This study examines population dynamics, climatic changes, and subsistence transitions in prehistoric East Asia (10–2 ka BP; corresponding to modern China, South Korea and Japan) using summed probability distributions (SPDs) of radiocarbon dates (n = 25189) and settlement data from the Atlas of Chinese Cultural Relics (n = 51432). Subsistence patterns were analysed through human isotopic data (n = 4111). The results reveal significant regional disparities in population trends. The initial population rise in East Asia was closely tied to the development of agriculture in core regions such as the Yellow and Yangtze River basins, where gradual demographic growth was supported by endogenous crop domestication and favourable climatic conditions. In contrast, agriculturally marginal zones experienced later and more rapid population increases driven by the diffusion of farming practices under deteriorating environmental conditions. Japan followed a distinct trajectory, where population growth during the Middle Jomon period was driven by intensifying resource exploitation and increasing social complexity rather than full-scale agriculture. Three phases of population decline were identified: (1) at 5.1 ka BP, linked to the decline of the Hongshan and Yangshao cultures; (2) a broader decline between 4.3 and 4.0 ka BP, affecting multiple regions, including the Qinghai-Tibetan Plateau, Upper Yangtze, Southeast China, and East Japan; and (3) a localized decline in the Hexi Corridor and Southwest China began at around 3.8–3.6 ka BP. Population declines in East Asia around 4.2 ka BP were asynchronous across regions and varied widely in timing and magnitude, indicating that the 4.2 ka rapid climate change event had uneven regional impacts. Rather than supporting a linear narrative of climate-driven subsistence collapse, our synthesis finds limited evidence for widespread agricultural failure: most regions responded through adaptive farming, technological innovation, and institutional reorganisation, pointing to transformative resilience through reconfiguration rather than collapse—though in some areas, demographic changes still occurred close in time to climatic change.
Proximal alluvial successions in continental rift basins preserve vital source-to-sink records, yet their high-energy depositional environments frequently obscure primary paleoclimatic signals through hydrodynamic sorting and early diagenesis. To disentangle these competing controls, we investigated a 181.0-m sediment core (XDZK02) from the extensional northern margin of the North China Craton. We establish a robust ∼3.6 Ma chronostratigraphy using 26Al/10Be burial dating, magnetostratigraphy, and 14C dating, integrated with continuous geophysical well logging with environmental magnetism. Our multi-proxy approach demonstrates that magnetic susceptibility variations in this setting are overwhelmingly facies-controlled rather than pedogenic. Magnetic maxima reflect the hydrodynamic concentration of coarse detrital minerals, corresponding to an anomalous high-gamma arkosic sand signature, whereas near-zero minima result from reductive dissolution under waterlogged oxbow lakes. By systematically filtering these autogenic overprints, we decode discrete watershed-scale allogenic events: (1) a profound ∼0.65-Myr depositional hiatus (0.90–0.20 Ma) signifying a major Middle Pleistocene tectonic inversion; (2) a ∼48 ka upstream river capture event that initiated severe downstream sediment starvation; and (3) a ∼17 ka regional uplift driving terminal terrace abandonment. Consequently, this study underscores the limitations of employing bulk magnetic susceptibility as a direct paleoclimate proxy in fluvial settings, emphasizing the necessity of rigorous, facies-controlled proxy decoupling to accurately decipher tectono-climatic signals in terrestrial archives.
Fish Lake provides a continuous, high-resolution freshwater paleoclimate archive of glacial and hydroclimate history from a catchment straddling the Colorado Plateau–Great Basin boundary in the western US. At >3600 m, the Fish Lake Plateau glaciates during stadials, making it an ideal site for tracking the region's glacial history. The high-resolution (>3.3 mm/decade) record contains multiple climate- and ecosystem-sensitive proxies. Geochronology relies on 210Pb and AMS 14C measurements on terrestrial macrofossils and charcoal, tephrochronology, and paleomagnetic measurements. Multiproxy analyses include indicators of glacial erosion (magnetic susceptibility, sediment density, % mineral matter, grainsize, scanning XRF) and biological productivity (biogenic silica, organic matter). These proxies show glacial inception during the local Last Glacial Maximum at 25.8 ka, coincident with Heinrich Stadial 2, with maximum down-valley ice expansion between 24.8 and 20.9 ka. Glaciers reached the shoreline but did not override the lake, and sedimentation rates did not exceed Holocene levels, as increased glacial erosion was offset by reduced productivity in the glaciated, turbid lake. Deglaciation began by 18.2 ka, was interrupted by a readvance under wetter conditions synchronous with Heinrich Stadial 1 and concluded with final catchment deglaciation ∼14.1 ka. After 13.7 ka, productivity proxies rise rapidly and remain high through the Holocene while erosion proxies drop abruptly. Comparison with the adjacent Bonneville pluvial lake-level record shows that glacial onset on the Fish Lake Plateau preceded the rise in Bonneville water levels at ∼24 ka by roughly a millennium, implying temperature decreases led P-E increases. Similarly, deglaciation onset preceded falling Bonneville water levels by several centuries.
