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Iron-based superconductors (IBS) have attracted intense interest from scientists around the world. The first FeSe0.5Te0.5 hybrid coil including one FeSe0.5Te0.5 single pancake coil (SPC) and eight YBCO double pancake coils (DPCs) was successfully fabricated and test in this study. The FeSe0.5Te0.5 tape used in the hybrid coil is encapsulated strengthen tape which is with 0.15 mm thickness and 10.5 mm width to withstand the high stress during the cold test. The FeSe0.5Te0.5 encapsulated tape exhibits good performance at 4.2 K cold test. YBCO DPCs were divided into two groups connected to both sides of the FeSe0.5Te0.5 SPC. The critical current of the FeSe0.5Te0.5 coil was measured under the background field increased from 0 T to 10 T. The transport critical current of the FeSe0.5Te0.5 SPC showed 108.1 A at self-field and 17.4 A at 10 T, which had almost the same performance as the short sample. The results in this study showed that the FeSe0.5Te0.5 coated conductor coil have good performance in high magnetic fields.

Archaeological records document a significant expansion of populations from the Last Glacial Maximum (LGM, ~23-19 ka) to the early Holocene (EH, ~9 ka) in Eurasia, which is often attributed to the influence of orbital-scale climate changes. Yet, information remains limited concerning the climatic factor(s) which were responsible for conditioning demographic patterns. Here, we present results from an improved Minimalist Terrestrial Resource Model (MTRM), forced by a transient climate simulation from the LGM to the EH. Simulated potential hunter-gatherer population densities and spatial distributions across Eurasia are supported by observed archaeological sites in Europe and China. In the low latitudes, potential population size change was predominantly controlled by precipitation and its strong influence on plant and animal resources. In the middle-high latitudes, temperature was the dominant driver in influencing potential population size change and animal resource availability. Different regional responses of potential populations to climate change across Eurasia - owing to variations in available food resources between the LGM and EH - provide a better understanding of human dispersal during the Late Pleistocene., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Pollen evidence from a 25.3-m-long section (~2.2–0.41 Ma) in the Jinyuan Cave, Liaodong Peninsula, indicates that from the Early–Middle Pleistocene, the climate showed a trend of gradual cooling and drying, with obvious fluctuations. The vegetation was represented by temperate broad-leaved forest from ca. 2.2 to 1.87 Ma, suggesting a relatively warm and humid climate. The period from 1.87 to 1.82 Ma witnessed an obviously cold and dry event, and coniferous and broadleaved mixed forests developed from 1.82 to 1.76 Ma. From 1.52 Ma to the Mid-Pleistocene Transition (MPT), the vegetation was dominated by forest steppe, and the climate became cold in the later stage. During the 0.59–0.41 Ma period, steppes developed, and the climate was cold and arid. At the same time, with climate variation, the faunal communities also changed obviously and co-evolved with vegetation types. In the early stage of the Early Pleistocene, the warm and humid climate was related to the presence of a wide range of thermophilous animals. From 1.7 to 1.5 Ma, the transition from forest to forest steppe might have promoted the emergence of certain grassland-adapted animals. During the MPT, grassland-adapted animals became dominant due to the flourishing forest steppe vegetation. The Middle Pleistocene witnessed the expansion of steppe and animals adapted to the arid grassland environment at that time.

Chronological sequences of Quaternary terrestrial mammalian faunas can provide important information about the evolutionary history of mammals, regional biostratigraphy and paleoenvironmental changes. Here we report the results of studies of a thick, nearly-continuous sedimentary sequence from Jinyuan Cave, in Liaoning Province, northeast China; the sequences contains four mammalian faunas ranging in age from the Late Pliocene to the late Middle Pleistocene. Detailed paleomagnetic and U-series age determinations date the upper unit of the sedimentary sequence to ~2.2–0.3 Ma. The results suggest that cave development and infilling were closely associated with the tectonic evolution of the Bohai Basin, including the subsidence of the basin and the uplift of the surrounding mountains, such as Luotuo Hill. Together with the large mammalian faunas from both south and north China, we suggest that these mammalian faunas were smaller in size and lower in species diversity during the Middle Pleistocene Transition (MPT) (1.2–0.7 Ma) than in the earlier and later Pleistocene. This indicates that major climatic variations during the MPT in north China may have reduced their taxonomic abundance and diversity. The extremely warm and wet interglacial climates that followed the MPT in monsoonal East Asia provided an ecological niche for the evolution and migration of these mammalian faunas, resulting in an increase in the numbers and diversity of mammals in East Asia.

The aeolian loess-paleosol sequences in the Chinese Loess Plateau (CLP) are an excellent archive of variations in atmospheric circulation in the geological past. However, there is no consensus regarding the roles of the East Asian winter monsoon and westerly winds in transporting the dust responsible for loess deposition during glacial and interstadial periods. We conducted detailed measurements of the anisotropy of magnetic susceptibility (AMS) on two parallel loess profiles covering the most recent 130 ka in the western CLP to determine paleowind directions. Results show that the magnetic lineations of the loess and paleosol units in both sections are significantly clustered along the northwest to southeast direction. These observations demonstrate that the prevailing wind system responsible for dust transport in the western CLP was the northwesterly winter monsoon, rather than the westerly winds. The AMS-derived dust-bearing wind direction was relatively stable during the last glacial and interglacial cycle in the western CLP, consistent with sedimentary and AMS evidence from the eastern CLP. Accordingly, it is reasonable to conclude that large areas of deserts and Gobi deserts areas located in the upwind direction were the dominant sources for the aeolian deposits of the Loess Plateau.

