Location map of Site U1391, and distribution of main ocean water masses in the northeastern Atlantic and western Mediterranean Sea After the Strait of Gibraltar re-opened at 5.33 million years ago, warm high-salinity Mediterranean outflow water (MOW) showered into the Gulf of Cadiz, north Atlantic, penetrating north along the Portuguese slope, even to the Norwegian- Greenland Sea region, which enhances the North Atlantic deep water density and helps drive Atlantic Meridional Overturning Circulation (AMOC). Due to the stronger current in the west Iberian margin, most study were limited to the last glacial- interglacial periods before the long term continuous sediments retrieved from the IODP339 cruise during November, 2011-January, 2012. As part of the post cruise scientific research, this study, supported by National Natural Science Foundation of China, Chinese Academy of Sciences and IODP-China, and lead by Prof. LI Baohua from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, performed large amount of micropaleontological work on core sediments from Site U1391 off the Portuguese margin. Quantitative benthic foraminifera, detailed stable isotope of both planktonic and benthic foraminiferal shells, and Mg/Ca ratios of benthic foraminiferal shells were used to reconstruct the long-term variation of Mediterranean outflow water with continuous record for the first time. Benthic foraminiferal faunal data from Site U1391 disclose the bottom water property over the last ~0.9 Ma. Variations of the index species or assemblages, such as Planulina ariminensis and the “elevated epibenthos” group suggest that the MOW intensity has typical glacial-interglacial cycles, an active MOW current during the interglacial periods and a sluggish MOW current during the glacial periods. Over the last ~0.9 Ma, the strength of MOW reached its peak at MIS 11, when the sea level was considered to rise up to ~20 m above the present high-stand, which confirms the influence of climate on the MOW current by waving the sea level stands. The above results was recently published in Global and Planetary Change: Qimei Guo, Baohua Li, Jin-Kyoung Kim, IODP Expedition 339 Scientists, 2017. Benthic foraminiferal assemblages and bottom water evolution off the Portuguese margin since the Middle Pleistocene. Global and Planetary Change, http://dx.doi.org/10.1016/j.gloplacha.2016.11.004
Although a majority of biologists are convinced that a mass extinction is underway on earth today, the human history with direct observatory data is too short to predict its future trend. At least five great mass extinctions occurred during the Phanerozoic and they caused at least 75% marine species rapidly to go extinct; they also seriously affected the species diversity on land once the terrestrial ecosystem developed. The causes and consequences of these mass extinctions have become the most useful analogs to understand whether the current global ecosystem is experiencing extinction or not. Recently, Prof. SHEN Shuzhong and Dr. ZHANG Hua from Nanjing Insititute of Geology and Palaeontolgy, Chinese Academy of Sciences reviewed previous multidisciplinary studies of the extinction patterns of fossil groups and their concurrent environmental changes of the five mass extinctions during the past 500 million years suggested that no catastrophic event wiped out all organisms on earth. However, all five mass extinctions were associated with serious environmental deteriorations and major palaeoclimatic changes. They thought that global changes of atmospheric CO2 and palaeotemperatrue (both icehouse and greenhouse), oceanic acidification, sea-level changes, and anoxia triggered by massive volcanisms were the most plausible causes of the past extinctions. Massive volcanism not only ejected a huge amount of CO2 and volcanic sulfates, but also caused a massive release of thermogenic CO2 and methane stored in the deposits of inland basins and continental shelf. Extraterrestrial impact, supernova explosion, and solar flares could instantaneously wipe out all organisms on earth, but they are not the main causes of the five mass extinctions during the earth history. This paper was published in Chinese Science Bulletin and financially supported by the National Natural Science Foundation of China and the Strategic Priority Research Program (B) of Chinese Academy Sciences. Reference: Shen S Z, Zhang H. What caused the five mass extinctions (in Chinese)? Chin Sci Bull, 2017, 62: 1119–1135, doi: 10.1360/N972017-00013.
