Convergent science supports the hypothesis that people using watercraft dispersed eastward from Asia to the Americas via the littoral zone of the North Pacific Rim during the Last Glacial Interval, ca. 17,000 years ago. This hypothesis is supported by evidence of preexisting maritime adaptions, seafaring, and coastal navigation along Asia’s Pacific coasts prior to 35,000 years ago. Digital paleogeographic reconstructions suggest the possible existence of an island archipelago along the southern shores of the Bering Land Bridge that may have facilitated coastal navigation eastward from northeast Asia toward the Northwest Coast (NWC) of North America. A 25-year multidisciplinary research program at Shuká Káa Cave on Prince of Wales Island, Alaska, and independent research at other localities along the NWC demonstrate the existence of a biotically viable coastal corridor extending from the southern coast of Beringia to areas south of the continental ice sheets by ca.17,000 years ago. Archeological evidence and genomic data from Shuká Káa Cave and other NWC sites document a late Pleistocene maritime aspect of the Western Stemmed Point tradition (WSPt). It is characterized by an informal locally sourced flake tool industry including stemmed and foliate bifaces. The unspecialized character of this lithic tool kit and the intensive emphasis on the production and use of organic artifacts facilitate mobility and a capacity for adaptation to diverse environments and circumstances. This suggests it may be ancestral to more specialized Paleoindian technological adaptations.
Skateholm is an iconic site in Late Mesolithic research. Its numerous human graves and well-preserved cultural layers have provided a wealth of knowledge on prehistoric forager lifeways. However, while several studies have focused on the origins of the interred humans, little is known about land use, hunting grounds, and long-distance relations. To address this, we analysed 12 unmodified teeth and 22 tooth-beads for sequential strontium isotope ratios (87Sr/86Sr) and conducted a use-wear analysis of the beads to assess usage extent and inheritance. The animal Sr data were contextualised within a high-resolution bioavailable Sr baseline of 1651 samples from Southern Scandinavia and the northern Central European plains and visualised with an Empirical Bayesian Kriging interpolated map. To fully utilise the sequential tooth data and establish probable areas of origin, the landscape around Skateholm was divided into 34 subregions, and its Sr ratios correlated with the tooth-specific Sr patterns. The relationship between teeth and subregions was examined with a Principal Component Analysis, where the Euclidean distances, through a Bayesian Gaussian-like model, were recalculated into probabilities of origin. Results show that all unmodified teeth and ca 40% of the tooth beads originated from an adjacent area to the west of the site, most likely representing the group territory and hunting grounds. The remaining tooth beads cluster into five non-local regions across Scania and Blekinge. By combining bead use-wear patterns with Sr data, we demonstrate extensive networks and inheritance practices, including a potential multi-generational use of tooth-beads from special animals. This novel approach to high-resolution Sr isotope analysis enables precise identification of local and non-local origins, offering significant potential for reconstructing mobility, transhumance, and landscape use in prehistoric societies worldwide.
This paper presents a reply to the recently published work by Fernández-Jalvo et al. (2026). Their paper focused on a critique of our original taphonomic interpretation of microvertebrate remains from the Middle Paleolithic assemblages of Tabun Cave Layer C (Fried et al., 2024). We address several material mischaracterizations and engage with substantive criticisms, clarifying and strengthening our original findings through further analysis. While acknowledging some legitimate concerns, we provide additional evidence that certain characterizations of our study do not fully capture its comprehensive scope and methodological rigor. Our original ‘signal-versus-noise’ framework established that pervasive post-depositional noise compromises many conventional taphonomic indices. However, molar digestion grading consistently provides a robust and noise-resistant signal for predator attribution. We present additional analyses confirming that the taxonomic restriction of molar digestion did not alter our conclusions and that evidence for hydrodynamic sorting is limited. Our response reinforces the central finding of Fried et al. (2024): molar digestion scoring reliably indicates a low-impact Category 1 raptor, such as Tyto alba, as the most likely primary accumulating agent for the Tabun Cave Layer C microvertebrate assemblages.
