Pleistocene-Holocene Transition Research Articles

Paleoenvironmental dynamics in central‐eastern Brazil during the last 23 000 years: tropical peatland record in the Cerrado biome

AbstractThe Cerrado biome is the second largest in Brazil, but the evolution of the Cerrado during the late Quaternary is not yet fully known. This study identifies paleoenvironmental changes during the last 23 000 years, based on a tropical mountain peatland record, in the Serra do Espinhaço Meridional in central‐eastern Brazil. A multi‐proxy approach was used that involved palynological analysis, stable isotopes (δ13C, δ15N), geochemistry, radiocarbon dating and multivariate statistics derived from a peatland core from Rio Preto (Minas Gerais state). The study reveals a very humid and cold climate during the late Pleistocene, with an increase in temperature and decrease in humidity at the Pleistocene–Holocene transition. During this period there was strong instability in the landscape (episodes of erosion). At the beginning of the Holocene there was a reduction in humidity with greater landscape stability. The current sub‐humid climatic conditions seem to have been established in the mid‐/late Holocene, with periods of landscape instability. Our findings agree with other Cerrado records that contradict previously established hypotheses, such as the Amazonian Refuge and the Pleistocene Arc.

Environmental Changes on Kunashir Island (Kuril Archipelago) during the Middle and Late Holocene

Sea level rise during the Pleistocene-Holocene transition period caused the formation of lagoon lakes along the western and eastern coasts of the Kuril Islands. These lakes include Lake Serebryanoye, located in the northern part of the South Kuril Isthmus near the Pacific coast of Kunashir Island (44°03'21" N; 145°49'46" E). The total thickness of sediments in the lake was 367 cm. They are characterized by diatom flora (334 species), representing various ecological groups: freshwater, brackish water, marine, marsh, lacustrine, rheophilic, planktonic, benthic. The analysis of diatoms made it possible to distinguish two complexes. As shown by radiocarbon dating, in the Middle Holocene (100.5-367 cm interval) the sediments corresponded to the lagoon stage, which changed in the Late Holocene (100.5-0 cm interval) to the freshwater lake stage. Palynological analysis showed a successive change of biocenoses, reflecting the development in the Middle Holocene of birch-broadleaved forests with the participation of Pinus koraiensis, Picea sp. The most abrupt change in biocenoses is observed at the boundary of the Middle and Late Holocene. This change of biocenoses is expressed by the dominance of conifers in the vegetation cover, represented by various species of Picea, Pinus, Abies, Larix. It also shows the relative cooling of the climate in the Late Holocene.

The terminal Pleistocene –ea rly Holocene cultural continuity in the north-central Caucasus: Evidence from Psytuaje rockshelter in the region context

• Psytuaje rockshelter is the first stratified late Epipaleolithic (EPP) site that was intensively investigated in the northern slope of the Central Caucasus. • The multidisciplinary research in Psytuaje rockshelter provides new important data about subsistence strategies and culture of the EPP hunter-gatherer groups. • Our study reveals cultural and technological similarities between late EPP assemblages in the north-central and in the north-western Caucasus, including those from Mezmaiskaya cave. • The new data indicates that the late EPP culture developed continuously across the Pleistocene–Holocene transition and up to the early Holocene.

Late quaternary hydrological changes in the southeastern amazon basin from n-alkane molecular and isotopic records in sediments of Saci lake, Pará state (Brazil)

The molecular distributions and isotopic ratios (δ13C and δD) of n-alkanes in sediments deposited during the last 35 cal kyr BP in Saci Lake, southeastern Amazonia, have been measured and interpreted for their paleoclimate information. A terrestrial origin for the odd carbon-numbered long-chain (>C27) n-alkanes has been inferred from molecular distributions. A shift in the n-alkane δ13C values across the Pleistocene-Holocene boundary coincides with a climate-induced floral change previously deduced from palynological analyses. Dry conditions during the late Pleistocene and mid-Holocene were confirmed by several n-alkane indices used to estimate the availability of moisture and by larger δD values. High ACL values indicate relatively dry conditions from 29 to 18.2 cal kyr BP and again from 8.0 and 5.0 cal kyr BP with a decrease in precipitation and an increase of grasses. Changes in the n-alkane C-29 isotopic compositions (δD and δ13C) were observed during the Pleistocene-Holocene transition, coinciding with a floristic change induced by climatic conditions that is also observed in palynological results from the same lake. The n-alkane C-29 δ13C values remain between −33.2‰ and − 35.7‰, which is representative for n-alkanes derived from C3 vegetation. These lines of evidence suggest a continuous gallery forest cover in the Saci Lake catchment for the last ~35 cal kyr BP in contrasted with the observed palynological changes which represent the dynamics of the vegetation on the upland areas. The n-alkane C-29 δD values are less negative in the Pleistocene and more negative during the Holocene in the lake record. These characteristics suggest more humid conditions during the Holocene than in the Pleistocene, probably associated with the South American Monsoon System (SAMS). However, an increase of approximately 10‰ occurs during the late Holocene, which coincides with the forest expansion around 5 cal kyr BP that is recorded in palynological data of Saci Lake and other records of the Amazon Forest. This change suggests that the D/H ratio is also influenced by the increase of the plant biomass, which would provide an enrichment of D in the isotopic signal as a function of regional moisture recycling caused by evapotranspiration.

