Late Pleistocene Sequence Research Articles

СLIMATIC AND PHYTOCENOTIC EVENTS OF THE LATE PLEISTOCENE (MIS 5-MIS 3) AT THE SOUTHEASTERN COAST OF THE GULF OF FINLAND

The paper analyses a debatable issue concerning the ranking of climatic-stratigraphic units within two marine isotope stages (MIS) - MIS 5 and MIS 4. Palynological records from the Mikulino interglacial sections of the northwestern Russian Plain which are most critical for correlations are reviewed. A representative series of numerical dates obtained by the IR-OSL method, and detailed palynological records enabled a detailed climatic-chronostratigraphic division of the Late Pleistocene sequence of the Voka reference section on the southeastern coast of the Gulf of Finland. The representative palynological spectra provide strong evidence of a warm interval of interglacial rank in the latter half of MIS 5, corresponding to the standard M6, M7, and M8 Mikulino palynozones. Additionally, they highlight a period of significant cooling during MIS 4, characterized by the dominance of periglacial vegetation formations in the study area. This challenges the viewpoint of the extensive Kalinin glaciation during that time, believed to have spread many hundreds of kilometers south of the Gulf of Finland. Data for MIS 3 reveal a two-fold alternation of interstadial and stadial (periglacial) climate intervals during the period between 39 ka and 33 ka.For the first time, detailed reconstructions and datings of climate-phytocenotic successions of paleoclimatic events approximately between 100 ka and 30 ka have been provided for the territory of the East European Plain (and Northern Eurasia as a whole). These events correspond to the latter half of MIS 5, MIS 4, and an interval between 39 ka and 33 ka during MIS 3.

Late Middle Pleistocene sequences in the lower Ob’ and Irtysh (West Siberia) and new multi-proxy records of terrestrial environmental change

The Middle Pleistocene environmental history of the north of West Siberia is very incomplete. Only a few poorly preserved paleoarchives are known so far in this huge part of Eurasia encompassing up to one million square kilometers. Here we present new data (micromammals, insects, plant macrofossils and luminescence dating) from the lower reaches of the Ob’ and Irtysh Rivers. We reconstruct the circumstances of the formation of the fossil-bearing sites Bolshaya Ob 440 km – Khashgort (BOB440) and Gornopravdinsk 2 (GP2) and compare the results with the current state of knowledge of the environmental change in this area. The combined evidence suggests that the fossil-bearing unit known as the Khashgort diagonal sands at BOB440 yields 1) a late Middle Pleistocene complex of fauna and flora of a cold terrestrial environment with tundra-like vegetation, 2) a Middle Pleistocene flora of interglacial environment with temperate vegetation, and 3) reworked fossils form the Late Cretaceous – Oligocene. Geochronometric data suggest that the Khashgort sand unit at BOB440 might have been formed during the Middle/Late Pleistocene transition. However, because of a high variation in results obtained on repeated samples from the same strata, some uncertainty of the luminescence dating remains, which requires further verification. The fossil-bearing fluvial sequence at GP2 represents the lower part of the Chembakchino Formation and encompasses the lower part of the Tobolian Horizon (correlated with Holsteinian). The micromammal complex comprises Dicrostonyx simplicior (intermediate morphological stage S2 sensu Smirnov et al., 1997), Lasiopodomys gregalis, Microtus nivaloides lidiae and other taxa, which are characteristic of the early evolutionary stage of late Middle Pleistocene faunas in the north of West Siberia. The paleoecological analysis of plant and animal remains at GP2 suggests an environmental change from cold, tundra-like landscapes at the Shaitanian/Tobolian transition (MIS 12 – MIS 11) to non-analogous open patchy landscapes with highly productive moss and herbaceous vegetation during the early Tobolian time.

A late Middle Pleistocene Middle Stone Age sequence identified at Wadi Lazalim in southern Tunisia

The late Middle Pleistocene, starting at around 300 ka, witnessed large-scale biological and cultural dynamics in hominin evolution across Africa including the onset of the Middle Stone Age that is closely associated with the evolution of our species—Homo sapiens. However, archaeological and geochronological data of its earliest appearance are scarce. Here we report on the late Middle Pleistocene sequence of Wadi Lazalim, in the Sahara of Southern Tunisia, which has yielded evidence for human occupations bracketed between ca. 300–130 ka. Wadi Lazalim contributes valuable information on the spread of early MSA technocomplexes across North Africa, that likely were an expression of large-scale diffusion processes.

