Late Pleistocene Research Articles

New insights into the Upper Pleistocene directed blast eruption, Popocatépetl volcano, México

Volcanic eruptions of the directed blast type are characterized by powerful explosions with a significant lateral pyroclastic density current (PDC) component that can travel at speeds above 100 m s–1 and affect hundreds of square kilometers around a volcano. This study presents preliminary results of a detailed fieldwork and stratigraphic study of deposits associated with the Ocoxaltepec Blast deposit, which originated from the Popocatépetl volcano during a strong eruption associated with the southwestward sector collapse of the volcanic edifice around 23,500 ka BP. Within the study area, which contains 58,870 inhabitants, we found 42 new sites where the blast deposit outcrops, in locations up to 25 km from the volcano crater, with thicknesses up to over 20 m. We divide these blast deposits into two categories: confined channel-fill PDC deposits and unconfined interfluve and upland PDC deposits. With the new data we have estimated the dispersion area of the directed blast to be approximately 338 km2. Twenty-nine of the new outcrops are located outside the hazard polygon associated with concentrated PDCs related to the lowest probability Plinian eruption currently considered from Popocatépetl.

Systematics and paleobiology of new bison occurrences from the Late Pleistocene of central Mexico

This study presents new findings of bison remains associated with alluvial plains in central Mexico dating back to the Late Pleistocene. These discoveries encompass eight sites in Hidalgo (Conejos, Ventoquipa, Barranca del Berrendo, Barranca Jagüey Viejo, Las Cajas, El Barrio, Monte Alegre, and San Gabriel Azteca) and two sites in Puebla (Barranca Policarpio and Barranca Xocoa). Biometrical analysis was conducted on the herein studied material, consisting of a horn core fragment, a skull fragment, two mandible fragments, five isolated teeth, and several postcranial remains. A comparative study with selected specimens indicates the presence of Bison antiquus and B. cf. latifrons. The record represents the first reported occurrences of these species for the states of Hidalgo and Puebla respectively. Furthermore, the analysis of carbon (δ13C) and oxygen (δ18O) isotopes in tooth enamel apatite from the material of Hidalgo and Puebla was used to characterize the bison's diet and habitat, providing evidence of the flexible dietary regime observed in Pleistocene bison populations and that were common inhabitants of mixed environments. Body mass estimation of some individuals (average weight ≈ 450 kg) is in the lower limit of B. antiquus populations from the Late Pleistocene of North America. New knowledge about the geographical presence of Bison antiquus and B. cf. latifrons in central Mexico is provided. Comparison with another bison record of these species from North America suggests a biochronological delay between them, representing a younger time interval for Bison antiquus (maximum age at 50 ka), allowing us to biostratigraphically constrain some Mexican localities containing bison remains.

Human exploitation of a straight-tusked elephant (Palaeoloxodon) in Middle Pleistocene deposits at Pampore, Kashmir, India

Stone tools in association with Pleistocene elephant remains were recovered from Pampore, Kashmir, India, in 2000 from channel deposits in the Pampore Member of the Upper Karewa Group of sediments, which are interpreted as Middle Pleistocene in age. In March 2019 the elephant remains were re-examined to establish taxonomy, cause of death and evidence of human intervention, alongside study of the stone tools and age of the site. This paper reports the results of this work. Most of the elephant remains, including skull and tusks, are from a large adult, but at least two other elephants are also represented. Taxonomic analysis shows that the adult belongs to the genus Palaeoloxodon, but with a mix of features not seen in typical Palaeoloxodon skulls from the Indian Subcontinent. Pathology of the skull indicates severe sinusitis, which may have contributed to the death. No cut-marks from butchery were found on the elephant bones, although three elephant bone flakes were identified, linking human intervention with elephants at the site. The small lithic assemblage is in fresh condition with some refitting artefacts, both suggesting minimal post-depositional movement. Most of the artefacts consist of flakes, flake tools and cores, but with several points and blades suggestive of an early Mode 3 prepared core technology. This might indicate a late Middle Pleistocene age for the site. Further dating evidence using amino acid racemisation on elephant tooth enamel is ongoing, but consistent with this age. The association of stone tools with humanly-modified elephant remains is rare, while prepared core technology is currently scarce further north or east in Asia in the late Middle Pleistocene. The significance of the discovery is discussed in the wider context of Middle Pleistocene elephant-human interaction.

