Quaternary, Volume 9, Issue 4 (August 2026) – 11 articles

Seafloor undulations are common on continental shelves and slopes, but their origin is often difficult to determine because similar ridge-and-trough morphologies may originate from depositional processes, post-depositional deformation, or a combination of both. This study investigates seafloor undulations offshore the Sinni River mouth, southern Italy, to assess their depositional, deformational, or hybrid origin, using high-resolution bathymetry, sparker seismic profiles, sub-bottom profiler data, and morphometric analysis. Bathymetric data reveal a seaward-deepening shelf-to-slope system affected by submarine canyons, troughs, slide scarps, crests/ridge, and fields of undulated seafloor. Seismic profiles show that the undulations are mainly developed within the shallow sedimentary wedge, where continuous to gently wavy reflectors pass laterally and downslope into sectors characterized by reduced reflector continuity, local reflector bending, minor reflector offsets, low-angle reflector surfaces, disturbed sediment bodies, vertical to subvertical acoustic anomalies, and locally chaotic to semi-transparent seismic facies. Deeper stratified deposits are generally more continuous, indicating that deformation is mainly confined to the upper sedimentary succession. Morphometric analysis of 65 seabed features distinguishes broader seafloor undulations, characterized by longer wavelengths, low relief, and higher L/H ratios, from shorter, steeper deformation-related sectors with lower L/H ratios. The integrated evidence indicates that the Sinni undulation field is best interpreted as a hybrid depositional–deformational system. Broad, low-relief undulations record depositional accumulation and seabed reworking within the upper sedimentary wedge, whereas shorter, steeper, and more asymmetric sectors indicate localized post-depositional deformation, possibly favored by weak fine-grained deposits, gas/fluid-related acoustic disturbance, slope steepening, and local sediment remobilization. Full article

Western Siberia is one of the largest high-latitude lowland peatland regions on Earth and stores vast amounts of organic carbon in landscapes where vegetation, hydrology and fire are strongly regulated by permafrost. However, the long-term interactions among fire disturbance, permafrost dynamics, peatland development and forest–mire vegetation change remain insufficiently resolved. Here, we reconstructed regional vegetation dynamics, local mire succession, permafrost evolution and fire activity in the subarctic Pur–Taz interfluve, Western Siberia, during the Early to Middle Holocene from 11.2 to 4.4 cal kyr BP. The study combines pollen, non-pollen palynomorphs, microcharcoal records, principal component analysis and comparison with modern surface-sample analogues. The record documents a transition from Early Holocene larch–birch forest-tundra with no close modern analogue to increasingly heterogeneous forest–mire and shrub-tundra landscapes. After 9.5 cal kyr BP, Betula pubescens declined and Picea obovata pollen increased, with the strongest spruce signal between ca. 5.5 and 4.7 cal kyr BP. However, this pattern did not necessarily reflect a uniform regional expansion of spruce. Integrated fire reconstruction, based on microcharcoal peaks, Gelasinospora-type and declines in Betula pubescens-type pollen, indicates that recurrent fires after 8.0 cal kyr BP preferentially affected well-drained birch–larch uplands, whereas wetter riparian habitats acted as refugia for spruce. This landscape contrast increased the relative contribution of Picea pollen from fire-protected valleys, producing an apparent, partly artefactual spruce expansion signal. Locally, an open lake present at 11.2 cal kyr BP was transformed into a peatland after ca. 9.7 cal kyr BP. Cooling associated with the 8.2 cal kyr BP event promoted permafrost aggradation and polygonal mire initiation, whereas subsequent thaw and subsidence favoured waterlogging and mesotrophic fen development. Repeated alternation between permafrost aggradation, oligotrophication, degradation and renewed waterlogging culminated in polygonal microrelief by 6.1–5.3 cal kyr BP. These results show that Holocene vegetation change in the Pur–Taz interfluve was not controlled by climate alone, but by spatially heterogeneous feedbacks among permafrost state, peatland hydrology, fire disturbance and pollen-source structure. The West Siberian record provides a palaeoecological analogue for anticipating nonlinear vegetation and fire-regime responses in permafrost lowlands under ongoing Arctic warming. Full article