Onthophagus pilauco sp. nov. (Coleoptera, Scarabaeidae): evidence of beetle extinction in the Pleistocene-Holocene transition in Chilean Northern Patagonia.

The South American Pleistocene–Holocene transition has been characterized by drastic climatic and diversity changes. These rapid changes induced one of the largest and most recent extinctions in the megafauna at the continental scale. However, examples of the extinction of small animals (e.g., insects) are scarce, and the underlying causes of the extinction have been little studied. In this work, a new extinct dung beetle species is described from a late Pleistocene sequence (~15.2 k cal yr BP) at the paleoarcheological site Pilauco, Chilean Northern Patagonia. Based on morphological characters, this fossil is considered to belong to the genus Onthophagus Latreille, 1802 and named Onthophagus pilaucosp. nov. We carried out a comprehensive revision of related groups, and we analyzed the possible mechanism of diversification and extinction of this new species. We hypothesize that Onthophagus pilaucosp. nov. diversified as a member of the osculatii species-complex following migration processes related to the Great American Biotic Interchange (~3 Ma). The extinction of O. pilaucosp. nov. may be related to massive defaunation and climatic changes recorded in the Plesitocene-Holocene transition (12.8 k cal yr BP). This finding is the first record of this genus in Chile, and provides new evidence to support the collateral-extinction hypothesis related to the defaunation.

Facies analysis and environmental interpretation of a late Pleistocene coastal lagoon sedimentary sequence containing a Coprinisphaera-bearing terrestrial episode (Kisimayo, southern Somalia)

For the first time, we here report trace fossils of dung beetle brood balls (Coprinisphaera ichnogenus) in late Pleistocene sediments from Somalia. The sediments containing these traces represent a lagoonal sedimentary sequence, cropping out along some quarry walls in the outskirts of the Kisimayo town. The terrestrial ichnofossils are accompanied by some shells of the giant land snail Achatina, which confirms the subaerial exposure. Indeed, the rock, generally strongly weathered, shows a texture of a foraminiferal packstone-grainstone, rich in bivalve and gastropod molds, of marine origin. The related facies stack is indicative of a period of environmental changes, which took place in a sheltered shallow water coastal area of a tropical carbonate shelf. For a short time, due to a slight lowering in sea-level, this lagoonal area experienced subaerial conditions with accumulation of wave- and wind-driven marine sand in a backshore zone, so allowing the development of environmental conditions suitable for the appearance of terrestrial trace fossils and Achatina. The discovery of Coprinisphaera represents one of the rare African records of the ichnogenus; it is also a unique example for the Indian Ocean’s African coast of a terrestrial episode being found within a lagoonal sequence.

Nota sobre la taxonomía de <em>Microtus</em> (Iberomys) (Arvicolinae, Rodentia) del Pleistoceno superior de la Gruta do Caldeirão (Tomar, Portugal) e interpretación paleoclimática de la asociación de roedores

Gruta do Caldeirão es un yacimiento arqueológico en cueva situado en Tomar (Portugal, oeste de la península Ibérica), que contiene una importante secuencia perteneciente al Pleistoceno superior, adscrita culturalmente al Paleolítico medio (Musteriense) y Paleolítico superior (Solutrense-Magdaleniense), que incluye industria lítica, restos humanos y restos de grandes y pequeños vertebrados. La revisión e interpretación de la asociación de roedores de la secuencia, previamente publicada en los años 90 del siglo pasado, nos ha permitido remarcar tres importantes conclusiones: 1) la única especie del subgénero Iberomys presente en la secuencia es la espe­cie endémica actual de topillo Microtus (Iberomys) cabrerae (topillo de Cabrera); 2) la asociación de roedores está dominada en toda la secuencia por especies relacionadas con bosques abiertos, como el ratón de campo (Apodemus sylvaticus) y especies relacionadas con espacios abiertos-húmedos como los topillos mediterráneo y lusitánico (Microtus (Terricola) spp.), remarcando la presencia de un hámster extinto (Allocricetus bursae) en el nivel K y tres especies de topillos que no tienen representación actual en la zona circundante a la cavidad (Microtus arvalis - topillo campesino, Microtus agrestis – topillo agreste y Chionomys nivalis - topillo nival); 3) Finalmente, el método del Modelo Bioclimático, aplicado a la asociación de roedores, otorga resultados acordes con que la ocupaciones solutrenses situadas entre los niveles H y Fa están relacionadas con un periodo frío equi­parado con el Último Máximo Glacial (LGM), indicado por las dataciones de radiocarbono y anteriores estudios de susceptibilidad magnética de la secuencia.