Changing surface ocean circulation caused the local demise of echinoid Scaphechinus mirabilis in Taiwan during the Pleistocene–Holocene transition

Abundant fossil specimens of Scaphechinus mirabilis, now occurring mostly in temperate waters, have been found in the Toukoshan Formation (Pleistocene) in Miaoli County, Taiwan. Environmental changes leading to its extirpation (local extinction) have thus far been elusive. Here, we reconstruct past environmental and oceanic conditions off northwest Taiwan by analyzing clumped isotopes, as well as stable oxygen isotopes, of well-preserved fossil echinoid tests collected from the Toukoshan Formation. Radiocarbon dates suggest that these samples are from Marine Isotope Stage 3 (MIS 3). Paleotemperature estimates based on clumped isotopes indicate that fossil echinoids were living in oceanic conditions that range from 9 to 14 °C on average, comparable with the estimate derived for a modern sample from Mutsu Bay, Japan. Notably, this temperature range is ~ 10 °C colder than today’s conditions off northwest Taiwan. The substantially lower temperatures during ~ 30 ka (MIS 3) compared to the modern conditions might be due to the rerouting of surface currents off northwest Taiwan when the sea level was ~ 60 m lower than today, in addition to the cooling caused by a lower atmospheric CO2 level during the Last Glacial Period. Colder waters brought here by the China Coastal Current (CCC) and the existence of shallow subtidal zones termed “Miaoli Bay” (mainly located in the present-day Miaoli county) during MIS 3 plausibly sustained generations of S. mirabilis, yielding tens of thousands of fossil specimens in the well-preserved fossil beds. The likely extirpation driver is the drastic change from a temperate climate to much warmer conditions in the shallow sea during the Pleistocene–Holocene transition.

Late glacial–Holocene record of Southern Hemisphere westerly wind dynamics from the Falkland Islands, South Atlantic Ocean

Abstract The Southern Hemisphere westerly wind belt (SHWW) is a major feature of Southern Hemisphere, midlatitude climate that is closely linked with the sequestration and release of CO2 in the Southern Ocean. Past changes in the strength and position of this wind belt are poorly resolved, particularly across the Pleistocene-Holocene transition, a time period associated with fluctuations in atmospheric temperatures and CO2 levels. We used dust geochemistry, particle size measurements, and paleoecological analyses from a peat sequence in the Falkland Islands, South Atlantic Ocean, to describe changes in the SHWW between 16.0 and 6.5 ka (thousands of years before CE 1950). Wind strength was low at ~51°S before and during the Antarctic Cold Reversal (ACR, 14.9–13.0 ka), intensified between 13.1 and 12.1 ka as atmospheric temperatures increased, and then weakened, reaching a minimum between 12.1 and 10.9 ka during the Early Holocene thermal maximum. Northwesterly air masses became more dominant from 12.0 to 10.2 ka, and wind strength remained low until our record was affected by a storm surge or tsunami ca. 7.8 ka. These data indicate a southward shift in the latitude of the SHWW, from north of 51°S prior to and during the ACR, at ~51°S before the onset of the Holocene, and south of 51°S during the early Holocene thermal maximum. This pattern suggests that the latitude of the SHWW was coupled with atmospheric temperatures through the Pleistocene-Holocene transition.