The Chinese Loess Plateau (CLP), with its extensive deposits of eolian dust and interbedded paleosols, provides a unique archive for reconstructing climate variability, particularly precipitation and monsoonal dynamics. This study examines the magnetic properties of 106 modern topsoil samples from the CLP to explore their spatial distribution and relationship with climate factors, provides a systematic, publication-quality comparison of CLP magnetic climofunctions from 1994 to the present day. Our results showed that topsoils were primarily composed of magnetite and maghemite, with grain sizes ranging from superparamagnetic (SP) to single domain (SD) and pseudo-single domain (PSD). Magnetic properties such as low-field magnetic susceptibility (χlf), anhysteretic remanent magnetization (χARM), and frequency-dependent susceptibility (χfd%) demonstrated a clear spatial trend, increasing from northwest to southeast in parallel with higher mean annual precipitation (MAP) and temperature (MAT). These findings highlight precipitation as a critical driver of magnetic enhancement through pedogenic processes, particularly during wet and dry cycles. Both MAP and MAT showed positive correlations with χARM/SIRM and χfd%, while correlations with χlf were weaker, reflecting the complexity of climate and soil interactions. We established new climofunctions linking MAP and MAT with χARM/SIRM and χfd%, and place these in the context of previous transfer functions for the CLP, underscoring the potential of magnetic proxies for high-resolution climatic reconstructions in monsoon-dominated regions.
Wallacea was an important region for maritime adaptation by Homo sapiens during the Late Pleistocene and Early Holocene. Evidence for maritime adaptation includes intensive use of shell tools and ornaments. Such evidence has been common in South and East Wallacea but scarce in North and West Wallacea. Here we report the first evidence for extensive use of shell tools and marine resources from a karstic cave site on Selayar Island in West Wallacea. The new evidence includes shell serrated points, scrapers, and fishhooks. Shell fishhooks are known from the Late Pleistocene in South and East Wallacea and the Ryukyu Islands of Japan. In Wallacea, the development and dispersal of such shell hooks and other shell tools occurred during the Terminal Pleistocene and Early Holocene, but is limited in South and East Wallacea to the islands of Timor, Alor and Kisar. Two hypotheses can be proposed to explain the absence of fishhooks in North and West Wallacea; (1) technological or cultural differences, or (2) environmental factors such as island size and the abundance of terrestrial resources. The serrated point is a representative cultural artifact from South Sulawesi, which are usually made of stone. The shell serrated point and fish hooks in Selayar provide significant insights into Early Holocene modern human activities on a small remote island between the large islands of Sulawesi and Flores, and demonstrate a high level of adaptation to the maritime environment. The technological analysis of the artifacts suggests advanced toolmaking techniques, emphasizing the critical role of marine resources in the daily lives of the prehistoric inhabitants in Selayar, an island with limited terrestrial resources, supporting hypothesis (2). We also discuss modern human maritime and island adaptation in Maritime Asia during the Late Pleistocene and Early Holocene from this comparative perspective.
Tree-ring stable isotopes from relict wood samples play an important role in climate reconstructions, but fire exposure, waterlogging, and post-excavation storage may bias the isotopic signal. Here, we test how thermal alteration and storage conditions affect holocellulose S13C and S18O values in archaeological oak (Quercus spp.) samples from southern Germany, focusing on the 1430-1444 CE period and considering a range of preservation states. We differentiate (i) dry-stored wood across four thermal-alteration categories (unaffected, intact, moderately charred, fully charred) and (ii) waterlogged wood kept wet after excavation, sampled at the outer surface and in the interior. We found no significant differences in holocellulose S13C and S18O values among unaffected, intact and moderately charred rings. Fully charred rings yielded no extractable holocellulose; however, their bulk-wood S13C values were systematically shifted to lower values while preserving the interannual variability. In waterlogged wood, surface holocellulose S18O values were lower and showed weaker coherency with the interior series, whereas holocellulose S13C showed no meaningful change. We conclude that moderate charring and waterlogging have limited effects on holocellulose-based tree-ring isotope signals in archaeological wood. For S18O in waterlogged wood, shallow surface samples should be avoided where possible, or a correction should be applied based on the mean offset across overlapping years. Our results support the inclusion of partially degraded archaeological and subfossil oak wood in isotope-based dating and paleoclimate reconstructions.