Radiocarbon dated malacological records of two Late Pleistocene loess-paleosol sequences from SW-Hungary: Paleoecological inferences

The two loess-paleosol sequences of Villánykövesd and Máza preserved specific paleoecological information of the Late Pleistocene environmental conditions in SW-Hungary. For malacological examinations, sampling of 12 cm intervals were used; homogenous amounts of sediment (ca. 5 kg) were collected. During the malacological examinations, more than 27,000 specimens were identified. Interpreting their environmental and climatic demands the paleoclimate and paleoenvironment of the last 80,000 years could be reconstructed. The results of the malacological investigations of Villánykövesd sequence indicated 5 malacological zones (MZs) by the snail species’ dominant occurrence. All of the 5 MZs indicate mild climatic conditions with only one cooling phase. The mild climatic conditions were reconstructed by the high dominance of thermophilous species, especially Pupilla triplicata. This warmth loving, xerophilous and open vegetation preferring species is present in the entire sequence, which indicates a refuge area of P. triplicata around Villánykövesd. At the Máza sequence, 9 MZs could be allocated with mainly dominance of cold resistant species, indicating cooler climatic conditions than at Villánykövesd. The reason of the high ratio of cold resistant species and the high number of MZs could be the geographic exposition of the Máza sequence. The Máza sequence is located in a bench between higher and lower reliefs on the northern pediment area of Mecsek Mountains. This indicates the presence of a fluctuation zone for the snail species in the area of Máza sequence. The Late Pleistocene sequences possess different climatic and environmental conditions during same timeframe, therefore we highlight that the previously reconstructed mosaic-like environmental patters in the Carpathian Basin are real properties in the region.

Seismic stratigraphic reconstruction of late Pleistocene lowstand wedges on the shelf margin and trough region of the Korea Strait: a review

This paper is a review of stratigraphic architectures and evolution history of late Pleistocene lowstand deposits on the outer shelf of Korea Strait. Located between the southeastern tip of the Korean Peninsula and the Tsushima Island, the Korea Strait is a seaway connecting the East Sea with the East China Sea. Detailed analysis of high-resolution seismic profiles and sediment data give a good evidence for the existence of three superimposed wedge-shaped sedimentary units that thicken seaward. The individual sedimentary wedges are characterized by seaward dipping and complex sigmoid-oblique prograding reflection configurations with some chaotic or hummocky reflectors. On the basis of distribution and external geometry, these sedimentary wedges are interpreted as a “shelf-margin or shelf-edge delta”, mainly related to falling and lowstand sea level. Occurrence of this delta type is a common constitute of the Quaternary shelf in the Korea Strait. Although the entire units have not been fully dated, it is believed that these wedges were deposited during late Pleistocene sea-level lowstands. Repeated falls and lowstands of sea level (isotopic stages 8, 6 and 2/4) resulted in the formation of lowstand prograding wedges along the present shelf margin and trough region, having been separated from the inner shelf deposits. During subsequent episodes of sea-level rise (isotopic stages 8/7, 6/5, and 2/1), the upper part of sedimentary wedges was eroded, and thin covered by thin transgressive sands. Consequently, the late Pleistocene sequences on the shelf margin and trough region in this area mainly consist of a succession of stacked lowstand prograding wedges formed during the regression and lowstand of sea level.