Beachrocks have been used as markers of past relative sea level (RSL). However, their wide range of occurrence from supratidal to subtidal zones poses challenges in constraining their indicative meaning, i.e., formation depth range relative to reference water levels. Here, we integrated lithofacies, petrographic, and geochemical analyses to infer the paleoenvironment and diagenetic processes of two emergent, parallel beachrocks (BRS1 and BRS2) in southwest Panay facing the Negros Trench forearc in the Philippines. We identified seven lithofacies with the topmost unit characterized by seaward-dipping foreset cross-stratifications, underlain by massive, hummocky, and cm-scale trough cross-stratification. Petrography, SEM-EDX, and δ13C–δ18O ratios of the cement indicate at least two cementation phases in predominantly marine pore water with the latter phase characterized by micritized cement. From these analyses, we interpreted a subtidal, upper shoreface paleoenvironment with an indicative meaning between mean lower low water and wave base. Bulk radiocarbon dates of beachrock cement indicate that the topmost lithofacies of BRS1 formed during 5855–4508 cal BP, whereas BRS2 formed during 3128–1825 cal BP. Based on the indicative meaning, real-time kinematic global navigation satellite system survey, and C-14 dating, we reconstructed a Holocene relative sea-level history along the Negros Trench forearc. The RSL misfits of beachrocks were generally higher compared to published Holocene glacial isostatic adjustment (GIA) models and sea-level indicators in surrounding islands. We attribute these misfits to tectonic uplift after ∼1800 cal BP which also ceased beachrock progradation. This study demonstrates the advantages of integrating these analyses in determining the indicative meaning of beachrocks.
This study investigates gravity-flow deposition in the supply-limited northern Ecuadorian margin to extend the paleoseismic record, using core and chirp dataset collected offshore the Esmeraldas and Pedernales segments. Event-bed architecture, benthic-foraminiferal and ichnological assemblages, and along-strike stratigraphy are integrated to reconstruct depositional processes and evaluate how margin morpho-structure and tectonic preconditioning control source-to-sink relationships, event-bed style, distribution, recurrence, and paleoseismic significance. Hemipelagic sediments are interbedded with single-pulsed (STu), multi-pulsed (MTu), amalgamated turbidites (ATu), volcaniclastic turbidites (VTu), and debrite–turbidite (DT) couplets. The internal architecture of MTu, ATu, and DT couplets reveals quasi-synchronous but temporally staggered flow pulses within a single composite event. In the northern zone, middle-bathyal-to-abyssal sources are routed through the Galera collision zone and Galera Fault, where landward- and steeply dipping structures favor larger, less frequent failures resulting in MTu–ATu and DT couplets. In the south, upper-to middle-bathyal sources are routed through gullies, where the seaward-dipping structures of the Atacames collision zone favor smaller, more frequent STu. Forty-five event beds deposited over ∼5 kyr (AD 1897 to 3403 BC) include 8 margin-wide MTu–ATu and DT couplets with a mean recurrence interval of 577 (+240/−239) yr, consistent with an ∼600-yr recurrence for Mw ≥ 8 earthquakes, and 29 basin-wide STu with multi-decadal recurrence intervals, consistent with Mw 7–7.5 earthquakes. Nine DT couplets in deeper chirp stratigraphy span ∼17 kyr across the lowstand and highstand but absent during the intervening transgression. Sea level acted as a secondary modulator, while earthquakes remained the principal, though not exclusive, trigger. These findings demonstrate the paleoseismic value of supply-limited trenches when depositional processes and tectonic preconditioning are evaluated.
