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A comprehensive understanding of modern pollen transport processes is a prerequisite for utilizing fossil pollen to elucidate the evolution of palaeoclimates and palaeoenvironments, especially in areas such as southwestern China where complex mountainous topography results in vegetation heterogeneity. In this paper, we selected four vertical profiles in mountainous regions of southwestern China, each with distinct plant communities, to investigate the relationship between modern pollen rain, vegetation types and vegetation cover, and to quantify the influence of environmental factors. Results show that pollen assemblages are generally representative of regional plant communities, although long-distant transport of arboreal pollen by valley winds can introduce signals from a much wider area. The calibrated arboreal pollen percentage (AP) and ratio of arboreal pollen to non-arboreal pollen (AP/NAP) serves as reliable quantitative proxies for vegetation cover, highlighting the importance of appropriate calibration when interpreting fossil pollen assemblages. Climate is the primary determinant of pollen distribution across these mountains, with mean temperature of the coldest month (MTCM) playing the most prominent contribution. Additionally, the impact of vegetation cover and soil nutrients on pollen distribution are also significant. Our modern study improves the accuracy of pollen interpretation for palaeoenvironmental reconstruction in mountainous regions of southwestern China. • Pollen assemblages can effectively depict the characteristics of mountain vegetation communities. • The calibrated AP percentage and AP/NAP can quantitatively indicate arboreal cover. • MTCM controls pollen distribution in different mountains of southwestern China. • Climate dominates pollen distribution below treeline and vegetation cover controls above treeline. [ABSTRACT FROM AUTHOR]

The sedimentary sequences of the Yangtze River delta comprise important Quaternary records of tectonics, sea-level oscillation, and climatic change; however, analysis is hampered by a lack of a reliable chronological framework. In this paper, we present an integrated chronology for two sedimentary sequences (core ZKW2 and ZKW4) on the southern side of the Yangtze River delta, based on magnetostratigraphy and absolute methods (OSL, 14C, and ESR dating). The basal ages of the core ZKW2 and ZKW4 are ca. 2.25 Ma and 2.96 Ma, respectively. The integrated chronology indicates significant increases in the sedimentary accumulation rate at ∼0.15 Ma, rather than the Matuyama-Brunhes boundary as indicated by magnetostratigraphy alone. The observed sedimentary transition is possibly controlled by regional subsidence of the Zhe-Min Uplift, and climate evolution during the last interglacial period. • High-quality magnetostratigraphy is obtained for the Quaternary sediments in the YRD. • The SARs of the YRD sediments significantly enhanced since ∼0.15 Ma. • Tectonics and climate factors jointly control the sedimentary evolution in the YRD. [ABSTRACT FROM AUTHOR]

Grain size is commonly used as a proxy to reconstruct past lake hydrology; however, published research rarely links grain size with modern processes, and uncertainties exist for interpretation. In this paper, we decompose the grain size frequency distributions (GSFD) for 196 lake surface sediments from 61 lakes and 9 reservoirs across the Inner Mongolia Plateau and adjacent areas and divide them into five GSFD components. We statistically analyze the relationship between the GSFD components and influencing variables to determine the taphonomic dynamics and their environmental implications. Within individual lakes, we found that GSFD component 4 (74.00–209.30 μm) and GSFD component 5 (209.30–592.00 μm) dominate near the lake margin and reduce toward the lake center in proportions. By contrast, GSFD component 2 (2.75–15.56 μm) increases toward the lake center. Therefore, the proportions of GSFD component 2, 4, and 5 reflect the relative distance to the lakeshore and allow inferences about lake area changes. We apply this large modern dataset to a sediment core obtained from Lake Wulanhushao (WLHS) on the Inner Mongolia Plateau and link the lake surface sediment-based GSFD components to BEMMA end-members of grain size records to define their environmental implications over the last 18.59 cal. kyrs BP. We found that the Lake WLHS has responded to the orbital and suborbital climate changes since the last deglaciation. Specifically, maximum lake transgression prevailed during the early to middle Holocene (11.70–7.10 cal. kyr BP), medium lake transgression dominated during 17.05–15.80 cal. kyr BP, and weak transgression developed during 14.60–12.90 cal. kyr BP. Maximum lake regressions prevailed before 17.05 cal. kyr BP, during 15.80–14.60 cal. kyr BP and 12.90–11.70 cal. kyr BP. Our reconstructed early Holocene maximum lake area is consistent with regional abiotic proxy-based moisture records, but contrasts with the regional biotic proxy-based moisture records, which reconstruct increasing moisture conditions. Our new method to determine lake area changes will provide valuable data to understand the climate dynamics of northern China. • We numerically revealed the environmental implications of grain size components of lake surface sediment. • Linking lake surface sediment grain size component to core end members provide basis for interpretations. • Maximum lake transgression prevailed during the early Holocene in northern China. • Abiotic proxies-based early Holocene lake transgression is distinct with biotic proxies' reconstructions. [ABSTRACT FROM AUTHOR]

The end Permian to Middle Triassic interval (∼252–242 Ma) witnessed the largest marine mass extinction and the most delayed recovery in the Phanerozoic. The nature and mechanism of these biotic and environmental changes remain unclear. This special issue focuses on the Triassic marine sediments in South China, which provide unique documentation of the collapse and recovery of marine ecosystems. Six papers focus on biotic changes and their ecological significance in Early and Middle Triassic times, documenting evidence from bivalves, marine reptiles, stromatolites, hybodontid teeth, vertebrate coprolites, and other putative fossils. Two papers study conodont biostratigraphy across the Permian-Triassic boundary (PTB) and Induan-Olenekian boundary. Two papers reconstruct the palaeoenvironments of the Early Triassic Chaohu Fauna and Middle Triassic Luoping Biota. Two further papers present new marine δ13C records and biomarker data and link them to volcanic eruptions in Early Triassic times. These new findings are important for understanding the co-evolution between biotic and environmental changes in the aftermath of Permian-Triassic boundary mass extinction. [ABSTRACT FROM AUTHOR]

The Mesozoic Dabashan Foreland Basin, a result of the Mianlue Ocean closure, formed through the collision and amalgamation of the South China and North China blocks. As such, it contains an important record of the tectonic processes leading to the formation of the Qinling Orogenic Belt; however, the timing of transition from basin to mountainous terrains remains debated. Geochronological studies indicate continental collision occurred in the mid-Permian to early Triassic, while some paleomagnetic data suggest a Middle to Late Jurassic occurrence time. Utilizing detrital zircon geochronology and trace element data, in this paper, we examine Triassic-Jurassic sediment provenance patterns during the evolution of the Dabashan Foreland Basin. Results show that in the Middle Triassic, the north Yangtze Block received detrital input from the southern margin of the North China Block. In the Late Triassic, significant tectonic inversion occurred, with detrital sources from the southern margin of North China Block, North Qinling, South Qinling, and the north Yangtze Block. During the early and Middle Jurassic, detrital sources gradually shifted to a dominance from South Qinling, indicating a phased southward migration of collisional orogenic belt sources. Combining thermal events, crustal thickness variations, and paleomagnetic data, we propose a novel model explaining oblique compression along the north Yangtze Block during the early Mesozoic. This model suggests that the Dabashan Foreland Basin likely predates the Middle Triassic, and we contend that crustal deformation and lateral shortening during Mesozoic accretionary orogeny between North China Block and South China Block may explain the debate over collision timing. • Provenance analysis dates Dabashan Foreland Basin to the Middle Triassic or earlier. • Frontal orogenic belt migration alters sediment sources to the basin. • Divergent views on collision timing may stem from crustal deformation. [ABSTRACT FROM AUTHOR]

Despite the importance of pastoralism, as an alternative or adjunct to farming in China's long history, a clear understanding of the spreading routes and mechanisms of pastoralism in China is lacking. Fungal spores can be a useful addition to zooarchaeological evidence and have been widely used to explore the origins and development of pastoralism in different regions of the globe. The northern Loess Plateau is one of the most important areas for the emergence and development of pastoralism in early China. The aim of this paper was to take the fungal spores in the Baihemiao (BHM) core that we extracted from a site in the Yulin region, combine them with the zooarchaeological records to explore their relationship with climate and environmental changes, and reconstruct the evolution of animal husbandry in the northern Loess Plateau since the mid-Holocene. The results indicate that the climatic conditions in the northern Loess Plateau during the first period of 6–4.2 ka were relatively humid, the number of domesticated herbivores was small, animal husbandry was not developed, and the spores of coprophilous fungi in the sediments mainly originated from wild herbivores. Fungal spores as well as zooarchaeological evidence reveal that cattle and sheep grazing developed rapidly in the region during the second period, c. 4.2–3 ka. We suggest that the arid climatic conditions during this period facilitated the development of pastoral activities in the northern Loess Plateau. However, this pastoral economy gradually weakened after 1.2 ka. • Sporormiella suggests a high volume of herbivore activities in the Baihemiao area in 6–4.2 ka. • Fungal spores and zooarchaeological record from the archaeological sites indicate that grazing activity was strong in 4.2-3 ka. • Arid climatic conditions facilitated the development of pastoral activities in the northern Loess Plateau in 4.2–3 ka. • Pastoralism weakened and declined during the period from 3 ka to 1.2 ka. [ABSTRACT FROM AUTHOR]

Human impact on the coastal plain of Southeast China has been well studied over late Holocene timescales; however, an understanding of anthropogenic impact in mountainous regions is still lacking. In this paper, we present records of vegetation, fire, and human impact, spanning the past 4000 years, with a resolution of ∼40 years, obtained from an upland peatland in Southeast China. The results reveal that climate change (dominated by the evolution of the East Asia Monsoon) was the most critical factor controlling vegetation before 1.0 cal kyr BP, while human impact gradually emerged as the primary driver after 1.0 cal kyr BP in the mountains of Southeast China. As such, the record of anthropic impact in mountainous regions lagged behind the signal from the coastal plains by some 2000–4000 years. As the population migrating from northern China dispersed into the mountainous regions of Southeast China, demand for agricultural land promoted slash-and-burn cultivation and the destruction of broad-leaf forest. • Three climatic stages identified spanning 4.0 cal kyr BP based on pollen and charcoal analysis. • Significant anthropogenic impact on mountain vegetation of Southeast China occurred in 1.0 kyr BP, lagged coastal plains by 2000–4000 years. • The population migrating from northern China dispersed into the mountainous regions of southeastern China in 1.0 kyr BP, urgent demand for cultivated land. [ABSTRACT FROM AUTHOR]