Late Pleistocene sequence architecture on the geostrophic current-dominated southwest margin of the Ulleung Basin, East Sea

High-resolution multichannel seismic data were collected to identify depositional sequences on the southwestern shelf of the Ulleung Basin, where a unidirectional ocean current is dominant at water depths exceeding 130 m. Four aggradational stratigraphic sequences with a 100,000-year cycle were recognized since marine isotope stage (MIS) 10. These sequences consist only of lowstand systems tracts (LSTs) and falling-stage systems tracts (FSSTs). Prograding wedge-shaped deposits are present in the LSTs near the shelf break. Oblique progradational clinoforms of forced regressive deposits are present in the FSSTs on the outer continental shelf. Each FSST has non-uniform forced regressional stratal geometries, reflecting that the origins of sediments in each depositional sequence changed when sea level was falling. Slump deposits are characteristically developed in the upper layer of the FSSTs, and this was used as evidence to distinguish the sequence boundaries. The subsidence rates around the shelf break reached as much as 0.6 mm/year since MIS 10, which contributed to the well-preserved depositional sequence. During the Quaternary sea-level change, the water depth in the Korea Strait declined and the intensity of the Tsushima Current flowing near the bottom of the inner continental shelf increased. This resulted in greater erosion of sediments that were delivered to the outer continental shelf, which was the main cause of sediment deposition on the deep, low-angled outer shelf. Therefore, a depositional sequence formation model that consists of only FSSTs and LSTs, excluding highstand systems tracts (HSTs) and transgressive systems tracts (TSTs), best explains the depositional sequence beneath this shelf margin dominated by a geostrophic current.

Late Quaternary depositional sequences and landforms in relation to sea-level changes in the Osaka intra-arc basin, Japan: A borehole database analysis

Development of Late Quaternary depositional sequences in the Osaka intra-arc basin was reconstructed, based on the analysis of sequence stratigraphy and new “Shazam stratigraphy”, using numerous and high-density borehole data. The latest Pleistocene to Holocene sequence (I) and the lower late Pleistocene sequence (II) underwent several significant phases: 1) formation of alluvial fans and terraces during regression from marine isotope stage (MIS) 5 to MIS 2; 2) formation of a boundary between the two sequences during rapid sea-level fall of ca. 30–20 ka; 3) development of ravinement surfaces by wave and tidal erosion during the transgression from MIS 2 to MIS 1; 4) development of barrier systems and coastal cliffs during the transgression to the maximum high-stand of 6–5 ka; and 5) progradation of alluvial fans, deltas and strand plains during the high-stand since 5 ka. Depositional facies and systems of the two sequences are different among the western study area around Kobe, the central area with the Nishinomiya-Amagasaki lowland, and the eastern area with the Osaka plain, due to differences in sediment flux, wave, tide, shore current, basement and landforms distribution such as plateau and hills. Development of the sequence II could be also affected by tectonic differences, which fault, fold structure, and flexure. Three regions with different landforms and depositional systems were identified within the Osaka basin. The systems of the three regions correspond to the three major types of the latest Pleistocene to Holocene transgressive/regressive depositional sequences and alluvial plains recognized in Japan.

New northwest Pacific radiolarian data as a tool to estimate past sea surface and intermediate water temperatures

A new radiolarian data set for transfer function estimates of past sea surface temperature (SST) and intermediate water temperature was developed in this study for the northwestern Pacific Ocean covering a region from 1° to 50°N and 120° to 167°E. We analyzed 87 sediments surface samples, selected 30 species and/or species group found in shallow water for estimating past summer SST and 17 species and/or species group found in the intermediate water for estimating past intermediate water temperature. Since the intermediate water temperature changes greatly between 200 and 500 m, our estimates provide values at 500 m because temperatures are relatively stable between 500 and 1000 m. In this context, we estimated past summer SST and intermediate water (at ~500 m) temperature within an error margin of 0.9 and 1.2°C, respectively. A test of the accuracy of our transfer functions, conducted on core samples provided by IODP Expedition 346 Site U1429 in the northern East China Sea, showed that the reconstructed summer SSTs fluctuated between 17.2 and 26.5°C in selected late Pleistocene sequences. These temperatures corresponded to modern winter and summer SST, respectively, which highlights the ability of our new database to accurately reconstruct summer SST. The reconstructed intermediate water temperature fluctuates between 3 and 8°C, which corresponds to the observed temperature range at depths of ~500 m at high and midlatitudes, respectively.