This paper presents a comprehensive assessment of megafauna confrontation using pikes, as recorded in historical accounts and ethnographic studies depicting techniques of hunter-gatherers, pastoralists, colonial hunters and others. In contrast to the two other basic spear types, the lance and the javelin, the impalement force of the pike is derived from the mass and speed of the charging or lunging animal. The historical data demonstrate that pike bracing was a common and fundamental technique used by spear-wielding individuals challenging megafauna, including ursids, pantherids, suids, bovids, and mounted equids, that confront humans aggressively and are not disadvantaged. In hunting, pikes were used most often in situations where the hunter influenced the animal’s behavior to draw a charge, leap or lunge. Braced spears (pikes) were also important for defending against predators and cavalry mounts that attacked in these ways. We examine such variables as animal size, trajectory and momentum, weapon rotation on its base, shaft diameter, frequency of cross bars, and point material (wood, osseous, lithic and metal). Variability in pike use is of significance to numerous archaeological and evolutionary topics that require assessment of human confrontation with Pleistocene megafauna, and approaches to archaeological pike identification are considered. Full article

This study investigates intraspecific morphometric variability in the archaeozoological assemblages from the multi-period site of Șoimuș-Teleghi (Hunedoara County, Romania), encompassing occupation phases from the Early Neolithic (Starčevo-Criș culture) to the Late Bronze Age. The new AMS radiocarbon dates obtained refine the chronological framework of the site. The results reveal pronounced morphometric variability in cattle (Bos taurus), with horncore flattening indices, dental dimensions, and postcranial measurements enabling the differentiation of males, females, and probable castrates—the latter suggesting traction-oriented management strategies. A notably large horncore from the Vinča level may indicate hybridisation between domestic cattle and aurochs (Bos primigenius). Sheep (Ovis aries) display an increase in estimated withers height from the Neolithic to the Late Bronze Age, potentially reflecting improved husbandry. The pig (Sus domesticus) scapula scatter plot indicates a female-dominated culling pattern, while postcranial elements suggest relatively robust forelimbs combined with more gracile distal limb segments. Among wild taxa, red deer (Cervus elaphus) and wild boar (Sus scrofa) exhibit clear sexual dimorphism and generally large body sizes, consistent with the selective hunting of prime adult males. Comparative analysis with contemporary assemblages from Transylvania, Banat, and Hungary situates the Șoimuș-Teleghi material within broader regional trends, while highlighting certain distinctive features, particularly the large dimensions of Early Neolithic cattle and the diachronic size increase observed in caprine. Full article

Norway spruce (Picea abies [L.] Karst.) is a paleoecologically relevant species in the Northern Hemisphere since the early Holocene. P. abies populations are sensitive to climate fluctuations; Asian treeline species are under nature protection. The thick wax and cuticle layers of spruce needles enhance their durability, making them frequent in glacial lake and peat bog cores. Their phytoliths are easily recognizable in sedimentary material and can be studied in subfossil tissues. The aim of this study is to assess the applicability of characteristic phytoliths from Norway spruce needles in paleoclimate research. We examined phytolith presence as a function of altitude in plant samples from three Carpathian Mountain ranges. Temperature data loggers were deployed at sampling sites to better characterize the thermal background of phytolith formation. Our results show a decreasing trend in phytolith presence with increasing elevation. The phytoliths formed by the transfusion tissue represent a sensitive type, indicating that spruce needle phytolith production responds to microclimatic variation. These findings are worth further investigation and validation. The study also provides a basis for refining the calculation method, contributing to the development of a potential “phytolith thermometer” for paleoclimatic reconstruction. Full article