Soil erosion and sediment transport are shaped by complex interactions between land–use management and rainfall forcing, yet the conditional nature of this interaction remains incompletely understood. Taking the Hekou–Longmen (Helong) District in the Yellow River Basin, a typical sediment source area, as the study region, this study investigated how rainfall conditions may influence the effectiveness of land–use change in regulating sediment connectivity. We reconstructed the spatiotemporal dynamics of sediment connectivity from 1990 to 2020 using the Index of Connectivity (IC) framework integrated with NDVI–derived vegetation dynamics, and explored its nonlinear relationship with rainfall thresholds using generalized additive models (GAMs). The results showed that large–scale vegetation restoration and soil and water conservation measures were associated with a long–term decline in sediment connectivity across most sub–basins, suggesting a gradual weakening of sediment transfer pathways in the study area. However, this relationship appeared to vary under different rainfall conditions. When rainfall was below the statistically inferred inflection point of approximately 65 mm in the Wuding River Basin, sediment connectivity showed a stronger association with land–use conditions, and vegetation restoration corresponded to lower sediment transfer potential. When rainfall was above approximately 65 mm, the influence of rainfall appeared to become stronger, and sediment connectivity showed signs of partial reactivation despite ecological restoration. These findings suggested that the inferred inflection point might vary under long–term land–use and vegetation changes. By linking land–use regulation with rainfall conditions, this study offered a potential perspective for understanding the coexistence of long–term sediment decline and episodic high–sediment events, and highlighted the importance of adaptive soil and water conservation strategies under different rainfall regimes.
Climate change is fundamentally altering debris flow triggering mechanisms in high-altitude regions, challenging the reliability of traditional early warning systems. We analyzed 214 debris flow sites in Bomi County, southeastern Tibet (1937-2024), integrating field surveys, remote sensing data, and meteorological observations. We evaluated the performance of an Intensity–Duration (I-D) threshold model calibrated on historical data (1950–2000) when applied to recent events (2001–2024), and developed a Temperature-Rainfall dual-parameter model. Our analysis reveals that debris flow frequency increased 7.1-fold from 2001 to 2010 (21 events) to 2011-2020 (150 events). The I-D model showed degraded performance: f false alarm rates increased from 12% to 28% and missed event rates from 8% to 19%. The dual-parameter model demonstrated superior performance (AUC = 0.87 vs. 0.74). We conclude that static, historically calibrated models become increasingly unreliable under warming, necessitating adaptive early warning systems with dynamic threshold adjustment, multi-parameter integration, and explicit uncertainty quantification. Our findings have critical implications for disaster risk management in cryosphere-influenced mountain regions worldwide.
Paleofire records represent a valuable resource for understanding long-term changes in biomass burning and fire activity, as well as their drivers. Furthermore, they offer a way to assess fire models under climatic conditions that differ from those prevalent in the contemporary era. However, further calibration studies are needed to refine the link between paleofire records and more detailed characteristics of paleofire regimes. In order to enhance our understanding of the charcoal proxy, we analysed microscopic charcoal abundance and morphology in 277 marine surface sediment samples from the eastern Atlantic Ocean off the Iberian Peninsula and the western Mediterranean Sea, and investigated their link with fire regime characteristics, climate and fuel over adjacent land in the Western Mediterranean region. Our results show that squared microscopic charcoal particles are correlated with forest fires, while elongated microscopic charcoal particles are associated with the combustion of open and mixed vegetation, so that tree vs grass burning can be inferred by the relative changes in mean microscopic charcoal elongation ratios. Microscopic charcoal concentrations are a function of fuel type, climate, fire frequency and burned areas.