The Dayao Paleolithic site, located in Inner Mongolia on the eastern margin of China's vast northwestern drylands, was a lithic quarry-workshop utilized by Pleistocene human migrants through the region. Determining the age of this activity has previously yielded controversial results. Our magnetostratigraphic and OSL dating results suggest the two artifact-bearing paleosols are correlated with MIS 5 and 7, respectively. Correlating paleoclimatic data with marine δ18O records leads us to conclude that two sandy gravel layers containing many artifacts in the lower part of the Dayao sequence were formed during MIS 9 and 11, if not earlier. Our results reveal that the earliest human occupation at the Dayao site occurred before ca. 400 ka during a relatively warm and moist interglacial period, similar to several subsequent occupations, documenting the earliest and northernmost archaeological assemblage yet reported in China's arid northwest. We conclude that the northward and southward displacements of the East Asian summer monsoon rain belt during past interglacial-glacial cycles were responsible for the discontinuous human occupation detected at the Dayao site. The penetration of this precipitation regime into dryland ecologies via the Huanghe (Yellow River) Valley effectively created a corridor for hominin migration into China's arid northwest.

Recently, rich fossiliferous deposits dated to the late Cenozoic have been discovered from Jinyuan Cave at Luotuo Hill, an extremely large-sized cave site situated within in the Dalian Puwan Economic Zone of Dalian Municipality, Liaoning Province in Northeast China. Abundant and diverse vertebrate fossils unearthed from different fossiliferous layers of Jinyuan Cave, a site of enormous size with a sedimentary thickness of over 40 m and its deposits can be roughly divided into three fossiliferous deposit units, altogether containing six fossiliferous layers belonging to different ages from the Late Pliocene to the Middle Pleistocene. Based on a combination of biostratigraphic and geochronological evidence, the fossil assemblages from Jinyuan Cave can be divided into three successive faunas that span the Late Cenozoic (ca. 3.60–0.35 Ma): the Wanghai fauna from upper faunal unit (Middle Pleistocene, 0.78–0.35 Ma), the Jinyuan fauna from middle-lower faunal unit (Early Pleistocene, 2.60–0.78 Ma) and the Luotuoshan fauna of the bottommost faunal unit (Late Pliocene, 3.6–2.6 Ma). The mammalian faunal evolution of Jinyuan Cave can be divided into four temporal stages during the late Cenozoic. The new discovered Jinyuan Cave provides a unique and nearly-continuous faunal and sedimentary sequence stretching from the Late Pliocene to the Middle Pleistocene, hugely significant for establishing the Quaternary Mammal Fauna Sequence of Northeast China for the first time based on a combination of biostratigraphy, geochronology, and for discussing the environmental background.

A multidisciplinary fieldwork and research project was recently begun at the Yangshang site (220–140 ka), a late Early Paleolithic locale in the western Chinese Loess Plateau. 1696 lithic artifacts and 337 faunal remains were recovered during the excavation. Sedimentological and paleoenvironmental investigations indicate the site preserves a relatively long and minimally disturbed archaeological sequence associated with paleoenvironmental changes during MIS 7–6. A detailed techno-typological analysis of Yangshang's lithic assemblages was undertaken to examine the influence of glacial cycles on late Middle Pleistocene hominin technological strategies in the western Chinese Loess Plateau. The results show that while the Yangshang site is dominated by quartz-based core/flake assemblages typical of most Early Paleolithic sites in North China, the lithic assemblages provide evidence that different provisioning systems existed during the penultimate glaciation. We argue that these shifts reflect changes in land use and mobility that were tied to climate change. Our results suggest that theoretically informed statistical analyses of so-called unchanging and crude lithic technology can yield meaningful evidence for behavioral shifts.

A large number of hominin fossil-bearing caves in South China have yielded evidence for the occupation of early modern humans during the Middle to Late Pleistocene. However, the geology of these caves and the paleoenvironmental context of human occupation remain poorly documented and understood. In this study, we obtained new ages yielded by MC-ICPMS uranium-series dating of speleothems from Zhiren Cave, Guangxi, where a partial early modern human mandible and 2 M have been recovered. The ages demonstrate that cave infilling of Zhiren Cave began at ~1 Ma, much earlier than the date previously suggested. Our dating results also suggest that fossils of anatomically modern human were deposited in Zhiren Cave during marine isotope stage (MIS) 6, between ~190 and ~130 ka, representing the oldest known anatomically modern human remains in East Asia. The cave's sedimentary processes and the paleoenvironmental changes were reconstructed based on detailed analyses of lithostratigraphy, grain-size, pollen assemblages and the chemical weathering intensity of the sediments inside Zhiren Cave. The results show that major climatic changes in the Middle Pleistocene led to the accelerated incision of local streams and the erosion of cave sediments by controlling the regional hydrological response during the Early to Middle Pleistocene. After ~300 ka, increased climatic contrasts between glacial and interglacial periods dominated the accumulation of sediments and the occupation of mammals and early modern humans in Zhiren Cave. Gradually desiccating climatic conditions and reduced forest cover during the penultimate glacial period (MIS 6) may have define a temporal window for the human occupation of Zhiren Cave, providing ideal environmental conditions. However, floodwater incursion and/or dense vegetation cover corresponding to a much warmer and wetter climate in the subsequent last interglacial (MIS 5) may have discouraged humans from further occupying Zhiren Cave.