Palaeoenvironmental and palaeoclimatic reconstruction of the Middle to Late Pleistocene sequence of Scladina Cave (Namur, Belgium) using the small-mammal assemblages

The habitat weighting, the bioclimatic model methods and the Simpson diversity index are applied to the small-mammals assemblage of Scladina Cave (border between High and Middle Belgium) in order to reconstruct the environmental and climatic fluctuations that are reflected on the Middle to Late Pleistocene sequence of the cave. The small-mammal data analyzed come from two surveys carried out at the entrance of the cave and allow us to identify within the section one cold episode: a dry, cool phase in the upper part of the sequence (probably associated with the MIS 3). The environmental and climatic data show an alternation of open meadows and woodland formations through both sequences, punctuated by peaks in local watery environments together with lower temperatures and higher precipitations rates than at present. Finally, a comparison of the small-mammal fossil assemblage from the studied surveys with the small-mammals assemblage from the Holocene deposits of Scladina Cave shows that layers related with MIS 5 temperate sub-stages (MIS 5c and MIS 5a) present environmental characteristics similar to those prevailing nowadays (a landscape dominated by woodland formations and water streams) in the area surrounding the cave. This is coherent with the available chronostratigraphic datasets on this part of the sequence, suggesting the record of the humid and temperate phases at the beginning of the Late Pleistocene.

A rallying point for different predators: the avian record from a Late Pleistocene sequence of Grotte des Barasses II (Balazuc, Ardèche, France)

The presence of processed birds in the archeological faunal record is considered key to assessing human dietary evolution. Taphonomic studies on birds from sites older than Marine Isotope Stage (MIS) 2 have become relevant in the last few years, leading to the proposal of more complex scenarios of human subsistence. Several works have demonstrated direct evidence of bird consumption by Homo prior to anatomically modern humans in Europe; however, others support the hypothesis of non-anthropogenic bird accumulations. This has led to the necessity of determining what elements or factors cause the human exploitation of birds in some archeological sites before the end of the Pleistocene. The Grotte des Barasses II site is located within this framework. Short-term human occupations have been attested by the presence of lithic tools and processed macrofaunal remains. Additionally, a small assemblage of bird bones has also been recovered. Here, we present a detailed taphonomic study with the aim of exploring possible relationships between these avian taxa and human occupations. Despite the fact that Neanderthals inhabited the cave, avian specimens show damage pointing to different causative agents. Direct evidence (digestion, gnawing) indicates that mammalian carnivores and nocturnal raptors were mainly involved in the accumulation of bird bones. We propose some factors that might determine whether or not small game was exploited in this specific locality and emphasize the importance of such analytical approaches in the general interpretations of the Pleistocene sites.

Late Pleistocene–Holocene monsoon variations on climate, landforms and vegetation cover in southwestern India: An overview

Signatures of monsoon variability preserved in the Late Quaternary sediments of southwestern India have been decoded and addressed using biological proxies along with geochronological data. Barring sediments beyond the threshold for conventional 14C dating, Late Pleistocene sequences have been recognized both in Konkan and Kerala basins. Konkan area has only subsurface continental/lacustrine Late Pleistocene, whereas Kerala coast has mixed facies. The landscape as well as the vegetation cover has been substantially modified and the fossil contents and related palaeoenvironment provided ample evidence to demonstrate the landscape and vegetation dynamics since Late Pleistocene. Evidence of Myristica swamps until Late Pleistocene and its subsequent replacement by riparian forest towards Late Holocene in Konkan has been a significant impact of monsoon variations on the tropical rain forests. The prevalence of such freshwater swamps and a sensitive habitat indicated that Konkan had enjoyed an extended period of rainfall due to the combined effects of both SW and NE monsoons until the Late Pleistocene. The tropical rainforest cover along Kerala coast has shrunken considerably and pieces of evidence suggest that the entire terrain west of Sahyadri (Western Ghats) was under dense forest cover during the Holocene Climatic Optimum (9.0–6.0 k yrs BP) when the region had witnessed heavy precipitation much higher than that of the present. The forest land has been converted into major wetlands and present ecology is unsuitable to support evergreen forests and it can be concluded that coastal plains and associated landforms were covered by thick tropical evergreen forests which got destroyed by flooding towards Middle Holocene. Development of a chain of wetland system all along Kerala coast, loss of sheltered habitat and mangrove cover, and loss of sensitive freshwater Myristica swamps are some of the significant aspects brought in while addressing the monsoon variability in southwestern India.

