Search Results (181)

Transitions within the syn-rift stage provide a key window for examining sediment-routing changes and associated sedimentary responses in lacustrine rift basins. In the Bohai Bay Basin, the interval from the third member (Es3) to the second member (Es2) of the Eocene Shahejie Formation records a transition from early strong rifting toward relatively stable rifting. The Qinan Sag, a secondary sag along the Qikou Sag margin, was sensitive to this transition. Using cores, well logs, three-dimensional (3D) seismic data, and heavy-mineral data, this study reconstructs the source configuration, palaeogeomorphology, depositional-system evolution, and Es3–Es2 source-related sediment-dispersal domains. The results show that the supply pattern shifted from coeval supply by a southern regional source and northern and western local sources during Es3 to southern regional-source dominance during Es2. Accordingly, Es3 contains strongly differentiated braided-delta, fan-delta, and subaqueous-fan assemblages. Es2 contains weakly differentiated shallow-water delta and beach-bar assemblages. Three source-related sediment-dispersal domains coexisted during Es3. During Es2, the northern domain was no longer identified, and the western gentle-slope belt evolved into a high-sand-ratio beach-bar belt. This reorganization was mainly controlled by the combined effects of source-configuration changes, geomorphic segmentation, and contrasting slope–A/S conditions (A/S = accommodation/sediment supply). Supply-pattern simplification and weakened geomorphic segmentation shifted sediment routing after basin entry from multiple, dispersed pathways to dominant-source-controlled focused routing. Moderate-to-steep slopes and higher relative A/S proxy values during Es3 favoured discrete, segmented sandy-deposit preservation; gentle slopes and lower relative A/S proxy values during Es2 promoted focused routing and preservation of sandy deposits along the dominant direction, with local shallow-water enrichment. Across the Es3–Es2 syn-rift stage transition, regional-source-related sediment routing showed stronger persistence; local-source-related routing more often weakened or terminated, with corresponding areas tending to show shallow-water redistribution and enrichment signals. Full article

This study investigates the distribution and concentration of microplastics (MPs) across the littoral profile of a beach, from dune base to offshore sector, including an estuarine channel and Sabellaria alveolata bioconstructions. The research was conducted at Pino di Lenne beach (Taranto, Ionian Sea), a wave-dominated, microtidal littoral system representing a unique natural laboratory with minimal anthropogenic pressure. An eco-friendly extraction protocol was used, combining methods that were already known in the literature. Olive oil proved highly effective in isolating a wide range of MP densities from sediment samples. Statistical analysis identified key accumulation zones, with the highest mean concentrations found in the submerged sandbar (2435 MPs/kg), Sabellaria bioconstructions (2324 MPs/kg), and the base of the dune (2065 MPs/kg). Fibres were the predominant morphology across all sub-environments. Distribution is interpreted as controlled by hydrodynamic processes and biological activity. The submerged beach drives MP transport, with the sandbar and shoreface acting as dynamic sinks. Sabellaria bioconstructions function as biological trap, actively incorporating MPs into their tubular structures. The dune base acts as a sink for wind-blown and storm-deposited plastics. These sub-environments function as critical littoral traps for MPs, essential for developing targeted monitoring and remediation strategies in similar coastal systems. Full article

Oil Detection Canines (ODCs) have been proven to detect spilled oil in various environments, including targets and residual oil sequestered along shorelines. A limitation within the capability is that an ODC detects and responds to all types of stranded hydrocarbons, including any from historical spills or naturally occurring chronic oils, such as tarballs washed up from offshore seeps. In locations historically known for chronic tar deposits, the value of a K9-supported Shoreline Cleanup Assessment Technique (SCAT) survey is limited when large numbers of tar deposits are present, because the canine detects and responds to all of them. This thoroughness can slow down SCAT surveys, reduce efficiency by requiring investigation of each response, and fatigue the canines from the number of alerts. A project supported by the Texas General Land Office (TGLO) was designed to investigate the ability of a trained ODC to discriminate hydrocarbons on a beach that represent a newly spilled oil while ignoring other potential “background” oils. In 2021, Texas Tech University’s Canine Olfaction Lab conducted a laboratory-based study to investigate canines’ ability to respond to weathered oil samples. This research demonstrated that trained canines could effectively discriminate between weathered oils in a laboratory environment. This knowledge was used to design a field program to conduct monthly surveys with two teams: one involved deploying two canines trained on a sample representative of relatively unweathered spilled oils, handled by citizen-scientist volunteers, and the other involved an ODC trained on a range of oil types. The field survey results show that a Specific Oil Detection Canine (SODC) can discriminate between unweathered oil deposits and other background deposits typical of chronic oiling at the same location. Field surveys indicated that SODCs consistently responded exclusively to target oil samples and disregarded naturally occurring background hydrocarbons, while a generalist ODC responded to all hydrocarbon sources present. Full article