Deep desert aquifers as an archive for Mid- to Late Pleistocene hydroclimate: An example from the southeastern Mediterranean

Many efforts have been made to illuminate the nature of past hydroclimates in semi-arid and arid regions, where current and future shifts in water availability have enormous consequences on human subsistence. Deep desert aquifers, where groundwater is stored for prolonged periods, might serve as a direct record of major paleo-recharge events. To date, groundwater-based paleoclimate reconstructions have mainly focused on a relatively narrow timescale (up to ∼40 kyr), limited by the relatively short half-life of the widely used radiocarbon (5.73 kyr). Here we demonstrate the usage of deep regional aquifers in the arid southeastern Mediterranean as a hydroclimate archive for earlier Mid-to-Late Pleistocene epochs. State-of-the-art dating tools, primarily the 81Kr radioisotope (t1/2 = 229 kyr), were combined with other atmosphere-derived tracers to illuminate the impact of four distinguishable wetter episodes over the past 400 kyr, with differences in climatic conditions and paleo-recharge locations. Variations in stable water isotope composition suggest moisture transport from more proximal (Mediterranean) and distal (Atlantic) sources to different parts of the region at distinct times. Large variability in the computed noble gas-based recharge temperature (NGT), ranging ~15–30 °C, cannot be explained by climate variations solely, and points to different recharge pathways, including geothermal heating in the deep unsaturated zone and recharge from high-elevation (colder) regions. The obtained groundwater record complements and enhances the interpretation of other terrestrial archives in the arid region, including a contribution of valuable information regarding the moisture source origin as reflected in the deuterium-excess values, which is unattainable from the common practice analysis of calcitic cave deposits. We conclude that similar applications in other deep (hundred-m-order) regional groundwater systems (e.g., the Sahara desert aquifers) can significantly advance our understanding of long-term (up to 1 Myr) paleo-hydroclimate in arid regions, including places where no terrestrial remnants, such as cave, lake, and spring sediments, are available.

Clovis points and foreshafts under braced weapon compression: Modeling Pleistocene megafauna encounters with a lithic pike.

Historical and ethnographic sources depict use of portable braced shaft weapons, or pikes, in megafauna hunting and defense during Late Holocene millennia in North and South America, Africa, Eurasia and Southeast Asia. Given the predominance of megafauna in Late Pleistocene North America during the centuries when Clovis points appeared and spread across much of the continent (13,050-12,650 cal BP), braced weapons may have been used in hunting of megaherbivores and defense against megacarnivores. Drawing from historical examples of pike use against lions, jaguars, boars, grizzlies, carabao and warhorses we consider the possibility of a fluted lithic pike. Associated osseous rods have been problematic as Clovis foreshafts due to the bevel angle and the apparent weakness of the splint haft when great strength is needed for deep penetration in megafauna hunting. However our review of Late Holocene pike use in megafauna encounters indicates the sharp tip becomes less important after hide or armor has been pierced because compression is sustained. Thus, foreshaft collapse after hide entry may not limit but rather increase the efficacy of the braced weapon. We conduct preliminary static experiments to model a fluted pike that adjusts during compression such that haft collapse and point detachment (when point jams on impact with bone) preserve the fluted biface, beveled rod and wooden mainshaft tip. In addition to Clovis point attributes and association with osseous rods, potential archaeological correlates of Clovis pike use include the high frequency of Clovis point isolates and concentrations of complete points with unbutchered mammoth remains at sites such as Naco in Arizona.

