Pleistocene Deposits Research Articles

K-feldspar pIRIR150 dating of the Late Pleistocene sediments in the NW Khangai Mountains (Mongolia) using a standardized dose-response curve approach

K-feldspar luminescence dating has been widely applied to constrain the timing of Quaternary sedimentation in different environments. However, the measurements are time-consuming. Meanwhile, anomalous fading and partial bleaching are the two potential problems inducing dating uncertainty. In this study, sand-size K-feldspar grains extracted from 32 luminescence samples from the northern slope of the Khangai Mountains, Mongolia, were dated using the post-infrared (IR) infrared stimulated luminescence protocol (pIRIR150. subscript shows the second stimulation temperature). The standardized dose-response curves (sDRCs) for luminescence dating, which could improve the measurement efficiency, were constructed. The K-feldspar luminescence chronology has been established after careful investigations of fading correction and bleaching degree of the signals. The sDRCs and individual DRC yield consistent ages, indicating that sDRCs are applicable for luminescence dating with an improvement in measurement efficiency. The fading corrected ages using the two fading correction models are generally in agreement. Based on age comparisons between the radiocarbon dates, the fading corrected pIRIR150 and IR50 ages, the pIRIR150 signal was not fully bleached for several samples. In contrast, some IR50 ages were overestimated due to fading over-correction. The investigated profiles have documented the sedimentary information since the last deglaciation.

Tephrostratigraphy of Pleistocene-Holocene deposits from the Detroit Rise eastern slope (northwestern Pacific)

The main goal of the study is to establish the spatial and temporal distribution of pyroclastic material from large explosive eruptions of the volcanoes of Kamchatka, the Kuril, and Aleutian Islands to create a generalized tephrochronological model and reveal patterns of explosive activity in this region. This paper presents new data on the composition of volcanic ash (tephra) found in the Pleistocene deposits of the northwestern Pacific from the eastern slope of the Detroit Rise (northwestern part of the Imperial Ridge), 450–550 km east of the Kamchatka Peninsula. Eleven layers and lenses of tephra aged from 28 to 245 ka, which were previously unknown, were studied in the core Lv63-4-2. Their stratigraphic position and age were determined based on age models developed in this study. Based on the geochemical composition of volcanic glass (determined using an electron microprobe), seven layers were correlated with tephra from several cores in the northwestern Pacific and the Bering Sea. The obtained results supplement the information on large explosive eruptions of volcanoes in the region and their periods of activity. They also allow the development of a generalized tephrochronological model of Quaternary deposits, which is necessary for stratigraphic correlation, and of paleooceanological and paleogeographic reconstructions.

Carnivores from the late Pleistocene locality Melitzia Cave (Mani peninsula, Greece)

ABSTRACT Mani peninsula is considered an important region for the Palaeolithic research of Greece. A considerable number of sites have been excavated to date, containing deposits with cultural remains from the Middle Palaeolithic, the Upper Palaeolithic, and the Neolithic period. Melitzia Cave is a cave locality filled with Upper Pleistocene deposits, yielding in the upper stratigraphic units fossil remains of numerous large mammals and small vertebrates along with cultural remains, indicating that the cave was inhabited by both humans and carnivores. The layers date to the Upper Pleistocene, and more specifically between 46,448–44,553 BP and 11,150–10,680 BP. The present study focuses on the recovered carnivore assemblage of Melitzia Cave, which has revealed the presence of Crocuta spelaea, Vulpes vulpes, Felis silvestris, Meles meles, Mustela nivalis, Martes sp., ?Ursus sp., and Carnivora indet., described in detail herein. This species composition is typical for the late Pleistocene of Southeastern Europe.