A research entitled “Precarious ephemeral refugia during the earliest Triassic” has published in GEOLOGY on May 1. Their findings highlight an assemblage including microbial mats, trace fossils, bivalves, and echinoids that represent a refuge in a moderately deep-water setting. A refuge describes an ecosystem that acts as a sanctuary for organisms during and immediately following times of environmental stress. The culprit was global warming associated with massive volcanic eruptions in Siberia, but modern-day events may lead to similar changes in today’s oceans. An international team of researchers at the University of Calgary and the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science have shown just how precarious the recovery of life was following Earth’s greatest extinction event, about 251.9 million years ago. A site near Shangsi in Sichuan Province, China highlights a short-lived community of organisms that may hold clues to forces shaping our planet today and into the future. Graduate student Amanda Godbold, Postdoctoral Fellow Shane Schoepfer, and Professors Shuzhong Shen and Charles Henderson are co-authors on a paper published online May 1, 2017 in Geology entitled “Precarious ephemeral refugia during the earliest Triassic”. Their findings highlight an assemblage including microbial mats, trace fossils, bivalves, and echinoids that represent a refuge in a moderately deep-water setting. A refuge describes an ecosystem that acts as a sanctuary for organisms during and immediately following times of environmental stress. The echinoids normally live in shallow-water environments, but in this case they sought refuge from lethally hot surface waters. The culprit was global warming associated with massive volcanic eruptions in Siberia, but modern-day events may lead to similar changes in today’s oceans. The community was short-lived, and was extinguished by a relatively minor ecologic disturbance as determined from the geochemistry of the host rocks, only to be replaced by a low-diversity community of ‘disaster taxa’, opportunistic organisms that thrive while others go extinct. The team envisages the earliest Triassic ocean floor as a shifting patchwork of temporary or ephemeral refugia, in which some communities survived and others died off depending on local conditions. As conditions improved throughout the Early Triassic these communities no longer had to cling to life in ephemeral refugia, but could expand into normal habitats around the world. The echinoids at this site are the ancestors of a diverse group of modern echinoids or sea urchins that live in reef communities, rocky shorelines and sandy shelves today. The study will help bring about a deeper understanding of how modern oceans might respond to intense global warming due to natural or anthropogenic effects. It could inform the management of our oceanic resources as they continue to be affected by environmental stressors. The rock record is cryptic, but it records events that have run their full course. If we can decipher the story, then it is possible to inform us better as to what might happen in the future as changes to our environment continue to occur. This study was supported by the National Science Foundation of China, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences, and a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant. Contact: Charles Henderson; cmhender@ucalgary.ca Shuzhong Shen; szshen@nigpas.ac.cn
Auroradiolites biconvexus in Sangzugang Formation photographed in the field Diagnostic characters of the recently established new genus of radiolitid rudist Auroradiolites include an entirely compact outer shell layer, a distinctly convex upper (left) valve and a robust myocardinal apparatus surrounding a strongly internally projected ligamentary infolding. Until now, A. biconvexus (previously considered as exclusively Late Albian in age) has been reported only from the Langshan Formation, which crops out along the northern portion of the Lhasa block, Tibet. Here, Dr. RAO Xin from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and her colleagues reported new Auroradiolites fossils for the first time in addition from the Sangzugang Formation of the Xigaze Forearc Basin, situated on the southern margin of the Lhasa block. A. biconvexus differs from the southwest Asian type species A. gilgitensis (Late Aptian to Albian) by its relatively larger size, more strongly domed left valve and distinct radial undulations of the outer shell layer. The characters of A. gilgitensis are further clarified from archived material from central Afghanistan, also newly identified and described herein. All Auroradiolites records to date are revised. The recognition of examples of A. biconvexus from Upper Aptian strata increases both the stratigraphical and geographical ranges of the species, indicating that it had already branched off from A. gilgitensis in the Late Aptian. Some new radiolitid specimens that combine both compact and cellular calcitic outer shell layer structures are also described from the Langshan Formation, but a number of internal differences from Auroradiolites cast doubt on their constituting a sister group to the latter and we assign them to Eoradiolites cf. hedini. Rather, the evolution of Auroradiolites directly from the ancestral radiolitid genus Agriopleura is favoured on the grounds of parsimony. So far, the genus Auroradiolites has been recorded from Iran, central and eastern Afghanistan, the type locality of Yasin in northwestern Pakistan, southern and northern Ladakh, the Lhasa block, as well as Hokkaido in northern Japan. During the Late Aptian to Albian interval, all these localities were associated with terranes and blocks that were limited to the northeastern margin of Tethys and the western Pacific margin, making Auroradiolites an indicator of a SW Asian to Pacific faunal province. Related information of this paper:：Rao Xin, Skelton W. Peter, Sano Shin-ichi, Li Cai, Pan Yanhong, Luo Hui, Cai Huawei, Peng Bo, Sha Jingeng, 2017. Evolution and palaeogeographical dispersion of the radiolitid rudist genus Auroradiolites (Bivalvia: Hippuritida), with descriptions of new material from Tibet and archived specimens from Afghanistan，Papers in Palaeontology, DOI:10.1002/spp2.1076