The decline of ancient societies has been often associated with hydroclimate instabilities. In this paper, we report phytolith records from the Yangtze River Delta of China, to reconstruct middle and late Holocene climate dynamics, and understand societal impacts. Our findings reveal that the area experienced a consistent decline in temperature and humidity punctuated by several rapid climate shifts. A distinct dry episode from 7000 to 6000 cal yr BP likely developed in response to weakened Atlantic Meridional Overturning Circulation (AMOC) and a southward shift of the intertropical convergence zone (ITCZ), resulting in a weakened East Asian summer monsoon (EASM) and a strengthened East Asian winter monsoon (EAWM). This dry condition would have favoured the emergence of dryland and facilitated rice cultivation in the lower Yangtze region. Another dry episode at 4500–4000 cal yr BP, which was probably associated with the widespread 4.2 ka climate event, and linked to a further retreat of the ITCZ and highly variable ENSO intensity, led to highly unstable hydroclimate conditions in the region. We argue that this event disrupted social resilience and culminated in the cultural collapse at the end of Liangzhu Culture. • Cooling trend since 8000 cal yr BP in response to decline of summer insolation. • Dry episodes at 7000–6000 and 4500–4000 cal yr BP. • Strength of AMOC and position of ITCZ jointly modulates the EASM. • Neolithic societal resilience shows varied responses to each dry episode. [ABSTRACT FROM AUTHOR]

Discriminating the provenance of fine-grained sediments is crucial for reconstructing paleogeography, sedimentary processes, and paleoclimate. In this paper, we investigate the South Bohai Coast to better understand source-to-sink systems in East Asia. This region is influenced by both distant sources such as the large-scale Yellow River and small local river sources flowing from the Luzhong Mountain area. Two Holocene sedimentary cores, dated using optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C chronology, were used to investigate the provenance of the fine-grained sediments over the last 7 kyrs. Clay mineralogy and relevant non-linear modeling were employed for provenance discrimination. The results show that the fine-grained sediments along the South Bohai Coast were mainly derived from the Yellow River during the periods of 7.0–5.4 ka and 4.5–2.6 ka, respectively, while the input from the Luzhong Mountain-derived rivers was greater during 5.4–4.5 ka and 2.6–0.2 ka, respectively. Fluvial activities and marine-terrestrial interaction driven by climate factors such as East Asian winter monsoon, temperature, and precipitation in river basins, dominantly influenced the provenance of fine-grained sediments from 7.0 to 2.6 ka. Anthropogenic impact on provenance increased after 2.6 ka. The chronology of the two cores showed extremely rapid sedimentation rate transitions at 5.2 ka and 1.5 ka, respectively, very likely attributed to anthropogenic-induced rapid progradation. Our study provides a model for better understanding the paleoenvironmental and paleogeographic evolution of a coastal area where multiple sources exist. • Anthropogenically high sedimentation rate in the South Bohai Coast in late Holocene. • Provenance discrimination of the fine-grained sediments in the South Bohai Coast since the mid-Holocene. • The major source of the fine-grained sediments in the South Bohai Coast changed episodically. [ABSTRACT FROM AUTHOR]

Coastal wetlands provide valuable ecosystem services and understanding their response to past climatic changes may help predict their possible future responses. In this paper, we obtained records of pollen, algae, sediment grain-size, and other environmental proxies, from a late Holocene sediment core (CFD-E) from the Caofeidian area, on the northwest coast of the Bay of Bohai, China. Our results indicate three major stages of environmental change. During Stage I (3500–2800 cal yr BP), arboreal pollen content was high (mostly >60%), especially for Pinus and Quercus , and the PCA sample scores on Axis 1 were negative indicating that regional vegetation was temperate broadleaved forest and the climate was wet. During Stage II (2800–2350 cal yr BP), the arboreal pollen content decreased substantially (mostly <40%), and the PCA Axis 1 sample scores were positive indicating a decrease in forest vegetation, grassland expansion, and a drier climate. During Stage III (2350–1400 cal yr BP), the arboreal pollen content increased again (mostly >40%), although it remained lower than during Stage I, indicating that forests expanded under a relatively humid climate while the wetland area decreased slightly. Our results also record the 2.8 ka and 2.4 ka events of monsoon weakening, which were characterized by increases in herbaceous pollen (indicating grassland expansion) and the drying of the regional climate. There are several differences in the regional expression of these two climatic events. During the 2.4 ka event, Chenopodiaceae pollen increased substantially (average of 42.0%), indicating the expansion of halophytes; whereas during the 2.8 ka event, an increase in Artemisia indicates the occurrence of a dry climate throughout the region. We suggest that the aridity during the 2.8 ka event was triggered by decreased solar activity and the resulting changes in the El Niño-Southern Oscillation, which weakened the East Asian summer monsoon. However, we suggest that the 2.4 ka event was driven by the weakening of the Atlantic Meridional Overturning Circulation. • Significant increase in halophytic vegetation during 3500–1400 cal yr BP • The 2.8 ka and 2.4 ka events were characterized by climate drying lasting ∼150 years. • During these two events the area of forest decreased and grassland expanded. [ABSTRACT FROM AUTHOR]

In this paper, we investigate Holocene precipitation changes in northern China to improve the understanding of the East Asian summer monsoon (EASM) and provide an environmental context for the development of Chinese civilisation. Our study is based on an analysis of 260 pollen samples from Holocene lacustrine sediments at Ningjinpo in northern China, and employs the biomisation method to reconstruct regional vegetation types and vegetation changes, and to decipher their driving factors, by incorporating regional climatic data and information on human activities. Results indicate that, in the early Holocene (10,000–8100 cal yr B.P.), regional climate was dry, with annual precipitation of 470 mm. In the middle Holocene (8100–3000 cal yr B.P.), a rapid increase was observed in precipitation, reaching 580 mm. During the late Holocene (2600–600 cal yr B.P.), climate became drier again, with annual precipitation decreasing to 480 mm. Between 10,000–600 cal yr B.P., vegetation exhibited distinct successional patterns dominantly influenced by climate, transitioning from meadow-steppe to forest, and then back to meadow-steppe. After 600 cal yr B.P., vegetation succession decoupled from climate change, with human activities emerging as the primary driving force, as indicated by the substantial increase in anthropogenic pollen and charcoal concentrations. In the future, under the combined influence of global warming and intensified human activity, the implementation of scientific environmental planning measures will become increasingly important for the restoration and sustainable development of regional vegetation ecosystems. • Unambiguous high-resolution precipitation record from the North China Plain. • Human activities variedly impact vegetation evolution since 2600 cal yr B.P. • A shift from natural to anthropogenic vegetation change happened at 600 cal yr B.P. [ABSTRACT FROM AUTHOR]

The Zhe-Min Uplift (ZMU) has undergone tectonic subsidence, which has been associated with a notable transgression in the northern marginal seas of China since the middle Pleistocene. However, its uplift history during the late Quaternary is still inadequate. The Old Red Sand (ORS) is a late Pleistocene deposit that is widely distributed along the southeastern coast of China. The ORS consists of partially-cemented fine- to medium-grained sand. In this paper, we focus on mud-rich ORS deposits of the Liushui area, Pingtan Island, Fujian Province, and report optically stimulated luminescence (OSL) ages, and new datasets of grain size, mineralogy (detrital zircon, clay and detrital minerals) and organic carbon and nitrogen isotope profiles to improve understanding of chronology, provenance, palaeoenvironmental evolution and tectonic infuence. Based on the OSL data, we hypothesize that the development of the ORS was associated with lower sea levels, with most deposition occurring within MIS4. Based on comparison of detrital zircon U Pb ages, the coarse fraction of the Liushui ORS was mainly derived from the Minjiang River, with modest input from weathering of coastal granites. The East Asian Winter Monsoon contributed some materials from the East China Sea shelf during the last glacial period, as indicated by the fine-grained nature of the Liushui ORS, low K-feldspar/plagioclase ratios, high dolomite content and the frequency of Neoproterozoic and Palaeoproterozoic detrital zircons. The deposition of the ORS was influenced by both the East Asian Winter Monsoon and sea level changes. The clay minerals in the mud layers of the Liushui ORS were dominated by kaolinite and illite, with little chlorite and no smectite, indicating that they originated from the Minjiang River. The TOC/TN ratios of the mud layers, as well as their isotope characteristics, indicate the organic matter was derived from marine sources, presumably during the transgression event in MIS5. The average uplift rate of the ORS was about 0.03 mm/yr. The uplift of the ORS provided new insights into the geological records of the ZMU, which differed from the subsidence observed in the northern region of the Minjiang River during the late Pleistocene. • The formation of the ORS was association with lower sea level, and the MIS4 was primarily the deposition stage. • During the last glacial, the more sediments from the East China Sea shelf were transported to the ORS by EAWM. • The mud layer was the transgression records during MIS5. • The distribution of the ORS was influenced by tectonic activity. [ABSTRACT FROM AUTHOR]

The Carnian Pluvial Event (CPE) induced an intense carbon-cycle disturbance and biological crisis at a global scale. The eruption of the Wrangellia Large Igneous Province (W-LIP) is considered a possible triggering mechanism; however, this cannot fully explain the significant differences in environmental perturbations across different regions. In this paper, we present detailed records of petrography, mercury geochemistry, carbon and sulfur isotopes, trace elements, and provenance data for the Triassic lacustrine facies of the Ordos Basin in the North China Plate, which provide insights into the important effects of volcanic activities, other than the W-LIP, on palaeoenvironment during the CPE interval. Massive emissions of SO 2 , CO 2 , and pyroclastic deposits resulting from these volcanic activities triggered four humid episodes, each characterized by lake-level rise, negative δ13C org excursion, a transition from mudstones to organic-rich shales facies, as well as algal bloom within a time span of 180 kyrs. The establishment of an age framework in the Ordos Basin enables comparative analyses of environmental evolution during the Carnian age across the North China Plate, the western Tethys domain, and the South China Plate. During the period of global climate perturbation driven by the W-LIP eruption, we conclude that short-term localized volcanic activities may have further induced high frequentcy environmental perturbations, which influenced biological shifts and increase organic carbon burial. These short-term volcanic activities with different occurrence times and frequencies complicate local-scale palaeoenvironmental evolutions, which may be an important reason contributing to significant differences in environmental perturbations during the CPE interval across different regions of the globe. • Four humid episodes and sedimentary changes occurred within 0.18Ma in the Ordos Basin during Carnian age. • Environmental changes in the Ordos Basin was related to the local volcanisms in its nearby Qinling orogenic belts. • Short-term local volcanisms can complicate the environmental evolutions in different parts of globe during the CPE interval. • Local volcanic processes may cause inconsistent environment perturbation in different parts of globe during the CPE interval. [ABSTRACT FROM AUTHOR]