Unsteady topography in the eastern Tianshan due to imbalance between denudation and crustal thickening

The Tianshan mountains have complex and variable topography and documenting their growth is important for understanding both intracontinental mountain building and the evolution of the global climate. We investigate whether this topography is in equilibrium with crustal influx (thickening) and sediment outflux (denudation). Based on literature, we estimate that the eastern Tianshan has been subject to a total crustal shortening rate of ∼9.4 mm/a across the Kuitun–Kuche transect, implying ∼1.3 mm/a of crustal thickening and a total crustal influx of ∼9 × 107 m3/a. We measured in-situ cosmogenic 10Be concentrations in modern river sands of 34 catchments to constrain recent (0–6 ka) basin-averaged denudation rates within the range and on its two flanks. Denudation rates range from 0.020 ± 0.002 to 0.53 ± 0.07 mm/a, averaging 0.20 ± 0.04 and 0.11 ± 0.02 mm/a in the north and south, respectively; these rates correspond to respective total sediment outfluxes of (542 ± 69) × 104 and (164 ± 24) × 104 m3/a. To ensure that these values can be compared to Pleistocene tectonic rates, we reconstructed Pleistocene denudation rates in seven of the studied basins. For this, we determined inherited in-situ cosmogenic 10Be concentrations from 11 cosmogenic depth profiles of abandoned fluvial terraces deposited in the Tianshan piedmonts. These data indicate that denudation rates have been relatively steady since the Pleistocene and thus that recent and Pleistocene sediment fluxes can be compared. These results show that crustal thickening outpaced denudation and sediment outflux by a factor of ∼10. Therefore, the Tianshan topography is not in dynamic equilibrium and is growing, even if materials are being subducted into the mantle. Consequently, to sustain this disequilibrium, the range grew laterally. This lateral growth and the inheritance of structures and basins are likely responsible for the complex topography of the range.

Application of Probabilistic Seismic Hazard Assessment to Understand the Earthquake Hazard in Attock City, Pakistan: A Step towards Linking Hazards and Sustainability

Within the last three decades, twelve major earthquakes (Mw > 6.0) have jolted Pakistan and contributed to a heavy death toll and an economic loss of billions of dollars, which is immense for any underdeveloped country. Despite the generalized description of seismic hazards in various regions of Pakistan, densely populated cities still require a detailed and integrated vulnerability analysis to overcome the impact of a significant earthquake. This study aims to integrate seismic hazard assessment schemes to understand the vulnerability of Attock city against an earthquake. It initially evaluates the threat from an earthquake due to tectonic activity in the region, splits the region (about 200 km radius) into six seismic zones and uses area source parameters. The ground motion prediction equations compatible with the study area’s seismotectonic environment are also used in this study. Peak horizontal ground acceleration (PGA) and 5% damped spectral acceleration are critical features of ground motions. The site classification is carried within Attock city, indicating the presence of SB (foundation condition with Vs30 = 760 m/s), SC (foundation condition with Vs30 = 400 m/s) and SD (foundation condition with Vs30 = 300 m/s). The peak ground accelerations for a return period of 475 years at the SB, SC and SD sites are estimated as 0.23 g, 0.28 g and 0.30 g, respectively. Uniform hazard spectra are obtained for each site classification at three return periods (475, 975 and 2475 years). Another possible threat can be the local site conditions of the study area, as Attock city exists on the unlithified sediments of upper Pleistocene to Recent alluvial deposits. That is why microtremor recordings are conducted at 20 sites within Attock city to understand the fundamental frequency (f0), horizontal to vertical spectral amplitude (A0) and Kg parameter, a seismic vulnerability index. The values of f0 are found between 0.6 and 9 Hz and A0 is observed between 2.1 and 5 Hz, whereas the Kg is estimated between 0.24 and 20 Hz. Despite evidence of the seismic vulnerability of Attock city, the current building designs and infrastructure development are not synchronized with the uniform hazard response spectra and the soil amplification, thus enhancing the exposure of the study area to disaster during a major earthquake. This study will be instrumental in pre-disaster mitigation strategies for urban planners and policymakers.

The Final Early Paleolithic of Azerbaijan (Based on the Garaja Site)

We descriЬe new findings relating to an Early Paleolithic site of Garaja on the Mingachevir Reservoir coast, Azerbaijan. Geological and geomorphological position of the area, structure of the Early–Middle Pleistocene deposits, faunal remains, and chronology are discussed. On the basis of geological characteristics and paleofauna (large mammals, mollusks) we tentatively date the site to the Bakunian age (0.8–0.4 Ma years ago). Artifacts, some 350 in number, found mainly on the surface, but reliably associated with lithological units, are described in detail. Primary reduction is dominated Ьy parallel fiaking, with occasional radial and "citron" cleavage. Most tools, made on peЬЬles and large fiakes, are large (handaxes, choppers, and side-scrapers). While the Garaja industry is generally homogeneous, the stratigraphic situation of the site and certain elements of technocomplex, such as solitary Levallois cores, a Quina scraper, and advanced forms of bifaces, indicate the presence of two chronologically and technologically successive complexes within the general Late Acheulean industrial tradition. Garaja correlates with other cave and open-air industries of the East and South Caucasus and adjoining regions dating to the first half of the Middle Pleistocene.