Cymodocea nodosa, growing at low water depth, is affected by various environmental changes and is expected to adapt to oxidative stress. Oxidative stress in living leaves (LC) and beach deposits (NC) of C. nodosa activated superoxide dismutase (SOD), which was higher in LC, leading to significant neutralization of the produced H₂O₂ and destruction of protein generation. Higher antioxidant capacity (using a UV/Vis spectrophotometer) to scavenge 2.2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS^•+) (IC₅₀: 5 in LC vs. 22 μg mL⁻¹ in NC) and OH^• (hydroxyl) radicals (IC₅₀: 132 in LC vs. 281.7 μg mL⁻¹ in NC), compared to 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) (IC₅₀: 63 in LC vs. 45 μg mL⁻¹ in NC) and superoxide anion (O₂^•−) radicals (IC₅₀: 190 in LC vs. 94 μg mL⁻¹ in NC), and similar reducing power (RP) were recorded in LC compared with NC extracts (IC₅₀: 53 in LC vs. 52 μg ml⁻¹ in NC). Phenolic compounds were not significantly lost during plant exposure on shores (mean value: 57.00 in LC vs. 45.48 mg g⁻¹ d.w. in NC). Phenolic compounds identified, using UHPLC-DAD analysis, in both LC and NC extracts were chicoric, trans-ferulic, caftaric, p-coumaric, sinapic, and trans-cinnamic acid and rutin hydrate, whereas caffeic acid, in traces, was identified in NC extracts. NC showed higher cytotoxic activity in inhibiting LS 174 colon cancer cells than LC. In cases of plant cultivation or management plans for seagrass meadows and their beach deposits, with the least possible impacts, both LC and NC extracts could be exploited for their antioxidant and anticancer properties. In a ‘case study’, the amounts of individual phenolic compounds that can be produced from NC utilization were estimated. Full article

Geosites in the Safi Province in Morocco are increasingly exposed to a combination of natural and anthropogenic factors (landslides, karstification, pollution, improper visitor behavior, etc.) that threaten their integrity and accelerate their degradation. Assessing geoheritage degradation risks is therefore a fundamental step in any geoconservation strategy, particularly given the growing impacts of climate change on Morocco’s Atlantic coastline. This study proposes a quantitative methodology for evaluating degradation risk by integrating extrinsic factors that can damage geosites. The methodology was applied to the Safi Province, an area characterized by exceptional geological diversity—ranging from coastal cliffs and marine terraces to karst systems, Quaternary deposits, and paleontological and archaeological sites of international significance such as Jbel Irhoud. Three main criteria were used to assess degradation risk: anthropogenic vulnerability, public use, and natural vulnerability, each supported by a set of detailed parameters enabling precise numerical evaluation. The results show that degradation risk in Safi’s geosites is primarily driven by a lack of awareness of and recognition of their geological importance, leading to public misuse, inadequate management, uncontrolled access, and unregulated extraction. Moreover, the region’s strong coastal dynamics amplify natural vulnerability, especially at geosites along exposed cliffs, beaches, and estuarine environments. Overall, the findings provide a comprehensive assessment of the condition of Safi’s geosites and constitute a valuable tool for the planning, prioritization, and implementation of effective protection and management measures, particularly in the face of increasing pressures associated with climate and environmental change. Full article

