Quaternary International最新文献

Sandy deserts/lands along the western edge of the Asian summer monsoon domain are regarded as the major dust source of the East Asia and Pacific Ocean. However, the climatic background of aeolian sand accumulation in sandy deserts/lands and the potential provenance linkage between sand accumulation in sandy deserts/lands and aeolian dusts in the Chinese Loess Plateau (CLP) remains controversial. Based on age data compiled from published studies, we analyze the climatic background of aeolian sand accumulation in the proximal sandy deserts/lands, and the potential linkage between aeolian sand accumulation and the synchronous aeolian dusts in the CLP. The following conclusions are achieved: 1) Aeolian sand accumulation is almost synchronous with the development of loess/palaeosol/lacustrine sediments within the proximal sandy deserts/lands, supporting the idea that in the proximal sandy deserts/lands the aeolian sand accumulated at the high regional effective moisture condition. 2) Coupled with climatic background in neighboring areas, the inconsistent changes during the latest ∼20 ka in accumulation rate between aeolian sands in sandy deserts/lands and loess in the CLP support the idea that the contribution from the proximal sandy deserts/lands to loess in the downwind CLP is limited.

Mountain forests are sensitive ecosystems. This is why in recent years the dynamics of these forest ecotones have been researched from several different approaches. One of these has been the paleoecological perspective, which is particularly interesting in the mountainous areas of the Mediterranean region, where interactions between climate, vegetation and anthropic activities have been documented for millennia. This is the case of the Sierra de las Nieves Natural Park (southwestern Baetic Cordillera), a mountainous area that constitutes an important refuge for flora in southern Iberian Peninsula. At present, endemic trees such as Abies pinsapo and Quercus faginea subs. alpestris are found. However, its strategic geographical location may also have served in the past as a refuge for other tree taxa. In order to reconstruct the vegetation history in this protected natural area, this research aims to use pedoanthracological analysis in an unexplored area of this mountainous system. The results obtained have allowed to identify a new paleopopulation of Abies, a finding that provides new keys on the paleobiogeography of this species. This is the oldest evidence of this genus and at the highest altitude of those found to date in the southwestern Baetic Cordillera, which would confirm that this fir tree was present in high elevations of the Sierra de las Nieves during the Pleistocene-Holocene transition. Likewise, the first anthracological evidence of Pinus nigra/sylvestris type in the southwestern end of the Baetic Cordillera has been obtained. Forest fires could have been one of the main factors which would be determined the shaping and evolution of the vegetation landscape, as suggested by the fire events identified from the soil analysis. This information can be useful for the conservation and adaptive management of the most threatened forests and their habitats in the face of global change.

In the context of global warming, the dynamics of East Asian Summer Monsoon (EASM) are of great significance for predicting future climate change. The variations of humidity indicated by various climate proxies in Central China are controversial. This study relies on pollen data retrieved from lacustrine sediment at the Anshang site in Anyang archaeological area, Central Plains of China to quantitatively reconstruct the change in PANN (mean annual precipitation). The results show that the region experienced three distinct dry-wet intervals during the ∼8.54 to ∼3.26 cal ka BP: the earlier portion of the mid-Holocene (∼8.5–∼6.0 cal ka BP) witnessed the higher PANN; the latter portion of the mid-Holocene (∼6.0–∼3.6 cal ka BP) enjoyed the highest PANN of the past ∼8500 years with a noticeable cold and dry event occurred around 4.2 cal ka BP; the late Holocene (∼3.6–∼3.2 cal ka BP) experienced the lower PANN. Periodic analysis on pollen-based precipitation further reveals ∼500-year and ∼800-year cycles, matching well with regional climate records. Our regional comparison suggests that the Central Plains of China shared similar climatic controls with the southern region of China during the ∼8.54 to ∼3.26 cal ka BP. Shifts of Western Pacific Subtropical High (WPSH), driven by the ENSO (El Niño-Southern Oscillation) conditions and SST (Sea Surface Temperatures) in the western tropical Pacific, regulated the positioning of the EASM-related rain-belt during ∼8.54 to ∼3.26 cal ka BP. This study provides more reliable variations of humidity in the Central Plains under the influence of the EASM, which is helpful to predict future climate change.