Low- and high-latitude influences have shaped the evolution of the Tibetan Plateau climate over the past 1.74 million years., The Tibetan Plateau exerts a major influence on Asian climate, but its long-term environmental history remains largely unknown. We present a detailed record of vegetation and climate changes over the past 1.74 million years in a lake sediment core from the Zoige Basin, eastern Tibetan Plateau. Results show three intervals with different orbital- and millennial-scale features superimposed on a stepwise long-term cooling trend. The interval of 1.74–1.54 million years ago is characterized by an insolation-dominated mode with strong ~20,000-year cyclicity and quasi-absent millennial-scale signal. The interval of 1.54–0.62 million years ago represents a transitional insolation-ice mode marked by ~20,000- and ~40,000-year cycles, with superimposed millennial-scale oscillations. The past 620,000 years are characterized by an ice-driven mode with 100,000-year cyclicity and less frequent millennial-scale variability. A pronounced transition occurred 620,000 years ago, as glacial cycles intensified. These new findings reveal how the interaction of low-latitude insolation and high-latitude ice-volume forcing shaped the evolution of the Tibetan Plateau climate.

Paleohydro-climatic changes in the habitats of early humans are closely related to their evolution and occupation of specific niches. In the Nihewan Basin of North China, a large number of archaeological sites dating back to the early Pleistocene have been discovered which record the occupation history of human ancestors in the region. However, thus far, studies of the history of paleohydro-climatic changes in the Nihewan Basin and their influences on human occupation remain insufficient. Here, we report the results of a systematic investigation of variations in the anisotropy of magnetic susceptibility (AMS) and magnetic susceptibility stratigraphy in the Heitugou (HTG) section to partially rectify this paucity of data and interpretations. The HTG section is located in the eastern Nihewan Basin where, in 2006, a Paleolithic site was discovered and excavated at the bottom of the sequence. By comparing detailed magnetic susceptibility sequences in the HTG section with those of the nearby Xiaochangliang and Dachangliang sections, we found that the sedimentation of the HTG section began about 1.9 Ma, indicating that the HTG archaeological site possibly records the earliest human occupation of middle-to-high latitude North China. Our studies of the AMS in the HTG section indicate that it is characterized by a primary sedimentary magnetic fabric without significant disturbance, demonstrating its potential for tracing regional paleo-hydrological changes. In most samples dating between 1.9 Ma and 0.4 Ma, the maximum susceptibility axes ( K max) cluster along the SE-NW vector, suggesting hydrodynamic changes tracable in the study area were mainly influenced by the Huliu River. In addition, a relatively weak K max direction biased towards the SW-NE axis was also observed, possibly generated by the predominant flow of the Sanggan River. These two rivers – the Huliu and Sanggan – determined the paleohydrological changes in the eastern Nihewan paleolake basin. Meanwhile, AMS studies also suggest multiple-phase hydrodynamic changes in the Nihewan Basin. Around 1.9 Ma, a thick layer of gravel was deposited in the study area due to the emergence of the Huliu River, or tectonic subsidence of the Nihewan Basin. Strengthened hydrodynamic changes and higher water-levels of the Nihewan paleolake may have driven early human ancestors to occupy higher topographic locations. Between 1.9–1.8 Ma, the paleolake expanded and the hydrodynamic regime weakened accordingly, which may correspond with the enhancement of the summer monsoon cycle in East Asia. Between 1.8–1.5 Ma, the sedimentary hydrodynamic regime strengthened noticeably early on, and subsequently weakened continuously. During the period from 1.5–1.3 Ma, as the East Asian summer monsoon regime intensified, warmer and wetter climatic conditions resulted in deepening of the Nihewan paleolake, which may have subsequently weakened influences from fluvial input and was associated with decreased sedimentary hydrodynamics. Between 1.3–0.9 Ma, high-frequency fluctuations in the AMS are noted, indicating a dramatic change in lacustrine hydrodynamics possibly attributable to the Mid-Pleistocene Transition (MPT) event. After 0.9 Ma, the Nihewan paleolake deepened again. Relatively high-amplitude fluctuations during this period reflect a cyclicity of 100 ka, possibly indicating that it was controlled by global ice volume. In concordance with other Paleolithic sites in the Nihewan Basin that have been chronometrically investigated, our studies at Heitugou reveal that paleohydro-climatic changes had a significant influence on early hominin activities in the Nihewan Basin, which shaped the spatio-temporal distribution of Paleolithic sites there. For example, during the early Pleistocene, early humans lived mostly on lower lake terraces in the eastern Nihewan Basin, when the lake level was still quite low. Subsequently, they moved to topographically higher sites due to gradually increasing lake levels. During the Middle and Late Pleistocene, when the Nihewan paleolake shrank, early humans moved toward the upper reaches of the Sanggan River, and were widely distributed along river courses across the Nihewan Basin during the Late Pleistocene in order to maintain home ranges near permanent water sources.

