Holocene Boundary Research Articles

Short-Term Climatic Oscillations in the Central Region of the East-European Plain at the Beginning of the Holocene Based on Palynological Studies of Lacustrine Deposits

The Preboreal (11.75–10.70 ka BP) is still the least paleogeographically studied time interval in the central part of the East European Plain. High-resolution multi-proxy studies of lacustrine sediments at the Seltso site located in the Desna River floodplain (Dnieper River basin) were conducted. Radiocarbon dating, loss-on-ignition determination, sedimentological and palynological studies and identification of Non-Pollen Palynomorphs in lacustrine sediments allow us to reconstruct changes in vegetation caused by rapid warming at the Younger Dryas–Holocene boundary, short-term climatic fluctuations within the Preboreal and subsequent resumption of warming. Initial Preboreal warming reached its maximum at about 11.5 ka BP when a relatively dry continental climate existed. Between 11.4 and 11.2 ka BP, a short-term cooling corresponding to the Preboreal Oscillation in Greenland occurred, as indicated by a significant reduction of woody vegetation and expansion of open plant communities. In the Late Preboreal, approximately 11.2–10.7 ka BP, warming resumed, which was accompanied by a decrease in the climate continentality. Comparison with high-resolution lithological and palynological data from eight reliably dated sections of the central East European Plain indicates that in northwestern and central Europe, the impact of the Preboreal Oscillation cooling on the vegetation and the lake ecosystems’ development was probably somewhat stronger.

Late Pleistocene and Holocene Sedimentation in the glacial Lake Sosednee, Magadan region

Lake Sosednee is located in the Yagodninsky district of the Magadan region. It was formed in the Late Pleistocene around 22,500 cal. years ago. The rock magnetic, geochemical, palynological, and mineralogical characteristics of the sediments of four cores, as well as moraine, and various grain size fractions of the hillslope sediments were studied. It has been established that the geochemical and rock magnetic properties of sediments from lake Sosednee reflect different sedimentation conditions, changing from the cold climate of the Late Pleistocene to the warm climate of the Holocene. In the lower part of the core, authigenic (hemogenic) formation of iron sulfides, including magnetic ones, was revealed. According to the rock magnetic and geochemical data, the Younger Dryas was identified, the end of which corresponds to the Pleistocene–Holocene boundary.

Late Quaternary human-environment relationship in the Ganga Plain, India

Here, we present the first-ever attempt to combine palaeoenvironmental records (n = 17) from dated stratigraphic sequences with Geographic Information System (GIS) spatial modelling of archaeological sites (3 phases; n = 306 sites) in the Ganga Plain. The spatial modelling assesses the distribution of archaeological sites and phases on maps showing changing elevation, geology, geomorphology, biome, and rainfall variability within the Ganga Plain, aiming to evaluate the human-environment relationship during the Late Quaternary Period.The compilation of oxygen and hydrogen isotopic composition (δ18O and δD values) and pollen-based environment reconstructions for the last ∼100 ka indicates high rainfall conditions during ∼100–75 ka, ∼10–5 ka, and ∼3.6–1.3 ka. Fluctuating rainfall conditions were observed during ∼75–25 ka and ∼18–15 ka, while the period from ∼25 to 18 ka was the weakest monsoon phase, marking the Last Glacial Maximum. Arid conditions were also observed during ∼15–10 ka and ∼5–3.6 ka. The archaeological review suggests the presence of the Acheulian culture, diverse Mesolithic cultures, and the Neolithic phase marked by advanced agriculture and pottery production in the Ganga Plain. The past environmental analyses show changes in settlement areas correlating with rainfall variations. Frequent climate changes and increasing population density during the Late Pleistocene-Early Holocene boundary probably forced prehistoric humans to adopt agricultural practices. The distribution of archaeological sites representing different cultural phases on the modern spatial maps of landscape variability (e.g., elevation, rainfall, geomorphology, and geology) reflects an intricate relationship between prehistoric human settlements, monsoonal rainfall, and climate-driven landform processes.Our assessment suggests that the integration of archaeological sites, geological mapping, vegetation analysis, and palaeoclimate records has the potential to provide valuable insights into ancient human-environment interactions. Therefore, we recommend continued interdisciplinary research in these fields to further enhance our knowledge of prehistoric societies and their responses to changing landscapes and climates in the Ganga Plain.