MIDDLE PLEISTOCENE NEOTECTONIC ACTIVATION OF THE MOUNTAIN BORDERING THE MUYA-KUANDA RIFT VALLEY (BAIKAL RIFT ZONE)

Geological and geomorphological studies of the northeastern branch of the Baikal rift zone have revealed structural features of sedimentary strata, as well as the features of lithology and interaction of heterochronous loose sedimentary complexes, block structure of rift valley bottoms and their mountain border, fault network, and activated Cenozoic faults. The Middle Pleistocene neotectonic uplift was identified on the southern slopes of the North Muya and the Kodar ranges and in the mountains bordering the Muya-Kuanda and Parama rift valleys. The authors have studied the parameters of this uplift, determined neotectonic movement amplitudes in the uplift areas, traced the marginal disjunctives and the kinematics of their movements, and identified homochromous sedimentary strata and determined their formation age.The activation of tectonic processes, during which the neotectonic uplift was formed, occurred in the early Middle Pleistocene, before the onset of glaciation. The formation of a dammed lake in the system of Muya-Kuanda rift valleys is associated with the tectonic damming of the Vitim River. During the Middle Pleistocene glaciation, the Kodar Range glaciers have twice formed the ice dams in the area of Lake Oron, which led to the emergence of dammed lakes in the Vitim valley connected with lakes in the Muya-Kuanda troughs. The shoreline of these lakes is preserved as a high rock terrace with an absolute height of 860±10 m along the perimeter of the rift valleys.In the Late Pleistocene, the terrace complex in the Muya-Kuanda rift valleys was mainly formed under the influence of climatic factor.

The use of the malacofaunistic method for reconstructing the palaeoecological conditions of the late late pleistocene to holocene based on material from the Tetyukhinskaya Cave Site, Southern Far East, Russia

Results of the study of terrestrial mollusc shells from the unconsolidated deposits of the Tetyukhinskaya Cave, Dalnegorsk, Primorsky Krai, Russia are presented. Brief species descriptions of the molluscs and their images complete the scarce information on the fossil Quaternary mollusc fauna of the region. With the help of malacological analysis, characteristic zones and malacological complexes were identified, which were used as indicators of the habitats near the cave entrance and in the adjacent territory. The data concerning the palaeoecological conditions of individual mollusc species confirm the development of broad-leaved and mixed forests, alongside open meadows with herbage vegetation in the region near the cave, towards the end of the Late Pleistocene and in the Holocene.

Quaternary floodings in the Zanzibar Channel (NW Indian Ocean, Tanzania) – Identifying palaeoceanographic patterns and palaeoenvironment using a multiproxy study

Multiproxy palaeoenvironmental analyses represent a promising tool for complex reconstructions of continent-sea or air-sea interactions in shallow marine environments. This is in particular illustrated by the case of strong climatic variations in the late Pleistocene to mid-Holocene. A unique combination of geochemical proxies (143Nd/144Nd, 87Sr/86Sr, δ18O and δ13C isotope analyses, n-alkane analysis and biomarker study) together with micropalaeontological data (foraminifera, calcareous nannoplankton and diatoms) allowed to precisely characterise two marine floodings (mid-Holocene and late Pleistocene) in the Zanzibar Channel (NW Indian Ocean, Tanzania). The climate of the late Pleistocene interval was arid compared to the Holocene. The fully oligotrophic environment characteristic of the late Pleistocene flooding (∼115–130 ka) was episodically interrupted by intervals of intense rainfall with episodes of increased nutrient input during the mid-Holocene (∼5–10 ka). The dominance of seaweed meadows in the Holocene and late Pleistocene contrasts with the modern environment dominated by seagrass ecosystems. Relatively non-radiogenic εNd signatures in the Zanzibar Channel during the Holocene and late Pleistocene indicate a strong influence of riverine input draining the Precambrian basement on the African mainland. The main inflow of seawater was from the south, consistent with the flow direction of the East African Coastal Current and the directions of the March to October monsoon winds. A promising tool for future applications as indicators of seagrass/seaweed meadow type ecosystems may be the presence of specific diatom taxa.

Tip-Tugai Cave, the First Cave Hyena Crocuta spelaea (Goldfuss, 1823) Den Found in the Urals.

The Tip-Tugai Cave (52°59'28.6″N, 57°00'22.3″E) is described as a new site with cave hyena Crocuta spelaea fossils. The bone-bearing layer was dated to marine isotope stage (MIS) 3 based on the species composition of the fauna of large and small mammals. Finds of abundant remains of cave hyenas of different ages and bones of large herbivores with hyena gnaw marks indicated that the Tip-Tugai Cave was used as a hyena den in the Late Pleistocene. This is the first cave hyena den described in the Urals.