The Middle Triassic Tredian Formation of the Salt Range, Pakistan, consists of sandstones with interbedded shale in the lower part and minor dolomite in the upper part. Conventional grain-size analysis has been widely used as a sedimentological tool to elucidate depositional environments and the mode of transportation of detrital sediments. This study presents the first integrated application of a Decision Tree Classifier (a machine learning model) with field and petrographic evidence to interpret grain-size statistics for the analysis of depositional environments of the Tredian Formation in the Salt Range, Pakistan. Stratigraphic sections of the Tredian Formation were measured and sampled in the Nammal Gorge and Zaluch Nala in the Salt Range for detailed sedimentological and grain-size analyses. The lower part of the Tredian Formation (Landa Member) consists of interbedded sandstone and shale (LF-1) characterized by large-scale slumps, parallel lamination, ripple marks, and cross-bedding. The LF-1 is overlain by the Katkhiara Member, which is dominated by thick sandstone (LF-2) with planar and trough cross-bedding and contains dolomite beds (LF-3) in the upper part. Grain-size statistics show that the sandstones are fine-to-medium-grained, well-to-very-well-sorted, near-symmetrical, and very platykurtic. Machine learning-based bivariate plots suggest that most of the samples are grouped, with some showing scattered trends. The Linear Discriminant Function (LDF) analysis indicates that the Tredian Formation was deposited in fluvial–deltaic to shallow marine environments with sand reworking and redistribution under aeolian/beach settings. The Decision Tree Classifier Model (DTCM) predicted fluvial to shallow marine depositional environments for the Tredian Formation and shows strong agreement with field-based lithofacies interpretation, demonstrating its reliability as a predictive tool. Thus, the present study demonstrates that integrating grain-size-based machine learning and statistical analysis with traditional sedimentology provides valuable insights into depositional settings and enhances the reliability of interpretations of ancient sedimentary environments. Full article

Small Mediterranean coastal lagoons are sensitive sedimentary environments where basin morphology, hydrodynamic processes, and inherited coastal structures interact to control sediment dispersal. This study investigates modern sedimentary patterns in Lake Porto Vecchio, a shallow coastal brackish pond within the Oliveri–Tindari lagoon system (NE Sicily, Italy), by integrating grain-size statistical and petrographic analyses, and morpho-bathymetric data. A total of 115 surface sediment samples were collected from the coastal pond’s shallow bottom, shoreline, adjacent beach, and shallow marine sector. Grain-size distributions were analyzed using mechanical sieving and laser diffraction, and textural parameters were calculated following Folk and Ward’s formula. Results reveal a well-defined spatial organization of siliciclastic sediments characterized by a grain-size gradient from gravelly coarse-grained sands along the shallow marginal platform to fine-grained sands and silts toward the deeper central basin. This pattern reflects a progressive decrease in hydrodynamic energy from the lagoon margins toward the basin depocenter. A partially lithified beachrock belt forms a shallow platform controlling sedimentation, trapping coarse sediments along the margins while promoting the accumulation of finer fractions in the inner basin. Grain-size discrimination diagrams further distinguish lagoonal sediments from adjacent marine deposits, highlighting the effectiveness of classical statistical approaches in reconstructing modern sedimentary processes. These results support a conceptual model in which inherited beachrock platforms act as key morphological control on sediment architecture in microtidal coastal lakes. Lake Porto Vecchio, therefore, represents a useful modern analog for interpreting similar lagoonal deposits preserved in the Quaternary sedimentary record. Full article

Oceanfront relief varies along coastlines and serves as the first barrier to wave and surge damage. However, forecasted increases in storm frequency and sea levels are anticipated to enhance coastal erosion, potentially weakening this protection. The land–sea transition is variable along the New England coast, USA, and this variability has produced a range of coastal morphologies that can vary over short distances. It is important to track the beach transition zone to better understand transformations of the system and related hazard risks. A combination of field and computer-based methods was used to evaluate the beach transition zone of southwestern Rhode Island to determine alongshore variability and dynamics. More specifically, a decadal-scale study was conducted to examine changes in morphology from 2011 to 2022, and a short-term study at South Kingstown Town Beach examined changes from November 2023 to January 2024 using time-series drone-derived elevations. Classification of over 500 cross-shore transects illustrated the dominance of sedimentary shorelines, with smaller areas of rocky outcrops and hardening. Analysis of four different years (2011, 2014, 2018, and 2022) determined that beaches with dune morphology were the most common type of transition zone (41–47% of the transects) and transects with a high bank upland were the next most frequent class (34–41%). Following Hurricane Sandy in 2012, a 6% decrease in the number of dune-classified transects was measured; however, one-third of those recovered dune morphology by 2022. The greatest beach transformations over the short-term study occurred in response to strong storms in the 2023–2024 winter season, during which lateral beach movement (erosion) exceeded 15 m in portions of South Kingstown Town Beach. Dune erosion was accompanied by overwash flooding and deposition, and the area remained low-lying and thus vulnerable to future impacts. The beach transition zone classification and insights from this research will be informative for future planning by coastal communities by determining at-risk shorelines based on underlying geology and the stability of morphological features. Full article