Living seed plants consist of Cycadales, Ginkgoales, Coniferales, Gnetales and angiosperms. The origin and phylogenetic relationships of these five group of living seed plants are poorly understood, in large part because of very imperfect knowledge of extinct seed plant diversity. Recently, Dr. SHI Gongle from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and colleagues from US, Mongolia, Japan and Russia studied three-dimensionally preserved, lignite plant fossils from the Early Cretaceous of Mongolia. Leaves of Podozamites and Pseudotorellia are dominant in the Early Cretaceous lignite floras of Mongolia. Podozamites and Pseudotorellia are common in Late Triassic to Early Cretaceous floras from Laurasia. Both are typically strap-shaped with parallel veins, and the two genera are often confused with each other if the leaves are found detached and their cuticles are not preserved. Podozamites is thought to be the leaf of a voltzialean conifer, but its epidermal features are poorly understood because its cuticle is extremely delicate. Pseudotorellia is commonly thought to be the leaf of an extinct ginkgoalean. It has a thick cuticle with stomatal complexes that have been described as haplocheilic. In one study the leaf morphology, cuticle, and stomata of Podozamites and Pseudotorellia are described based on excellently preserved material from the Early Cretaceous of central Mongolia. Podozamites harrisii has transversely oriented, paracytic (probably syndetocheilic) stomata that are regularly arranged in longitudinal files. Pseudotorellia resinosa and Pseudotorellia palustris have scattered, longitudinally oriented stomata in which the two guard cells are sunken and surrounded by 2–5 specialized lateral subsidiary cells and 1–3 unspecialized polar cells. Association evidence and similarities in cuticular structure suggest that Po. harrisii was produced by the same plant as the seed cone Krassilovia. The distinctive stomatal pattern of Po. harrisii and Krassilovia, is also seen in some species of Swedenborgia and Cycadocarpidium, suggesting these plants may all belong to the same natural group. Cycadocarpidium, Krassilovia and Swedenborgia have previously been treated as conifers, but their transversely oriented, paracytic stomata hint instead at a possible relationship with Bennettitales and Gnetales.
Transversely oriented, paracytic stomata of Podozamites Pseudotorellia has been long considered a ginkgoalean leaf based on its venation and features of the cuticle. Like extant Ginkgo, Pseudotorellia has two veins that enter the leaf base and stomata that are sparsely scattered in ill-defined stomatal bands on the presumed abaxial surface. Pseudotorellia was also thought to be produced by the same plant as the ovulate organ Umaltolepis Krassilov based on their repeated association, similarities in the structure of their cuticles, and similarities between the scale leaves at the base of the stalk of Umaltolepsis and the scale leaves on dwarf shoots that bore Pseudotorellia. However, Abundant new material from the Early Cretaceous of Mongolia shows that Umaltolepis is a seed-bearing cupule that was borne on a stalk at the tip of a short shoot. Each cupule is umbrella-like with a central column that bears a thick, resinous, four-lobed outer covering, which opens from below (Fig. 2). Four, pendulous, winged seeds are attached to the upper part of the column and are enclosed by the cupule. In spite of the similarity of Pseudotorellia leaves to those of living Ginkgo. Umaltolepis seed-bearing structures are very different from those of Ginkgo but very similar to fossils described previously as Vladimaria. Umaltolepis and Vladimaria do not closely resemble the seed-bearing structures of any living or extinct plant, but are comparable in some respects to those of certain Peltaspermales and Umkomasiales (corystosperms). Vegetative similarities of the Umaltolepis plant to Ginkgo, and reproductive similarities to extinct peltasperms and corystosperms, support previous ideas that Ginkgo may be the last survivor of a once highly diverse group of extinct plants, several of which exhibited various degrees of ovule enclosure.
Reconstruction of Umaltolepis mongoliensis.
The two studies were recently published in Journal of Systematic Palaeontology and PNAS. The studies have benefited from Professor ZHOU Zhiyan from NIGPAS and supported by the NSFC, the Youth Innovation Promotion Association, CAS and Nanjing Institute of Geology and Palaeontology. Reference: Shi Gongle, Herrera F., Herendeen P.S., Leslie A.B., Ichinnorov N., Takahashi M., Crane P.R., 2017. Leaves of Podozamites and Pseudotorellia from the Early Cretaceous of Mongolia: stomatal patterns and implications for relationships. Journal of Systematic Palaeontology, DOI: 10.1080/14772019.2016.1274343. Herrera F., Shi Gongle, Ichinnorov N., Takahashi M., Bugdaeva E., Herendeen P.S., Crane P. R., 2017. The presumed ginkgophyte Umaltolepis has seed-bearing structures resembling those of Peltaspermales and Umkomasiales. PNAS 114, E2385–E2391.