Ecological Constraints and Drivers for Human Dispersals and Adaptations in the Late Pleistocene and Early Holocene Environments of the East Siberian Arctic

Starting roughly 50,000 years ago, the Arctic region of East Siberia remained continuously populated by groups of anatomically modern humans including the most uncomfortable episodes in the development of the late Quaternary environment; for some of them, human presence in the area became ephemeral. At present, archaeological fossil records allow for distinguishing three main stages in human occupation of the area: Early (~50 to ~29 ka, MIS 3), middle (~29 to ~11.7 ka, MIS 2), and late (from 11.7 to ~8 ka). For most of the time, they the populated open landscapes of the Mammoth Steppe, which declined at the onset of the Holocene. Human settlement of the Arctic was driven by various abiotic and biotic factors and thus archaeologically visible cardinal cultural and technological changes correspond to the most important paleoclimatic and habitat changes in the late Pleistocene and early Holocene. Successful peopling of the Arctic was largely facilitated by the adoption of critically important innovations such as sewing technology based on the use of the eyed bone needle and the manufacture of long shafts and pointed implements made of mammoth tusks. Mammoth exploitation is seen in mass accumulations of mammoths formed by hunting. An obvious connection between archaeological materials and such accumulations is observed in the archaeological record. In the lithic technology, the early stage is presented by archaic-looking flake industries. Starting the LGM, the wedge-core based-microblade technology known as the Beringian microblade tradition spread widely following the shrinkage of the mammoth range. At the late stage, starting at the Holocene boundary, microprismatic blade technology occurs. In all stages, the complex social behavior of the ancient Arctic settlers is revealed. The long-distance transport of products, knowledge, and genes occurs due to the introduction of the land transportation system. Initial human settlement of this region is associated with carriers of the West Eurasian genome who became replaced by the population with East Asian ancestry constantly moving North under the pressure of climate change.

Reconstructing the Paleoenvironmental Evolution of Lake Kolon (Hungary) through Palaeoecological, Statistical and Historical Analyses

The research utilizes an interdisciplinary approach, combining geological, ecological, and historical methods. It delves into the environmental evolution of Lake Kolon over a span of 17,700 years, shedding light on the intricate interplay between geological processes and ecological changes. The historical, statistical (PCA, DCA), and palaeoecological analyses centers on a core sequence situated in the heart of the lake, building upon previous research endeavors (pollen, malacological, macrobotanical and sedimentological analyses with radiocarbon dating). Forest fires occurred at the end of the Last Glacial Maximum (LGM); the boreal forest–steppe environment changed into temperate deciduous forest at the Pleistocene–Holocene boundary; human-induced environmental change into open parkland occurred; and from medieval times, communities used the land as pasture. This type of reconstruction is crucial for understanding how ecosystems respond to climate change over time, which has broader implications for modern-day conservation efforts and managing ecosystems in the face of ongoing climate change.

A new extinct species of Scybalophagus dung beetle supports the collateral extinction hypothesis at the Chilean South American Pleistocene–Holocene boundary

ABSTRACTThe extinction of megaherbivores (weighing over 1000 kg) at the Pleistocene–Holocene boundary caused drastic changes at multiple trophic levels. However, few examples of Pleistocene insect extinction have been reported in the literature. Here we describe a new extinct dung beetle species, Scybalophagus brellenthinae sp. nov., based on fossil remains recorded from an Upper Pleistocene sequence from Chilean Northern Patagonia (Osorno city: 40°34′S, 73°07′W) dated between ~16 400 and ~12 800 cal a bp. S. brellenthinae is shown to be a species of the genus Scybalophagus based on the following morphological characters: a bidentate clypeus, teeth separated by U‐shaped emargination; protibiae with three major denticles on the external margin, separated by minor denticles, present at the base of the protibiae; and mesotibiae with prominent transverse carinae. Additionally, this new species can be clearly distinguished from extant species of the genus by its shiny green color. Extant Scybalophagus are true dung beetle species that depend on fresh mammal dung for their nest development. Therefore, we suggest that the mass extinction of the megaherbivores during a period of drastic environmental change at the Pleistocene–Holocene boundary in southern South America induced the collateral extinction of S. brellenthinae. Thus, this study provides new insights into dung beetle diversity of the past.