New Data on the Distribution of Southern Forests for the West Siberian Plain during the Late Pleistocene: A Paleoentomological Approach

Subfossil remains of insects and branchiopod crustaceans (Cladocera and Notostraca) found in three late Pleistocene deposits in the Novosibirsk region in the vicinity of the village of Suzun have been described. The calibrated radiocarbon dates for these deposits were 24,893–25,966 cal BP (Suzun-1), 20,379–20,699 cal BP (Suzun-2), and 27,693–28,126 cal BP (Nizhny Suzun), which correspond to the onset of marine isotope stage 2 (MIS 2). The insect assemblages of these deposits are mainly represented by Coleoptera, which are noteworthy for high taxonomic and ecological diversity. At least 194 beetle species from 21 families have been found altogether. Of them, 74 species were found in the Pleistocene deposits of Western Siberia for the first time. All deposits were similar in species composition of beetles; Carabidae and Curculionidae prevailed everywhere. The ecological composition was dominated by steppe and tundra-steppe species; aquatic and riparian groups were also well represented. The Cladoceran and notostracan taxa revealed in Suzun-1 and Suzun-2 are characteristic of recent steppes rather than the forest zone of Western Siberia. The studied entomocomplexes are congruent with the periglacial “Otiorhynchus-type” fauna that inhabited the southern part of the West Siberian Plain at the end of the Pleistocene and had no close contemporary analogues. Cold and dry conditions, as well as the prevailing open landscapes of the tundra-steppe type, were the reconstructed conditions for this fauna. At the same time, the Suzun-1 and Suzun-2 entomocomplexes had a distinctive feature, namely a high proportion of forest species associated with both coniferous and deciduous trees. According to these data, at the beginning of MIS 2 in the Upper Ob region, spruce forests with the participation of small-leaved species (birch) were present. They were probably confined to river valleys and were not widely distributed.

Geochemistry of Holocene–Late Pleistocene sediments in the Berezovka River valley (Near-Yenisey Siberia)

Despite their great importance, Holocene–Late Pleistocene sediments are poorly studied in the valleys of rivers in the Krasnoyarsk forest-steppe territory. We present the first detailed study of the geochemical composition of the first floodplain terrace sediments in the valley of the Berezovka River, and the continuous accumulation that occurred at the Late Pleistocene-Holocene (from 20833 ± 519 cal yr BP). This is of great fundamental importance and is the basis for further studies on the influence of anthropogenic activities on the natural environment in the Krasnoyarsk agglomeration. The sediments were covered by modern alluvial dark-humus hydrometamorphosed soil. Macromorphological studies and investigation of the humus content have revealed a well-developed process of humus formation and humus accumulation, a gley process. The measured contents of some elements (U, Pr, Rb, V, Bi, Cd, As, Th, Ga, Co, and Sm) exceeded the respective Clarke values for the Earth’s crust. The distribution of most elements and their accumulation in the Middle-Late Holocene (from to 5477–4985 to 1241–803 cal yr BP) in the middle of the sediment profile is explained by the high content of mud and clay minerals. Based on the coefficients of radial migration, we established that most of the studied elements were introduced into the sediments during high water levels and floods. The values of palaeomarkers indicate a change in climatic conditions in the Late Pleistocene and Holocene from dry and cold to more humid and warm, and from arid and cold (in the Early Holocene) to modern climatic conditions, respectively.