Stratigraphic distribution of geochemical results in this study The major diversification of animal life known as the Cambrian explosion commenced at the end of the Ediacaran Period, but did not reach its peak until Stage 3 of Cambrian Series 2. This remarkable escalation of biological complexity has long inspired hypotheses about the potential intrinsic or extrinsic catalysts driving early animal evolution. Environmental free oxygen is essential for the maintenance of many metabolic and physiological processes in metazoans, and low atmospheric oxygen content has often been viewed as a barrier to the evolution of large, metabolically active animals. Existing studies have found some evidence for oxygenation events in Cambrian Series 1-2, but the temporal relationship between Cambrian oxygenation and the Cambrian biological explosion remains controversial. For this study, XIANG Lei from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his colleagues conducted a series of geochemical analyses on the upper Lantian, Piyuancun, and Hetang formations in a drill well, part of the lower Yangtze Block in western Zhejiang. Iron speciation results indicate that the entire studied interval was deposited under anoxic conditions, with three intervals of persistent euxinia occurring in the uppermost Lantian Fm., the lower Hetang Formation (Fm.), and the upper Hetang Fm. Molybdenum (Mo) and uranium (U) contents and Mo/TOC and U/TOC ratios from the anoxic/euxinic intervals in this study, combined with published data from the sections in the middle and upper Yangtze Block, suggest that the oceanic Mo reservoir declined consistently from the Ediacaran to Cambrian Stage 3, while the size of the oceanic U reservoir remained relatively constant. Both metals were depleted in the ocean in lower Cambrian Stage 4, before increasing markedly at the end of Stage 4. The lack of an apparent increase in the size of the marine Mo and U reservoir from the upper Ediacaran to Cambrian Stage 3 suggests that oxic water masses did not expand until Cambrian Stage 4. The increase in marine Mo and U availability in the upper Hetang Fm. may have been due to the expansion of oxic water masses in the oceans, associated with oxygenation of the atmosphere during Cambrian Stage 4. This expansion of oxic waters in the global ocean postdates the main phase of Cambrian diversification, suggesting that pervasive oxygenation of the ocean on a large scale was not the primary control on animal diversity following the Ediacaran-Cambrian transition. Reference: Xiang, L., Schoepfer, S. D., Shen, S. Z., Cao, C. Q., Zhang, H. *, 2017. Evolution of oceanic molybdenum and uranium reservoir size around the Ediacaran-Cambrian transition: evidence from western Zhejiang, South China. Earth and Planetary Science Letters 464, 84-94.
Chemostratigraphic profiles of the Lantian Formation The coevolution of life and environment is highlighted in the recent debate on the possible relationship between ocean oxygenation and animal evolution in the Neoproterozoic. Some argue that the progressive oxygenation of the Earth’s surface in the late Neoproterozoic removed the final environmental hurdle to animal evolution, whereas others counter that atmospheric pO2 levels were sufficiently high to support basal animal metabolism in the Mesoproterozoic, long before the rise of animals themselves. Building upon previous work, Dr. WANG Wei from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and her colleagues recent attempts to test these competing hypotheses are focused on the compilations and meta-analyses of redox proxies. While these meta-analyses offer a critical view of the big-picture redox trend through the Neoproterozoic, they omit the more nuanced picture of spatial heterogeneity and often lack the stratigraphic resolution to appreciate the temporal dynamics of Neoproterozoic redox evolution. Ediacaran successions in South China, particularly the Doushantuo Formation, are highly fossiliferous. They are ideal targets for focused and integrated geochemical analysis at high resolution to infer the impact of redox conditions on evolution, ecology, and taphonomy. Previous studies of the Doushantuo Formation have been focused on shelf sections in the Yangtze Gorges and surrounding areas. To fully understand the Ediacaran redox structure of South China, it is necessary to gain insights from sections in deep-water slope and basinal facies. High-resolution chemostratigraphic analysis of integrated geochemical data—including δ13Ccarb, δ13Corg, δ34Spyr, δ34SCAS, and δ15Nsed—from the Lantian Formation deposited in deep-water environments in South China allows a better resolution of the spatial patterns and temporal variations of Ediacaran oceanic redox conditions. A large spatial gradient of δ13Ccarb, with a magnitude of >10‰, is confirmed to be present in the lower Doushantuo/Lantian Formation. It is proposed that this gradient is largely due to the influence of 13C-depleted authigenic/diagenetic calcite cements in organic-rich and carbonate-poor