Wheat and barley evolved from large-seeded annual grasses in the arid, low latitudes of Asia; their spread into higher elevations and northern latitudes involved corresponding evolutionary adaptations in these plants, including traits for frost tolerance and shifts in photoperiod sensitivity. The adaptation of farming populations to these northern latitudes was also a complex and poorly understood process that included changes in cultivation practices and the varieties of crops grown. In this article, we push back the earliest dates for the spread of wheat and barley into northern regions of Asia as well as providing earlier cultural links between East and West Asia. The archaeobotanical, palynological and anthracological data we present come from the Tongtian Cave site in the Altai Mountains, with a punctuated occupation dating between 5,200 and 3,200 calibrated years bp, coinciding with global cooling of the middle–late Holocene transition. These early low-investment agropastoral populations in the north steppe area played a major role in the prehistoric trans-Eurasian exchange. The spread of wheat and barley involves evolutionary and human adaptation but has been difficult to date properly. Findings from a cave site suggest a much earlier transfer of cereal grains across Eurasia.

As one of the most complete archaic human fossils, the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens. However, the unsystematic recovery of this cranium and a long and confused history since the discovery impede its accurate dating. Here, we carried out a series of geochemical analyses, including non-destructive X-ray fluorescence (XRF), rare earth elements (REE), and the Sr isotopes, to test the reported provenance of the Harbin cranium and get better stratigraphic constraints. The results show that the Harbin cranium has very similar XRF element distribution patterns, REE concentration patterns, and Sr isotopic compositions to those of the Middle Pleistocene-Holocene mammalian and human fossils recently recovered from the Harbin area. The sediments adhered in the nasal cavity of the Harbin cranium have a 87Sr/86Sr ratio of 0.711898, falling in the variation range measured in a core drilled near the Dongjiang Bridge, where the cranium was discovered during its reconstruction. The regional stratigraphic correlations indicate that the Harbin cranium was probably from the upper part of the Upper Huangshan Formation of the Harbin area, which has an optically stimulated luminescence dating constraint between 138 and 309 ka. U-series disequilibrium dating (n = 10) directly on the cranium suggests that the cranium is older than 146 ka. The multiple lines of evidence from our experiments consistently support the theory that the Harbin cranium is from the late Middle Pleistocene of the Harbin area. Our study also shows that geochemical approaches can provide reliable evidence for locating and dating unsystematically recovered human fossils, and potentially can be applied to other human fossils without clear provenance and stratigraphy records., Graphical abstract, Public summary • Unsystematic recovery of the Harbin fossil cranium and a long history since the discovery impede its accurate dating • Geochemical analyses, including non-destructive X-ray fluorescence, rare earth elements, and the strontium isotopes, suggest that the fossil cranium was from a bed of lacustrine sediments aged between 138 and 309 thousand years ago in the Harbin region • Uranium-series disequilibrium dating directly on the cranium suggests that the cranium is older than 146 thousand years

It has recently become clear that several human lineages coexisted with Homo sapiens during the late Middle and Late Pleistocene. Here, we report an archaic human fossil that throws new light on debates concerning the diversification of the Homo genus and the origin of H. sapiens. The fossil was recovered in Harbin city in northeastern China, with a minimum uranium-series age of 146 ka. This cranium is one of the best preserved Middle Pleistocene human fossils. Its massive size, with a large cranial capacity (∼1,420 mL) falling in the range of modern humans, is combined with a mosaic of primitive and derived characters. It differs from all the other named Homo species by presenting a combination of features, such as long and low cranial vault, a wide and low face, large and almost square orbits, gently curved but massively developed supraorbital torus, flat and low cheekbones with a shallow canine fossa, and a shallow palate with thick alveolar bone supporting very large molars. The excellent preservation of the Harbin cranium advances our understanding of several less-complete late Middle Pleistocene fossils from China, which have been interpreted as local evolutionary intermediates between the earlier species Homo erectus and later H. sapiens. Phylogenetic analyses based on parsimony criteria and Bayesian tip-dating suggest that the Harbin cranium and some other Middle Pleistocene human fossils from China, such as those from Dali and Xiahe, form a third East Asian lineage, which is a part of the sister group of the H. sapiens lineage. Our analyses of such morphologically distinctive archaic human lineages from Asia, Europe, and Africa suggest that the diversification of the Homo genus may have had a much deeper timescale than previously presumed. Sympatric isolation of small populations combined with stochastic long-distance dispersals is the best fitting biogeographical model for interpreting the evolution of the Homo genus., Graphical abstract, Public summary • More than 100,000 years ago, several human species coexisted in Asia, Europe, and Africa • A completely preserved fossil human cranium discovered in the Harbin area provides critical evidence for understanding the evolution of humans and the origin of our species • The Harbin cranium has a large cranial capacity (∼1,420 mL) falling in the range of modern humans, but is combined with a mosaic of primitive and derived characters • Our comprehensive phylogenetic analyses suggest that the Harbin cranium represents a new sister lineage for Homo sapiens • A multi-directional “shuttle dispersal model” is more likely to explain the complex phylogenetic connections among African and Eurasian Homo species/populations

DNA 5-methylcytosine modification plays an important role in the regulation of a variety of biological functions in both prokaryotic and eukaryotic organisms. Previous studies show that DNA Cytosine-5-methylation is predominantly associated with restriction-modification system in bacteria. IPF4390 is deduced to be a putative type II DNA Cytosine-5 methyltransferase from a fresh water cyanobacterium, Microcystis aeruginosa. Both its substrate sequence specificity and catalytic mechanism need to be revealed. In this study, the cloning, expression, purification, DNA binding assays and crystallization of IPF4390 are reported. Results of DNA binding assays demonstrate that IPF4390 can specifically recognize and bind two double-stranded DNAs containing GGNCC (N = A, T, C or G) sequences (HgiBI: 5′-ATAA GGACC AATA-3’; TdeIII: 5′-ATAA GGGCC AATA-3′). Therefore, IPF4390 is probably capable of blocking endonuclease cleavage once restriction sites containing these sequences. Moreover, the crystal of IPF4390 in the presence of TdeIII was obtained, and its X-ray diffraction data were collected and scaled to a maximum resolution of 2.46 A.