Southwestern China, a biodiversity hotspot, underwent dramatic climate change following the Last Glacial Maximum and intensive human activity also exerted a major impact since the late Holocene. In this paper, we report a pollen record from Yilong Lake in Yunnan Province, southwestern China, to understand vegetation response to long-term climatic variation and human activities at a regional-level over the last 27,000 years. Findings show that temperate and coniferous taxa were dominant before 18 cal kyr BP reflecting the glacial climate. Between 18 and 14 cal kyr BP, thermophilic taxa increased in response to global deglaciation. A notable shift from deciduous to evergreen forests occurred at approximately 14 cal kyr BP, after which pollen concentration increased but pollen diversity decreased. Pollen assemblages indicated dense forests, primarily composed of evergreen oaks developed under warm and strong summer monsoon conditions from 13 to 8 cal kyr BP. High rates of vegetation change occurred during the middle Holocene before vegetation diversity gradually increased during the Holocene Thermal Optimum, with high variability of precipitation in the Yilong Lake region. Anthropogenic forcing progressively became the main factor affecting vegetation composition and vegetation change rates over the past three millennia. • We reported a pollen record from Yilong Lake in Yunnan province, China. • Cold-tolerant taxa dominated before 18 cal kaBP after which thermal-like taxa increased. • Evergreen forests replaced deciduous forests around 14 cal kaBP. • Vegetation change rates peaked in mid-Holocene with mega-thermal but frequent droughts. • Departure of vegetation and potential climax occurred in late-Holocene due to human activities. [ABSTRACT FROM AUTHOR]

The periodicities of the climate change have long been explored by researchers not only because they reflect the inherent characteristics of the climate systems, but also because they are the foundations of climate-change predictability. This paper reports the periodicities of the hydroclimate variations reconstructed from a lacustrine sequence at Tiancun section (TC section) in the Luoyang Basin within the Central Plains of China and the sequence covers the first half of the Holocene. Our reconstruction shows that the hydroclimate variations at the TC section during the period from ∼10,135 and ∼ 5890 cal. yr BP were well corresponding with the effective soil moisture variations recorded by the stalagmite δ13C sequence at the Magou Cave. This corresponding relationship suggests that when the effective soil moisture increases (i.e., more negative δ13C values), the ratio of evaporation over precipitation in the paleolake at the TC section decreased, resulting in lower CaCO 3 content. It also suggests that when the effective soil moisture increases, more inflowing water entered the paleolake, resulting in coarser sediments. Our reconstruction also shows that the hydroclimate variations or lake level variations in the Luoyang Basin were characterized by millennial-scale quasi-periodicities that were most likely paced by the changes in ITCZ (Inter-tropical Convergent Zone) position and also by alterations in ENSO-like phase. And, both (ITCZ and ENSO) were most likely regulated by the solar activity. Our further analysis shows that the hydroclimate in the Luoyang Basin also experienced centennial-scale variations. Specifically, the grain size data express the following cycles: 692-year, 538-year, 217-year, 170-year and 123-year, all at the 99% confidence level. And, the CaCO 3 content data express the following cycles: 202-year, 184-year, 169-year and 85-year, all at the 99% confidence level. These cycles are approximately coincident with the widely-reported solar-activity cycles. • This paper reports the periodicities of the hydroclimate variations reconstructed from a lacustrine sequence in the Central Plains of China and the sequence covers the first half of the Holocene. • The hydroclimate variations were primarily paced by changes in ITCZ position and also by alterations in ENSO-like phase. And, both (ITCZ and ENSO) were most likely regulated by solar activity. • The centennial-scale hydroclimate variations were approximately coincident with the widely-reported solar-activity cycles. [ABSTRACT FROM AUTHOR]

The Heinrich Stadial 2 (HS2) event is poorly defined in the Greenland δ18O ice core record; however, it can be identified in stalagmite records from China. In this paper, we reconstruct an absolutely-dated and high-resolution calcite δ18O record from Shima Cave, central China, covering the interval from 26.0 to 23.9 ka BP, with a temporal resolution of ~16 years. By integrating our newly reported record with all available δ18O records of Marine Isotope Stage 2 from China, which are securely 230Th/U-dated, we calculate the timing of the onset, termination and duration of HS2. The statistical results show that the prominent HS2a phase started at ~24.4 ± 0.1 ka BP and ended at ~23.6 ± 0.1 ka BP, lasting approximately 0.8 ± 0.3 ka. If the onset of the Dansgaard-Oeschger 2 event in the Greenland δ18O record is synchronous with the termination of HS2a, then the GICC05 chronology should be adjusted by +230 years to align it with stalagmite results. Further investigation of HS2 shows that Chinese cave records exhibit a distinct two-fold structure, corresponding to HS2a and HS2b, as observed in marine sediment cores, particularly those recovered around the Atlantic Ocean. These records show comparable changes in relative amplitudes during the HS2a and HS2b phases, which could possibly be related to different weakening episodes in the Atlantic Meridional Overturning Circulation. • An ~16-year-resolution East Asian summer monsoon (EASM) history covering the onset of Heinrich Stadial 2 event. • Statistical analyses of timing for Heinrich Stadial 2. • Globally pervasive twofold structure during Heinrich Stadial 2. [ABSTRACT FROM AUTHOR]

The terrestrial Yanliao Biota in northeastern China represents a Jurassic biodiversity hotspot. Abundant and diverse fossils include the oldest known representatives of several groups of plants, invertebrates, and vertebrates that thrived in a forest ecosystem under a humid and warm climate. Since the early 21st century, discoveries associated with the Yanliao Biota have significantly improved our understanding of Jurassic terrestrial ecosystems. However, a robust chronostratigraphic framework is required to calibrate the biota with key evolutionary events and to improve understanding of possible links between evolution and tectonism. In this paper, we report novel 40Ar/39Ar ages for two tuff layers (161.4 ± 0.8 Ma and 161.6 ± 0.6 Ma) positioned directly above the less-studied but salamander fossil-rich beds in Reshuitang, near Lingyuan, Liaoning Province, China. These new age data improve knowledge of the timing of diversification of early salamanders. We also review all reported age data and summarize significant fossils from classic Yanliao outcrops. Our study indicates that the Reshuitang fossil beds were deposited slightly later than the well-known Daohugou fossil beds situated ∼15 km away in Inner Mongolia and somewhat earlier than the Linglongta fossil beds in western Liaoning Province. These findings advance understanding of the Jurassic world during an episode of pronounced climatic warming. • We provide detailed age calibration for the Jurassic Yanliao Biota. • Our study allows us to understand Jurassic terrestrial ecosystems. • A robust chrono-stratigraphy reconstructs the link between life and climate. [ABSTRACT FROM AUTHOR]

The palaeoecology of Ginkgo through deep time, including its ecophysiology and heterophylly, remains poorly understood due to the limitation of quantitative methods. In this paper, we report well-preserved leaves of Ginkgo henanensis sp. nov. from the Paleocene Dazhang Formation of Luanchuan, Henan Province, China. Our understanding of the ecophysiology and heterophylly of the genus has been improved by the discovery. These fossils are distinguished by heterophyllous leaves that can range in morphology from bilobed to multi-lobed forms. Thus, unlike other Cenozoic Ginkgo with entire-margined leaves, this is the first well-established Cenozoic taxon that has exclusively lobed leaves similar to Mesozoic-type ginkgos. A useful leaf ecophysiological functional trait that offers quantitative insights into morphological heterophylly and the mechanism of leaf shape selection is the dry leaf mass per area (LMA) of Ginkgo. Leaf shape changes, including the evolution of heterophylly, are linked to functional adaptation. There are two groups of LMAs for four fossil G. henanensis specimens: 120.9 g/m2 to 131.3 g/m2, and 184.5 g/m2 to 187.4 g/m2. The results of the reconstructed fossil LMAs, which serve as quantitative evidence of G. henanensis ' heterophylly, also point to the existence of various leaf survival strategies within G. henanensis. Additionally, both groups of G. henanensis have LMAs that are higher than those of extant Ginkgo biloba , indicating that this species has a slower return ecological strategy than its current equivalent. This strategy may have helped to decrease the rate of nutrient cycling, which supported Ginkgo to thrive in a wider variety of ecological niches in the Paleocene than it does today. These findings close a knowledge gap in the evolution of Ginkgo. • Species similar to the Mesozoic multilobed Ginkgo still present in the Paleocene. • The feasibility of existing methods to reconstruct the leaf mass per area of fossil Ginkgo is tested. • Heterophylly of fossil Ginkgo are quantitatively proved. [ABSTRACT FROM AUTHOR]

A transition from cereal-based agriculture to pastoralism in North China occurred around 3600 cal yr B.P., and corresponded to Northern Hemisphere cooling and the onset of an arid climate over North China. In this paper, we investigate the mechanisms for the ~3600 cal yr B.P. climate transition that may have triggered this change in Chinese civilization based on a compilation of 33 high-resolution paleoclimate records spanning the 4000–3000 cal yr B.P. interval. Results show that North and South China experienced a meridional dipole pattern of the climate change. From 4000 to 3600 cal yr B.P., the region north of 30°N was wet and the region south of 30°N was dry, then from 3600 to 3000 cal yr B.P., the pattern reversed with a drier north and a wetter south. We found that this climate transition was related to the onset of a more El Niño-like state in the tropical Pacific Ocean after ~3600 cal yr B.P., which resulted in more precipitation in South China but less precipitation in North China. Climate in the marginal monsoon areas of North China deteriorated, becoming more cold and arid, and pastoralism replaced cereal agriculture as the dominant mode of subsistence. Our study highlights the important role of the paleo-El Niño-Southern Oscillation (paleo-ENSO) for the evolution of civilization in China. • North China transitioned to pastoralism around 3600 cal yr B.P. • A shift in East Asia's dipole climate pattern was observed at the same period. • This climate change was influenced by the paleo-ENSO. • The paleo-ENSO significantly impacted the progression of Chinese civilization. [ABSTRACT FROM AUTHOR]

The Jehol Biota comprises significant fossils that help to elucidate the evolution of Early Cretaceous terrestrial ecosystems. In this paper, we provide three new zircon U Pb age constraints (124.3 ± 1.5 Ma, 124.9 ± 1.6 Ma, and 121.5 ± 1.4 Ma) from the base to the top of the Jiufengshan Formation (Xinganling Group) at the Naketa section in the north Great Xing'an Range of eastern Inner Mongolia, China, within a succession that contains the typical Eosestheria - Ephemeropsis trisetalis - Lycoptera davidi (EEL) assemblage of the Jehol Biota. Combined biostratigraphic and radio-isotopic dating suggests that the Jiufengshan Formation in the Naketa section corresponds to the upper part of the Yixian Formation and the lower part of the Jiufotang Formation, making it Barremian to earliest Aptian in age. Our findings allow us to test a widely accepted hypothesis about the migration and radiation of the Jehol Biota, and show that these organisms preserved within the lower part of the Jiufengshan Formation reached the Naketa area during the second and third evolutionary stages. The preservation of Jehol elements in the Naketa section provides valuable clues regarding the evolutionary history of the Jehol Biota and its spatiotemporal development. Furthermore, our study allows us to explore possible links between evolutionary processes and concurrent tectonism in the North China Craton, as the timing of this Jehol migration occurred when the tectonic setting changed from a compressional to an extensional regime. • We provide detailed fossil records and robust age for the far north Jehol outcrop. • This study refutes the widely accepted model for the Jehol migration. • Our results test the link between biological radiation and tectonic activity. [ABSTRACT FROM AUTHOR]