Past vegetation reconstruction maps and paleoclimatic variability inferred by pollen records in southern Patagonia Argentina since the Late Glacial-Holocene transition

Palaeoecological reconstructions document past vegetation distribution with estimates of the communities boundaries shifts. This work presents a compilation of palaeoecological studies from southern Patagonia Argentina as a contribution to a better understanding of the composition and distribution of Andean and extra-Andean plant communities. Paleoenvironmental reconstructions are based on pollen sequences from different types of deposits located in the forest, forest-steppe ecotone and steppes between 46° and 51°S. The comprehension of modern pollen and its relation with the actual vegetation is a critical component of palaeoecological research. Models of the current relationship pollen-vegetation-climate were applied to interpret these sequences. Their integration made it possible to reconstruct the spatio-temporal patterns of vegetation and past climatic changes since the Late Glacial-Holocene transition. Four areas were selected to map past vegetation communities; three lake basins: Pueyrredón, San Martín and Argentino, and the Deseado Massif. The local conditions given by the geomorphology of each site were also taken into account. The vegetation reconstruction during the Pleistocene-Holocene transition came from records located in the Deseado Massif only, and indicated steppes, without modern analogues, linked to arid and cold conditions. During the Holocene, plant communities were sensitive to moisture conditions related to westerly winds or Atlantic-derived precipitation events. Taxa related to the anthropogenic impact of the past centuries were found at all sites, both in Andean and extra-Andean Patagonia.

New record of mollusks from the El Molino mammoth site, Parras, Coahuila, Mexico

We present new Late Pleistocene and Holocene records of a land and freshwater malacofauna assemblage from the mammoth bearing site El Molino in Parras, Coahuila, northern Mexico. We identified 19 mollusk taxa, 14 species were found within the Late Pleistocene sediments and 10 species in the different strata belonging to the Holocene. The gastropods Gastrocopta tappaniana, Pupilla hebes and Habroconus sp. are new Late Pleistocene records for Mexico, the first two being previously recorded for United States Pleistocene deposits. New Mexican Holocene fossil records include Euglesa casertana, Galba humilis, Gastrocopta cristata, Zonitoides arboreus, Hawaiia minuscula, and Deroceras laeve. The habitat requirements of the El Molino site malacofauna assemblage provides additional information on the environmental changes that occurred during the Pleistocene-Holocene transition. Woodland associated, hygrophilic and hydrophilic malacofauna suggest a humid forested and grassland habitat during the Late Pleistocene, which subsequently changed to xeric conditions with the colonization of xerophytic and aridity-tolerant aquatic species during and after the Pleistocene-Holocene transition at the study area.

Large-scale climatic drivers of bison distribution and abundance in North America since the Last Glacial Maximum

As the dominant large herbivore in midcontinent North America since the terminal Pleistocene, bison (Bison spp.) have been a fundamental component of ecosystems and economies. Despite the importance of bison in late Quaternary North America, large-scale (regional to continental) patterns of bison biogeography are not well understood. Here we integrate archaeological and paleontological bison occurrence data with simulated climate data to better understand long-term drivers of bison distribution and abundance in North America. We used these records to model bison distribution and abundance over the past 20 thousand years at 1-thousand-year intervals. Our results show that late Quaternary changes in the distribution and abundance of bison were influenced by large-scale trends in temperature and precipitation. The distribution of bison since the Bølling–Allerød Interstadial (ca. 14 ka) is primarily explained by seasonal temperature patterns (mean temperature of the coldest quarter is the most important variable for 12 of the 14 1-thousand-year intervals). The modeled climate of bison distributions progressively narrowed since the Last Glacial Maximum (ca. 20 ka) as bison populations retracted from disjunct Pleistocene refugia and congregated in midcontinent rangelands. Through the Pleistocene-Holocene transition, bison experienced rapidly warming summer temperatures that increased faster in midcontinent North America than other regions and the continent as a whole. Model results suggest that Holocene bison abundance was influenced by hydroclimatic shifts that affected the quality and availability of forage. Bison abundances decreased through the dry early and mid-Holocene and increased when moisture availability improved in the late Holocene. We infer that bison have thrived under a broad range of environmental conditions since the Last Glacial Maximum and that the climatic and biogeographic space occupied by bison narrowed in recent millennia.