FeSe0.5Te0.5 coated conductor as a kind of 11-type iron-based superconductor is currently attracting much attention. Recently, the bare FeSe0.5Te0.5 coated conductor tapes were developed by Shanghai Jiao Tong University and verified their superconductivity. For the future application, the FeSe0.5Te0.5 tapes should be subjected to the high electromagnetic forces and stress–strain. In this study, the authors encapsulated the bare FeSe0.5Te0.5 coated conductor tapes with copper layers to enhance the mechanical performance. The reversible critical current performance of the bare and the copper encapsulated FeSe0.5Te0.5 tapes under uniaxial tensile strain was tested. The critical currents of two kinds of tapes were measured over a wide range of applied uniaxial tensile strain by the U-shaped bending spring, respectively. The results show the critical performance of the bare FeSe0.5Te0.5 tapes decreases linearly with respect to tensile strain. The copper encapsulated FeSe0.5Te0.5 tapes have better performance than the bare tapes, with an irreversible tensile strain limit of 0.15%. In addition, the actual irreversible tensile strain limit of the copper encapsulated FeSe0.5Te0.5 tapes reaches 0.29% after considering the influence of the cooling process.

Early Palaeolithic wooden implements are exceptionally rare. The best known are the spears and throwing sticks from Schöningen, Germany dated to ca. 300–330 thousand years (kyr) ago 1,2 and the 171-kyr old digging sticks from Poggetti Vecchi, Italy 3. Here, we report a unique assemblage of 35 wooden implements from the site of Gantangqing, southwestern China, which was found associated with stone tools, antler soft hammers and cut-marked bones, and is dated to ca. 361–250 kyr at 95% probability. The wooden implements include digging sticks and complete, small, hand-held pointed tools. The tips of several had starch grains of plants with starch-rich rhizomes. We suggest that most of these tools were used for digging the rhizomes of sub-aquatic plants on the edges of an ancient lake. This discovery provides the earliest tangible evidence for the exploitation of sub-surface plant foods in the Middle Pleistocene. It also highlights the probable role of plant foods (especially underground storage organs [USOs]) in sub-tropical and tropical environments in which a wide variety of edible plants were available, and implies that hominins had a detailed knowledge of which plants, and which parts of plants, were edible. These tools also show that organic materials played an important role in Middle Pleistocene technology, and the sophistication of many of these tools off-sets the seemingly “primitive” design of stone tools in the East Asian Early Palaeolithic.

Lacustrine sediments from the Northeast Plain of China are an ideal archive for recording the climatic history and variability of the East Asian monsoon during the Quaternary in mid-latitude East Asia. However, the lack of a high-resolution stratigraphy and high-precision geochronology of these sediments has limited our understanding of the mechanisms of Quaternary climatic and environmental changes in the region. In this study, we present a high-resolution magnetic susceptibility stratigraphy and precise paleomagnetic and optically stimulated luminescence (OSL) chronologies for core Qiananlingzi (QAL) from the Northeast Plain. Paleomagnetic data were obtained using alternating-field (AF) demagnetization with a peak AF of 80 mT and increments of 2.5−10 mT. In addition, OSL dating was conducted on coarse-grained quartz (90−150 µm) using the single aliquot regenerative dose (SAR) protocol. Correlation of the recognized polarity intervals of the QAL core to the geomagnetic polarity timescale was achieved by combining the magnetostratigraphic and OSL geochronologic data. The results indicate that the sedimentary sequence spans the interval from the Olduvai normal subchron to the end of the Brunhes normal chron. According to the lithology and the magnetic susceptibility record, the core can be divided into four intervals, from bottom to top: the Qian’an Formation (fluvial yellow-green, brown-red and grey-brown silty sand, interbedded with brown-black silty clay, with gravel layers in the lower part); the Lingzi Formation and Lindian Formation (lacustrine grey-green clay interbedded with grey-white silty sand, with fossil bivalves); and a loess-like soil (predominantly brown-yellow clayey silt, alternating with fluviolacustrine grey-white, brown and black clay). The magnetic susceptibilities (MS) of the sediments of the lower fluvial Qian’an Formation and upper loess-like soil strata are generally higher, indicating the neoformation of strongly magnetic minerals under predominantly oxidizing conditions. By contrast, lower MS values occur in the lacustrine sediments of the Lingzi Formation and Lindian Formation, which indicate a reducing environment. Overall, the MS record of the QAL core exhibits clear orbital-scale variations, with higher MS values in coarse-grained silt layers, and lower values in fine-grained clay layers. After the application of a 300 mT DC field, the isothermal remanence (IRM) is only 70%, and a hysteresis loop remained unclosed at 500 mT. These characteristics indicate the substantial presence of high-coercivity magnetic minerals in the intervals with low MS values. Thermomagnetic measurements ( χ - T ) curves show an abrupt decrease in the heating curve at 580°C, indicating that magnetite is the dominant magnetic mineral, and a further decrease above 580°C indicates the presence of hematite. After the application of an applied DC field of 300 mT, the IRM reached 90%, the hysteresis loop was closed, and the heating limb of the χ - T curve did not decrease significantly after 580°C, indicating that low-coercivity magnetic minerals contributed substantially to the magnetic properties within the intervals of higher MS. The lacustrine sediments of the core were dated to ~1180‒450 ka based on paleomagnetic and QSL dating, and interpolation of the age-depth relationship suggests that Songnen paleo-lake existed for ~730 ka. The grain-size record of the loess in the northeastern monsoon region shows no evidence of drought events at 450 ka, and records of MS and FeD/FeT from the deposits of the loess Plateau indicate a trend of increasing summer monsoon precipitation at this time. Therefore, the disappearance of the paleo-lake may be related to the multiple episodes of subsidence of the Yishu fault, which caused a diversion of the discharge of the Songhua River from the Songnen paleo-lake to the Sanjiang Plain. The high-resolution MS record and the precise chronology obtained in this study indicate that the lacustrine sedimentary sequence of QAL core can potentially resolve orbital-scale paleoclimate changes during the middle Pleistocene in mid-latitude East Asia. The Mid-Pleistocene Transition (MPT) is one of the most important climatic events in Quaternary paleoclimatology, and it is necessary to understand the response of different climatic systems to the MPT. Detailed environmental magnetic, sedimentological and geochemical studies of lacustrine sedimentary strata in the Northeast Plain in China should be carried out to explore the paleoclimatic record of the area, including the regional climatic response to the MPT.