The Nihewan Basin in North China contains the densest concentration of early Pleistocene Paleolithic sites outside Africa. This paper introduces a new archaeological site complex at Madigou (MDG) that was systematically excavated from 2011 to 2014 in the northeastern part of the Nihewan Basin. The site contains fossils and well-preserved stone artefacts in fluvio-lacustrine sediments. Our magnetostratigraphic results situate the MDG sedimentary sequence in the early Brunhes normal chron and the late Matuyama reverse chron, including the Jaramillo normal subchron. The MDG artifact layers are positioned within the pre-Jaramillo Matuyama chron, with an estimated age of ca. 1.2 Ma, close to the onset of Mid-Pleistocene climate transition. The MDG core and flake technology includes bipolar flaking of siliceous dolomite cobbles, and freehand flaking of chert and brecciated chert block fragments. Mammalian fauna and pollen compositions indicate that the MDG hominins lived in an open habitat varying from lightly-wooded grassland to an ecosystem dominated by sparse steppe near the shore of the Nihewan paleolake. Our combined results in the fields of archaeology, paleontology, palynology and magnetochronology suggest that innovations in technological behavior may correlate with adaptations to high environmental variability during the start of Mid-Pleistocene climate transition. • Nihewan in north China is a key area for research on the early human occupation out of Africa. • Madigou (MDG) is a newly discovered Early Pleistocene site complex in the Nihewan Basin. • Magnetostratigraphic results show that early humans occupied the MDG site ca. 1.2 Ma. • MDG hominins lived in an open habitat and practiced a core and flake technology. • Human adaptations correlate with climate variability during the onset of the Mid-Pleistocene transition (MPT). [ABSTRACT FROM AUTHOR]

In this paper, correlation between modern leaf physiognomy and climate in China are examined, to optimize the use of leaf characters as a palaeoclimate proxy. A large dataset was compiled, recording the distribution of leaf physiognomic characters among 3166 native dicot trees species across 732 calibration grids on a county level. Grids span a range of ecological environments (tropical rainforests to alpine shrubs) across humid areas. Thirteen climatic parameters were included for each grid and 22 leaf physiognomic characters were scored for each tree species. The correlation between leaf physiognomic characters and climatic parameters were calculated based on single linear regressions (SLR) and multiple linear regressions (MLR). Results indicate clear spatial distribution patterns, linked to latitude, exist for all leaf characters, with temperature (Coldest Month Mean Temperature, CMMT) and precipitation (Growing Season Precipitation, GSP) being the main climate controls. Moreover, because leaf characters are more closely correlated with Precipitation during the Three Wettest Consecutive Months (P3WET), rather than with Precipitation during the Three Driest Consecutive Months (P3DRY), seasonal variations in rainfall associated with the Asian Monsoon might especially influence leaf physiognomic characters. Closer correlations between leaf physiognomy and climate are seen using MLR compared with SLR; therefore Mean Annual Temperature (MAT) and Mean Annual Precipitation (MAP) based on MLR equations provide the most promising basis for palaeoclimate reconstructions in China. • Spatial distribution of 21 leaf physiognomic characters in China is established. • Relationships between leaf physiognomic characters and climatic parameters are established. • The seasonal variations in rainfall under the Asian monsoon climate shapes leaf physiognomic characters. • Paleoclimate can be reconstructed based on such large-scale modern dataset. [ABSTRACT FROM AUTHOR]

In this paper, we critically review the half-century (1962–2022) history of study of Oligocene to Pliocene mammal-bearing successions in the eastern Linxia Basin, Gansu Province, China. Despite great strides in our understanding of the regional geology and the discovery of a large quantity of mammal fossils, there remains major discrepancies concerning the definition and age assignment of the formations that comprise the Linxia Group. This has resulted in the development of two competing schemes for its subdivision: the first scheme was proposed by geologists of the Lanzhou University and the Institute of Tibetan Plateau Research, and the second scheme is associated with paleontologists of the Institute of Vertebrate Paleontology and Paleoanthropology. In an attempt to solve these discrepancies, a five year project was initiated in 2017, and herein we report the main findings as follows: (1) The Jiaozigou Formation does not extend into the Miocene, with its top calibrated at about 23 Ma; (2) The Liushu Formation, as defined in the Maogou section, should be considered as the penecontemporaneous shallow water facies of the coarse-grained Hujialiang Formation of Middle Miocene age; (3) The widespread Hipparion -bearing deposits along the Guangtong River, which have been also referred to the "Liushu" Formation represent a different stratigraphic unit and should be given another name to eliminate confusion following further stratigraphic analysis. • A brief, but comprehensive review of the studied history of the Linxia Basin. • We pointed out ambiguous opinions and misunderstandings in previous studies. • A reliable chronology of precise sedimentary sequences was established with constraints of accurate mammal fossils. [ABSTRACT FROM AUTHOR]

Orbital forcing is a fundamental driver of Earth surface systems. The understanding of feedback responses to orbital forcing remains limited, with one of the most distinguishing features being its inherent nonlinearity. In this paper, we present geological evidence demonstrating nonlinearity during the greenhouse climate state, as exemplified by the Middle Triassic lacustrine-delta succession of the Ordos Basin in China. By combining the radio-isotopic and astronomical timescale, it suggests that lacustrine black shale facies were developed during early Ladinian hyperthermal episode, while deltaic facies were developed before and after the hyperthermal episode. The lacustrine redox cycles exhibit dominant precession cycles with a period of ∼20 kyr, whereas these precession cycles tend to be covered by the eccentricity and obliquity cycles with periods of ∼100 kyr and ∼ 33 kyr respectively in the deltaic detrital-input cycles. The diverse manifestations of orbital cycles in various environments can be explained by the nonlinear feedbacks. It is proposed that feedback mechanisms result from the combination effects of direct and indirect hyperthermal events, which are respectively manifested by the climatic processes (p CO 2 level) and sedimentary processes. Sedimentary processes can enhance the influence of eccentricity through smoothing and memory effects, as supported by statistical analysis. The variations in atmospheric p CO 2 may also contribute to the feedback of eccentricity and obliquity cycles through climate threshold and intertropical convergence zone, as supported by paleoclimate simulation and land-ocean correlations. • Ladinian warming event results in the nonlinear responses to the orbital forcing. • p CO 2 directly influences the orbitally cyclic patterns of the Triassic climate. • Indirect sedimentation feedbacks include smoothing, memory and threshold effects. [ABSTRACT FROM AUTHOR]

The 4.2 ka event was a period of global drought and climate cooling linked to the widespread disruption of Neolithic culture. However, the detailed climatic changes during this period are not completely understood. In this paper, we report a high-resolution pollen record for the Dayanghu wetland in the Zhejiang region of southeastern China, which we use to infer mean annual precipitation (MAP) fluctuations during the period spanning 4600–4000 calendar years before present (cal. yr BP). There was a long-term trend of decreasing MAP during this interval, consistent with weakening of the East Asian Summer Monsoon since the mid-Holocene. This trend was punctuated by episodes of relatively high MAP at 4350–4320, ca. 4260, and 4220–4200 cal. yr BP, and extreme droughts at 4200 and 4150 cal. yr BP. We propose that solar activity promoted El Niño events and contributed to dramatic MAP fluctuations in the Dayanghu wetland. La Niña events and negative-phase intervals of the Pacific Decadal Oscillation may have been responsible for the extreme drought at 4200–4150 cal. yr BP. In summary, we propose a close relationship between MAP and solar forcing, with short-term enhanced solar activity increasing the intensity of the East Asian Summer Monsoon and contributing to increasing decadal variability in the inner tropical Pacific, which ultimately leads to increased precipitation variability in southeast China. The results improve our understanding of the detailed climatic features of the 4.2 ka event. • High-resolution pollen record for ca. 4.2 ka for the Zhejiang region, China. • Pollen-based mean annual precipitation was quantitatively reconstructed. • Long-term droughts tended to occur during 4600–4000 cal. yr BP. • La Niña-dominated ENSO contributed to a catastrophic drought at 4200–4150 cal. yr BP. [ABSTRACT FROM AUTHOR]

The Qilian-Qaidam Orogenic Belt is a component of the western Central China Orogenic Belt, and records a nearly complete evolutionary history of the South Qilian and North Qaidam oceans (branches of the Proto-Tethyan Ocean). However, the timing and process of amalgamation of the microblocks of the western Central China Orogenic Belt and the closure time of the South Qilian and North Qaidam oceans remain uncertain. The Olongbuluke Terrane (OLT), located in the central of the Qilian-Qaidam Orogenic Belt, contains well-developed Precambrian to Paleozoic sedimentary successions that shed light on the tectonic history of these ocean basins. In this paper, detrital zircon U Pb ages combined with ophiolitic, magmatic and high-pressure to ultrahigh-pressure metamorphic records and field investigations, indicate that the OLT was part of a passive continental margin during the early Paleozoic and there was a microblock, named the North Qaidam Terrane (NQT), lying between the Qaidam Block and the OLT. A marked provenance change occurs in the OLT after ca. 517 Ma, which is inferred to record the collision between the OLT and NQT. Later, the North Qaidam oceanic plate subducted under the NQT, and the North Qaidam Ocean closed at ca. 450 Ma. The similar detrital zircon U Pb age spectra of contemporaneous deposit flysch sequences in the Shihuigou Formation (OLT) and the Balonggonggaer Formation (the South Qilian Accretionary Belt) indicates the onset of collision between the OLT and Central Qilian Terrane occurred at ca. 458 Ma. The detrital zircon U Pb age spectra of microblocks from the early Paleozoic strata of the northern Tibetan Plateau share a North Indian affinity, indicating that the closure of the Proto-Tethyan Ocean may relate to the formation of the Gondwanan landmass. • The North Qaidam Terrane may exist between the Qaidam Block and the Olongbuluke Terrane. • The Olongbuluke Terrane collided to the North Qaidam Terrane at ca. 517 Ma. • The onset of collision between the Olongbuluke Terrane and the Central Qilian Terrane at ca. 458 Ma. • The closure of Proto-Tethys may relate to the formation of the Gondwana landmass. [ABSTRACT FROM AUTHOR]