Bioerosion traces are a powerful tool for reconstructing benthic paleo-communities through the geological record. The late Quaternary marine deposits of Patagonia (Argentina) are elongated ridges parallel to the present coast, rich in sand, gravel and shells, the latter being the main substrate for bioerosion traces. However, the ichnological studies in the Quaternary are scarce in high latitudes of the Southern Hemisphere. This work describes for the first time the bioerosion traces recorded in shells belonging to diverse taxa of mollusc from Quaternary deposits in Puerto Lobos, Southern of San Matias Gulf (Patagonia, Argentina). This study complements the scarce information on bioerosion traces in the Southern Hemisphere. A total of 710 mollusc shells were obtained from four Quaternary beach ridges at Puerto Lobos. As a result, 15 ichnotaxa were recorded for the first time in the site, 13 of them for the first time in the Holocene of San Matías Gulf. Through qualitative analysis, bioerosion patterns were observed in the late Quaternary of Puerto Lobos. The abundance of worm and sponge borings in the Pleistocene could be related to warm and sediment-free waters. On the contrary, the results of the bioerosion study in the Holocene and recent samples were very similar. This could indicate that the same environmental factor controlled both bioerosion patterns. For the Holocene, it was observed that the bioerosion pattern is mainly represented by trace produced by suspension and filter-feeding organisms, such as bryozoans, among others. Together with the increase in ichnodiversity, this could indicate an increase in nutrient availability in the San Matías Gulf associated with upwelling events. Therefore, our results reinforce the hypothesis proposed by previous authors that the upwelling events currently observed in the study area began during the mid-Holocene.

The substantial volume of timber recovered from the aftermath of the eruption of Vesuvius in 79 AD offers a valuable resource for gaining insights into the timber trade during Roman times. Silver fir emerges as the dominant species in construction within the Vesuvian region. While this species once thrived more abundantly along the Apennines, it now exists only in small, isolated groups, raising the possibility that the Romans contributed to its scarcity. Nevertheless, the origins of the substantial quantity of silver fir wood discovered in Pompeii, Herculaneum, and the surrounding areas remain unclear. This study examines 35 wood samples obtained during the excavation of the Moregine site, an ancient commercial port located a mere 600 m to the south of Pompeii's walls. Dendrochronological analysis successfully dated 19 out of the 35 samples. Despite silver fir not being the ideal species for dendroprovenancing analysis, certain observations can be made regarding its likely foreign origin. The correlation with chronologies of different species of Central European origin, the presence of species such as spruce/larch among the structural material and the existence of different groups among the material analysed are strong indications that demonstrate the foreign origin of at least some of the timber. Dendrochronological data further support that the wood trade played a strategically significant role in the economy of ancient Rome.

Shallow-sea environmental variations in the eastern Arabian Sea (EAS) have been related to monsoon variability, poorly ventilated intermediate water, and primary productivity changes. To understand these conditions, benthic foraminiferal assemblages, oxygen isotope ratios, and total organic carbon content have been examined in sediment Core SK291/GC13 from the EAS. We aim to retrieve decadal to centennial time-scale changes in past oxygenation and paleoproductivity during the last 7400 calibrated years before the present (cal yr BP). Our proxy data suggest that the oxic benthic foraminifera species were dominant during ∼7400–6000 cal yr BP. The change from oxic to dysoxic occurred during ca. 6000–3500 cal yr BP, and transition from dysoxic to suboxic environmental conditions happened at ca. ∼3500 cal yr BP. These changes are contemporaneous with weakening of the Indian summer monsoon beginning at ∼5500 cal yr BP which culminated into a major arid phase so-called ca 4.2 ka event in the Indian subcontinent. The EAS experienced low productivity during the early phase of our studied interval (∼7400–6000 cal yr BP) and higher productivity in the middle Holocene (6000–3000 cal yr BP), as revealed by the total organic carbon and benthic assemblages. Furthermore, productivity increased in the warm period and decreased in the Little Ice Age on a decadal scale. The spectral analysis of total organic content and suboxic species indicates a 23-year Hale (solar) cycle during the last millennium, indicating a close relationship between solar activity and monsoon variability. The strengthening of the El Nino-Southern Oscillation perhaps amplified due to increased solar activity in the last millennium, which influenced the climate of the EAS. The study highlights paleo-oxygenation shifts based on benthic foraminiferal assemblages, which are crucial for understanding changes in the oxygen minimum zones (OMZs) and their potential impacts on marine ecosystems.

Rapid and minimally destructive methods for estimating the endogenous organic content of subfossil bone save time, lab consumables, and valuable ancient materials. Fourier transform infrared (FTIR) spectroscopy is an established method to estimate bone protein content, and portable spectroscopes enable field applications. We review the ability of benchtop and portable FTIR indices to predict %N and %collagen from 137 bone specimens drawn from eight taxa. We also explore associations of these indices with the endogenous DNA content estimated for 105 specimens. Bulk bone elemental abundance and crystallinity index data reflect diagenetic alteration of these specimens, which come from a variety of depositional environments in four countries (Madagascar, Greece, Monaco, and Germany). Infrared (IR) indices from benchtop and portable units perform similarly well in predicting observed sample N content and collagen yields. Samples that include little collagen (0–5 wt%) tend to have similar IR index values, and we present a Bayesian approach for the prediction of collagen yields. Bone type best explains variation in target species DNA content (endogenous DNA being particularly abundant in petrosals), but low IR index values were consistently associated with minimal DNA content. We conclude that, although portable FTIR fails to distinguish collagen preservation among poorly preserved samples, a simple approach with minimal sample preparation can effectively screen bone from a variety of taxa, elements, and environments for the extraction of organics.