As a significant component of the global climate system, the East Asian monsoon (EAM) is crucial in understanding general climate change. The response of sensitivity and extent of the EAM to orbital-timescale climate change remains controversial. The composition of oxygen isotopes of authigenic (pedogenic) carbonate in loess deposits from the Northeastern Tibetan Plateau was measured, which is at the modern northwestern boundary of the present-day EAM, and compared with equivalent data from northeastern China under the influence of the EAM and two selected sites in the zone under the influence of the westerlies (Bayanbulak (Xinjiang) and Kesselt (Belgium)). The data enable discussion of the paleoclimatic implication of δ18O of carbonate in loess deposits and extension (changes) of the EAM-affected area during the Last Glacial Maximum and early Holocene. The δ18O values of authigenic carbonate at the Northeastern Tibetan Plateau were close to those from the westerly climate zone, but higher than those from regions affected by the Asian monsoon during the Last Glacial Maximum and early Holocene. This indicates that precipitation moisture sources at the Northeastern Tibetan Plateau were likely not directly derived from the EAM during Last Glacial Maximum and early Holocene. In contrast, the westerlies and locally recycled or evaporated moisture were possibly the dominant influencing factors of the relatively δ18O-enriched soil water and the authigenic carbonate in Northeastern Tibetan Plateau. Further study of loess carbonate records from the Northeastern Tibetan Plateau will reveal the past climate changes in the plateau region and provide valuable clues for the interaction between the Asian monsoon and westerly climate systems.

Our understanding of the chronological sequence of Pleistocene land mammal faunas (including hominids) preserved in caves and fissures in the karstic terrain of subtropical southern China has been greatly impeded by the discontinuous nature of the strata yielding the fossils. A contributory issue is the lack of suitable elements for numerical dating, especially for the Early Pleistocene cave sediments. Here we present new magnetostratigraphic dating results for five cave sedimentary sequences in the Bubing Basin, Guangxi Zhuang Autonomous Region, which contain the typical Pleistocene Gigantopithecus fauna and Ailuropoda–Stegodon fauna of southern China. The five karstic caves are situated at elevations ranging from 252 m to 191 m above sea level. The integrated dating results reveal that the five cave sedimentary sequences span an age range from the late Gauss normal Chron to the early Brunhes normal Chron. The faunas are assigned to >2.6 Ma (Mohui–houshan Cave), 1.95–1.78 Ma (Mohui Cave), 0.99–0.78 Ma (Baolai Cave) and ∼0.7 Ma (Upper Wuyun and Ganxian Caves). Furthermore, by combining our new magnetostratigraphy work with previously published magnetostratigraphic, U–series and electron spin resonance dating results, a chronological sequence of the Plio–Pleistocene mammalian faunas from cave sites in southern China has been established. The chronological sequence contributes to an improved understanding of the evolutionary processes of Plio–Pleistocene land mammals, as well as of early humans in subtropical southern China.

The East Asian summer monsoon affects precipitation and hence vegetation in the densely populated Northwest Pacific region, yet a long-standing controversy exists concerning the spatial and temporal dynamics of the Holocene Optimum (HO) in the East Asian Monsoon Region. Here we use a detailed 14,000-year record reconstructing vegetation variations from a strategically selected crater lake from Northeast China, as well as a compilation of previous paleoclimatic studies, to show that the HO began around 6,000 Cal a BP in Northeast China, significantly later than generally recognized. By comparing our paleoenvironmental data with Holocene vegetation records from other regions of East Asia, we identified a marked northward shift for the onset of the HO from ∼ 10 , 260 Cal a BP in South China to ∼ 6 , 000 Cal a BP in Northeast China. The gradual northward transgression of the vegetation change could be caused by both the temperature and precipitation changes in different regions. Finally, we fitted a regression model of the start of the HO period versus latitude, which allowed us to make predictions for the beginning of the HO at different geographical locations. This study reveals a strong relationship between latitude and the initiation of the HO, and provides a window towards better understanding the forcing of vegetation changes in the East Asian monsoon region.