Nucleation-assisted microthermometry: A novel application to fluid inclusions in halite

Halite deposits have long been utilized for interrogating past climate conditions. Microthermometry on halite fluid inclusions has been used to determine ancient water temperatures. One notable obstacle in performing microthermometric measurements, however, is the lack of a vapor bubble in the single-phase liquid inclusions at room temperature. (Pseudo-) isochoric cooling of the inclusions to high negative pressures, far below the homogenization temperature, has commonly been needed to provoke spontaneous vapor bubble nucleation in the liquid. High internal tensile stress in soft host minerals like halite, however, may induce plastic deformation of the inclusion walls, resulting in a wide scatter of measured homogenization temperatures. Nucleation-assisted (NA) microthermometry, in contrast, employs single ultra-short laser pulses provided by a femtosecond laser to stimulate vapor bubble nucleation in metastable liquid inclusions slightly below the expected homogenization temperature. This technique allows for repeated vapor bubble nucleation in selected fluid inclusions without affecting the volumetric properties of the inclusions, and yields highly precise and accurate homogenization temperatures.In this study, we apply, for the first time, NA microthermometry to fluid inclusions in halite and we evaluate the precision and accuracy of this thermometer utilizing (i) synthetic halite crystals precipitated under controlled laboratory conditions, (ii) modern natural halite that precipitated in the 1980s in the Dead Sea, and (iii) Late Pleistocene halite samples from a sediment core from Death Valley, CA. Our results demonstrate an unprecedented accuracy and precision of the method that provides a new opportunity to reconstruct reliable quantitative temperature records from evaporite archives.

Neotectonic indications of Al-Shihaby fan on Iraqi-Iranian borders

Al-Shihaby alluvial fan is considered a significant and major geomorphologic phenomenon that evolved on the east side of Mesopotamia. It is located in the Wasit Governorate, near the Iraqi-Iranian borders. The fandom's dominant trend is southwest-northeast. This study aims to enhance our understanding of the indications and continuity of the fan's neotectonic activity. To reach this aim, we used software such as Arc GIS, Global Mapper, and Surfer, in addition to using data from USGS to identify the stages of the fan. A merging of spectral bands (composite bands), a contour map, and longitudinal and transverse topographic sections were done to analyze and interpret the neotectonics of the study area. This study concluded that the fan has passed through five stages in different periods and that its continuation to the present indicates that the fan is still active. These five stages recognized within the fan belong to the Pliocene- Late Pleistocene age range. Each stage is a breakpoint in sedimentation, and when tectonic activity occurs, the next stage begins. Besides that, the study concludes that the elevation range of the area from the cross sections is from 15 m in the southwest of the area to 120 m in the northeast above sea level from the elevation map derived from the DEM file. Besides that, the increase in sediment thickness on the western side of the fan compared to the eastern side, which belongs to the streams on the west side of the fan, in addition to the deposition of the alluvial fan, was related to the Mandali-Badra-Amara Faults (Zagros Front Fault (ZFF)) and its activity, as well as the relative uplifting of the Hemrin structure versus the subsidence of the Mesopotamia Plain.