Analyzing microplastics in marine organisms is essential for understanding the ecological and toxicological impacts of marine microplastic pollution in coastal food webs. This study investigated microplastic ingestion in three edible invertebrate species commonly found on Vietnamese sandy beaches, wedge clam Donax sp., hermit crabs Pagurus sp., and horn-eyed ghost crabs Ocypode ceratophthalmus, which differ in feeding modes and mobility, using micro-Fourier Transform Infrared spectroscopy (µ-FTIR) with a detection limit of 20 µm. Results showed that all three species ingested microplastics, with ingestion patterns varying according to species-specific traits and habitat-related feeding behaviors. The highly mobile crabs Ocypode ceratophthalmus (omnivore) and Pagurus sp. (scavenger) were found to partially reflect the polymer pollution in their ambient environment. The higher ingestion rate and diversity of polymer types observed in sedentary Donax sp. suggest that this species could serve as a potential bioindicator for microplastic pollution, given its mixed suspension and deposit feeding habits that integrate pollution from both the water column and beach sediments. Overall, these results reveal widespread microplastic ingestion among edible beach fauna, highlighting potential ecological and human health concerns, and emphasizing the need for targeted pollution management and increased public awareness. Advancing our understanding will require larger datasets and controlled experiments to more robustly assess species-specific responses and the likelihood of trophic transfer. Full article

Beach nourishment is a widely adopted nature-based solution for coastal erosion; however, its design efficacy and morphodynamic resilience under extreme wave conditions remain inadequately quantified, posing challenges for coastal hazard assessment. This study integrates physical-model experiments and XBeach numerical simulations to investigate the hydrodynamic and morphodynamic behavior of nourished beaches subjected to typhoon-driven extreme wave conditions at a headland-bay beach on Meizhou Island, China. Physical-model experiments were conducted to examine shoreline response and sediment redistribution under extreme waves for three nourishment tests. XBeach simulations resolved wave-induced currents, water-level variations, and sediment transport processes, enabling continuous tracking of nearshore hydrodynamics and beach profile evolution for three nourishment tests during Typhoon Doksuri. Results indicate that nourishment geometry and groin configuration play a dominant role in wave breaking patterns, sediment transport pathways and erosion–deposition distributions. Groin positions strongly influence alongshore sediment transport. Relocating the groin to an accretional zone reduces lee-side erosion and promotes a more stable shoreline. Steeper nourishment foreshore slopes promote offshore wave shoaling and breaking, enhancing fast wave-energy dissipation, shifting erosion seaward and limiting landward erosion extent. Consistent responses from both experimental and numerical results demonstrate that nourishment stability under extreme wave conditions is better characterized by the combined effects of erosion extent, erosion length, erosion depth, erosion volume, and alongshore and cross-shore sediment redistribution. The integrated physical–numerical approach provides a practical framework for assessing beach nourishment stability during coastal hazard events and offers guidance for the design and evaluation of resilient beach nourishment in wave-dominated, typhoon-prone coastal regions. Full article

The 1964 M7.5 Niigata earthquake remains one of the most significant natural laboratories for understanding seismic–induced soil liquefaction and its dependence on geological setting. Among global field case histories, Niigata stands out for the exceptional documentation of liquefaction triggering, lateral spread displacements, and soil–structure interaction. This paper reexamines the event from an engineering–geologic perspective, emphasizing how Holocene coastal and fluvial depositional processes beneath the Echigo Plain controlled the spatial and stratigraphic distribution of liquefaction during the 1964 earthquake. The most severe ground deformations occurred in fluvially reworked sands derived from three major Holocene dune and barrier island systems (CSD1,2,3) formed along the paleo–shoreline of the Sea of Japan. The largest of these, a mid–Holocene transgressive barrier complex deposited to a thickness of 50–60 m of beach and aeolian sand between 8 and 5 ka B.P., now lies buried 5–8 km inland beneath fine–grained alluvial deposits. Tectonic downwarping and deltaic progradation by the Shinano and Agano rivers redistributed these sands into loose, saturated fluvial facies beneath modern Niigata city. Quantitative geotechnical analyses demonstrate that liquefaction occurs within these reworked Holocene units rather than anthropogenic fills. Full article