Assessing Pleistocene–Holocene climatic and environmental change in insular Near Oceania using stable isotope analysis of archaeological fauna

ABSTRACTIn comparison to temperate and arid regions, environmental responses to the Last Glacial Maximum and the Terminal Pleistocene and Holocene boundary remain poorly known for many parts of the tropics, making it challenging to unravel human–landscape interactions across this timeframe. This is particularly the case in insular Near Oceania, where sea‐level fluctuations and potential changes in forest cover may have had major impacts on hunter–gatherer populations. Here, we apply stable carbon and oxygen isotope analyses to small‐mammal teeth from four Pleistocene–Holocene (spanning from 29 000 years ago to the late Holocene) sequences in the Bismarck Archipelago to reconstruct changes in environments directly exploited by human populations in this part of the world. Our results show a subtle response of tropical habitats in Near Oceania to relatively arid conditions during the late‐glacial period, something that has also been observed at sites in South and Southeast Asia, followed by a Terminal Pleistocene–Holocene expansion of tropical forest cover. Nevertheless, site‐based variability in environmental responses across this period highlight the need for more multidisciplinary studies of human occupation sequences in a region that is becoming increasingly central to exploring human adaptations, environmental modifications and social network development over the past 20 000 years.

Reconstructing the Paleoenvironmental Evolution of Lake Kolon (Hungary) through Integrated Geochemical and Sedimentological Analyses of Quaternary Sediments

Lake Kolon (Hungary), situated in the middle of the Turjánvidék area between the saline lakes of the Danube valley and the Homokhátság, is one of the most significant natural aquatic habitats in the Danube–Tisza Interfluve region. The central question of this study is how the lake changed, and how environmental factors and human activities have influenced these paleoenvironmental changes in Lake Kolon. A multiproxy analysis of a core sequence (loss on ignition, grain size, magnetic susceptibility, and geochemistry) provided crucial insights. Notably, correlations are observed in the following relationships: (1) clay, organic matter, and elements derived from organic sources, such as Na, K, and Zn; (2) MS, sand, inorganic matter, and elements originating from inorganic sources, such as Fe, Al, Ti, Na, K, and P; and (3) carbonate content and elements originating from carbonate sources, such as Ca and Mg. The lake’s paleoenvironment underwent significant changes in the past 27,000 years. Late-Pleistocene wind-blown sand provided the bottom for an oligotrophic lake (17,700 BP), followed by a calcareous mesotrophic Chara-lake phase (13,800 BP). Peat accumulation, along with the eutrophic lake phase, began at the Pleistocene–Holocene boundary around 11,700 BP. From 10,300 BP, with the emergence of an extended peatland phase, the percentage of organic matter (peat) increased significantly. Anthropogenic changes occurred from around 9000–8000 BP due to the different emerging cultures in the Carpathian basin, and from 942–579 BP due to the Hungarian settlements and activity nearby, respectively.

Magnetic–Mineralogical Anomalies at the Pleistocene–Holocene Boundary in Lacustrine Sediments of Northeastern Russia

Magnetic–Mineralogical Anomalies at the Pleistocene–Holocene Boundary in Lacustrine Sediments of Northeastern Russia

Diatom responses and geochemical feedbacks to environmental changes at Lake Rauchuagytgyn (Far East Russian Arctic)