The Kimberley region of north-west Australia offers a valuable lens to examine the variability of multiple regional climate systems within the context of human migration and settlement of the Sahul and now Australian continent. Despite its importance, reconstruction of past hydroclimate in the Kimberley has been challenged by its semi-arid environment, which limits archive preservation, and by its remoteness. In recent years, however, a growing body of work has demonstrated the potential of a diverse range of atypical archives for reconstructing Kimberley hydroclimate. Here we present the current state of understanding of the hydroclimate of the Kimberley, drawing on environmental reconstructions spanning the last 65,000 years. Our synopsis is that the Kimberley experienced a drier climate during the last glacial compared with the Holocene, although there remains much discrepancy between records, particularly those from early Marine Isotope Stage 3, when precipitation levels higher than present are indicated by some records. Records suggest that either dry conditions or high variability marked the MIS 2/1 transition before a wet early Holocene, leading into increased hydroclimate variability in the mid-late Holocene. There remains a sparsity of records for this vast region. The obtainment of long, high temporal resolution records is required to resolve discrepancies between existing records, and to shed light on possible causes of local scale palaeoclimate variability and extremes.
The Jomon Transgression was a relative sea-level rise that reached a highstand at 7 ka, during which Tokyo Bay formed a semi-enclosed embayment known as Okutokyo Bay (2200 km(2)). More than 600 Jomon shell middens occur on the surrounding uplands, making this region one of the most densely concentrated shell-midden areas worldwide. Reconstructing shoreline evolution and shell-midden distribution during this transgression provides a representative framework for understanding shell-midden formation processes. We obtained 36 new radiocarbon ages from the Shinoyama Shell Midden, the largest midden in the innermost part of Okutokyo Bay, and we compiled 63 previously published ages from five sediment cores and two shell-midden sites. These data were integrated with sedimentary facies, paleowater-depth reconstructions, relative sea-level changes, Holocene basal topography, and the spatial and temporal distributions of 28 shell middens. We found that (1) river-mouth flats developed in the innermost part of Okutokyo Bay during the peak of the Jomon Transgression (highstand of at least +4 m); (2) shell middens formed between 8 and 6 ka were more closely associated with the spatial dynamics of river-mouth flats than with contemporaneous shoreline positions; and (3) shell-midden formation was largely restricted to within similar to 2 km of river-mouth flats.
The Zambezian Biome, located between equatorial and southern Africa, is an important region for the study of biogeography and human evolution. Reconstructing Quaternary environmental conditions in the region has been challenging because the basin’s paleoenvironmental record is not clearly in-phase with either the eastern or southern African records. Here we use sequential intra-tooth sampling of enamel to provide the first high-resolution terrestrial records of precipitation seasonality in Malawi over the last 22,000 years, using 333 measurements of δ13C and δ18O in 62 teeth, and 20 measurements of triple oxygen isotopes (paired δ18O-δ17O) in 10 teeth from the Kasitu Valley, Mzimba District. We show that seasonality in northern Malawi has shifted over the last 22,000 years and propose that the end of the Last Glacial Maximum was drier and more seasonal than today. These results provide a framework for testable palaeoecological and archaeological expectations, including the predictable aggregation of herbivores near water sources and increased importance of riparian habitats for human foragers during arid periods.
Migration to islands requires developing subsistence strategies with limited resources. Okinawa Island, a remote subtropical island in Japan, was colonized by Homo sapiens at the end of the Pleistocene. Recent excavations at the Sakitari Cave site have revealed that Pleistocene people used freshwater crabs and snails as food resources between 35,000 and 13,000 years ago. Because long-term use of specific resources can affect animal populations, this study examined temporal changes in the proportions of animal taxa and size variation in freshwater crabs and snails obtained from Sakitari Cave. The results showed that terrestrial mammals were limited in their food consumption, and the proportion of freshwater resources increased during the Last Glacial Maximum and/or after deer extinction. And no size-reduction was observed in freshwater crabs and snails. These small-sized aquatic animals have high reproductive capacity and population density, and thus can be utilized for a long period of time on the island.