Maludong is a Terminal Pleistocene fossil-bearing cave located on the northern edge of the Southeast Asian tropical zone, southeastern Yunnan Province. Hominins from the cave include remains with affinities to archaic hominins and others with an apparent mixture of archaic and modern traits all deriving from deposits dating from the Bolling-Allerod interstadial. The sedimentary sequence of the cave appears to be largely anthropogenic in origin and records a nearly continuous record of fire lasting close to 1000 years. The fauna comprise only extant taxa and point to a rather biased sample with a preponderance of artiodactyls and carnivores, many of which show evidence for anthropogenic breakage and burning. A new analysis of the mammal fauna recovered during excavation, palaeohabitat reconstruction and stable isotope analysis of deer teeth and bones indicates the cave was located within or close to a closed forest environment. The mammal taxa also indicate a large body of water existed in the vicinity of Maludong, suggesting the modern lakes Datun Hai and Chang Qiao Hai were much larger at the time. Maludong may document an entirely novel ecological and behavioural scenario involving archaic and modern human interaction, economic exploitation and ceremonial behavior involving secondary burial practices.

The rarity and poor preservation of hominin fossils from the East Asian Early Pleistocene hamper our understanding of their taxonomy and possible phylogenetic relationship with other members of the genus Homo. In the 1970s, four isolated hominin teeth were recovered from the Meipu site, southern China, which biostratigraphic analysis placed in the late Early Pleistocene. Early reports assigned the teeth to late Homo erectus. Since then, the teeth have not been re-evaluated, nor has reliable dating been performed at the Meipu site. Here, biostratigraphic and paleomagnetic dating allow for a more precise chronological constraint of the Meipu hominins in the late Early Pleistocene, between 780 ka and 990 ka, making them one of the few known hominins for this time in mainland Asia. The comparison of the morphology of the Meipu teeth with other members of the genus Homo reveals that the Meipu teeth preserve traits such as moderate shoveling of the I1, the square crown contour of M1, and a buccolingually wider lingual cusp in P4 that make them closer to early Homo specimens from Africa and Homo ergaster from Dmanisi (Georgia). In addition, the Meipu teeth exhibit features that are more typical for late mainland East Asian H. erectus, such as the moderately convex I1 labial surface and a pronouncedly convex I2 labial surface. In these features, the Meipu hominins are morphologically intermediate between African/Dmanisi early Homo and East Asian Middle Pleistocene hominins. This study contributes to a better understanding of the morphologies and the taxonomic status of East Asian Early Pleistocene hominins, a time period for which the hominin evidence with secure stratigraphic context is scarce.

The highlands in southwestern China experience pronounced fluctuations in the hydroclimate with profound impacts on agriculture and economics. To investigate the drought history of this region beyond instrumental records, a tree ring cellulose oxygen isotope (δ18Oc) chronology was developed for the period 1733-2013 using samples collected from six Larix trees in the low-latitude highlands (LLH) of southwestern China. The analysis revealed that δ18Oc is significantly correlated with the rainy season (May-October) precipitation and relative humidity, as well as drought severity. The δ18Oc chronology accounts for 46% of the observed variance in the rainy season precipitation and it was subsequently used to reconstruct precipitation. The reconstructed precipitation reveals an apparent drying trend since 1840, accompanied by increasingly frequent drought events since 1970. Interdecadal variability is also present, characterized with two distinct wet periods in 1740-1760 and 1800-1900 and two drier periods in 1760-1800 and 1900-2013. On the interannual timescale, the LLH precipitation was modulated collectively by the El Nino-Southern Oscillation (ENSO) and the Indian Ocean dipole (IOD). There appears to be an enhanced precipitation-IOD relationship since 1970 in response to the increase in positive-IOD events, implying an increasing likelihood of drought for the southwest China LLH.

We recently proposed a non-reciprocal acoustic device based on an indirect interband transition by applying space-time density modulation in a two-dimensional acoustic waveguide formed by a water core sandwiched by metal claddings [1]. By performing a series of the Finite Difference Time Domain (FDTD)simulations, we demonstrated the nonreciprocity of wave propagation and obtained optimum parameter sets of the modulation length and the wavevector shift. To further optimize the present model toward practical applications, we extend the model to the waveguide with the core filled with a solid medium and search for its optimum matching conditions for the mode transition. Since our approach is based on a linear dynamic system, high efficiency can be achieved with wide-band tunability. Practical device implementation for wideband tunable operation can be proposed via the tolerance analyses for the phase matching condition.

