18O. The successive shallowing-upwards sedimentary sequences persisted thanks to subsidence related to the tectonically controlled depocenters located in the south of the Sierra de Montearagón-Carcelén. The differential subsidence, evidenced by the increasing thickness towards the south of the sector under study, suggests the activity of listric faults that controlled the depocenters. This is the first report of the Cenomanian transgression in this sector of the External Prebetic and the first record of the very extensive mangrove swamp that developed close to the land that emerged.

Resolving the term “offshore aquaculture” by decoupling “exposed” and “distance from the coast”

The terms “offshore” and “open ocean” have been used to describe aquaculture sites that are further from the coast or in higher energy environments. Neither term has been clearly defined in the scientific literature nor in a legal context, and the terms are often used interchangeably. These and other related terms (for example “exposed”, “high-energy”) variously refer to aspects of a site such as the geographic distance from shore or infrastructure, the level of exposure to large waves and strong currents, the geographic fetch, the water depth, or some combination of these parameters. The ICES Working Group (ICES, 2024) on Open Ocean Aquaculture (WGOOA) therefore identified a need to define the terminology to reduce ambiguity for these types of aquaculture sites or more precisely, to: (1) promote a common understanding and avoid misuse for different classifications; (2) enable regulators to identify the characteristics of a marine site; (3) allow farmers to be able to assess or quantitatively compare sites for development; (4) equip developers and producers to identify operational parameters in which the equipment and vessels will need to operate; (5) provide insurers and investors with the terminology to consistently assess risk and premiums; and (6) circumvent the emergence of narratives that root in different cognitive interpretations of the terminology in public discourse. This paper describes the evolution of the use of the term “offshore aquaculture” and define the most relevant parameters to shift to a more definitive and robust term “exposed aquaculture” that can inherently relay clearer information. Adoption of this more definitive definition of “exposed” will allow the user to define a site with more than just distance from shore. Key differences and the importance of these terms are discussed that affect various interest groups. Follow-up articles in this compilation from scientific members of the WGOOA as well as other scientists outside ICES are incorporated that develop a set of definitions and a rigorous exposure index.

Facies of Quaternary Sediments In Bunga Village, North Luwuk District, Banggai Regency, Central Sulawesi

Abstract The distribution of Quaternary sedimentary rock deposits in Indonesia is quite extensive, and one of them is in the Quaternary coral reef units, which are evenly distributed along the eastern arm of Sulawesi. The research was conducted in Bunga Village, North Luwuk District, Banggai Regency, Central Sulawesi Province. This research was motivated by the lack of geological data, so the topic of developed facies became an interesting topic to be researched. Data was collected from a cliff at the coordinates 0053′57,57.1″N-122054′43′6″E. Stratigraphic measurements aim to determine the facies, depositional environment, and sedimentation mechanisms developed in the study area. The research was conducted using the method of field data collection and laboratory analysis. Collecting field data was carried out with measured stratigraphic with a 1:100 scale and taking several rock samples. Laboratory analysis was carried out in paleontological and petrographic analysis, which was carried out to determine the composition of the constituent rock and fossil identification, especially foraminifera in thin sections of rock that were selected. Based on the study’s results, the total rock layers measured in the study area were 15 m. Facies found in the stratigraphic path of the study area are floatstone facies, rudstone facies, allochemic sandstone facies, polymict conglomerate facies. The type of deposition environment of limestone and allochemic sandstone in the study area is on the foreslope, while the conglomerate facies is included in the fan delta deposition environment. Overall, the sedimentation dynamics in this area are in a high energy environment, indicating that the facies that developed were deposited with a sediment gravity flow mechanism.The results of the analysis of fossils found Cyclammina cancellata sp., Orbulina universa sp., Globigerina bulloides sp., and Trilobatus immaturus sp., which indicates the limestone in the study area was deposited in the Late Pleistocene to early Holocene.