Seismo-stratigraphic evidences for deep base level control on middle to late Pleistocene drift evolution and mass wasting along southern Levant continental slope (Eastern Mediterranean)

Since early Pliocene, a counterclockwise surface gyre transported Nile derived silt and clay northeastwards along the Levant coast, where a basinward prograding plastered drift emerged. Based on high-resolution seismic reflection data we develop a middle to late Pleistocene sequence stratigraphic scheme for this plastered drift. For creating stacked sections of the seismic data we used the common reflection surface (CRS) stack technology which enhanced lateral reflection continuity and visibility of deep reflections. The shelf comprises stratigraphic sequences which show classical, systems tract like stacking patterns of sea level controlled sequences such as offlapping forced regression deposits or diachronous ravinement surfaces which formed during base level rise. On the slope, base level was periodically located well below the wave base and thus rather controlled by hydrodynamics, presumably by high-velocity contour currents. Hence, the term ‘deep base level’ is introduced. The deep base level controlled especially down and backstepping slope deposits. This example shows that care has to be taken when interpreting subsurface data containing typical systems tract like seismic sequences, since such geometries do not necessarily imply shallow water deposition of the sediments. A chronostratigraphic analysis based on the seismic stratigraphy indicates that base level fluctuations were related to eccentricity driven glacio-eustatic fluctuations. Periodic mass wasting, facilitated by foreset over-steepening and possibly triggered by salt tectonics or erosion by the contour current occurred during late base level fall or early base level rise.

Assessing the effects of temporal ambivalence on defining palaeosystem interrelations, and applicability to the analysis of archaeological survey data

We present a possibility-based method with applications to the analysis of archaeological survey data under constraints of temporal ambivalence. The method is a generalizable heuristic for automated learning and data mining that estimates the set of possible responses associated with ambivalent numerical data, by (i) assessing the degree of epistemic ambivalence that is carried in a data set with ambivalent information, and by (ii) monitoring the effects of this degree on data analysis, enabling the adaptation of classical data analysis to the treatment of both crisp and fuzzy information. Owing to the strong methodological foundations of the application, a detailed introduction of the ambivalent paradigm is presented first so its adaptability to archaeological survey data can be followed later. The approach is demonstrated in selecting informative features of uncertain palaeosystems by ambivalent Principal Component Analysis (PCA), and exemplified with archaeological survey data collected in the Sierra de Atapuerca and the Arlanzon valley (Burgos, Spain), focusing on the effects of temporal ambivalence on the analysis of associations between lithological palaeoenvironments and Middle Palaeolithic technologies in an open-air context. Although survey data in this region is affected by varying degrees of temporal ambivalence that, on occasion, span several isotopic stages of the late Pleistocene sequence, its effects on feature selection, regarding PCA, are not significant enough to produce contradictory reprojections of palaeolithological data onto the principal space, thanks to a gradual stabilization of the relief in the Middle Arlanzon valley, on a regional scale, during the late Pleistocene. By applying correlation-based dissimilarity distances and cluster analysis to the grouping of ambivalent score patterns, ambivalent features that describe the palaeolithological context of the Middle Palaeolithic scatters can be grouped on the PC1 × PC2 principal plane into four contexts with a similar palaeolithological evolution among group members: the Mesozoic crest of the Sierra de Atapuerca (Group 1), the Neogene levels of the Villalval-Rubena platform (Group 2), lithologically mixed areas between fluvial valleys and Neogene hills (Group 3), and the valleys of the Arlanzon, Pico and Vena rivers (Group 4). In none of these groups the evolution of the local palaeolandscape is notable enough, once again on a regional scale, to produce conflicting descriptions of the palaeolithological signatures where the archaeological scatters occur, although Group 3 (a geographical interface between different lithological palaeoenvironments) has been more dynamic than the rest of environments over the time range the lithic scatters would have formed.