The abrupt weakening of the East Asian summer monsoon (EASM) during Younger Dryas (YD) has been attributed to freshwater discharge into the North Atlantic ocean and resultant Northern Hemisphere cooling. Recent studies have found that sea ice variability in the Nordic Sea during the YD exerted a great influence upon the northern high-latitude climate. However, the influence of sea ice upon EASM evolution during YD event remains unclear. In this paper, we report two precisely-dated speleothem oxygen isotope records from the EASM-dominated region of central China. Our records archive abrupt changes in EASM variability during the YD event. Initially, there was a significant strengthening of the EASM during the mid-YD following the gradually increased Atlantic meridional overturning circulation (AMOC). Later this trend reversed at ∼12.15 ka due to northern high-latitude sea ice fluctuations and a consequent reduction of AMOC. At the YD termination, abrupt intensification of the EASM was synchronous with the rapid decline of sea-ice and recovery of the AMOC indicating that sea ice variability was a significant influence on high latitude climate and EASM variation during the YD. • A new speleothem δ18O record show significant EASM strengthening during mid-YD. • Mid-YD oscillation in EASM linked with NH sea ice variability. • Abrupt EASM intensification at YD termination synchronous with the rapid decline of sea ice. • Drier interval following the YD termination in central China. [ABSTRACT FROM AUTHOR]

The location of the Yellow River estuary controls the pattern of mud dispersal and therefore influences the ecology of China's marginal seas. However, little is known regarding the Holocene history of Yellow River avulsion. The Yangtze estuary, south of the Yellow River estuary, may provide some clues, as a large amount of Holocene sediments has accumulated in a major paleovalley in this area, incised during the Last Glacial Maximum (LGM). In this paper, we identify clay contributions from the Yellow River in the three Holocene cores (TZ, DY, and HM) of the Yangtze estuary using provenance analogues of clay geochemistry associated with the modern rivers, and reveal the history of Yellow River avulsion into the South Yellow Sea. The results show that clay geochemistry in the Holocene cores is similar to that of the Yangtze River, except for the period of ∼9.5–7.0 cal. kyr B.P. when it is represented by lower element contents more closely similar to those of Yellow River clays. Provenance end-member analysis shows 40%–60% clays of the Yangtze paleovalley was derived from the Yellow River during this period. These findings indicate that, at least, one channel of the Yellow River avulsed southward into the South Yellow Sea during the early to middle Holocene (∼9.5–7.0 cal. kyr B.P.). Fine-grained sediments from the Yellow River paleoestuary could be transported southward to the Yangtze paleovalley by enhanced marine energy during the early to middle Holocene. This study, not only, provides new evidence for Yellow River avulsion in the Holocene, but also sheds light on the impact of the Yellow River sediments on the depositional system along the coast of China, especially in the Yangtze delta. • Three Holocene cores of the Yangtze estuary are analyzed for clay geochemistry. • Geochemistry analogue with the modern rivers identifies clay provenance of cores. • Yellow River clay contributes high to the Yangtze estuary in early-middle Holocene. • Yellow River ever flowed into the South Yellow Sea during ∼9.5–7.0 cal. Kyr B.P. [ABSTRACT FROM AUTHOR]

High-latitude permafrost peatlands are sensitive to global warming, and understanding their paleohydrological evolution is critical for assessing future hydrological and environmental changes. This paper presents a diatom record from a peat deposit covering the past 3300 years to reconstruct the moisture and acidity conditions in the Tuqiang permafrost peatland in the northern Greater Khingan Mountains of northeast China. Our findings are integrated with previously published records of plant macrofossils, palynology, and geochemistry from the same profile. From 3300 to 2800 cal yr BP, planktonic and benthic diatoms were equally abundant, indicating relatively high moisture conditions, while the low abundance of acidophilous diatoms reflects relatively high pH during this interval. Pollen data show dominance by sedges with input from the surrounding Pinus forest, while LOI data and lithology suggest that the site was a non-peat accumulating wetland. During the period 2800–1100 cal yr BP, the dominance of planktonic diatoms indicates a wetter local environment, concurrent with the dominance of peat-forming sedges (Eriophorum), indicating the development of a peatland. Between 1100 and 500 cal yr BP, a short-lived increase in acidophilous diatoms (Eunotia) marks a decrease in pH. Since 500 cal yr BP, the dominance of benthic diatoms reflects a drier environment, while a vegetation shift from an Eriophorum -dominated rich fen to a Sphagnum- and Ericaceae-dominated poor fen. An increase in Eunotia diatoms prior to the Sphagnum peak may indicate that diatoms are more sensitive to local acidified habitats than moss. Peatland development in the northern Greater Khingan Mountains was likely induced by the onset of a cooler and wetter climate starting at approximately 2800 cal yr BP, a scenario supported by regional paleoclimate records. Since 700 cal yr BP, the peatland has been affected by both anthropogenic activities and climatic changes, as a drying climate and intensified human activities around the study area reduced diatom species diversity and peat accumulation. Under the background of future global warming and enhanced human activities, the decreasing species diversity and carbon accumulation rate of peatlands in high-latitude permafrost regions need more attention. • Diatoms can indicate local moisture and acidity in permafrost peatlands. • Diatoms are likely more sensitive to microhabitats than bryophytes. • TQ peatland formed after 2800 cal yr BP caused by the cooler and wetter climate. • Rich-fen shifted to poor-fen which co-influenced by deforestation and dry climate at LIA. [ABSTRACT FROM AUTHOR]

The Salawusu River Valley cuts through the Mu Us Desert in north central China, and lies at the interface of the East Asian Summer and Winter Monsoonal regions. Exposed at numerous locations in the valley side are extensive late Quaternary deposits, consisting of interbedded aeolian sands, fluvio-lacustrine units and palaeosols. Due to the importance of the location in potentially elucidating both summer and winter monsoonal regimes, and the quality of the sedimentary record, the region has a rich history of study, and yet even within the Holocene sequence, many conflicting interpretations have arisen based on studies on different sections. This paper aims to synthesize and explore these differences by exploring the lateral continuity of the Holocene sequences along a ~ 45 km reach of the valley, and presenting new, detailed physical and geochemical analyses of three sections, focusing on the lacustrine Holocene Dagouwan Formation. The absence of the lacustrine unit at several locations confirms that rather than representing a single lake, the Dagouwan Formation instead represents a series of palaeolakes, probably at least partially hydrologically isolated from each other by aeolian sands. All begin with sand-dominated deposits during the early−/mid-Holocene, which is interpreted as the result of abundant sand-supply to the north and west, under the influence of an enhanced East Asian Winter Monsoon, and all switch to silt-dominated, more carbonate-rich deposits during the mid−/late-Holocene, which is attributed to an enhanced East Asian Summer Monsoon bringing loessic silts from the Chinese Loess Plateau to the east and south. The timing of this change, perhaps as late as 5.5 ka, supports the idea of a relatively enhancement late mid-Holocene of the summer monsoonal circulation in the region. However, despite the proximity of the sections and consistent analytical approaches, marked differences between the sections occur in all proxies studied. The timing and rate of the switch from sand- to silt-dominated lacustrine deposition varies between the sites by as much as 2000 years within just a few kilometres of each other, and at some sites the switch was gradual, whereas at others it was very rapid. Similar dramatic variations are also seen with organic carbon content, carbonate content, C:N ratio, and especially the δ13C isotopic ratio. These point to the lake basins behaving very differently, and emphasize that consideration must be given to the local geomorphology and palaeolimnological evolution of individual sections. • Differences in lacustrine Holocene monsoon records in northern China are explored. • The occurrence of the lakes is geomorphologically, not climatologically, controlled. • Different sections of similar units represent different lakes with varied histories. • Consistent changes in sediment suggest mid-Holocene decline of winter monsoon. • Study of individual sections or proxies cannot be used to infer regional climate. [ABSTRACT FROM AUTHOR]

Abstract The Eocene was an interval of climate evolution, when the extreme high temperatures of the earliest Cenozoic gave way to a global cooling trend. Fine-grained lacustrine sediments of Eocene age from northeastern China represent an excellent archive to study long-term environmental and climatic changes at high-resolution. The Huadian Basin is a Cenozoic, fault-bounded basin in Jilin Province, northeastern China. Though small in area, it contains numerous oil shale- and coal-bearing layers, which provide an abundant Middle to Late Eocene palynoflora. Eighty-five palynomorph genera and one hundred palynomorph species were identified in the Huadian Formation, allowing to distinguish 4 palynozones. The nearest living relatives of the recovered palynomorph taxa suggest the presence of subtropical evergreen and deciduous broad-leaved forests during deposition of the Huadian Formation. Using the coexistence approach (CA), we calculated seven paleoclimatic parameters, which indicate a subtropical warm and humid climate with a mean annual temperature above 13.6 °C and a mean annual precipitation of at least 887 mm. However, the climate became cooler and drier during the transition from the lower Oil Shale Member to the upper Carbonaceous Shale Member. Palaeoclimatic data from the various Middle and Late Eocene basins of northeastern China (i.e., the Huadian, Fushun, Yilan, Hunchun and Jishu basins) were compared with data from North American and European basins. Middle Eocene climate in the Northern Hemisphere was generally warm and humid, and the mean annual temperature and precipitation in northeastern China were similar to those in North America, though slightly lower than those of Europe. Similar trends in temperature and precipitation on different continents support the existence of a global Mid-Eocene cooling event. This paper is the first systematic study of Middle to Late Eocene seasonality in the Huadian Basin. Our results show an apparent differentiation in both temperature and precipitation between summer and winter, supporting the view that the East Asian Monsoon was established in northeastern China already during the Middle to Late Eocene. This Middle and Late Eocene monsoon was likely driven by the development of Pacific trade winds and an alternating, seasonal high- and low-pressure system over Siberia. The climatic changes observed in our dataset, especially the precipitation changes, appear to have played an important role in controlling oil shale formation in the Huadian Basin. A warmer and more humid climate, with abundant precipitation and high subsidence rates, formed a deeper Huadian depositional lake. High productivity and stable stratification provided the abundant organic matter and favorable preservation conditions necessary for oil shale accumulation. Highlights • The Middle-Late Eocene palynoflora were firstly systematically studied in Huadian Basin. • We quantitatively estimated the Middle-Late Eocene climate based on CA method. • A globally cooler phase was recognized in the Middle Eocene. • Climate seasonality in the Middle-Late Eocene supports the EAM was already prevalent in NE China. • Changes in climate, especially precipitation, play an important role in oil shale formation. [ABSTRACT FROM AUTHOR]