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analysis of bone collagen has become a cornerstone method for reconstructing the diets of past populations. This critical review moves beyond the mere presentation of data to examine the theoretical foundations, methodologies, and applications of this approach. The principles of the method are based on isotopic fractionation during photosynthetic pathways (C₃, C₄, and CAM) and the trophic-level enrichment of ¹⁵N, which together enable the differentiation of plant food sources and the identification of consumer trophic position, respectively. The methodology encompasses sampling strategies, challenges posed by diagenesis, collagen extraction protocols, including the Longin method, and quality-control criteria (collagen yield, C:N ratio). Key applications include the reconstruction of baseline diets, the determination of weaning practices, and the identification of social inequalities. However, confounding factors—such as climate-driven variation in baseline nitrogen values, physiological effects (disease, lactation), and the consequences of human activities (manuring)—can complicate interpretation. Future directions include compound-specific amino acid analysis, multi-isotope approaches, and Bayesian modelling. In conclusion, isotopic data require a contextual and interdisciplinary approach to achieve a realistic understanding of diet and socio-cultural dynamics during the Quaternary. Full article

Fluvial superfloods are geomorphologically significant episodes due to their enormous energy and extremely low recurrence in the geological record. Their rarity is particularly notable in areas far from the major continental glacial masses. Hydraulic constrictions in the Lower Ebro River gorges caused the accumulation of fluvial deposits, as floodwaters from the Ebro River were forced upstream into the tributary valleys of the Móra Basin. The most illustrative example is the Comte Creek, where two depositional units of different ages show upstream flood accumulations (extending up to ~4 km) with very high-energy sedimentary structures, followed by downstream reworking during backflow. Two-dimensional hydraulic simulations indicate that peak discharges reaching 385,000 m³·s⁻¹, with water depths of approximately 28 m in the confluence area, would have been required to transport sediments to the observed outcrop positions. Luminescence dating of the slackwater deposits indicates that the formative processes occurred during the latest Middle Pleistocene or the Last Interglacial (Eemian). Full article

This study investigates the spatial variability of benthic foraminiferal assemblages across the shoreface–inner shelf transition of the Porto Pino coastal system (SW Sardinia, western Mediterranean). Porto Pino is a microtidal, wave-dominated embayment characterized by an environmental gradient extending from siliciclastic shoreface sands to mixed bioclastic sediments associated with the Posidonia oceanica meadow. A total of 33 sediment samples were analyzed for grain size, benthic foraminiferal assemblages, morphotypes and diversity indices. Cluster analysis and Principal Component Analysis (PCA) were used to investigate the spatial variability of the assemblages. Three main benthic foraminiferal assemblages were identified, each corresponding to a distinct benthic habitat: shallow unvegetated shoreface sands, a transitional zone near the upper limit of the P. oceanica meadow, and deeper mixed bioclastic sediments associated with its lower boundary. The distribution of the foraminiferal assemblage reflects the combined influence of hydrodynamic energy, substrate composition, water depth, and proximity to the meadow. Diversity indices indicate generally low-stress environmental conditions, whereas morphotype composition reflects changes in habitat structure and substrate characteristics along the shoreface–inner shelf gradient. These results demonstrate that benthic foraminifera effectively track environmental and sedimentological gradients in Mediterranean embayed systems and highlight their value for environmental reconstructions and biomonitoring applications. Full article