The multiscale temporal characteristics of epidemic evolution and their relationship with climate variability remain inadequately elucidated. To clarify the multiscale temporal variability and underlying mechanisms governing epidemic outbreaks during the Ming-Qing period, we applied the Complete Ensemble Empirical Mode Decomposition (CEEMD) method to decompose epidemic intensity series. This decomposition revealed pronounced variations at annual, inter-decadal, and centennial scales, corresponding to eight distinct periodic components of 3, 7, 16, 33, 75, 292, 511 and 844 years. Significantly, the contribution rate of epidemics peaked at the annual scale, reaching 66.52% in total, indicating the high frequency of epidemic occurrences during this period. Moreover, annual to inter-decadal epidemic fluctuations exhibited synchronization with ENSO variability. Comparative analysis and cross-spectral analysis further identified significant synchronous variations and shared periodic components between epidemic evolution and ENSO, indicating that regional hydrological change controlled by ENSO primarily drove epidemic patterns during the Ming-Qing period. On longer inter-decadal and centennial scales, the periodic components identified by CEEMD demonstrated remarkable alignment with solar activity cycles. This finding demonstrates that solar activity modulates regional temperature and precipitation through an air-sea coupling amplification mechanism, thereby governing epidemic outbreaks. Against the backdrop of contemporary global warming and projected intensification of ENSO variability, the risk of epidemic occurrence and spread may substantially increase in the near future.
Tabun Cave (Mount Carmel, Israel) is a key site in palaeoanthropology, preserving fossil remains of both Neanderthals (Tabun C1) and Homo sapiens (Tabun C2). Small mammal assemblages from Layer C offer critical palaeoecological insights, but recent analyses have revealed methodological inconsistencies and misinterpretations of taphonomic signals. In this study, we reorganize and reanalyse the raw taphonomic data from Fried et al. (2024) using established small mammal taphonomic frameworks, particularly those developed by Andrews (1990). Our results highlight the importance of conducting complete taphonomic analysis, based on identifying accumulation agents, assessing post-depositional processes, and avoiding interpretive errors. This work serves as a critical reappraisal of the taphonomic methodology itself, demonstrating its robustness when fully applied and advocating for its refinement and broader integration in microvertebrate palaeoecology.
Understanding the evolution of past ice sheets is essential for comprehending Earth's climate and improving its prediction. However, information about the oldest Quaternary continental glaciations is scarce due to preservation limitations and methodological challenges in dating. This study focuses on the Lower Pleistocene succession underlying the oldest preserved tills in the Baltic region, NE Europe, providing a unique opportunity to reconstruct environmental conditions prior to the first advance of the Fennoscandian Ice Sheet (FIS) into the area. As the succession occurs mostly in subsurface, we analyzed borehole cores using polished specimens and thin sections to identify depositional processes, and applied a combination of 26Al/10Be burial and authigenic 10Be/9Be dating to establish a chronostratigraphic framework. Our results reveal a complex depositional history preceding the first FIS advance. The lowermost Daumantai Formation represents alluvial sedimentation, later disrupted by a mass-wasting event that produced the Kalviai diamicton. Previously misinterpreted as glacial till, the Kalviai diamicton is redefined here as a cohesive debris-flow deposit, likely reflecting increased hydrological instability associated with climatic perturbations during the Middle Pleistocene Transition. Overlying the preElsterian interdiamicton beds indicate renewed alluvial sedimentation within the same basin. 26Al/10Be burial dating evaluated using an inverse modeling approach yields a weighted mean age of 973 +/- 62 ka for the preElsterian interdiamicton alluvial succession, indicating deposition during the Early Pleistocene and predating the Elsterian glaciation in the Baltic region. In contrast, the authigenic 10Be/9Be ratios point to a discernible variability across the Pleistocene. Assuming the inverse model burial age, the temporal change of ratios could be estimated by back-calculation from 10.19 to 11.69 & times; 10-9 (Daumantai Formation), decreasing to 5.56-8.35 & times; 10- 9 (pre-Elsterian interdiamicton beds), and further declining to the present-day range of 4.47-6.45 & times; 10-9. The contrasting performance of burial 26Al/10Be and authigenic 10Be/9Be dating highlights the sensitivity of meteoric 10Be systems to sediment recycling and variable initial ratios in low-accommodation alluvial settings. The documented paleoenvironmental changes provide a significant refinement of the regional Quaternary stratigraphy.