This paper discusses the paleogeography and plate tectonics of the Silurian using five global and twelve regional scale maps. These maps illustrate the distribution of major tectonic elements such as subduction zones, spreading centres, transform faults and main volcanic areas 435 and 425 Ma ago. The regional maps show the global paleogeographic configuration combined with palaeoenvironmental and palaeolithofacies distribution. The paleogeographic analysis shows that the continents of Gondwana, Laurentia, Laurussia, Siberia, South China and North China were separated by the Iapetus, Rheic, Paleoasian (Prototethys), Paleotethys, Panthalassa and Mongol-Okhotsk oceans. Spreading of the Rheic and Paleotethys oceans constituted the main Silurian extensional event. The Scythian-Turan-South Kazakhstan-Junggar-Tarim-North China chain of continents moved north-westwards, and this led to a gradual narrowing of the Paleoasian Ocean. The Caledonian-Scandian orogeny that resulted from the collision of Baltica, Avalonia and Laurentia constituted the main convergent event during Silurian times. [Display omitted] • Paleogeographic and plate tectonics maps of the Silurian. • Caledonian orogeny – collision of Baltica, Avalonia and Laurentia. • Spreading of the Rheic and Prototethys oceans. • Paleoenvironment and palaeolithofacies distribution. • Organic-rich rock distribution. [ABSTRACT FROM AUTHOR]

The arid regions of northwestern China are dominated by extensive areas of mobile sand dunes. These features cause environmental problems and exert global climatic impacts; however, due to the lack of systematically-applied indicators of aeolian activity, direct evidence of past changes in aeolian activity is unreliable, especially for aeolian sand source regions. In this paper, we analyze the end-member (EM) distributions of various types of surface soil across the Tengger Desert in northwestern China, and devise a sensitive proxy for aeolian activity using a spatio-temporal substitution approach. This proxy is then used to evaluate a Quaternary aeolian succession and to understand the response of aeolian activity to regional climate change. Our results suggest that gradual increases in the coarse-grained EM components 3–5 reflect enhanced dune mobility and reduced vegetation coverage, which are a direct function of the intensity of regional aeolian activity. In the aeolian section, coarse- and medium-grained sand layers resemble modern semi-mobile and mobile dunes, whereas fine-grained sand layers are analogous to vegetated fixed/semi-fixed or semi-mobile dunes. Combining this record with independent multi-proxy evidence from the same section leads us to conclude that strong aeolian activity coincided with a dry climate, sparse vegetation cover, and strong surface winds during the Last Glacial Maximum, and that these conditions gradually attenuated at the beginning of the Last Deglacial. These inferences are in accord with independent paleoclimate records from this region, confirming that the intensity of aeolian activity in the southeastern Tengger Desert is closely associated with large-scale climate change. Our findings show that our EM proxy can be used to infer the intensity of aeolian activity and to reliably reconstruct the evolution of deserts in northwestern China. [Display omitted] • Coarse grain-size End-members (EM) 3–5 are a proxy of the strength of aeolian activity. • This proxy is applied to a palaeo-aeolian sequence to reconstruct the history of desert evolution. • Aeolian activity was closely associated with large-scale climate change. [ABSTRACT FROM AUTHOR]

Ecosystems in arid regions with sandy substrates are vulnerable to various environmental challenges. Understanding the vegetation evolution of such regions over a long timescale and the possible drivers of change is important for optimizing ecological restoration. In this paper, we present multi-proxy data to understand Holocene vegetation dynamics and their drivers in the Horqin Sandy Land in northern China. Phytoliths are used to reconstruct vegetation; grain size and magnetic susceptibility are used to reconstruct the climate; and sedimentary charcoal contents and the numbers of regional archaeological sites are used to reconstruct the fire activity and human activity intensity, respectively. Results indicate that the Horqin Sandy Land was covered mainly by grassland vegetation during the Holocene, and that the trajectory of vegetation evolution was as follows: sparse and species-poor Leymus chinensis grassland from 9300 to 6150 cal yr BP, relatively sparse and species-rich mesophytic herb grassland from 6150 to 2300 cal yr BP, and dense and species-rich L. chinensis grassland from 2300 to 250 cal yr BP. Climate change was the main driver of vegetation evolution, but fire and human activities also influenced the vegetation to varying degrees. Fire made the greatest contribution to the vegetation change during the 6150–2300 cal yr BP interval, and human activities contributed throughout the 8200–2300 cal yr BP interval. The evolution of plant species richness and the number of C 3 plants show a significant ∼1000-yr periodicity during 9300–4500 cal yr BP, which we speculate was caused by the effect of solar activity on East Asian monsoon intensity, which likely controlled the vegetation change on a millennial timescale. • The Holocene vegetation in Horqin Sandy Land is qualitatively reconstructed. • Climate dominated the vegetation evolution, while fire and human activity were additional influences. • The vegetation change shows a ∼ 1000-yr periodicity during 9300–4500 cal yr BP. • The vegetation change on a millennium cycle was likely driven by the solar activity. [ABSTRACT FROM AUTHOR]

This paper presents the Miocene squirrels of the Linxia Basin in Gansu Province, and a paleoenvironmental and palaeoecological analysis based on the remains collected recently by screen-washing nine localities of early to late Miocene age. The assemblages contain 12 sciurid species (nine genera, three subfamilies), including squirrels with different adaptations, predominantly ground squirrels and chipmunks. Our analysis suggests that Miocene squirrels in Linxia reflect a relatively dry climate and open shrub-steppe environment, and favorable dispersal across Eurasia. The Linxia Miocene squirrels show close taxonomic composition with contemporary faunas known from the Mongol-Xinjiang highland and adjacent regions, implying that northern China represents a single biotic province with uniform paleoenvironment. In addition, the Linxia squirrels are quite different from those found in Yunnan in southern China, which are dominantly tree and flying squirrels that suggest a humid forest biotope. The differences in distribution indicate that Miocene squirrel faunas of China showed distinct provinciality and latitudinal ecological variation. Already in the Miocene we see evidence for predecessors of the present-day Palearctic and Oriental zoogeographic provinces of North and South China. • Rich Miocene Linxia Basin squirrel assemblages show distinctive adaptions. • Preferred habitat and ecology indicate open versus forested environments. • Miocene squirrels across China indicate zoogeographic province precursors. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the Holocene record of extreme flood events in the upper Minjiang River valley of the eastern Tibetan Plateau, China. Slackwater deposits (SWDs), the fine-grained sediments of palaeofloods, were identified within debris flow deposits at a tributary mouth and in channel expansions along the bedrock gorge. Eight palaeoflood SWDs were dated to between 6.0 ± 0.9 ka and 4.6 ± 0.9 ka using optically-stimulated luminescence analysis in combination with the minimum age model and represent at least two phases of palaeoflood events. The palaeoflood history in the upper Minjiang River Valley is consistent with the record of the mid-Holocene flood events in the mainstream of the Yangtze River. These mid-Holocene extreme flood events were closely related to strong ENSO activity and variability of the monsoon climate in the eastern Tibetan Plateau. In our study area, minimum palaeoflood discharges were estimated as 6500–7800 m3/s by the step-backwater method. These estimated discharges are less than the values inferred for the outburst flood that occurred in the upper Minjiang River Valley in 1933. Flood-inundation maps show that palaeoflood SWDs were deposited in low-velocity backwater zones. Our palaeoflood reconstructions are important for improving regional records of maximum flood and help to develop risk analysis for rare flood events. • Sedimentary characteristics of palaeoflood records in complex environment were identified. • Palaeoflood discharges were estimated to be 6500–7800 m3/s at the three study sites. • Palaeoflood results redefine the envelope curve of the regional maximum floods. • Response of mid-Holocene (6.0–4.6 ka) extreme flood events to climate variability. • Palaeoflood reconstructions help to develop risk analysis for rare flood events. [ABSTRACT FROM AUTHOR]

Major reorganizations in climate and tectonic regime occurred in East Asia during the Pleistocene, resulting in large-scale environmental changes. In this paper a detailed geochemical and mineralogical record of these changes is presented from a distal alluvial fan sedimentary sequence in the northern Weihe Basin. We established that, in addition to glacial-interglacial variation, there are three distinctly different units deposited over the past 1 m.y. These units are the result of variations in the overall tectonic regime in the northern Weihe Basin. Fine-grained detrital minerals were predominantly delivered during colder climatic periods, whereas evaporative minerals were dominantly deposited during the warmer, interglacial periods, probably as a result of strong seasonal contrast. This compositional variation demonstrates the importance of climate control on hinterland erosion, surface runoff, chemical weathering and evaporation. Al-normalized ratios of indicative major elements relative to average loess composition, indicate important variations in sedimentary processes, mostly related to sediment flux. Si-enrichment is an index for past flooding events, while Fe enrichment, just like K and Ti, reflects influx of clays. In contrast, Ca and Mn are strongly enriched throughout the core, associated with the authigenic precipitation of carbonates, especially during interglacial periods. The lower (~ 1000–690 ka) and upper (~ 330–0 ka) units of the core are characterized by relative intense and frequent flooding, which coincided with extensive ponding in the study area. In the middle unit (~ 690–330 ka) increased salinity levels caused by evaporation, as reflected in the high Sr/Ca ratio and dolomite abundance, led to increased carbonate precipitation. Simultaneously, the increased influx of fine sediments indicates increased clay production in the source area as a result of a more intense summer monsoon strength after 600 ka. [ABSTRACT FROM AUTHOR]

In this paper, stable isotope (δ 13C, δ 18O) analyses of five equid species from the Linxia Basin, northwestern China, were conducted to investigate dietary niche turnover during a critical Pliocene-Pleistocene phase in the evolution of Old World Equidae. In the Early Pliocene Shilidun fauna, Proboscidipparion pater is inferred to have mainly fed on C 3 grasses in open grasslands as indicated by their relatively high δ 13C values (−9.1 ± 0.4‰, five teeth, n = 61), whereas Cremohipparion licenti and Sivalhippus platyodus were possibly mixed feeders inhabiting woodlands and grasslands because of their comparatively low δ 13C values (−10.8 ± 0.6‰, seven teeth, n = 36; −10.6 ± 0.6‰, nine teeth, n = 35). Inhabiting the same environments, both C. licenti and S. platyodus went extinct, possibly, because climatic changes led to a decline in woodlands resulting in greater competition. In the Early Pleistocene Longdan fauna, Proboscidipparion sinense had higher δ 13C values (−9.1 ± 0.5‰, four teeth, n = 23) than coexisting Equus eisenmannae (−10.2 ± 0.5‰, eight teeth, n = 57), implying that P. sinense had a stronger grazing preference compared to E. eisenmannae. Ecomorphological analyses (body size, tooth crown height, and enamel surface complexity) reveal that P. pater and P. sinense had dental characteristics consistent with a strong grazing preference. Therefore, P. pater might have been preadapted to open grasslands during the warm and humid Early Pliocene, which helped its descendent P. sinense persist into the Pleistocene. The results of this study reveal distinct dietary niches for these equids for the first time and shed light on some aspects of the evolutionary history of Equidae in East Asia. • Dietary niche partitioning of five fossil equids were reconstructed through stable isotopes in East Asia for the first time. • Preadaption to open grasslands of Proboscidipparion pater during the Pliocene helped this genus persist into Pleistocene. • Cremohipparion licenti and Sivalhippus platyodus went extinct due to interspecific competition on habitats in Pliocene. • Early Pleistocene hipparion Proboscidipparion sinense occupied more open environments than coexisting Equus eisenmannae. [ABSTRACT FROM AUTHOR]