The Macaronesian archipelagos host exceptionally well-preserved coastal sedimentary deposits formed during the warmest period of the Last Interglacial episode, the Marine Isotope Substage 5e (MIS 5e). Numerous MIS 5e fossiliferous outcrops occur, scattered across several islands of the Canary Archipelago. Among these is San Juanito, a small outcrop located in the eastern sector of Punta del Hidalgo (northeast Tenerife Island), where MIS 5e sediments are distributed over an area of approximately 480 m². A multidisciplinary study was conducted, aiming to: (i) determine the age of the fossiliferous sediments; (ii) define the stratigraphic relationships between the sedimentary deposit and the underlying/overlying volcanic sequences; (iii) assess the taxonomic richness and the functional palaeobiodiversity of this palaeosite; and (iv) provide a comprehensive palaeoecological reconstruction of the MIS 5e environment. Based on two key ecostratigraphic indicator species for the Canarian MIS 5e, the San Juanito sequence is here assigned to the Last Interglacial. Qualitative sampling yielded forty mollusc taxa, including three gastropods that represent new records—Alvania johannae Moolenbeek & Hoenselaar, 1998, Krachia tiara (Monterosato, 1874), and Barleeia unifasciata (Montagu, 1803)—bringing the current MIS 5e checklist for the Canary Islands to 202 gastropods and 80 bivalves. The highly cemented matrix of the San Juanito deposits prevented the collection of standardized 1 kg bulk sediment samples. Nevertheless, we strongly recommend adopting this quantitative approach in future studies of suitable MIS 5e outcrops across the archipelago. The faunal assemblage indicates that the San Juanito region was dominated by rocky shores during the MIS 5e, much like today. This paleoenvironmental reconstruction is based on the high frequency of species associated with hard substrates—including echinoids, vermetids, fissurellids, and patellids—and the overwhelming dominance (95%) of epifaunal gastropods. Full article

Research in quantitative paleohydrology shows that a phase of very high river discharge on the northern Eurasian plains in the late Pleniglacial (about 18–14 ka BP) was followed by a much less studied phase of reduced discharge and small-channel formation. To characterize this morphohydrological metamorphosis, we investigated the morphometry of small meandering paleochannels on floodplains at 132 river-valley sites in the Volga basin. On average, the widths and meander wavelengths of these paleochannels are approximately half those of modern channels. The ages of the paleochannels range from 10 to 4 ka BP. The hydrological regime of small mid-Holocene meandering rivers was reconstructed using morphometric relationships, principally the power-law relationship between bankfull channel width and mean maximum flood discharge and the relationship between maximum discharge and contributing basin area. The mean reconstructed daily maximum runoff depth for small catchments in the Volga basin during the snowmelt period in the mid-Holocene was about 5 mm/day, approximately half the modern value. The ratios between mean annual and mean maximum runoff depths in the mid-Holocene were estimated from modern regional analogues of the ancient climate, using climate models for the 6 ka BP time slice. Annual river runoff depths in the Volga basin in the mid-Holocene were then calculated from these analogue ratios and the daily maximum runoff depths. The mean annual runoff depth in small catchments was about 100 mm, almost half the current runoff in the Volga River basin. The annual Volga River runoff volume in the mid-Holocene was approximately 132 km³, compared with the current value of 250 km³. This decline in river runoff in the Volga basin resulted in a low stand of the Caspian Sea in the early–middle Holocene, with a calculated potential sea level of −65 to −79 m abs. Full article

Karst poljes in the Dinaric karst are widely infilled with Quaternary sediments. In the Bribir–Ostrovica karst polje, these sediments were investigated using geomorphological mapping and multiproxy analysis of lake sediment cores, including grain size, mineralogical, total organic and inorganic carbon (TOC, TIC), and ostracod analyses, coupled with radiocarbon dating. A key sediment core (OSP-3) recovered a ~470 cm long sedimentary sequence dating back to 13,200 cal yr BP. The floodplain to wetland environment occurred at the Late Pleistocene to Holocene transition (ca. 12,100 cal yr BP), evident by the first appearances of ostracods and an increase in TOC. More stable lake conditions prevailed between 9600 and 7200 cal yr BP, with dominant carbonate deposition and abundant ostracods. During the Middle and Late Holocene, increased clastic input and reduced ostracod presence indicate a shallow, dynamic water body influenced by erosion and periodic flooding. Lake sedimentation was strongly controlled by local karst topography, with a maximum lake depth of ca. 6 m. The Bribir–Ostrovica paleolake represents a rare terrestrial Holocene paleoenvironmental record from the Dinaric karst of the eastern Adriatic coast and provides valuable context for interpreting the nearby Neolithic archaeological site of Krivače as a lakeside settlement. Full article