Filling the Void: Rock-art Continuity Over the Pleistocene–Holocene Boundary in Eastern Iberia

In this paper we study several panels with incised engravings, which have been discovered in recent years, from two shelters in the area of the River Martín (Teruel), Cañada de Marco and Los Borriquitos. They are of great scientific interest for several reasons. Firstly, because they represent an expansion of the Late Upper Palaeolithic engraving facies of Mediterranean Iberia, limited until now to ten sites. In these two new sites, these incised engravings are underlying Levantine and Schematic pictographs, and occasionally are interstratified with Levantine paintings, an exceptional fact which is published in its entirety for the first time. These stratigraphic relationships reflect continuity/change dynamics during the Pleistocene–Holocene transition and throughout the Holocene artistic cycle, topics which are crucial on a European scale. Finally, we have identified iconographic continuities between Epimagdalenian engravings and Levantine art, suggesting a possible link between these two graphic expressions. These findings may constitute solid support for the hypothesis about the pre-Neolithic origin of the exceptional Levantine art of the Iberian peninsula.In memoriam Ramiro Alloza

Environmental changes since 14 ka BP in the southernmost Kuril islands (North-Western Pacific) and regional correlation of events

• New data on climatic changes at the late Pleistocene-Holocene boundary for Kurils. • Climate fluctuations and volcanic ash-falls were mail drivers in lake-mire evolution. • The lake level was highest during warmer and humid climate of the Allerød. • Younger Dryas cooling in the Kuril Islands was less distinct than on the continent. • Pollen record vegetation changes on the land bridge at Late Glacial–early Holocene. Despite considerable progress in understanding Late Pleistocene and Holocene palaeoenvironmental changes worldwide, there are still very few such data for the Far East, and Kuril islands, in particular. Here, the sea level rise during the Late Glacial–Holocene transition was accompanied by a loss of the land connectivity culminating into the development of isolated islands. The ecosystems evolution and importance of isolation for vegetation dynamics on islands are still insufficiently understood. We investigated a unique natural record of environmental change since 14 ka has been recently discovered in lake–mire complex on Kunashir Island. The sediments include 12 tephra layers from Kunashir and Hokkaido volcanoes. The lake level was highest during warmer and humid climate of the Allerød. Diatom assemblages indicated the higher lake level between 12 730–12 160 cal yr BP. The first half of Younger Dryas was characterized by heavy snowfalls. Cooling attributed to the Younger Dryas in the Southern Kurils was less distinct than on the continent. The pollen assemblages recorded changes in vegetation on the land bridge. At the end of the Pleistocene large areas were occupied by birch forests and shrub pine. The broadleaf species first appeared at the end of Allerød. Starting from the Pleistocene-Holocene transition and during the early Holocene , the role of conifers sharply increased. In the middle Holocene the proportion of broadleaf trees in forests increased. Coniferous forests became abundant during the Little Ice Age. Short-tern climatic fluctuations correlate well with regional pattern, particularly with fluctuations of the moisture supply.

An age-depth model and revised stratigraphy of vertebrate-bearing units in Natural Trap Cave, Wyoming

Excavations at Natural Trap Cave (NTC) began in the mid-1970's and quickly yielded evidence of a diverse steppe fauna that existed during the Last Glacial Maximum (MIS 2) along the western slope of the Bighorn Mountains in north central Wyoming. NTC is a karst pit cave with a 24.5 m vertical drop into a roughly 43 m wide bell-shaped ‘Main Chamber’ and during the course of early excavations a plugged entrance to a fossil-bearing ‘Lower Chamber’ was discovered. Stratigraphic relationships below the entrance to the Main Chamber of the cave were originally studied in the mid-1970's, but were never formally published. Although stratigraphy, taphonomy, and depositional circumstances were briefly discussed over the following years, little has been done to correlate the numerous stratigraphic schemes used by various authors. In this study, four stratigraphic sections were measured and analyzed to establish an easily modifiable lithostratigraphic system of nomenclature. We provide the first correlations of all stratigraphic nomenclature used throughout excavations at NTC to facilitate comparisons with current and previous collections and publications. By leveraging more than 100 radioisotopic dates we developed an age-depth model and chronostratigraphic framework to further interrogate spatiotemporal relationships between strata, paleoenvironmental proxies, and fossil assemblages. Deposition is shown to be discontinuous; sediment accumulation in the study area is restricted to the buildup through peak penultimate and Last Glacial maxima. More recent (<10 ka) Holocene deposits unconformably cover the eroded surface of underlying Pleistocene strata. There is active reworking of sediments with transport and deposition of reactivated material within the Lower Chamber. We note that the two hiatuses coincide with interglacial periods and may reflect changing depositional circumstances within the cave such as extended periods of non-deposition, erosion, or bypass (possibly leading to deposition in the Lower Chamber). Contrary to previous reports, we demonstrate that it is unlikely a prominent snow cone existed or contributed to the pattern of sediment and fossil distribution within the study area, furthermore, we do not observe a continuous Pleistocene-Holocene transition in the study area. Further stratigraphic work will be needed to better understand the interrelationship between Main and Lower chamber deposits and the evolution of sediment accumulation in NTC.