Quartz luminescence sensitivity enhanced by residence time in the critical zone

The emerging use of quartz luminescence properties to characterize Earth-surface processes shows promise, with optically stimulated luminescence (OSL) sensitivity proposed as a valuable tool for provenance or sediment history tracing. However, the geologic processes that lead to quartz sensitization remain unclear. Here we study the impact of source rock and surface processes on the luminescence properties of quartz sand from bedrock and modern and Late Pleistocene alluvium generated from a mountainous catchment in northern Utah, USA. Continuous wave and linear modulated OSL are used to characterize the luminescence sensitivity and intensity of the fast-decay component. We compare the OSL sensitivity with sand-grain provenance and with proxies for surface processes such as topographic metrics, cosmogenic 10Be-derived erosion rates, chemical weathering indices, and magnetic susceptibility. Late Pleistocene sediment has low OSL sensitivity and a weak fast-decay component, similar to bedrock samples from the source area. In contrast, modern alluvium is dominated by the fast-decay component and has higher and more variable OSL sensitivity, with no clear relationship to upstream bedrock source. There is, however, an inverse relationship between OSL sensitivity and catchment-averaged erosion rates and a positive relationship with chemical weathering indices and magnetic susceptibility. These metrics suggest that the modern alluvium has experienced increased residence time in the shallow critical zone compared to the Late Pleistocene sediments. We suggest that changes in hillslope processes between the effectively wetter, cooler Pleistocene and the dryer, warmer conditions of the Holocene enhanced the luminescence properties. The results suggest that climatic controls on rates and processes of chemical and mechanical weathering and sediment transport and residence within the critical zone are encoded in the luminescence properties of quartz sand.

Dental microwear analysis of Kudaro cave bears: Insights into dietary evolution from the Middle to Late Pleistocene

The dietary changes of early cave bear populations from the Middle to Late Pleistocene are poorly understood. In this study, we analysed 60 m1 through dental microwear analysis of three diachronic Middle (Ursus praekudarensis and U. praekudarensis/kudarensis) to Late Pleistocene (U. kudarensis) populations inhabiting the Kudaro 1 and Kudaro 3 caves in the Southern Caucasus. The diet of all populations was inferred to be omnivorous, although it changed over time, adapting to the climatic and ecological conditions of the period. Bones from U. praekudarensis/kudarensis populations accumulated throughout the year; thus, microwear suggests an average annual diet dominated by plant resources. The widespread presence of hypercoarse scratches in U. kudarensis and U. praekudarensis populations suggests animal protein intake during the hyperphagia. The presence of omnivorous guild competitors and harsh conditions in a high-altitude environment could have driven the Caucasian cave bears to consume animal protein as a fallback diet during their predormancy period. Furthermore, the cave bears' capacity for dietary flexibility through time highlights the ability of cave bears to withstand climatic changes, while competition with other omnivorous species could have driven their dietary niche during their hyperphagia period towards animal protein consumption throughout the Middle to Late Pleistocene.

Late Middle Pleistocene Wolstonian Stage (MIS 6) glaciation in lowland Britain and its North Sea regional equivalents – a review

Two major glaciations have been identified on land in England during the Middle Pleistocene. The earliest occurred during the Anglian Stage (= Elsterian, c. Marine Isotope Stage, MIS 12), evidence for which is best developed in lowland Britain, as well as offshore in the southern North Sea and Irish Sea basins. The second took place during the late Middle Pleistocene, with the most compelling evidence found in the West Midlands, intermediate between the Hoxnian (= Holsteinian; broadly MIS 11) and Ipswichian (= Eemian; broadly MIS 5e) interglacial stages during the Late Wolstonian Substage. Until recently this younger glacial episode was less clearly represented in the Pleistocene record and, as a result, had been little studied and weakly defined. Interpreted as the Moreton Stadial glaciation during the Late Wolstonian Substage (= Late Saalian Substage/Drenthe Stadial, c. MIS 6), it was originally recognized in the English Midlands, subsequently being identified in Yorkshire, Lincolnshire and northern East Anglia, and potentially further SW as far as the Bristol Channel. Mapping, in particular by members of the British Geological Survey, however, resulted in the Wolstonian Stage glacial deposits being thought to pre‐date the stage. This was particularly so in East Anglia where there was considerable controversy concerning the number and relationships of glacial sequences, during the 1970–1980s. Yet to the west of East Anglia there remained unequivocal evidence for glaciation during the stage, particularly in Fenland and the eastern English Midlands. Recent radiometric dating across lowland Britain on glacial sediments long thought to belong to a glaciation event in the Wolstonian Stage have now placed a geochronological control on the established regional stratigraphy and confirmed that glaciation occurred in two phases between 199 and 147 ka during the Late Wolstonian Substage. The glacial events of the British Middle Pleistocene can clearly be correlated with the European continent.