The Ordovician-Silurian (O S) transition witnessed dramatic tectonic, climatic, marine, and biological coevolution, during which organic-rich black shale was widely deposited and is considered an important source rock. However, the potential links between the differential enrichment pattern of organic matter and climate fluctuations and paleoenvironmental evolution during this period are still unclear. In this paper, the Late Ordovician-early Silurian black shale in a JieLong (JL) section in South China was identified by graptolitic fossils, total organic carbon (TOC) content, X-ray diffraction (XRD), scanning electron microscopy (SEM) and geochemical analysis. The results show that the provenances of sedimentary rocks are all granodiorite-like. According to the variations in the TOC content and geochemical indicators, four layers are delineated. Under warm and humid climatic conditions, sea level rise and unstable seasonal upwelling led to Unit 1 organic matter enrichment controlled by high primary productivity, anoxic conditions and effective smectite production. Unit 2 organic matter burial was controlled by cold, arid and oxic environmental conditions, but primary productivity was still relatively high. After the end of the glacial period, warm and humid climatic conditions and rapid transgression were the main factors affecting the burial of organic matter in Unit 3. Under hot and humid climate conditions, higher terrigenous detrital inputs and unfavourable preservation environments, the dilution of organic matter in Unit 4 was accelerated. The corrected chemical index of alteration (CIA corr) values show that the study area experienced a climate change of alternating cold and warm conditions in response to the climate fluctuation during the glacial-interglacial period. The CIA corr value is negatively correlated with the TOC content, while the generation of available clay minerals (smectite) in warm and humid climates is usually consistent with the enhanced burial flux of organic matter, supporting the important role of climate fluctuations in the accumulation of organic matter. Finally, a comparison of the data from the present study with geochemical data from different profiles in South China reveals the role of climatic fluctuations during the O S transition in controlling paleoenvironmental evolution and organic matter enrichment, while such a heterogeneous factor is usually associated with global or regional geological events. Our study highlights this differential enrichment mechanism as a combined response of multiple factors and provides important implications for glacial-interglacial organic matter enrichment mechanisms. • Rapid changes of weathering indices imply climatic fluctuations during the Late Ordovician-Early Silurian. • Four different patterns were established for organic matter accumulation across the O/S. • Climate fluctuations and the heterogeneity nature of ocean systems explain the regional variations of OM accumulation. [ABSTRACT FROM AUTHOR]

In this paper, we examine the Early to Middle Holocene evolution of a prominent group of ground-water fed lakes in the southeastern hinterland of the Badain Jaran Desert (BJD) of northwest China. Specifically, we describe a sediment profile record from the Taoerlegetu (TR) palaeolake basin using multiple proxies of total organic carbon (TOC), total nitrogen (TN), C/N ratio, δ13C org , grain size and mineral composition based on a well-dated trench profile. As C/N values suggest that sedimentary organic matter mainly originated from aquatic plants, δ13Corg values can be used as a qualitative proxy for water level because aquatic plants in different biotopes (water depth) have different δ13C values. Our results show that from 10.9 to 9.1 cal kyr B.P., water level rose slowly, and aquatic macrophytes occupied the lake basin. From 9.1 to 5.5 cal kyr B.P., water level reached an even higher level and phytoplankton replaced macrophytes as the major contributor to organic matter. The humid episode of the lakes in the hinterland of the BJD in the early Holocene might be related to the increased groundwater supply from the northeast region of the Tibet Plateau. These findings are consistent with earlier studies of lacustrine and peat sediments found in periphery of the modern lake group, which indicate that their geographic extent may have been larger in the past. A relative drought period recorded in the studied succession from 8.5 to 8.0 cal kyr B.P. marks an interval of reduced ground-water transport from the Tibet Plateau. This interval probably corresponds to the "8.2 ka cold event" and provides evidence that this widespread climate episode influenced groundwater processes across inland Asia. • The δ13C org value could be used as a qualitative indicator for the change of water level. • Lakes in the hinterland of the Badain Jaran Desert shows different evolution progress with these in the edge. • The main water source of lakes in the hinterland of the BJD in the Early Holocene comes from the Tibet Plateau. [ABSTRACT FROM AUTHOR]

As a consequence of the end-Permian mass extinction, microbes proliferated in the post-extinction shallow marine ecosystems, in which they grew as various microbially induced sedimentary structures (MISSs) in siliciclastic settings. This paper reports, for the first time, the discovery of abundant MISSs from the lowest Triassic sandstones of shallow-water margin origin in the Zhihema sections of the southern Qilianshan region, West China. The sandstones are characterized by well-developed cross-beddings and ripple marks, and a Claraia -dominated bivalve assemblage of middle-late Griesbachian age. These sedimentary structures, together with the bivalves, suggest a high-energy peritidal zone of a shoreface setting in a clastic shallow sea environment. Seven types of MISSs are recognized and described here: pictograph-like sand cracks/crack-fills, polygonal sand crack-fills, erosional remnants, multidirectional linear grooves, sinuous crack-fills, fusiform sand cracks/crack-fills, and leveled ripple marks. Most of the newly found MISSs are morphologically comparable with their ancient and modern counterparts. Detailed optical microscope and scanning electron microscope (SEM) analyses reveal that thin clayey laminae and filamentous mica grains are aligned parallel to bedding plane, and that the matrix-supported quartz grains, overall, are oriented; both of which are interpreted to indicate biogenic origin. The biogenic origin of these MISSs is reinforced by the presence of copious putative nanoglobules and filamentous biofilm-like organic objects in the interspaces of clay minerals in laminated layers. These nanometer-scale objects are interpreted as bacterial bodies or remains that have been replaced with inorganic minerals upon fossilization. The presence of MISSs on the northern margins of Paleo-Tethys indicates that the post-extinction microbial mats had expanded their distributions from low-latitude to moderate-high latitude regions. Moreover, unlike some previously reported microbial mats that contain very rare body and trace fossils, the southern Qilianshan MISSs were found in association with abundant vertical burrows and bivalves, suggesting that the MISS-forming microbial mats may have served as oases for trace-making organisms and opportunistic bivalves to flourish in shallow-marine habitats immediately after the end-Permian mass extinction. [ABSTRACT FROM AUTHOR]

Abstract: Fluvial systems in tropical regions are not only the lifeline for modern civilizations there but also form an important continental archive for reconstructing Quaternary palaeoclimates and palaeoenvironments. Tropical rivers drain through a variety of geological and geomorphological settings across the world and have been studied for their hydrology, sediment transport characteristics, facies models, stratigraphic development and flood hazards. This paper presents an overview of the research on tropical rivers globally and identifies major gaps and unanswered research questions. As a part of the IGCP 582 on Tropical Rivers, the participants of this project are continuing to tackle many of these issues. The collection of papers in this special issue is an outcome of this activity and presents new data on processes and alluvial stratigraphy of the tropical rivers from China, India, South America and northern Australia. [Copyright &y& Elsevier]

The response of terrestrial ecosystems to Eocene hyperthermal events remains poorly understood. In this paper, we report palynological assemblages from an astronomically-calibrated Eocene succession in the Fushun Basin of northeast China, in which previous δ13C studies have identified the Eocene Thermal Maxima 2 and 3 (ETM2, ETM3), the Early Eocene Climatic Optimum (EECO), and the Middle Eocene Climatic Optimum (MECO). In the samples that are directly associated with hyperthermal events, palynoassemblages show significant increases in the abundance of conifer pollen, especially Abietineaepollenites and Taxodiaceaepollenites , and fern spores of Polypodiaceaesporites , while angiosperm taxa reduce in frequency. Quantitative palaeoclimate parameters derived through the application of the Coexistence Approach to palynological assemblages indicate marked changes in temperature and humidity during hyperthermal events. These changes were most significant during ETM2 when mean annual temperature increased by 3–5 °C and mean annual precipitation increased by approximately 600 mm above background levels, but similar perturbations are also associated with the other hyperthermal events. An increase in organic abundance in lacustrine oil shale facies during hyperthermal events may imply that elevated humidity drove enhanced runoff, nutrient supply, and eutrophication of the hydrologically-open lake basins at a time when terrestrial carbon export from humid forests was also enhanced. Findings demonstrate that short-term bursts of Eocene warming drove major turnovers in the mid-latitude vegetation of Asia, reworking landscapes, and transforming regional hydrology. • We describe palynoassemblages from an astronomically-calibrated Eocene succession in northeastern China. • Palaeoclimate analysis of assemblages indicates that MAT and MAP increased during hyperthermal events. • Eocene Thermal Maximum 2 showed the largest rise of MAP (3–5 °C) and MAP (600 mm) • Short-term bursts of Eocene warming drove major turnovers in the mid-latitude vegetation of Asia, reworking landscapes and hydrology [ABSTRACT FROM AUTHOR]

Reconstructing Holocene changes in regional sea level is useful for understanding future sea-level scenarios. In this paper we examined the sedimentology, pollen, foraminifera, and organic matter properties of a well-dated profile from the Subei Basin that spans the last 6.7 ka. By integrating our findings with the archaeological record, we investigated mid- to late Holocene vegetation responses to relative sea-level fluctuations and considered the impact of climatic variations on cultural development. In the middle Holocene, the rapid and abrupt expansion of salt marsh vegetation (Chenopodiaceae, Cyperaceae, and Poaceae) suggests a relative rise in sea level. From 5.7 to 4.2 cal ka BP, lowland swamps were settled by Neolithic communities, as indicated by peak levels of microscopic charcoal and a significant rise in herbaceous pollen species, such as Cyperaceae, Typha , Myriophyllum , and Poaceae. From 4.2 to 3.7 cal ka BP, a major increase in Chenopodiaceae abundance and a δ13C excursion were observed along with a decrease in Cyperaceae and Poaceae levels, which revealed that human activity significantly decreased following the 4.2 ka climate event. Evidence suggests that the area under investigation experienced a relatively high sea level between 6.7 and 6.0 ka, a relative decrease in sea level between 6.0 and 5.7 ka, a steady sea-level condition between 5.7 and 4.2 ka, and gradual replacement by a freshwater marsh between 5.7 and 4.2 ka. The pollen and δ13 C records demonstrate that the relative sea level rose quickly from 4.2 to 3.7 ka, which could correspond to the 4.2 ka event. Enhanced El Niño-Southern Oscillation (ENSO) variance and intense climatic events in eastern China were the driving forces behind the mid-late Holocene relative sea-level shift. The rise in relative sea level eventually led to the collapse of the Qingdun and Jiangzhuang sites in the Subei Basin. Our results provide independent vegetation evidence of the simultaneous changes in relative sea level and variations in climate. • Vegatation and environment changes are investigated from ∼6700 cal a BP. • The significant relative sea-level rise in the Subei Plain during 4.2–3.7 cal ka BP. • The rise in relative sea level led to the collapse of the Qingdun site and Jiangzhuang site in the Subei Basin. [ABSTRACT FROM AUTHOR]