Radiocarbon dated malacological records of two Late Pleistocene loess-paleosol sequences from SW-Hungary: paleoecological inferences

The two loess-paleosol sequences of Villanykovesd and Maza preserved expressive paleoecological information of the Late Pleistocene environmental conditions of SW-Hungary. For malacological examinations sampling of 12 cm intervals were used and homogenous amounts of sediment (cca. 5 kg) were collected. During the malacological examinations more than 27,000 specimens were identified. Adjusting their environmental and climatic demands the paleoclimate and paleoenvironment of the last 80,000 years could be reconstructed

Marine sedimentary record of Meltwater Pulse 1a along the NW Barents Sea continental margin

The upper continental slope of the Storfjorden-Kveithola Trough Mouth Fans (NW Barents Sea) contains a several m-thick late Pleistocene sequence of plumites composed of laminated mud interbedded with sand/silt layers. Radiocarbon ages revealed that deposition occurred during about 130 years at a very high sedimentation rate of 3.4 cm a−1, at about 7 km from the present shelf break. Palaeomagnetic and rock magnetic analyses confirm the existence of a prominent, short-living sedimentary event. The plumites appear laterally continuous and were correlated with the sedimentary sequences described west of Svalbard and neighboring glacial depositional systems representing a major event at regional scale appointed to correspond to the deep-sea sedimentary record of Meltwater Pulse-1a. We also present new sedimentological and geochemical insights, and multi-beam data adding information on the palaeoenvironmental characteristics during MWP-1a and ice sheet decay in the NW Barents Sea.

Holocene Environmental Change at Wonderwerk Cave, South Africa: Insights from Stable Light Isotopes in Ostrich Eggshell

Sparse records and discontinuous and/or poor chronologically resolved data hinder construction of reliable palaeoenvironmental sequences for the interior of South Africa. Wonderwerk Cave occupies a central position in the interior where the Kalahari Thornveld/dry woodland vegetation and generally arid conditions are expected to be sensitive to subtle past climate perturbations, and evidence from this site has been key to forming views on environmental change in the interior. A compilation of existing data including principal component analysis of pollen suggested broad trends, ranging from variably arid and open in the early Holocene to moister conditions from about 7500 to 5000 years, followed by aridity thereafter. In an effort to better establish the nature and timing of shifts from the Late Pleistocene sequence onwards, we analyse carbon and oxygen isotope ratios in a robust sample of ostrich eggshell from Wonderwerk Cave. The resulting data are then placed within a temporal framework established by Bayesian modelling of existing radiocarbon dates and compared against shifts in the Wonderwerk cultural sequence. Several shifts and trends in aridity include an arid to moist shift in layer 4b near 6000 years, coincident with a cultural shift within the Wilton assemblage, and thereafter an aridification trend culminating at about 2000 years with the appearance of the ceramic LSA.

Deciphering site formation processes through soil micromorphology at Contrebandiers Cave, Morocco

Contrebandiers Cave preserves a Late Pleistocene sequence containing Middle Stone Age (MSA) so-called Maghrebian Mousterian and Aterian occupations, spanning from ∼126 to 95 ka (thousands of years ago), followed by spatially restricted Iberomaurusian industries. Micromorphological analyses, complemented by instrumental mineralogical identification and fabric orientation, allowed for the reconstruction of the main site formation processes at the site. Initial deposition is characterized by local reworking of marine shelly sands dating to Marine Isotopic Stage 5e (MIS5e). The subsequent stratification reveals sedimentary dynamics predominantly associated with gravity-driven inputs and contributions from weathering of the encasing bedrock, at the same time that anthropogenic sediments were being accumulated. The allochthonous components reflect soil degradation and vegetation changes around the cave during the last interglacial. Human occupations seems to be somewhat ephemeral in nature, with some stratigraphic units apparently lacking archaeological components, while in others the human-associated deposits (e.g., burned bones, charcoal, and ashes) can be substantial. Ephemeral breaks in sedimentation and/or erosion followed by stabilization are mainly discernible microscopically by the presence of phosphatic-rich laminae interpreted as short-lived surfaces, peaks of increased humidity and colonization by plants. More substantial erosion affects the uppermost Aterian layers, presumably due to localized reconfigurations of the cave's roof. The subsequent Iberomaurusian deposits are not in their primary position and are associated with well-sorted silts of aeolian origin. While the effects of chemical diagenesis are limited throughout the whole stratigraphic sequence, physical bioturbation (e.g., by wasps, rodents, and earthworms) is more pervasive and leads to localized movement of the original sedimentary particles.