Lake Faro (Cape Peloro coastal lagoon, NE Sicily, Italy) is a distinctive Mediterranean coastal lake characterized by the coexistence of a shallow platform and a steep-sided deep basin within a very limited area. This study provides a sedimentological and geological characterization of the present-day lake floor based on grain-size, petrographic, statistical, and GIS-based analyses, with the aim of clarifying the relationship between basin morphology and modern depositional processes. The lake floor is subdivided into two main bathymetric domains. The shallow platform (<10 m water depth) is dominated by modern coarse-grained, very poorly sorted sediments, including gravel and very coarse- to medium-grained sand, deposited under high-energy, low-confinement conditions comparable to beach and open-lagoon environments. In contrast, the deep basin (>10 m water depth) is characterized by modern finer, organic-rich sediments with extremely poor sorting, reflecting lower-energy and more confined depositional conditions. A key new finding is the identification of upper Holocene beachrocks beneath the modern unconsolidated sediments of the shallow platform, which likely exert a significant morpho-structural control on platform development. Overall, the results highlight the strong influence of bathymetry on sediment distribution in coastal lake systems and provide a reference framework for comparable Mediterranean lagoon environments. Full article

The Bahamas is an ideal location for studying the calcium carbonate sedimentation of Holocene strandplains in relation to seaward progradation. We use ground-penetrating radar (GPR) to image and interpret the fine-scale stratigraphy of three carbonate strandplains on Crooked Island, The Bahamas. GPR has been extensively used to analyse the interiors of clastic strandplain deposits worldwide, while tropical carbonate settings have received less attention. Due to the lack of outcrops in our study area on Crooked Island, we validate the interpretation of the 2D profiles by comparing them with a 3D GPR data volume collected adjacent to and over a Pleistocene aeolianite outcrop on San Salvador Island, where porosity layering can be directly observed. Data processing employed state-of-the-art techniques adapted from the petroleum industry to enhance the visualisation of reflection amplitude on the GPR images. Our data support a model in which the progradation of carbonate sediment preserved in strandplains was deposited through a combination of storm processes and gradual sediment progradation. Full article

Artificial reefs (ARs) are eco-friendly coastal protection infrastructures that mitigate wave-induced erosion while maintaining hydrodynamic connectivity and supporting ecological functions. This study evaluates the protective efficacy of a shellfish-algae reef system—a new type of AR—within the Houlong Bay coastal restoration project (Quanzhou, China) using an integrated numerical modeling approach. A coupled model system was established, incorporating MIKE 21 FM for hydrodynamics, MIKE 21 SW for waves, and MIKE ZERO ST for sediment transport, using unstructured triangular grids to resolve complex coastal topography. The model was validated against field data, including tidal currents and wave heights, showing good agreement. Pre-implementation simulations identified key coastal issues: insufficient wave attenuation in the southern fishery port segment, which results in localized erosion. Post-project simulations demonstrate that the novel integrated system—comprising shellfish-algae reefs, broad gentle beaches, and coastal vegetation—effectively reduced nearshore current speeds by approximately 0.15 m/s and attenuated significant wave heights by up to 70% during typhoon events. Short-term (1-year) sediment evolution showed mild deposition (0.1–0.8 m) at the toe of the artificial beach, which is consistent with design expectations. Long-term (10-year) simulations further confirmed coastal stability, with minimal long-term shoreline retreat (maximum 15 m) and low net alongshore sediment transport (annual average: 800 m³). This study provides a validated, data-driven reference for the design and implementation of AR-based restoration strategies in semi-enclosed bays, highlighting their dual role in erosion control and sustainable coastal management. Full article

Sediment transport in alluvial channels is strongly controlled by the grain-size distribution of bed and suspended materials. This, in turn, influences river morphology by modifying the cross-sectional area and course of the channel. Statistical parameters such as mean, standard deviation, skewness, and kurtosis provide quantitative indicators of the energy conditions that control sediment transport and deposition. This study examines the depositional characteristics of sediments in the Ganga River in Varanasi City, India, employing a novel combination of linear discriminant function (LDF) and sediment transport index (STI). The LDF results reveal distinct depositional environments: Y₁ and Y₂ values indicate deposition in a low-energy fluvial environment similar to beaches, Y₃ values suggest shallow marine settings, and Y₄ values point to mixed deltaic and turbid current depositional environments. Additionally, CM diagrams show rolling and suspension as the dominant sediment transport mechanisms. Shear stress analysis combined with STI highlights significant depositional features, with minimal erosion observed throughout the study area. The study provides an operational framework for mapping erosion-deposition patterns on alluvial point bars that are transferable to other sand-bed rivers worldwide where detailed hydraulic data are limited but detailed grain-size and DEM information are available. Full article