Abstract: In their recent paper, ; Anti-phase oscillation of Asian monsoons during the Younger Dryas period: Evidence from peat cellulose δ13C of Hani, Northeast China, Palaeogeography, Palaeoclimatology, Palaeoecology 297, 214–222) discuss bulk peat sample cellulose δ13C data from a fen in northeast China as a proxy for East Asian summer monsoon intensity during the Late Glacial period. Based on their own results, cited papers, and an extensive re-interpretation of sedimentological and palynological data from nearby Lake Sihailongwan, construct a hypothesis of contrasting moisture conditions in northern and southern China, with wet conditions in the north during the Younger Dryas period and an anti-phase behaviour of Indian- and East Asian summer monsoon intensity. However, we do not approve of the re-interpretation of our Lake Sihailongwan data by and must strongly reject it. We show here that neither the fen data, nor the Lake Sihailongwan data or any other cited data allow for the sound assumption of an intensified East Asian summer monsoon in northeastern China during the Younger Dryas. The Late Glacial variability of the fen data found by can be easily explained by changes in the plant assemblage down core and thus by the composition of the peat. Furthermore, the use of bulk peat cellulose δ13C data as a precipitation proxy remains unproven for that area. Hence, there is no basis for a model contrasting Indian and East Asian summer monsoons during that period. [Copyright &y& Elsevier]

Glacier retreat in high altitude areas triggered by anthropogenic warming exerts a profound impact on the ecology of glacier-fed lakes. In this paper, we report on the results of a multi-proxy analysis of a Lateglacial (13.3–11.3 cal kyr B.P.) core obtained from the glacier-fed Kanas Lake in the Altai Mountains, China, to understand the responses of aquatic ecosystems to meltwater influxes. Core intervals with high sand fractions and enriched silicon dioxide and zirconium (~11.5, 11.7, 11.8, 12.2 and 13.0 cal kyrs B.P.) reflect intense meltwater pulses from alpine glaciers. In the core, these pulses generally coincide with low abundance of littoral cladocerans, high abundance of planktonic Pediastrum , and high phosphorus concentrations. Our results suggest that intense meltwater influxes not only brought nutrients (nitrogen and phosphorus) into the lake and promoted phytoplankton growth, they also generated cold, turbid water masses and restricted the growth of benthic algae and invertebrates. Therefore, we infer that future anthropogenic warming may lead to significant changes in the structure and function of aquatic ecosystems in glacier-fed lakes worldwide. • We study the impact of Lateglacial meltwater influx on the aquatic ecology of Kanas Lake, China. • Intense meltwater influx delivered nutrients to the lake and promoted the phytoplankton growth. • Intense meltwater influx also generated turbid and cold waters and restricted the benthic organism growth. • Future anthropogenic warming may lead to significant changes in aquatic ecosystems of glacier-fed lakes worldwide. [ABSTRACT FROM AUTHOR]

The Early Cretaceous Jehol Biota in northern China is a terrestrial lagerstätte that contains exceptionally-preserved fossils, including birds, dinosaurs, pterosaurs, mammals, insects, and flowering plants. The biota underwent three developmental phases, with relatively limited biodiversity in an early phase that rapidly diversified in a middle phase; however, the relationship between this biological radiation and climate remains uncertain. In this paper, we study fossils from the early-to-middle phases of the Jehol Biota preserved in the Lower Cretaceous (middle Valanginian-lower Barremian) Dabeigou and Dadianzi formations of Hebei Province to ascertain climatic impact on biotic evolution. The occurrence of a cool to warm climate turnover during the deposition of these strata is inferred based on a synthesis of geochemical and paleontological evidence. Palaeogeographic distribution of the middle phase of the biota is wider and positioned more southerly than that of the early phase, possibly indicating that the biota in the early and middle phases lived in boreal and temperate climate realms, respectively. Biotic diversity shows an increasing trend from the early phase to the middle phase of the Jehol Biota, closely coinciding with the cool to warm turnover of the climate. The body sizes of some taxa in the middle phase were significantly smaller than those in the early phase, which is also interpreted as a climatic effect. This study represents the first attempt to correlate the response of terrestrial evolution of the Jehol Biota to climate change, with a focus on Early Cretaceous paleotemperatures. • The Lower Cretaceous of northern Hebei record early-middle stages of Jehol Biota. • Climate change from cool to warm during early development of Jehol Biota. • Warming climate enabled the diversification of the Jehol Biota. [ABSTRACT FROM AUTHOR]

Eocene hyperthermal events are thought to be closely linked to rapid increases in atmospheric CO 2. It is important to better understand the atmospheric triggers of these extreme events; however, reconstruction of p CO 2 from sedimentary records remains challenging. Eocene hyperthermal events (Eocene thermal maximum, ETM; Early Eocene Climatic Optimum, EECO; Mid-Eocene Climatic Optimum, MECO) are well documented in the Fushun Basin of northeast China, but the source of organic matter (OM) used as a p CO 2 archive in previous studies includes land plants, algae, mixed land and aquatic organisms in the Ypresian, Lutetian and Bartonian intervals, respectively. In this paper, we calculate p CO 2 concentrations using δ13C TOC and δ13C 27 – 31 and discuss the factors influencing discrepancies based on various calculations. Results show that both δ13C TOC and δ13C 27 – 31 from single OM sources are reliable proxies for p CO 2. During the ETM2, ETM3, EECO and MECO intervals, p CO 2 was 638–2277 ppm, and palaeotemperature was approximately 2.6–8.9 °C higher than present. The background and peak values of p CO 2 during hyperthermal events were compared with those related to methane hydrate, OM oxidation and volcanic sources of p CO 2 carbon. The comparison revealed that p CO 2 values associated with the ETM2, ETM3, EECO and MECO events were more consistent with those calculated by OM oxidation and locally overlapped with volcanic sources. These results indicate that these p CO 2 estimates of hyperthermal events are predominantly derived from terrestrial OM oxidation and were influenced by volcanism. • Continuous p CO2 records of the Eocene in Northeast Asia was Reconstructed • Multi method reconstruction of p CO 2. • The p CO 2 content of ETM2 events in the Eocene was the highest, followed by ETM3, EECO and MECO events. [ABSTRACT FROM AUTHOR]

The South Qinling Belt is a key area for understanding the collisional history of the South China and North China blocks during the Lopingian (late Permian) and Triassic. This paper establishes the first integrated timescale based on conodont biostratigraphy and δ13C carb records from a continuous end Permian to the end-Early Triassic succession at Yiwagou, South Qinling Platform (SQP). Ten Early Triassic conodont zones are established. They are, in ascending order, Hindeodus parvus , H. postparvus , Neospathodus dieneri , Eurygnathodus costatus and E. hamadai , Novispathodus waageni - Scythogondolella mosheri , Pachycladina - Parachirognathus assemblage, Triassospathodus hungaricus , Ns. robustispinus and T. clinatus zones. Our record of δ13C carb fluctuations shows close correspondence to known Early Triassic carbon isotope fluctuations and, in combination with the conodont data, helps achieve a high-resolution age model for the region. The use of E. costatus as a good auxiliary marker for the Induan-Olenekian boundary (IOB), within palaeolatitudes of 40°N-40°S, is supported but it can not replace the use of Nv. waageni , because the former is absent in higher-latitude and cooler regions. The conodont faunas from the Palaeo-Tethyan Yiwagou section closely resemble those from the Northern Yangtze Platform (NYP), but they differ somewhat from the contemporaneous Nanpanjiang Basin at species level. Thus, the Qinling Sea was likely well connected with the NYP in the Early Triassic, but was more isolated from the Nanpanjiang Basin. The remarkable reappearance of Hindeodus fauna around the IOB at Yiwagou implies that the shallow-water Qinling Sea was a refuge area for this genus long after its disappearance elsewhere. • Conodont biostratigraphy and δ13C carb records from end Permian to the end-Early Triassic succession at Yiwagou, South Qinling Platform. • Discussion of index conodont for the Induan-Olenekian boundary. • Comparison of the conodont faunas between the eastern Paleo-Tethyan Yiwagou, South China and the western Paleo-Tethyan Europe. • The shallow-water Qinling Sea was a refuge area for Hindeodus fauna after Griesbachian. [ABSTRACT FROM AUTHOR]

The end-Triassic mass extinction (ETE), one of the five largest mass extinctions, occurred at 201.6 Ma. It was characterized by dramatic declines in marine and terrestrial ecosystems and was approximately synchronous with the eruption of the Central Atlantic Magmatic Province (CAMP). Loss of marine biodiversity is linked to extreme global warming while the cause of floral destruction in terrestrial ecosystems remains open to debate. In this paper, biomarker records of higher plants are reported from terrestrial facies in the Haojiagou section of the high palaeolatitude Junggar Basin, northwest China. Strata around the ETE interval are marked by sharp increases in the abundances of cadalene, retene, pimanthrene and furans, which are synchronous with "fern spikes". These results are interpreted as indicating the demise of land vegetation and the enhanced burial of higher plants, consistent with palynological evidence for the loss of floral diversity. The fluctuations in the abundance of n -alkanes series and conversion of n -alkanes peak patterns coincide with wildfires indicated by polycyclic aromatic hydrocarbons. Based on integrated stratigraphic correlation, the increased burial of higher plants, wildfires and CAMP volcanism are synchronous both in the Haojiagou section and other classic Triassic-Jurassic boundary sections globally. We propose that widespread deforestation may be due to CAMP-derived acid rain and the rapid and large-scale demise of vegetation may have provided moisture-free fuels for wildfires. • Higher plant biomarkers are first reported in a high palaeolatitude terrestrial basin across the Triassic-Jurassic transition. • Similar biomarker features are witnessed at worldwide marine and terrestrial sections, suggesting a global deforestation. • Extensive deforestation and wildfires during the ETE period could be initially caused by the CAMP-originated acid rainfalls. [ABSTRACT FROM AUTHOR]