Abstract. This study is based on multiproxy data gained from a 14C-dated 6.5 m long sediment core and a 210Pb-dated 23 cm short core retrieved from Lake Rauchuagytgyn in Chukotka, Arctic Russia. Our main objectives are to reconstruct the environmental history and ecological development of the lake during the last 29 kyr and to investigate the main drivers behind bioproduction shifts. The methods comprise age-modeling, accumulation rate estimation, and light microscope diatom species analysis of 74 samples, as well as organic carbon, nitrogen, and mercury analysis. Diatoms have appeared in the lake since 21.8 ka cal BP and are dominated by planktonic Lindavia ocellata and L. cyclopuncta. Around the Pleistocene–Holocene boundary, other taxa including planktonic Aulacoseira, benthic fragilarioid (Staurosira), and achnanthoid species increase in their abundance. There is strong correlation between variations of diatom valve accumulation rates (DARs; mean 176.1×109 valves m2 a1), organic carbon accumulation rates (OCARs; mean 4.6 g m−2 a−1), and mercury accumulation rates (HgARs; mean 63.4 µg m−2 a−1). We discuss the environmental forcings behind shifts in diatom species and find moderate responses of key taxa to the cold glacial period, postglacial warming, the Younger Dryas, and the Holocene Thermal Maximum. The short-core data likely suggest recent change of the diatom community at the beginning of the 20th century related to human-induced warming but only little evidence of atmospheric deposition of contaminants. Significant correlation between DAR and OCAR in the Holocene interglacial indicates within-lake bioproduction represents bulk organic carbon deposited in the lake sediment. During both glacial and interglacial episodes HgAR is mainly bound to organic matter in the lake associated with biochemical substrate conditions. There were only ambiguous signs of increased HgAR during the industrialization period. We conclude that if increased short-term emissions are neglected, pristine Arctic lake systems can potentially serve as long-term CO2 and Hg sinks during warm climate episodes driven by insolation-enhanced within-lake primary productivity. Maintaining intact natural lake ecosystems should therefore be of interest to future environmental policy.

Sedimentary facies characterization through CPTU profiles: An effective tool for subsurface investigation of modern alluvial and coastal plains

ABSTRACTCone penetration tests, a method that is typically used to determine the engineering properties of soils, can be used as an effective tool for refined subsurface stratigraphic investigations of alluvial and coastal plains, aside from the geographic location. High‐resolution calibration of piezocone penetration tests (CPTU) with 20 sediment cores enabled the detailed characterization of alluvial, deltaic and coastal depositional systems of the Po Plain. Twelve cored facies associations, typical of alluvial and coastal plain environments, were characterized based on four distinct CPTU profiles: basic cone resistance (Qc), sleeve friction (Fs), water pore pressure (U) and friction ratio (FR). Sandy facies associations (fluvial/distributary channel, bay‐head delta, transgressive barrier, delta‐front/beach‐ridge) typically have high (>4 MPa) Qc, low‐to‐negative U and low (<2%) FR. Muddy deposits (well‐drained/poorly‐drained floodplain, swamp, lagoon and prodelta) exhibit opposite trends. Heterolithic facies associations (crevasse‐levée, offshore/delta‐front transition) display characteristic seesaw profiles. Plotting of late Quaternary deposits onto the latest version of the cone penetration test typical soil behaviour chart (Robertson, 2010) enables the identification of distinctive facies associations reflecting distinctive grain size. CPTU interpretation leads to sedimentary facies recognition well beyond the simple lithological differentiation and, in particular, allows the refined characterization of clay‐rich and silt‐rich depositional units (swamp clays and peats, central‐inner and outer lagoon, proximal/distal prodelta deposits) that exhibit only subtle differences in lithology. CPTU data can also serve for the accurate detection of key stratigraphic surfaces with potential engineering applications, such as the Pleistocene–Holocene boundary. This latter, a common feature of several alluvial and coastal plain successions, is commonly marked by an abrupt upward decrease of basic cone resistance and sleeve friction from Late Pleistocene, pedogenized, stiff strata to overlying Holocene, organic‐rich, soft deposits. This study offers an updated CPTU‐facies characterization method that could be suitable for subsurface investigations of modern alluvial and coastal plains worldwide.

Stratigraphic reassessment of Grotta Romanelli sheds light on Middle-Late Pleistocene palaeoenvironments and human settling in the Mediterranean

During the last century, Grotta Romanelli (Southern Italy) has been a reference site for the European Late Pleistocene stratigraphy, due to its geomorphological setting and archaeological and palaeontological content. The beginning of the sedimentation inside the cave was attributed to the Last Interglacial (MISs 5e) and the oldest unearthed evidence of human occupation, including remains of hearths, was therefore referred to the Middle Palaeolithic. Recent surveys and excavations produced new U/Th dates, palaeoenvironmental interpretation and a litho-, morpho- and chrono-stratigraphical reassessment, placing the oldest human frequentation of the cave between MIS 9 and MIS 7, therefore embracing Glacial and Interglacial cycles. These new data provide evidence that the sea reached the cave during the Middle Pleistocene and human occupation occurred long before MISs 5e and persisted beyond the Pleistocene- Holocene boundary.