Late Upper Palaeolithic ornaments from Vlakno cave, Croatia

This paper presents the richest prehistoric assemblage of ornaments in the Eastern Adriatic discovered to date, found in the Late Upper Palaeolithic layers of Vlakno cave, Croatia. The abundance and multiform of bead types indicate that the site was likely used as a workshop for ornaments, i.e. that production was performed on site. Technological and use-wear analysis of each taxon used for beads allowed us to elaborate on its mode of production, use, and overall position of the Vlakno cave site and its role in the regional context during the Late Pleistocene.

Diagnosis of archaeological bones: Analyzing the state of conservation of lower Pleistocene bones through diagenesis methods

Initial physicochemical assessment of cultural materials plays a critical role in the research and management of cultural heritage, serving as a foundation for comprehending deterioration mechanisms and developing effective conservation treatments. However, this knowledge is more advanced in several cultural materials such as artwork or historic buildings, than in bone and fossils. This study focuses on bone material conservation, applying diagenetic methods for characterizing and assessing the state of conservation of archaeological bones from Pit 1 at Barranc de la Boella (BB), an open-air archaeological site from the late Early Pleistocene, from a conservation perspective.Microstructural analyses, including mercury intrusion porosimetry (MIP) and histological analysis, alongside microchemical analyses through Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR), and FTIR with KBr pellets and X-ray Diffraction (XRD), were conducted to evaluate the decay processes affecting the bones. Results indicated poor bone preservation characterized by high porosity, significant microbial attack, collagen degradation, and the potential recrystallization of bioapatite into fluorapatite. These findings underscore the substantial challenges presented by open-site conditions to preservation efforts and highlight the need for suitable conservation treatments, such as consolidation to reinforce the microstructure.The study emphasizes the importance of characterizing archaeological bones to understand the factors influencing their preservation states and guide conservation works in this material. This work contributes to the knowledge of diagenesis studies to standardize the diagnosis of the state of conservation on archaeological bones.

Eccentricity control on fluvial sedimentation in the tropics during the Middle-Late Pennsylvanian icehouse (∼306–314 Ma, Upper Silesian Basin)

Far-field effects of the Late Paleozoic glaciation (∼340–260 Ma) recorded in well-dated stratigraphic intervals of the Pangea can be instrumental in detecting the short-term variability of icehouse climate and deconvolving the climate mechanisms. This study examines the Cracow Sandstone Series (CS), which provides a snapshot of the Middle to Late Pennsylvanian (∼306–314 Ma) fluvial sedimentation in the eastern equatorial Pangea (Upper Silesian Basin, ∼2°N paleolatitude). Spectral estimates of borehole lithological data suggest predominant ∼100-kyr eccentricity pacing of coal-bearing fluvial cycles and persistence of this pattern across the onset of Late Pennsylvanian aridification. The immediate climatic and depositional controls involve changes in seasonal precipitation along the Intertropical Convergence Zone and resulting fluctuations in sediment input. The prominence of eccentricity pacing and suppression of precession-scale variability in the fluvial environment contrasts with the frequency spectra of seasonal insolation series – an issue comparable to the “100-kyr problem” of the Late Pleistocene. The traditional explanation considers the eccentricity component being imposed as a far-field response to glaciation, analogous to the Pleistocene carbon-cycle feedback. Here we propose an alternative possibility that calls upon time-integrated insolation at the equator and the role of semi-annual wet/dry cyclicity in transferring variance from precession-scale insolation changes to the modulating eccentricity term. Autogenic processes in the fluvial system might have participated in “shredding” the precessional and semi-precessional signals. The alternative scenario is decoupled from high-latitude climate and would imply a muted climate sensitivity of the eastern equatorial Pangea to glaciation. The individual options cannot be evaluated with the Upper Silesian data alone, but offer testable hypotheses, potentially helpful in revealing the short-term structure of glaciation and climate teleconnections during the Late Paleozoic.