Limaces and Unifaces in the Paiján Industry, Peru, and the Early Prehistory of America

ABSTRACT On the coast of Peru, early human occupation is represented by the Paiján tradition. As well as the stemmed bifacial projectile points, “limaces” are characteristic of this paleo American lithic complex, in comparison with similar forms of the European Mousterian, a term that has been changed to "uniface" because of the variety of shapes in Paiján assemblages. In contrast with the Mousterian expedient technology, unifaces are highly curated tools that are discarded following repeated sequences of use and resharpening that finally render them non-functional. The discovery of a cache of two little-used unifaces in a bifacial knapping workshop shows the process of reduction to which the unifaces encountered so far have been subjected. Unifaces are generally found in the context of occupations dating from the Pleistocene-Holocene transition (Paleo-American stage) throughout America. Unifaces should be considered as one of the characteristic tool types of this stage, besides the lithic projectile points.

Strong and lasting impacts of past global warming on baleen whales and their prey.

Global warming is affecting the population dynamics and trophic interactions across a wide range of ecosystems and habitats. Translating these real‐time effects into their long‐term consequences remains a challenge. The rapid and extreme warming period that occurred after the Last Glacial Maximum (LGM) during the Pleistocene–Holocene transition (7–12 thousand years ago) provides an opportunity to gain insights into the long‐term responses of natural populations to periods with global warming. The effects of this post‐LGM warming period have been assessed in many terrestrial taxa, whereas insights into the impacts of rapid global warming on marine taxa remain limited, especially for megafauna. In order to understand how large‐scale climate fluctuations during the post‐LGM affected baleen whales and their prey, we conducted an extensive, large‐scale analysis of the long‐term effects of the post‐LGM warming on abundance and inter‐ocean connectivity in eight baleen whale and seven prey (fish and invertebrates) species across the Southern and the North Atlantic Ocean; two ocean basins that differ in key oceanographic features. The analysis was based upon 7032 mitochondrial DNA sequences as well as genome‐wide DNA sequence variation in 100 individuals. The estimated temporal changes in genetic diversity during the last 30,000 years indicated that most baleen whale populations underwent post‐LGM expansions in both ocean basins. The increase in baleen whale abundance during the Holocene was associated with simultaneous changes in their prey and climate. Highly correlated, synchronized and exponential increases in abundance in both baleen whales and their prey in the Southern Ocean were indicative of a dramatic increase in ocean productivity. In contrast, the demographic fluctuations observed in baleen whales and their prey in the North Atlantic Ocean were subtle, varying across taxa and time. Perhaps most important was the observation that the ocean‐wide expansions and decreases in abundance that were initiated by the post‐LGM global warming, continued for millennia after global temperatures stabilized, reflecting persistent, long‐lasting impacts of global warming on marine fauna.

Late Pleistocene palaeoenvironments and a possible glacial refugium on northern Vancouver Island, Canada: Evidence for the viability of early human settlement on the northwest coast of North America