Adaptions in subsistence strategy to environment changes across the Younger Dryas - Early Holocene boundary at Körtiktepe, Southeastern Turkey

The site of Körtiktepe in southeastern Turkey is one of few sites in the Upper Mesopotamia basin that attests continuous, permanent occupation across the boundary from end of the colder, drier Younger Dryas (YD) into the comparatively wetter and warmer Early Holocene (EH). This allows for the study of the degree of environmental change experienced on a local level over this boundary as well as for the study of the adaptations that the occupants of the site undertook in response to these changes. The mammal assemblage of Körtiktepe remains relatively stable across the YD – EH transition with the main contributors to diet being mouflon ( Ovis orientalis) and red deer ( Cervus elaphus) in approximately the same quantities, although the contribution of aurochs ( Bos primigenius) increases in the EH. The most significant changes can be seen in the shift in avifauna remains, with a sharp increase of waterbirds during the EH. It is proposed that these shifts reflect changes in the local environment with an increase in woodland cover as well as expansion of local waterways, which is generally consistent with previously published archaeobotanical studies. In terms of species exploited, mortality profiles as well as size distribution of mammals, a great deal of continuity is observed. This suggests that over this particular period the local impact of the beginning of the Early Holocene was not overly dramatic, allowing for cultural continuity of previously established subsistence strategies.

Лесостепное Подонье на рубеже плейстоцена и голоцена и проблема трансформации индустрий "переходного периода"

The article discusses the problem of transition from the Paleolithic to theMesolithic through the prism of industry transformation. For the territory of the Middle Don, it was previously considered by P.I. Boriskovsky, S.N. Zamyatnin, V.P. Levenk, A.A. Formozov, A.N. Bessudnov, A.A. Bessudnov, and I.V. Fedyunin. The first monograph on the Mesolithic of the Middle Don concluded that there was no continuity between the Late Paleolithic and Early Mesolithic industries. The materials of the study were industries and faunal remains of sites, natural-scientific reconstructions of the natural environment in the Final Paleolithic and Early Mesolithic of the forest-steppe Podonye. The main research methods were: technical and typological analysis and synthesis, generalization of the data of the reference monuments of the Pleistocene and Holocene boundary. In the Late Glacial period, the upper reaches of the Don and its course up to the mark of modern Voronezh were occupied by periglacial tundra, to the south all the spaces of the Don basin, including the Azov Sea, were occupied by periglacial steppes. The border of the forest-steppe and steppe zones actually corresponded to the modern one. Within the interval of the Bølling (warming, 12.4–12 thousand years BP) – the Older Dryas (cooling, 12–11.8 thousand years BP) – the Allerød (warming, 11.8–10.9 thousand years BP), the periglacial hyperzone disintegrates. The Oldest Dryas was the time of a continental climate with very harsh winters and hot summers. The Allerød was an analogue of the Bølling with a more oceanic and humid climate. At the beginning of the Holocene, climatic characteristics approached modern standards. In the Late Glacial period (21–12 cal. thousand years BP), the faunal complex was formed by mammoth, horse, bison, reindeer, wolf, arctic fox, hare, woolly rhinoceros, tur, spotted hyena, and wolverine. In the Holocene, the composition of the animal world and, accordingly, the objects of hunting/gathering change. In all the studied sites of the Final Paleolithic and the Early Mesolithic there is a horse; elk bones were found at the sites of Samotoyevka, Plautino 2, Borshchevo 2. A certain part of the diet of the population of Nazarovka were mollusks. The available data show an intermittent picture of the development of the cultures of the Final Paleolithic and the Early Mesolithic in the forest-steppe Don, with which researchers who consider the problem from a migration perspective agree. The reasons may be related both to the large number of chronological gaps between the dated monuments and to the nature of human adaptation to new conditions. For the group of monuments related to the Zamyatninsky culture, there is no reliable data on the genesis and manifestation of stable features in the industries of the final Paleolithic. The Borshchevo II industry with three cultural layers may be autochthonous in the chronological interval under consideration, but the example of this monument within the Kostenkovsko-Borshchevsky district is unique and isolated. In the local Mesolithic, the legacy of these industries does not manifest itself. In turn, the sites of the early Mesolithic of the Zimovnik culture have no genetic roots in the Final Paleolithic of the forest-steppe Podonye.