Reactive iron (FeR) plays an important role in the long-term burial of sedimentary organic carbon (OC). However, the temporal changes in the iron-bound OC (FeR-OC) preservation since the last glacial period and the controlling factors remain unclear. Here, we analyzed the FeR, FeR-OC and stable carbon isotopes in core DZ39 (slope) and JW2 (basin) from the South China Sea (SCS). We investigated the effects of productivity, terrestrial input and redox conditions on FeR-OC preservation and quantified the burial flux and stock of FeR-OC. In core DZ39, the fraction of FeR-OC in total OC (fFeR-OC) averaged 16.8% during the last glacial period, 9.0% during the deglaciation and 8.6% during the Holocene. In core JW2, fFeR-OC averaged 11.5% during the deglaciation and 19.3% during the Holocene. The sedimentary records from the two cores diverge during the Holocene. These variations were jointly controlled by marine OC supply, terrestrial FeR input and redox conditions. During the last glacial period, more oxygenated conditions and sufficient marine OC and terrestrial FeR inputs promoted high fFeR-OC in DZ39. During the deglaciation, relatively reducing conditions and declining marine OC and terrestrial FeR inputs lowered fFeR-OC in both cores. In the Holocene, increasingly reducing conditions further decreased fFeR-OC in DZ39, whereas the more oxygenated conditions increased fFeR-OC in JW2. The FeR-OC stock of SCS since the last glacial period was estimated at 21 Pg C. These results reveal contrasting FeR-OC preservation patterns between the slope and basin and highlight the importance of FeR in OC sequestration on glacial-interglacial timescales.
This study presents a multidisciplinary analysis of the Pleistocene sedimentary sequence from the Grotta Maggiore di San Bernardino, located in the Berici Hills, a subalpine region of north-eastern Italy. A combination of sedimentology, micromorphology, mineralogy, and optically stimulated luminescence (OSL) dating is used to reconstruct depositional processes and palaeo-environmental conditions for the site. Stratigraphic and micromorphological analyses reveal that the sequence reflects an interplay of geogenic and anthropogenic processes, with frost action, solifluction, and aeolian inputs alternating with accumulations of hearths, bones, and lithic debris. The sedimentary environmental proxies, integrated with biological data from a molluscan assemblage, point to alternating moist and more arid episodes, consistent with wider climatic fluctuations. The single-grain OSL ages presented here provide an improved radiometric framework for these deposits, indicating that accumulation of Units VII–IV spanned the interval from Marine isotope Stage (MIS) 8 through MIS 7 and into MIS 6. The chronology is consistent with palaeo-environmental evidence for alternating cold and interglacial conditions recorded within the sequence. These new dating results complement and expand upon minimum age estimates obtained previously using electron spin resonance and uranium series (ESR-US) dating, as well as non-finite radiocarbon ages published for the top of the sequence (Unit II – deposited sometime prior to early MIS 3). The updated chronological framework not only refines the temporal context of the archaeological and palaeontological assemblages but also anchors local sedimentation patterns to regional paleoclimatic oscillations. Overall, the results suggest that the San Bernardino deposits preserve a complex interplay of natural sedimentation from slope and aeolian processes, karstic inputs, and anthropogenic activity, offering critical insights into both site formation processes and human presence during the Middle Pleistocene.
This study presents a multi-proxy reconstruction of Holocene growing season thermal conditions (GDD5) in Central Europe based on Betula nana subfossil leaf micro-phenology and pollen data from a 12-m-long sediment sequence at Linje peatland. A site-specific inference model was developed using modern B. nana leaves to estimate growing season heat accumulation. The model shows lower sensitivity compared to subarctic calibrations but captures variability in GDD5 within the local climatic range. Overlapping undulation index (UI) values observed in modern and subfossil material across differing thermal conditions highlight the importance of regional calibration. Reconstructed GDD5 trends indicate variability in growing season conditions during the Early Holocene and from ∼5450 cal. yr BP to the present and show the strongest agreement with pollen-based estimates during the first half of the Late Holocene. As GDD5 is an important factor controlling agricultural productivity, such reconstructions are important for understanding past changes in seasonality and their potential implications for prehistoric land use and settlement dynamics. The results demonstrate the applicability of combined micro-phenological and palynological approaches for reconstructing past growing season thermal conditions.