The global climate system experienced a series of drastic changes during the Cenozoic. In Asia, these include the climate transformation from a zonal pattern to a monsoon-dominated pattern, the disappearance of typical subtropical aridity, and the onset of inland deserts. Despite major advances in the last two decades in characterizing and understanding these climate phenomena, disagreements persist relative to the timing, behaviors and underlying causes. This paper addresses these issues mainly based on two lines of evidence. First, we compiled newly collected data from geological indicators of the Cenozoic environment in China as paleoenvironmental maps of ten intervals. In confirming the earlier observation that a zonal climate pattern was transformed into a monsoonal one, the maps within the Miocene indicate that this change was achieved by the early Miocene, roughly consistent with the onset of loess deposition in China. Although a monsoon-like regime would have existed in the Eocene, it was restricted to tropical-subtropical regions. The latitudinal oscillations of the climate zones during the Paleogene are likely attributable to the imbalance in evolution of polar ice-sheets between the two hemispheres. Secondly, we examine the relevant depositional and soil forming processes of the Miocene loess-soil sequences to determine the circulation characteristics with emphasis on the early Miocene. Continuous eolian deposition in the middle reaches of the Yellow River since the early Miocene firmly indicates the formation of inland deserts, which have been constantly maintained during the past 22 Ma. Grain-size gradients between loess sections indicate northerly dust-carrying winds from northern sources, a clear indication of an Asian winter monsoon system. Meanwhile, well-developed Luvisols show evidence that moisture from the oceans reached northern China. This evidence shows the coexistence of two kinds of circulations, one from the ocean carrying moisture and another from the inland deserts transporting dust. The formation of the early Miocene paleosols resulted from interactive soil forming and dust deposition processes in these two seasonally alternating monsoonal circulations. The much stronger development of the early Miocene soils compared to those in the Quaternary loess indicates that summer monsoons were either significantly stronger, more persistent through the year, or both. These lines of evidence indicate a joint change in circulation and inland aridity by the early Miocene and suggest a dynamic linkage of them. Our recent sensitivity tests with a general circulation model, along with relevant geological data, suggest that the onset of these contrasting wet/dry responses, as well as the change from the "planetary" subtropical aridity pattern to the "inland" aridity pattern, resulted from the combined effects of Tibetan uplift and withdrawal of the Paratethys seaway in central Asia, as suggested by earlier experiments. The spreading of South China Sea also helped to enhance the south-north contrast of humidity. The Miocene loess record provides a vital insight that these tectonic factors had evolved by the early Miocene to a threshold sufficient to cause this major climate reorganization in Asia.

Intermontane basins in the southern piedmont of the Qinling Mountains are important sources of information on hominin occupation and settlement, and provide an excellent opportunity to study early human evolution and behavioral adaptation. Here, we present the results of a detailed magnetostratigraphic investigation of the sedimentary sequence of hominin-bearing Bailong Cave in Yunxi Basin, central China. Correlation to the geomagnetic polarity time scale was achieved using previously published biostratigraphy, 26Al/10Be burial dating, and coupled electron spin resonance (ESR) and U-series dating. The Bailong Cave hominin-bearing layer is dated to the early Brunhes Chron, close to the Matuyama-Brunhes geomagnetic reversal at 0.78 Ma. Our findings, coupled with other records, indicate the flourishing of early humans in mainland East Asia during the Mid-Pleistocene climate transition (MPT). This suggests that early humans were adapted to diverse and variable environments over a broad latitudinal range during the MPT, from temperate northern China to subtropical southern China.

The Tibetan Plateau is the highest and one of the most demanding environments ever inhabited by humans. We investigated the timing and mechanisms of its initial colonization at the Nwya Devu site, located nearly 4600 meters above sea level. This site, dating from 40,000 to 30,000 years ago, is the highest Paleolithic archaeological site yet identified globally. Nwya Devu has yielded an abundant blade tool assemblage, indicating hitherto-unknown capacities for the survival of modern humans who camped in this environment. This site deepens the history of the peopling of the “roof of the world” and the antiquity of human high-altitude occupations more generally.

Compared with annual tree-ring cellulose δ 18 O, intra-annual cellulose δ 18 O has potential to reconstruct precipitation with higher resolution and stronger signal intensity. Annual tree-ring cellulose oxygen isotope values (δ18O) of Fokienia hodginsii provide a promising proxy of monsoon-season precipitation in Southeast China. Measuring intra-annual cellulose δ18O values may reveal the seasonal variability of precipitation and the associated climate influences. Here, we examine intra-annual variation of cellulose δ18O values in Fokienia hodginsii and Cryptomeria fortune from Fujian Province, Southeast China. Both species exhibited considerable intra-annual variations in cellulose δ18O (range ~6 ‰) with a consistent pattern of enriched values near the annual ring boundary and depleted values in the central portion of the ring. Seasonal patterns in the tree-ring δ18O values generally followed changes in precipitation δ18O values. Compared with annual tree-ring cellulose δ18O, intra-annual cellulose δ18O has potential to reconstruct precipitation with higher resolution and stronger signal intensity. July tree-ring cellulose δ18O is significantly correlated (r = −0.58, p

Evolutionary processes in hominoid primates were closely related to global and/or regional environmental changes, and therefore palaeoenvironmental reconstruction is fundamental for understanding how environmental changes shaped their evolution. Here, we present pollen data from the 16-m-thick Shuitangba (STB) section, Yunnan Province, southwestern China, bearing remains of the hominoid Lufengpithecus lufengensis of the terminal Miocene; and use principal component analysis to reconstruct the palaeovegetation and palaeoclimate during the key period when the hominoid lived. Our results show that before the STB hominoid appeared (Zone A), the vegetation was dominated by subtropical evergreen broad-leaved taxa with a few temperate deciduous taxa (e.g., Quercus, Castanea/Castanopsis, Alnus). The development of aquatic plants commencing at the ~ 12 m depth is a prominent feature, indicating a warm and humid climate. During the time when the hominoid lived (Zone B), evergreen broad-leaved forests with evergreen Quercus were predominant, while grasses including Poaceae began to expand, and simultaneously conifers decreased, indicating a warm climate. The significant presence of aquatic pollen taxa in subzone A-2 and Zone B suggests the occurrence of lacustrine or swampy environments. In contrast, in Zone C, the vegetation changed to coniferous forest, indicating cooler and drier conditions. These results provide substantive evidence of the vegetation conditions when the hominoid lived, suggesting that the greater diversity of vegetation and the warm humid climate, compared to the present day, would have favoured its survival.