Granite geomorphology studies the formation and evolution of landscapes developed on igneous rocks, covering more than 15% of the continents. In Brazil's Northeastern Semi-Arid region, lajedos (rock platforms/rock outcrop) are significant residual landforms, especially in the municipalities of Quixadá and Quixeramobim, Ceará, located in the Ceará Central Domain within the Borborema Province, (Brazil). This research analyzes the morphostructural control on the orientation of these formations, aiming to identify patterns related to regional geological structures. The methodology included a literature review, acquisition and processing of cartographic data, as well as the application of geoprocessing tools and statistical analysis. The Global Moran's I Spatial Autocorrelation Index and the Local Indicator of Spatial Association (LISA) were used to assess the spatial correlation of the lajedos. Results indicated a predominant northwest (NW) orientation in the Quixadá-Quixeramobim plutons. In the Quixeramobim pluton, a strong spatial correlation was found, particularly near the Senador Pompeu Shear Zone (ZCSP). In contrast, the Quixadá pluton showed a more localized spatial association. This study highlights the importance of statistical and spatial analysis for granitic relief evolution. It suggests that factors such as lithology, mineralogy, and geological structures should be integrated into future research to better explain the spatial distribution of lajedos.
The purpose of this paper is to understand the preservation of human footprints formed in estuarine settings, with a specific focus on survival time and morphological modification. To this end, we conducted a taphonomic study by creating five trackways at two different sites on the intertidal mudflats of a modern estuary in North Wales. Trackways were monitored across multiple tidal cycles using photogrammetry to create timelapsed orthomosaics and digital elevation models. Our results exhibit a pattern of morphological footprint decay for individual tracks, while showing persistence at the same time. Under progressive influence of the tides, anatomical detail decreases, push-up ridges erode, and footprint outlines become wider with eventual sediment infill. Despite this, individual tracks remain identifiable and biometric inferences (e.g., foot length) are consistent throughout, with intra-trackway variability comparable to changes observed over time. Estimates for a complete removal of the tracks at the study sites are after five to seven days (10–14 tidal cycles). This will vary between sites as with variations in sediment properties, local hydrodynamics, and track orientation. We suggest that tidal duration is critical for footprint preservation and stress that taphonomic processes are different at sites with aeolian sediment formation. While site-specific, our results offer broader insights into the formation and survival of Quaternary footprints in dynamic coastal environments.
During the cold stage of Marine Isotope Stage 2 (MIS 2; 30–14.7 ka), vegetation dominated by pinaceous conifers expanded across the Japanese Archipelago. This study investigated new plant macrofossil data from eight sites in various regions of Japan and provided calibrated radiocarbon ages for previously reported assemblages to clarify the temporal and spatial distribution of vegetation and its species composition during this period. Subalpine conifers, which had a limited distribution in early MIS 2 (30–26.5 ka), expanded into the lowlands of central and western Japan during the Last Glacial Maximum (LGM; 26.5–19 ka) before becoming restricted to inland and higher-altitude areas in the Oldest Dryas (19–14.7 ka). In contrast, temperate conifers that had expanded until early MIS 2 became confined to the Pacific side of central Japan during the LGM. Temperate deciduous broad-leaved trees were restricted to regions south of 38°N during the LGM, but they expanded northward in the Oldest Dryas. During the LGM, forests in lowland and hilly areas in central and western Honshu were dominated by subalpine conifers rather than the deciduous broad-leaved forests or temperate coniferous forests previously suggested by paleovegetation maps. The vertical ranges of subalpine conifers and temperate deciduous trees overlapped more widely during the LGM than at present, suggesting that subalpine conifers expanded into warmer, drier habitats whereas deciduous broad-leaved trees were confined to moist valleys. Furthermore, Pinus subgen. Haploxylon and Corylus heterophylla were widely distributed, possibly providing nutrient-rich nuts, particularly high in calories, lipids, and proteins for Paleolithic populations.