Age and Natural Environment of the Horse Hunters' Site Sholma I in the Right Bank of the Volga in Chuvashia

The paper presents new data on the dating and paleogeography of the Sholma I site, which has been studied by the authors since the early 2000s on the Tsivil River in Chuvashia. Two AMS dates obtained from horse bones from the 2017 excavation: 10838-10717 Cal BC (95,4%) (UOC-8154) и 11131-10846 Cal BC (95,4%) (UOC-8155) confirmed the authors ' opinion expressed in 2009 that the site of the final Paleolithic functioned in the natural conditions of the interstadial warming of the Allerød at the end of the ice Age. Results of a soil study of samples in 2017, in particular, analyzes for the content of gross phosphorus and microbiomorphs carried out by A. A. Golyeva are highlighted. Analogies to the features of the blade stone industry and trapezoid inserts of throwing weapons in the sites of the Pleistocene and Holocene boundary are revealed. As a result, the authors have outlined two possible directions of communication of specialized hunters who came to the Middle Volga region with a characteristic set of combat weapons in the conditions of interstadial warming. It could be south-east and south-west directions. The south-eastern one is represented by complexes with trapezia of the lower layers of the Shiderty 3 site in north-eastern Kazakhstan and the Gora Mayak settlement in the Samara trans-Volga region, and the south-western one – by the sites with trapezia and other forms of inserts that existed during Allerød in the valleys of the Seversky Donets and the Middle Don.

Small game hunting in montane rainforests: Specialised capture and broad spectrum foraging in the Late Pleistocene to Holocene New Guinea Highlands

Moving into montane rainforests was a unique behavioural innovation developed by Pleistocene Homo sapiens as they expanded out of Africa and through Southeast Asia and Sahul for the first time. However, faunal sequences from these environments that shed light on past hunting practices are rare. In this paper we assess zooarchaeological evidence from Yuku and Kiowa, two sites that span that Pleistocene to Holocene boundary in the New Guinea Highlands. We present new AMS radiocarbon dates and a revision of the stratigraphic sequences for these sites, and examine millennial-scale changes to vertebrate faunal composition based on NISP, MNI, and linear morphometric data to shed light on variability in hunting practices, processes of natural cave deposition, and the local palaeoenvironment at the end of the LGM through to the Late Holocene. We show that Yuku was first occupied at least c. 17,500 years ago and that Late Pleistocene–Early Holocene hunters targeted a wide range of small-bodied and agile species from the mid-montane forest, with a particular focus on cuscus (Phalanger spp.). At Kiowa, occupied from around 12,000 years ago, a similar range of species were targeted, but with an added emphasis on specialised Dobsonia magna fruit bat hunting. We then integrate other zooarchaeological data from the wider Highlands zone to build a model of generalist-specialist hunting dynamics and examine how this more broadly contributes to our understanding of tropical foraging during the Late Pleistocene and Holocene.

Overkill, glacial history, and the extinction of North America’s Ice Age megafauna

The end of the Pleistocene in North America saw the extinction of 38 genera of mostly large mammals. As their disappearance seemingly coincided with the arrival of people in the Americas, their extinction is often attributed to human overkill, notwithstanding a dearth of archaeological evidence of human predation. Moreover, this period saw the extinction of other species, along with significant changes in many surviving taxa, suggesting a broader cause, notably, the ecological upheaval that occurred as Earth shifted from a glacial to an interglacial climate. But, overkill advocates ask, if extinctions were due to climate changes, why did these large mammals survive previous glacial−interglacial transitions, only to vanish at the one when human hunters were present? This question rests on two assumptions: that previous glacial−interglacial transitions were similar to the end of the Pleistocene, and that the large mammal genera survived unchanged over multiple such cycles. Neither is demonstrably correct. Resolving the cause of large mammal extinctions requires greater knowledge of individual species’ histories and their adaptive tolerances, a fuller understanding of how past climatic and ecological changes impacted those animals and their biotic communities, and what changes occurred at the Pleistocene−Holocene boundary that might have led to those genera going extinct at that time. Then we will be able to ascertain whether the sole ecologically significant difference between previous glacial−interglacial transitions and the very last one was a human presence.