Multi-proxy palaeoecological analyses of lake cores from two sites on northern Vancouver Island reveal previously undocumented non-arboreal environments in the region during the late Pleistocene. Radiocarbon, pollen, sedimentary ancient DNA (sedaDNA), diatom, and grain size analyses indicate that Topknot Lake on the west coast of northern Vancouver Island was not glaciated in the last 18,500 years, extending into the hypothesized regional glacial maximum. A cold herb-shrub coastal tundra existed at the site from ca. 17,500–16,000 cal BP with species including willows (Salix), grasses (Poaceae), sedges (Cyperaceae), heathers (Ericaceae), and sagebrush (Artemisia). SedaDNA analysis also supports the presence of rare non-arboreal taxa at Topknot Lake during this interval including Jacob's-ladder (Polemonium), bistort (Bistorta), and wild berries (Rubus). After ca. 16,000 cal BP and through the terminal Pleistocene, pine (Pinus), alder (Alnus), and ferns formed open forests under cool and dry conditions. At Little Woss Lake in the mountains of north-central Vancouver Island, fir (Abies) stands dominated from ca. 14,200–14,100 cal BP, then were replaced by open pine woodland with alder and ferns from ca. 14,100–12,000 cal BP. SedaDNA corroborates these plant taxa as well as indicating grizzly bear (Ursus arctos horribilis) and Chinook salmon (Oncorhynchus tshawytscha) in and around the basin by ca. 14,100 cal BP. Mixed conifer forests of pine, western hemlock (Tsuga heterophylla), and alder spread into the island's interior ca. 12,000–11,100 cal BP during the Pleistocene-Holocene transition. The records from these two lakes demonstrate the diachronous development of postglacial ecosystems on northern Vancouver Island. Furthermore, these data provide key evidence for environments that could have supported human populations on the northwest coast of North America for several millennia during the terminal Pleistocene.

Pleistocene mitogenomes reconstructed from the environmental DNA of permafrost sediments

Traditionally, paleontologists have relied on the morphological features of bones and teeth to reconstruct the evolutionary relationships of extinct animals.1 In recent decades, the analysis of ancient DNA recovered from macrofossils has provided a powerful means to evaluate these hypotheses and develop novel phylogenetic models.2 Although a great deal of life history data can be extracted from bones, their scarcity and associated biases limit their information potential. The paleontological record of Beringia3-the unglaciated areas and former land bridge between northeast Eurasia and northwest North America-is relatively robust thanks to its perennially frozen ground favoring fossil preservation.4,5 However, even here, the macrofossil record is significantly lacking in small-bodied fauna (e.g., rodents and birds), whereas questions related to migration and extirpation, even among well-studied taxa, remain crudely resolved. The growing sophistication of ancient environmental DNA (eDNA) methods have allowed for the identification of species within terrestrial/aquatic ecosystems,6-12 in paleodietary reconstructions,13-19 and facilitated genomic reconstructions from cave contexts.8,20-22 Murchie etal.6,23 used a capture enrichment approach to sequence a diverse range of faunal and floral DNA from permafrost silts deposited during the Pleistocene-Holocene transition.24 Here, we expand on their work with the mitogenomic assembly and phylogenetic placement of Equus caballus (caballine horse), Bison priscus (steppe bison), Mammuthus primigenius (woolly mammoth), and Lagopus lagopus (willow ptarmigan) eDNA from multiple permafrost cores spanning the last 40,000 years. We identify a diverse metagenomic spectra of Pleistocene fauna and identify the eDNA co-occurrence of distinct Eurasian and American mitogenomic lineages.

Optimal Linear Estimation (OLE) Modeling Supports Early Holocene (9000–8000 RCYBP) Copper Tool Production in North America

The discovery and development of metal as a tool medium is a topic of global interest. A fundamental research goal involves establishing the timing of human experimentation with naturally occurring copper ore, which is commonly associated with sedentary, agrarian-based societies. However, in North America, there is well-documented millennia-scale exploitation of copper as tool media by small, seasonally mobile hunter-gatherer groups in the western Great Lakes. Archaeologists have suggested that Late Paleoindian groups may have begun using copper as a tool medium almost immediately after they entered the Lake Superior basin. However, only a few radiocarbon dates support such early use of copper. Here, we use optimal linear estimation modeling to infer the origin date for copper tool production in North America. Our results show that the invention of copper as a tool media likely occurred shortly after the first pioneering populations encountered copper ore during the Pleistocene-Holocene transition. The origin dates modeled here (ca. 8100 RCYBP) reveal several important features about the behavior of pioneering hunter-gatherer populations. Moreover, our results suggest that this phenomenon represents the earliest known use of metal for utilitarian copper tool production.