Chemical Composition of Sediments and Its Changes in the Center of the Modern Hydrothermal System in the Middle Valley of the Oceanic Ridge Juan de Fuca, Hole 858B ODP

The article presents the results of a study of changes in the chemical composition of Pleistocene sediments from Hole 858B, 38.6 m deep with a temperature gradient of 10‒11°C/m, drilled in the Middle Valley of the Juan de Fuca oceanic ridge (Northeast Pacific) in the “Dead Dog” hydrothermal field, in 20 m from “black smoker” with a temperature of 276°C. The content of petrogenic elements in these sediments was studied by XRD. For the first time, data on a large set of trace elements were obtained for this object using the ICP MS method. The change in the chemical composition of sediments occurred in the process of solution-rock interaction under conditions of a rapid increase in temperature downwards the section. In the Unit I, in its upper part (1.97‒10.41 m), the sediments are slightly altered at a temperature of about 17°C. In the lower part of the Unit I (12.70‒25.31 m) under conditions of average temperature (112‒197°C), the change in the content of petrogenic elements and trace elements is well pronounced. The chemical composition of the sediments of the Unit IIB and the Unit IID (25.31‒38.6 m) is most strongly changed in the temperature range from 112‒197°С to 320‒330°С. Changes in the content for most macroelements and trace elements in the sediments of Unit IIB and Unit IID are similar, with the difference that the decrease in the content of chemical elements is more pronounced in the sediments of the Unit IID. In them, the content of Cu, Zn, Ga, Rb, Sr, Ag, Cd, Sb, Cs, Ba, Tl, Bi, except for U, is significantly lower than in background sediments. The sediments of the the IID, as well as the sediments of the Unit IIB, contain less Ca, Na, K, P and more Mg. A lower content of chemical in these sediments can be considered as their removal from sediments under the process of solution-sediments interaction and enrichment of the solution with them, and their higher content, as its introduction into sediments from solution and, accordingly, depletion of these chemical elements in the solution. The results of studying the chemical composition of metalliferous sediments (Unit III, 0‒1.97 m) and sulfide layer IV (10.41‒12.70 m), as well as the chemical composition of unaltered background sediments from Holes 855A, C, D are presented.

The influence of subsurface architecture on scour hole formation in the Rhine–Meuse delta, the Netherlands

Abstract Scour holes are common features in deltaic rivers which can destabilise embankments through oversteepening of the river bed. Their development has been studied extensively from the hydraulic perspective, but another important control is the erodibility of the river bed which varies considerably due to thickening of heterogeneous deltaic substrate towards the coast. Therefore, we assessed the influence of delta-scale geological heterogeneity and local subsurface architecture on scour hole formation in addition to the hydrodynamic controls. We (1) created an inventory of 165 scour hole locations in the Rhine–Meuse delta, (2) assessed the hydrodynamic conditions at the locations, (3) extracted geometric characteristics and (4) determined the subsurface architecture from geological data. Central and lower delta branches have 0.6–0.7 scours per km while upper delta branches have less than 0.2. Downstream, 58% of scour holes were related to architectural elements, notably sand bodies from former Holocene channel belts and Early Holocene cohesive beds. These scours have steeper slopes due to higher proportions of cohesive sediments near the river bed. Furthermore, scours related to channel belt sand bodies are limited in downstream length and depth, up to maximum of approximately two times the water depth. From our results, we provide a delta-scale explanatory framework that relates the position of present-day river channels with respect to Pleistocene river deposits and Holocene fluvio-deltaic deposits to scour hole formation. Upstream rivers are incised in Pleistocene deposits showing less local variation in erodibility. The majority of scour holes here relate to engineering works. In central and lower delta branches, geologically inherited heterogeneity of the Holocene substrate at critical depths near the channel bottom adds to anthropogenic induced scours and results in high abundances. This demonstrates that downstream variation in subsurface architecture should be considered as a key control on scour locations and characteristics for management purposes.