A new glacial varve chronology along the southern Laurentide Ice Sheet that spans the Younger Dryas–Holocene boundary

Abstract Glacial varves can detail ice-margin positions and provide a proxy for meltwater discharge at resolutions comparable to those of the Greenland ice core archives, and thus they can be critical paleorecords for assessing the response of both ancient and modern ice sheets to climate change. Here we provide an ∼1500 yr varve chronology straddling the Younger Dryas (YD)–Holocene boundary (11.65 cal. kyr B.P.), the first such chronology in North America. The varves are from glacial Lake Agassiz (central North America). The chronology is pinned on accelerator mass spectrometry radiocarbon-dated terrestrial macrofossils at the base of a widespread red-clay bed deposited during flooding from the Lake Superior basin. We illustrate the utility of this record by examining ice-margin retreat and melting through the late Younger Dryas and across the Holocene boundary. The ice margin receded at a constant rate, not only during the late YD, but for at least 300 yr after the onset of the Holocene. In contrast, varve thicknesses increased at the boundary, and a moraine formed over a 50 yr period, perhaps in response to the warming climate. Our expectation is that this time series will continue to be developed, expanded, and refined because it promises to be the longest and most geographically extensive glacial varve data set in North America.

The upper limb skeleton and behavioral lateralization of modern humans from Zhaoguo Cave, southwestern China.

Aims of the study are to initially describe and comparatively evaluate the morphology of the new Zhaoguo M1 upper limb remains, and contextualize upper limb functional adaptations among those of other worldwide Upper Paleolithic (UP) humans to make inferences about subsistence-related activity patterns in southwestern China at the Pleistocene-Holocene boundary. The preserved Zhaoguo M1 skeletal remains include paired humeri, ulnae, and radii, among others. These specimens were scanned using micro-computed tomography to evaluate internal structural properties, while external osteometric dimensions of the Zhaoguo M1 upper limb elements also were acquired. Both sets of measurements were compared to published data on Neandertals, and Middle and Upper Paleolithic modern humans. The upper limb elements of Zhaoguo M1 display a suite of characteristics that generally resemble those of other contemporary Late UP (LUP) modern humans, while robusticity indices generally fall within the upper range of LUP variation. The Zhaoguo M1 upper limb elements display fewer traits resembling those of late archaic humans. The Zhaoguo M1 individual exhibits diaphyseal asymmetry in several upper limb elements suggesting left hand dominance. When evaluating the full range of magnitudes of humeral bilateral asymmetry in the comparative sample, Zhaoguo M1 falls at the lower end overall, but yet is relatively higher than contemporary LUP modern humans specifically from East Eurasia. The Zhaoguo M1 individual suggests typical LUP modern human upper limb morphology persisted in southwest China until the end of the last glacial period. Upper limb bone asymmetry of Zhaoguo M1 also indicates that behavioral activities attributed to a hunter-gatherer tradition apparently extended through the Pleistocene-Holocene transition in this region.

To the formation of the biodiversity of the Russian Far East

Plants diversity and riches of specific floras in the Russia’s Far East is determined not only and not somuch by a modern ecotopes diversity, as by the expression in the stale of the limit of permafrost soils, by the spread ofconsolidated boreal-nemoral ecosystems, by the situation of the Holocene boundary, ancient and early Holocene, presenceof the "small" and “big” migratory ways promoted the savings of a vascular plants diversity (RSR) by all praterritory, andthe “bridges” of a land. These bridges provided, first, resettlement of plant species from the West in dry late Pleistocene,updating of floras by Daurian-Mongolian steppe species, secondly, by returning of the species lost in the cold periods dueto their migration from the south, from refuges, by presence of refuges from fire, and elementary pyrogenic degradationof flora and vegetation reduces RSR on the order. However to the north from 50º N. L. on continent and Sakhalin islandand with 46º N. L., from Urup island on the Greater Kuril Islands refuges and isolates for maintenance high RSR has novalue or even it reduces, preserving more cold-resistant and cold-loving flora. Poverty of flora of coasts of KamchatkaPeninsula is connected with this phenomenon.