Sapropel S1 corresponds to the latest deoxygenation event that occurred in the Mediterranean Sea between ∼10.2 and 6.8 cal kyr BP. However, terrestrial deposition coeval with Mediterranean Sapropel S1 remains poorly understood. Through the integration of sedimentological, paleontological, geochemical (TOC, TN, δ13C, δ15N) and chronological data within a regional onshore-offshore framework, this study investigates the Upper Pleistocene-Holocene fill of the Biferno paleovalley system (Southern Italy) and characterizes the S1-equivalent (S1eq) succession.The results document a continuous S1eq record comprising three stratigraphic intervals (S1aeq, S1breakeq, and S1beq) that can be correlated with the corresponding offshore S1 phases. Facies evolution from poorly-drained floodplain to estuarine deposits reflects Holocene relative sea-level rise and paleovalley drowning. Bulk geochemical proxies display strong stratigraphic control, with δ13C and δ15N trends closely tracking facies shifts and Organic Matter (OM) sources.Onshore-offshore correlation and comparison with other Adriatic paleovalley systems reveal a marked decoupling in organic-carbon accumulation during the S1 break, consistent with the progressive landward migration of river mouths during the Holocene transgression. This evolution promoted enhanced terrigenous OM storage within paleovalleys while reducing its export toward deeper basin sectors.These findings indicate that paleovalley systems constitute key transient repositories of sediment and organic carbon during rapid transgression and provide a valuable terrestrial archive for reconstructing the evolution of the Adriatic source-to-sink system during Mediterranean Sapropel S1 deposition. Their stratigraphic record offers a critical link between continental and marine systems, providing new constraints on the environmental processes accompanying S1 deposition in the Adriatic and Mediterranean regions.
This paper presents the first systematic palaeoclimatic reconstruction of southern Italy, primarily focusing on the Puglia region, from 1000 to 1800 CE. Although documentary sources provide a wealth of climatic information for this area, they primarily record anomalies rather than normal climatic conditions, offering no baseline for comparison.To address this issue, we compiled a relational dataset comprising 526 documentary climate events, 285 of which were selected for quantitative analysis using the Pfister seven-point scale. We developed a Bayesian state-space model integrating these observations with CHELSA-TraCE21k palaeoclimatic simulations, which provide informative priors linked by a first-order autoregressive process. Observations enter the model through an ordinal logistic likelihood. The resulting posterior should be interpreted as a simulation-anchored latent climate state, informed primarily by documented extremes, rather than as a direct reconstruction of centennial annual-mean conditions.The temperature posterior indicates predominantly negative anomalies from the 15th century onward, broadly consistent with a Little Ice Age cooling phase, although the magnitude is influenced by the strong representation of extreme cold events and the 16th-century estimate is largely determined by the prior and temporal persistence.The precipitation reconstruction reveals a more complex picture: the CHELSA-TraCE21k prior exhibits a progressive drying trend not reproduced by an alternative forced simulation (ModE-Sim), while the documentary posterior remains closely aligned with the forced simulation. This agreement suggests that the prior–posterior divergence may reflect a regional feature of CHELSA-TraCE21k, although alternative explanations, including documentary reporting bias and model assumptions, cannot be excluded. Posterior uncertainty reflects data availability, with narrower credible intervals in well-documented periods.We compare both posterior reconstructions with two products from the Modern Era Reanalysis framework (ModE-RA and ModE-Sim), using anomalies re-baselined to a common reference period, and find broad agreement for temperature but a more informative divergence for precipitation. This comparison assesses consistency across climate products and highlights the sensitivity of the inferred precipitation trajectory to the simulation product used as prior, rather than providing an independent validation of either reconstruction. This framework can be applied to other regions where discontinuous historical evidence must be integrated with simulation-derived climate baselines.
Testate amoebae are known among the proxies for paleolimnological investigations but, despite their recognized importance and recent findings, they have not been sufficiently studied in alpine lakes, particularly in Europe. The present study analyzes fossil testate amoeba assemblages from the Upper Balma Lake (2216 m a.s.l., Western Alps, Italy) to reconstruct ecological changes over the past 1200 years. 21 species belonging to 5 genera were identified, with Centropyxis and Difflugia being the most abundant. Multivariate statistical analyses, combined with sedimentological and geochemical data, revealed five paleoenvironmental phases corresponding to known climatic events, including the Medieval Climate Anomaly, the Little Ice Age, and the Recent Warming period. Assemblage composition and diversity were related to grain size variations, nutrient input, and trace element concentrations (e.g., As, Mn, Mo) and periods of climatic stability were associated with higher biodiversity, while cold or disturbed intervals, marked by floods or sediment reworking, resulted in reduced abundances and diversity. In recent decades, a decline was observed for the genus Centropyxis, possibly indicating reduced oxygenation and changes in contaminant levels. Comparative analysis with the Lower Balma Lake, located downstream in the same area, highlighted the influence of morphological/hydrological differences between lakes on species distributions.The findings underscore the value of testate amoebae as sensitive bioindicators and their applicability in paleoecological reconstructions of alpine lakes. This study contributes to understanding long-term ecological responses to climate change and provides insights into flood regime variability in high-mountain environments.