EARLY PLEISTOCENE SEROTINE BAT <i>EPTESICUS PRAEGLACIALIS</i> (VESPERTILIONIDAE, CHIROPTERA) FROM THE TAURIDA CAVE IN CRIMEA

The cranial and mandibular remains of a large serotine bat Eptesicus praeglacialis Kormos, 1930 are described from the Lower Pleistocene deposits of the Taurida cave in the central Crimea. This is the first finding of the skull material of E. praeglacialis and the first record of the species in Crimea. Judging by the tooth wear stages, the remains of both young and adult specimens are present in the taphocenosis. The small mammal tooth marks on the bones (caused by eating the remnants of soft tissues) in the absence of signs of digestion, characterizing materials from the predatory bird pellets, indicate that the taphocenosis includes the remains of E. praeglacialis individuals that used the cave as a shelter and died there. This corresponds to the idea of appearance of hibernation in caves as a climatically determined ecological adaptation in some European forest-dwelling bats (including Eptesicus) at the Pliocene–Pleistocene transition.

UNA NUEVA ESPECIE DE LUTREOLINA THOMAS, 1910 (MARSUPIALIA, DIDELPHIDAE) DEL PLEISTOCENO TEMPRANO DE LA PAMPA AUSTRAL (PROVINCIA DE BUENOS AIRES, ARGENTINA)

We describe Lutreolina tonnii sp. nov. (Mammalia, Metatheria, Marsupialia, Didelphimorphia, Didelphidae), recovered from Early (or Early–Middle) Pleistocene deposits of the coastal cliffs near Necochea City in Buenos Aires Province, Argentina. Its holotype, a right maxillary with M1-3, indicates that it belongs to the largest species of the genus, including extinct and extant species. It also differs from other species of the genus in having more anteroposteriorly compressed protocones in the upper molars. It differs from the living species in that the maxillary-jugal contact is less horizontal in its posterior two-thirds, has a deeper ectoflexus in M3, and has a shallow but distinct internal (lingual) crest linking the bases of stylar cusps B and D in M1-3. The new species is the fourth known up to now for the South American record, and the third for the Plio–Pleistocene of the Pampean Region, thus suggesting a considerable diversity for this genus in mid-latitudes of this continent by the end of the Cenozoic Era.

Natural geochemical hazard as a pseudo-component of negative environmental impact of mining complexes

The paper presents the authors’ research findings that enable to avoid unreasonable charges for negative environmental impact by applying mathematical statistics and GIS technology, modern methods of geochemical sample data processing, as well as by analysis of the dynamics of engineering-geological phenomena in the mining complexes areas. The authors’ data on the manifestation of high concentrations of toxic elements in some landscape components on the territory of mining complexes are provided. The latter, according to the authors, are associated with the outcrop of molybdenum ore occurrences, which were previously blocked by thin Pleistocene deposits. Then, due to sloughing of these deposits, molybdenum compounds began penetrating to the environment components.

Particle size distribution: An experimental study using southern African reduction methods and raw materials.

We experimentally created a particle size dataset that is based on reduction sequences and raw materials typical of the Middle and Later Stone Age in southern Africa. The reason for creating this new dataset is that current particle size frameworks are based, almost exclusively, on flint and western European knapping methods. We produced the dataset using knapping methods and raw materials frequently encountered in the southern African archaeological record because we wanted to test whether it has the same distribution as particle size datasets experimentally created in Europe, and to initialise the production of a database for use in the analysis of lithic assemblages from southern African Late Pleistocene deposits. We reduced 117 cores of quartz, quartzite, jasper, chalcedony, hornfels, and rhyolite. The knapping methods selected were unidirectional, discoidal, Levallois recurrent and bipolar flaking. In this article we compare this new particle size distribution dataset with the results obtained from previous experiments. We found that the southern African dataset shows a wider size range distribution, which seems to be explained by differences in knapping methods and raw materials. Our results show that there is overlap between the distribution of the southern African experimental knapping dataset and the sorting experiment conducted by Lenoble on flint artefacts in a runoff context. This article shows that a particle size analysis is not sufficient on its own to assess the perturbation of an archaeological assemblage and must be coupled with other analytical tools.