Sea-level rise was a key factor changing environments during the Early Holocene in Northwest Europe. It affected Mesolithic hunter-gatherer communities by inundating large areas in the current North Sea, commonly referred to as Doggerland. In this paper we present novel inundation models for the southern North Sea providing visualisations of lateral inundation driven by sea-level rise and relate it to frequency analysis of radiocarbon dates from archaeological sites. These improve on previous studies that relied on bathymetric data, which includes post-inundation overprints of Holocene sedimentation and erosion, and thus significantly underestimates the timing of inundation in some areas.

We constructed a paleoDEM (a composite elevation grid of the top of the Pleistocene) for the eastern part of the southern North Sea; and sea level surfaces that combine relative sea-level curves from glacio-isostatic adjustment models optimised for Britain and southern Scandinavia respectively. We corrected our paleoDEMs for tectonic background basin subsidence, and in the inundation modelling account for pre-compaction elevation of peat in coastal areas. We evaluated the impact of these model components on our results and describe the possible inundation history of Doggerland. We suggest earlier inundation than predicted by previous models, showing significant area loss around 10.5–10 ka cal BP.

Palaeogeographic changes are compared with archaeological radiocarbon data using a dates-as-data approach. Composite Kernel Density Estimate and permutation tested Summed Probability Distributions are used as a proxy for the visibility, nature and intensity of human activity. Results indicate key periods of growth and decline recorded in the dataset, as well as regional differences in growth rate, some correlating with inundation phases. Chiefly, we find elevated growth rates around 10.5–10 ka in northwest Germany and the Netherlands, contemporaneous with the abovementioned phase of extensive area loss, and moreover, with changes in culture and practices on Early Mesolithic sites.

However, the spatiotemporal distribution of archaeological data is significantly influenced by accessibility and preservation of sediments of a certain age. We discuss the importance of inundation modelling and sediment data in understanding how landscape taphonomy affects archaeological patterning, especially in dates-as-data approaches.

This paper presents sedimentological and paleobotanical studies of the deposits from Last Glaciation (Late Nemunas, Late Weichselian) in the middle reaches of the River Nemunas in southern Lithuania. Spores, pollen, and other palynomorphs in the intercalated sediments between the diamicton (glacial till) beds were analyzed, and the paleogeographical and paleoclimatic conditions of their sedimentation were assessed using the modern analog technique (MAT). The two till layers from the Last Glaciation, characterized by significant differences in their composition, testify to a difference in glacier movement paths in the region. The continuous sedimentation process between glacial tills provides evidence of global climate changes during the Last Glaciation and the restructuring of glacial lobes during deglaciation in the southeastern part of the Scandinavian Ice Sheet. The sedimentation process and vegetation composition bear witness to an open landscape of steppe-tundra, scattered wooded areas, and the emergence of thermophilic vegetation afterward, suggesting increased annual temperatures and higher humidity. The available data enable the identification of the Balbieriškis interstage period within the Late Nemunas Glaciation (Upper Nemunas Formation) between the Grūda and Baltija stages (Grūda and Baltija subformations) in the regional Quaternary stratigraphic scheme. This period correlates with the Marine Isotope Stage 2 (MIS 2).

Projectile implements are one of the most frequent transformed lithic blanks within the Upper Paleolithic assemblages. Since the first taxonomic studies, their morphological variability has been used as primary fossil director to define specific regional trends and diachronic phases. However, an exhaustive analysis of manufacturing methods and techniques applied to shape this gear category is extremely rare. In fact, during the Late Epigravettian, except for a certain typological variability, the lack of detailed studies resulted in an apparent homogeneity in armatures production. In this paper, a technological and traceological approach applied to reconstruct the whole chaîne opératoire of armatures manufacture in three Northern Italian sites dated between 17,000 and 12,000 cal BP demonstrates important variations in how projectile implements are fashioned, concerning shape, production methods and retouch techniques. Moreover, a large-scale comparison suggests how renewals in projectile implements production in North-Eastern Italy may result from long-distance connections between human groups over the western Late Epigravettian territory.