Marmot hunting during the Upper Palaeolithic: The specialized exploitation at Grotte di Pradis (Italian pre-Alps)

In the last few years several studies have reassessed the attraction and the role of small game in the subsistence economy of hunter-gatherers across Europe and the Mediterranean region since the Middle Paleolithic. The exploitation of small mammals intensified during the Pleistocene-Holocene transition, when some unusual faunal assemblages were recorded in the Alpine arch and the Prealpine belt. In this region marmot became a relevant resource during the Late Glacial, albeit the relative foraging systems were mostly focused on the exploitation of medium and large size herbivores. In this report we present zooarchaeological data from Grotte di Pradis (northeastern Italy) which displays a faunal assemblage composed of at least 637 marmot individuals, representing about the 99% of the total remains. Taphonomic evidence suggests a standardized processing of marmot carcasses finalized to the deferred consumption and utilization of different resources. The intensive exploitation together with the acquisition through repetitive hunting events and the ecological and ethological factors proper of this animal, substantially affected its definition of prey type and its ranking in terms of energy return balance. Hence, in this particular context marmot might be regarded as a high-ranked resource, seasonally exploited within a well-established logistical mobility system which reflects a repetitive regional phenomenon peculiar of the alpine area throughout the Late Glacial.

14,000-year Carbon Accumulation Dynamics in a Siberian Lake Reveal Catchment and Lake Productivity Changes

A multi-proxy paleolimnological analysis of a sediment core sequence from Lake Malaya Chabyda in Central Yakutia (Eastern Siberia, Russia) was conducted to investigate changes in lake processes, including lake development, sediment and organic carbon accumulation, and changes in primary productivity, within the context of Late Pleistocene and Holocene climate change. Age-depth modeling with 14C indicates that the maximum age of the sediment core is ∼14 cal kBP. Three distinct sedimentary units were identified within the sediment core. Sedimentological and biogeochemical properties in the deepest section of the core (663–584 cm; 14.1–12.3 cal kBP) suggests a lake environment mostly influenced by terrestrial vegetation, where organic carbon accumulation might have been relatively low (average ∼100 g OC m−2 a−1), although much higher than the global modern average. The middle section of the core (584–376 cm; 12.3–9.0 cal kBP) is characterized by higher primary productivity in the lake, much higher sedimentation, and a remarkable increase in OC delivery (average ∼300 g OC m−2 a−1). Conditions in the upper section of the core (&amp;lt;376 cm; &amp;lt; 9.0 cal kBP) suggest high primary productivity in the lake and high OC accumulation rates (average ∼200 g OC m−2 a−1), with stable environmental conditions. The transition from organic-poor and mostly terrestrial vegetation inputs (TOC/TNatomic ratios ∼20) to conditions dominated by aquatic primary productivity (TOC/TNatomic ratios &amp;lt;15) occurs at around 12.3 cal kBP. This resulted in an increase in the sedimentation rate of OC within the lake, illustrated by higher sedimentation rates and very high total OC concentrations (&amp;gt;30%) measured in the upper section of the core. Compact lake morphology and high sedimentation rates likely resulted in this lake acting as a significant OC sink since the Pleistocene-Holocene transition. Sediment accumulation rates declined after ∼8 cal k BP, however total OC concentrations were still notably high. TOC/TNatomic and isotopic data (δ13C) confirm the transition from terrestrial-influenced to aquatic-dominated conditions during the Early Holocene. Since the mid-Holocene, there was likely higher photosynthetic uptake of CO2 by algae, as suggested by heavier (isotopically enriched) δ13C values (&amp;gt;−25‰).

Plant use and vegetation trends in Algeria from Late Glacial to Middle Holocene: Charcoal and seeds from Gueldaman GLD 1 cave (Babors d'Akbou)

Vegetation dynamics during the Pleistocene–Holocene transition and the beginning of farming are major topics for palaeoenvironmental sciences, especially interesting in ecologically sensitive areas, such as in North Africa. However, there are still important geographic and chronological gaps of environmental information in this region. Archaeobotanical record from Gueldaman GLD 1 deals with these issues, as it presents the longest archaeobotanical sequence available nowadays for Algeria, which includes these moments of major changes in landscapes. This topic has been approached from an interdisciplinary point of view, focused on the analysis of various types of plant remains that result in the reconstruction of both environment and use of plant resources. Results reveal the existence of a postglacial phase of plant colonization with Cupressaceae formations, which are gradually integrating some elements of sclerophyllous vegetation, such as several species of Pistacia, well documented both in charcoal and seed records. Neolithic levels show a shift in vegetation composition, as Olea europaea dominates the spectra, accompanied by strawberry tree and evergreen Quercus, among others. The presence of Olea in earlier chronologies has resulted from intrusions from the Neolithic levels: a set of radiocarbon dates has made it possible to evidence this process and detect the extent of the intrusions, which are inherent to cave records.