Развитие культуры денисовского человека на Алтае

The cultural and chronological stratum of the Pleistocene deposits in Denisova Cave, Altai, is the most complete and lengthy in North and Central Asia today. The comprehensive research of the stone and bone industries in the Paleolithic cave layers helped to trace the process of local development of the most antique Altai’s people, who lived 300,000 to 30,000 years ago. The layer-by-layer analysis of stone artifacts helped to identify the stages of material culture of the-then cave dwellers. The most ancient archaeological site in the bottom of the Pleistocene stratum formed ca. 300,000-150,000 years ago is classified as Early Middle Paleolithic. The subsequent development of the Middle Paleolithic traditions is reflected by the discoveries from the layers that formed 150,000-50,000 years ago. According to archaeological, paleoanthropological and paleogenetic data, the development of the Middle Paleolithic site of the cave is associated mostly with the Denisovans. The deposits of the Early Upper Paleolithic uncovered bone remains of only that population. Bone needles with eyes, sets of personal jewelry and symbolic artifacts in the cultural and chronological stratum of Denisova Cave dating back to the period 50,000 years ago all testify that one of the earliest Upper Paleolithic cultures in Eurasia was formed in Altai.

Insights into U-Th-Pb mobility during diagenesis from laser ablation U-Pb dating of apatite fossils

We studied the feasibility of using laser ablation inductively coupled plasma mass spectrometry (LA–ICPMS) for U-Pb dating of vertebrate and invertebrate apatite fossils. Two specimens of Carcharodon Carcharias from Pleistocene (2.58–0.01 Ma) sediments in Baja California peninsula, Mexico, give Gelasian ages of 2.0 ± 0.4 Ma and 2.0 ± 0.6 Ma which are consistent with the palaeontologic record reported for this species suggesting that the U-Pb system in the shark teeth remained closed until the present. Dentine data from an Oligocene (33.9–23.0 Ma) shark tooth, Otodus angustidens, from El Cien Formation, Mexico, give an anomalously young age of 19 ± 0.2 Ma with a low 207Pb/206Pb value of 0.65. This age is largely controlled by a sub-population of anomalously radiogenic data with low concentrations of U and Pb suggesting remobilization of Pb from high to low U domains. Regressing relatively non-radiogenic data from high U and Pb domains using a fixed average crustal value for initial common 207Pb/206Pb gives an age of 28.6 ± 0.2 Ma, which agrees with U-Pb zircon ages from tuff horizons in the sequence. Enamel from the same shark tooth is much lower in U and Pb and shows evidence for substantial mixing with radiogenic Pb from the dentine. Apatite shells from a brachiopod specimen, Lingula cobourgensis, and conodont fossils contain high U concentrations and significant proportions of radiogenic Pb. Some conodont specimens show high Th/U ratios combined with evidence of significant excess 206Pb. The amount of excess 206Pb requires a minimum Th partition coefficient of about 16,000 and likely much higher suggesting enrichment by ion exchange rather than recrystallization. In some cases conodonts with low Th/U can be precisely dated. A specimen of I. simulator gives an age of 302 ± 4 Ma which is consistent with its well constrained Gzhelian range (303.7–298.9 Ma). We conclude that processing LA–ICPMS data at the single cycle level allows more precise absolute dating of fossils. In some cases, separate regression of totally reset and partially reset domains can resolve ages of early and late diagenesis.

Ain’t no mountain high enough? New records of Notiomastodon platensis (Mammalia, Proboscidea) from Colombia and the Quaternary dry corridor of the Cauca valley

ABSTRACT In this study, we present new records of the extinct South American proboscidean Notiomastodon platensis from three new fossiliferous sites in the riverbed of Cauca River, in the department of Valle del Cauca, Colombia. The fossil specimens were found in late Pleistocene deposits and include immature to senile Notiomastodon platensis individuals, comprising abundant dental and post-cranial materials. A review of the geographic distribution of the Notiomastodon platensis records in Colombia suggests that this giant mammal used the inter-Andean valleys as migratory corridors, possibly due to the presence of more suitable environmental conditions (lower temperatures and dry-forest) and energy-saving terrains, avoiding more prominent Andean hills. In addition, the Cauca Valley deposits stand out as having palaeontological significance to the comprehension of the late Pleistocene of the western region of South America.