Palaeogenomic data from a Late Pleistocene coprolite clarifies the phylogenetic position of Sicilian cave hyena

Cave hyenas (genus Crocuta) were among the most representative large carnivorans of Eurasian ecosystems during the Middle-Late Pleistocene. They are close relatives of the extant African spotted hyenas, the only extant member of the genus Crocuta. However, the taxonomy of these forms is still debated. Using palaeogenetic and palaeogenomic evidence, previous studies suggested a complex evolutionary history between spotted and Eurasian cave hyenas. Up to now, no molecular data have been retrieved from their Mediterranean counterparts, leaving a gap in the understanding of population dynamics of the genus Crocuta. To investigate the relationships of the Sicilian hyena to other cave and extant spotted hyenas we obtained palaeogenomic data from a Late Pleistocene coprolite chronologically dated between 32 and 21 Ka. Surprisingly, we found that the Sicilian genome forms a basal lineage of cave hyena. Moreover, results show that the Sicilian cave hyena is less admixed with African spotted hyena than the German and Russian specimens are, thus rejecting any large scale gene flow from Africa to Sicily. Our findings show that the genetic structure of European cave hyenas was more complex than previously documented, and offers new insights into the phylogeny of the genus Crocuta.

Deep-seated gravity instability of the southern apron of the Ischia volcanic island (Tyrrhenian Sea, Italy)

Ischia Island is an active volcano representing the emerged sector of an E-W trending volcanic ridge largely extending undersea. Its collapsing behaviour, mainly in the form of fast-moving, terrestrial and submarine debris avalanches, has been recognized during the Holocene, but much less is known about previous gravity-driven processes. Using high-resolution multibeam bathymetric data and seismic reflection profiles, we provide evidence that the Island's southwestern flank has been involved in a slow-moving, deep-seated slope deformation that has displaced large volumes of its apron since the Late Pleistocene and until very recent or contemporary times. A long tongue of deformed seafloor, spreading up to 45 km from the Island over an area of 330 km2, between 500 and 1300 m water depths, has been detected along its southwestern slope. Different types of mass movements, genetically associated with each other, characterize this landslide: 1) a basal slump anticline, corresponding to a bulge on the bathymetry detaching at about 400 m sub-bottom depth; 2) an intermediate-mass movement chiefly consisting of debris avalanches and debris/turbiditic flows; 3) an upper mass movement consisting of hundred-metre size slumps detaching at relatively shallow depths. Conservative estimates indicate that at least 50 km3 of volcano-clastic and hemipelagic deposits have been mobilized, most of which comprise the basal slump anticline. This submarine landslide can be explained as a gravity failure of the continental slope unrelated to volcanism or rather as a process related to the dynamics of the volcanic edifice, which would imply volcano-spreading.

Ichnological analysis of glacially-influenced sediments from the late Pleistocene to Holocene on the southeastern Canadian margin: Implications for palaeoclimate and palaeoceanography

The study of trace fossils in glacially-influenced margins provides valuable insights into the changes in palaeoclimate and palaeoceanography during glacial-interglacial periods, by providing biological and ecological data of the benthic environment. Here we present a comprehensive ichnofabric characterisation of a sediment core located on an inter-canyon ridge on the SW Grand Banks Slope off Newfoundland, covering the Late Pleistocene–Holocene period (0–∼23 ka). The core analysis reveals 12 ichnogenera and an escape structure, with Phymatoderma, Tasselia, and Zoophycos being prominent and relatively abundant at specific levels. By examining the distribution of bioturbation content and degree along the core, we establish a strong association between moderate to high bioturbation and cold periods. The Last Glacial Maximum exhibits the highest abundance and diversity of trace fossils, particularly the deposit-feeding Phymatoderma and the deposit-feeding/equilibrium trace Tasselia, indicating benthic adaptation to seasonal food input and relatively high sedimentation rates. Conversely, the warmer deglaciation period shows limited bioturbation. Salinity stress may account for the abrupt decline in bioturbation degree during the early deglaciation. Additionally, the occurrence of large-sized Zoophycos coincides with the Younger Dryas cold event during the last deglaciation. These findings highlight the complexity of palaeoceanographic conditions and benthic environments in proximal glacially-influenced sites compared to distal hemipelagic and pelagic sites. The interplay between down-slope processes (such as turbidity currents and hyperpycnal flows) and along-slope processes (like contour currents) plays a crucial role in shaping the unique sedimentological regime of depositional sites and subsequently affecting the ichnofauna in glacially-influenced margins.