The Quaternary has long been divided based on climatic changes, and this is evident today in terrestrial, marine and ice-core records. The main stratigraphic units of the Quaternary are glacial (glaciation) and interglacial periods. The recognition of the short-lived climate oscillations within glaciations have led to a further subdivision into relatively warm interstadials and cold stadials. These millennial-scale climate periods have characterised and punctuated the Pleistocene, especially during glacial periods. Here we review the use and meaning of interstadials and stadials in continental, marine (oxygen isotope stratigraphy) and ice sheet (Greenland ice cores) environments.
Organic carbon (OC) stored in Arctic watersheds for millennia can be remobilized and transported to lakes as climate change alters environmental conditions. The radiocarbon (14C) age of OC in lake sediments provides insight into carbon storage and cycling. Bulk lake sediment 14C ages integrate many OC pools, whereas macrofossil 14C ages generally represent the time of sediment deposition. The offset between them (Δ age) provides insight into lateral carbon transfer. We analyzed Δ age from five lakes in Alaska, Russia and Siberia, using 191 bulk sediment 14C ages paired with new (n = 87) and existing macrofossil 14C ages spanning 20,000 years. Lake-averaged Δ age ranges from several hundred to nearly 10,000 years. By comparing Δ age with sediment physical properties, we find that petrographic OC provides a first-order control on Δ age magnitude, followed by impacts of productivity (driven by climate) and erosion rates (driven by landscape stability). Δ age was much larger in the late Pleistocene than the Holocene, reflecting more productive vegetation and thicker organic horizons during the Holocene, which reduced older OC release and increased younger OC production. On millennial time scales, total productivity is a major control on the proportion of old carbon that accumulates in Arctic lakes, but sediment flux exerts a stronger influence on OC accumulation overall. These results underscore complex interactions between climate, geomorphology and carbon storage, with implications for understanding past and future carbon fluxes in a warming Arctic.
Comparable speleothem δ18O values over eastern China during past four peak interglacials suggest similar East Asian summer monsoon (EASM) intensities, but large orbital insolation and land-sea thermal contrast variations highlight varying EASM intensities, supported by loess and marine records. To resolve this paradox, we focus on the Last Interglacial (∼127 ka) and Holocene (∼6 ka) using an isotope-enabled fully coupled climate model. Our model reproduces a stronger EASM but comparable speleothem δ18O values during the Last Interglacial relative to Holocene. The stronger EASM, driven by enhanced land-sea thermal contrast arising from a higher insolation, induces lighter precipitation δ18O over eastern China via the rainout process. However, this lighter signal is overwhelmed by heavier δ18O arising from moisture source location and composition changes, yielding slightly heavier δ18O over eastern China. Our results highlight speleothem δ18O values retain significant but incomplete sensitivity to the EASM intensity, which helps reconcile conflicting proxies for monsoon variability and comprehensively understand past monsoon dynamics.
Northeast Africa and Southwest Asia present a rich record of hominin occupations between ca. 100 and 50 thousand years ago (ka) at a critical biogeographic crossroads, with differences in physical landscapes, environmental responses to climate change, and varied population histories contributing to archaeological diversity. Research in Arabia has identified previously unexplained technological heterogeneity amongst stone tool assemblages. To investigate this pattern, we compiled a database of Levallois blank attributes to quantify patterns of variability observed across sites in Northeast Africa, Arabia, and the Levant. A range of alternate explanations for variability within this comparative dataset are explored using Simple Mantel tests and Multiple Matrix regressions including assemblage age, landscape setting, palaeoenvironmental conditions, assemblage size, composition and raw material use, site type, and population history. The results highlight that shape variability in Levallois blanks across the region is best explained by differences in population history. We then train logistical regression models to differentiate the population history associated with Levallois blanks with a >93% agreement rate and apply this model to key Arabian assemblages dating to ca. 55 ka. The results strongly support a Neanderthal attribution. We interpret these findings in the context of wider debates surrounding Neanderthal expansions and a wider role for Arabia in South-West Asian hominin demography.