Sedimentary facies and clay mineralogy of the late Pleistocene Landsort Deep sediments, Baltic Sea — Implications for the Baltic Ice Lake development

ABSTRACT The Landsort Deep is the deepest part of the Baltic Sea and contains an excellent high-resolution late Pleistocene sediment record suitable to study the retreat history of the southern margin of the Fennoscandian Ice Sheet and the development of the ice-marginal Baltic Ice Lake (BIL) from ~13.5 to 10.5 ka BP. The studied cores are from the lithostratigraphic Units V and VI of Hole M0063C that were recovered during the Integrated Ocean Drilling Program (IODP) Expedition 347. The subdivision and interpretation of the studied BIL record are based on the identification of seven distinct sedimentary facies, grain size characteristics, detrital clay minerals, water and carbon content, and physical properties. The ice-rafted debris (IRD) in the lowermost part of Unit VI indicates a proximal glaciolacustrine environment. The onset of the Fennoscandian Ice Sheet deglaciation during the warm Bølling/Allerød interstadial caused a rise of the proglacial lake water level and the transition from ice-proximal (IRD-containing sediments) to ice-distal varved sediments (rhythmically laminated silty clays) detected within the middle part of Unit VI. This depositional unit of constant sedimentation was followed by the first drainage event of the BIL, which led to the deposition of a distinct clay-rich interval representing erosion and redeposition of the emerged lake bottom sediments. The reduced grain size of the overlying sediments is associated to the onset of cooler climate conditions and a possible ice sheet readvance during the Younger Dryas that resulted in a decrease of meltwater release and sediment availability. The higher sand content and kaolinite peak are associated to a rapid ice retreat and the release of abundant sediment laden meltwater plumes at the end of the Younger Dryas. The final drainage of the BIL enabled the erosion of coastal clay sediments, and the termination of the ice lake stage led to enhanced clay sedimentation to the Landsort Deep.

Revised age and stratigraphy of the classic Homo erectus-bearing succession at Trinil (Java, Indonesia)

Obtaining accurate age control for fossils found on Java (Indonesia) has been and remains challenging due to geochronologic and stratigraphic uncertainties. In the 1890s, Dubois excavated numerous faunal fossils—including the first remains of Homo erectus—in sediments exposed along the Solo River at Trinil. Since then, various, and often contradictory age estimates have been proposed for the Trinil site and its fossils. However, the age of the fossil-bearing layers and the fossil assemblage remains inconclusive. This study constructs a chronostratigraphic framework for the Trinil site by documenting new stratigraphic sections and test pits, and by applying 40Ar/39Ar, paleomagnetic, and luminescence (pIRIR290) dating methods. Our study identifies two distinct, highly fossiliferous channel fills at the Trinil site. The stratigraphically lower Bone-Bearing Channel 1 (BBC-1) dates to 830–773 ka, while Bone-Bearing Channel 2 (BBC-2) is substantially younger with a maximum age of 450 ± 110 ka and an inferred minimum age of 430 ± 50 ka. Furthermore, significantly younger T2 terrace deposits are present at similar low elevations as BBC-1 and BBC-2. Our results demonstrate the presence of Early and Middle Pleistocene, and potentially even late Middle to Late Pleistocene fossiliferous sediments within the historical excavation area, suggesting that Dubois excavated fossils from at least three highly fossiliferous units with different ages. Moreover, evidence for reworking suggests that material found in the fossil-rich strata may originate from older deposits, introducing an additional source of temporal heterogeneity in the Trinil fossil assemblage. This challenges the current assumption that the Trinil H.K. fauna –which includes Homo erectus-is a homogeneous biostratigraphic unit. Furthermore, this scenario might explain why the Trinil skullcap collected by Dubois is tentatively grouped with Homo erectus fossils from Early Pleistocene sediments at Sangiran, while Trinil Femur I shares affinities with hominin fossils of Late Pleistocene age.

First record of a fossil coral (Anthozoa) from Pleistocene deposits at Terra Ceia, North Carolina

A fossil coral of the genus Solenastrea Milne Edwards & Haime (Anthozoa: Scleractinia: Faviidae) is reported from Pleistocene deposits exposed near the town of Terra Ceia in Beaufort County, North Carolina. The specimen is similar in gross and corallite morphology to Solenastrea hyades (Dana) which is common in Neogene and Quaternary sediments of North Carolina, but has been altered by vadose diagenesis, making confident assignment to species challenging. The specimen is the first coral recovered from the Terra Ceia locality which has, up to now, yielded only mollusks.