sediments deposited in deep-water facies. A pronounced negative δ13Ccarb excursion in the upper Doushantuo/Lantian Formation, however, is spatially consistent and does not display a > 10‰ depth gradient. This negative excursion has been previously described as EN3 (Ediacaran Negative excursion 3) in South China and regarded as equivalent to the Shuram excursion in Oman. The δ34Spyr record seems to show a spatial pattern, with more negative δ34Spyr values in deeper-water facies. The spatial pattern of δ34Spyr is interpreted as evidence for a chemically stratified basin, with predominantly euxinic deep waters where pyrite precipitated in the water column has lower δ34Spyr values. The δ15Nsed record of the Lantian and Doushantuo formations is consistent. The δ15Nsed data suggest nitrate limitation and denitrification is often quantitative. The Lantian and Doushantuo formations do not preserve highly positive δ15Nsed values characteristic of partial denitrification in suboxic environments of modern oxygen-minimum zone. Integrated TOC, TN, δ34Spyr, and Fe speciation data suggest that oscillation between oxic and euxinic conditions is characteristic of the Lantian Formation. Macrofossils in the Lantian Formation include morphologically complex macroalgae and putative animals. Stratigraphic distribution of these fossils is largely restricted to euxinic black shales.The euxinic environments were punctuated by brief oxygenation events when macroalgae and putative animals thrived, but were subsequently decimated and preserved when local environment switched to euxinic conditions. Reference: Wang W, Guan C, Zhou C, Peng Y, Pratt L M, Chen X, Chen L, Chen Z, Yuan X, Xiao S. Integrated carbon, sulfur, and nitrogen isotope chemostratigraphy of the Ediacaran Lantian Formation in South China: Spatial gradient, ocean redox oscillation, and fossil distribution. Geobiology. 2017. doi: 10.1111/gbi.12226
Hyphae with clamp connections within tracheids of the primary xylem of the fossil stem Shanxioxylon sp. Widespread coal deposits during the Carboniferous and Permian Periods of the late Paleozoic. A widely accepted explanation for this peak in coal production is a temporal lag between the evolution of abundant lignin production in woody plants and the subsequent evolution of lignin-degrading Agaricomycetes fungi, resulting in amounts of lignin-rich plant material accumulated. Recently, Dr. WAN Mingli and Prof. WANG Jun from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences reported the occurrence of fossil fungi in silicified cordaitalean stems from the Cisuralian (Permian) Taiyuan Formation of Yangquan City, Shanxi Province, North China. Fungi occur within parenchymatous cells of the pith and tracheids of the primary xylem. The fossil fungal hyphae consist of branching, septate hyphae with clamp connections and, therefore, are assigned to Basidiomycetes. The clamp-bearing hyphae from the Asselian–Sakmarian of North China are the first evidence for unequivocal basidiomycete body fossils in the Cathaysia. This discovery provides the first evidence of cordaitalean stems colonized by basidiomycetous fungi. Although the lower systematic affinities of the fungi currently remain unsolved, their existence sheds light on the multiple levels of biological association and interaction that had shaped the Permian terrestrial ecosystems. Their work also deny the fungal evolutionary lag hypothesis by the direct palaeontological evidence. This work is supported by Chinese Academy of Sciences, State Key Laboratory of Palaeobiology and Stratigraphy, and the National Natural Science Foundation of China. Related information: Wan, M., Yang, W., He, X., Liu, L., Wang, J., 2017. First record of fossil basidiomycete clamp connections in cordaitalean stems from the Asselian–Sakmarian (lower Permian) of Shanxi Province, North China. Palaeogeography Palaeoclimatology Palaeoecology, 466, 353-260. doi: 10.1016/j.palaeo.2016.11.050
The same specimen photographed in transmitted white light and infared light microscope A collection of low-grade metamorphosed rocks from Lvchun, Yunnan, Southwest China were found to contain a variety of highly mature microfossils comprising cryptospores, trilete spores, and dispersed plant fragments (tubular structures) as well as a small number of marine palynomorphs (acritarchs and scolecodonts), by Dr. LIU Feng from Nanjing Institute of Geology and palaeontology, Chinese Academy of Sciences and his colleagues. Infrared microscopic examination enabled the recognition and description of 38 species. Based on its correlation with previously established palynozonations and independent age evidence from acritarchs and graptolites, the palynomorph assemblage from Lvchun is attributed to the early Ludlow age. This new age constraint suggests that at least the upper level of these presumably Llandovery rocks in Lvchun belongs to the early Ludlow age. The palynomorph assemblage of Lvchun from Indo-China terrane share many taxonomic similarities with coeval findings from Tunisia and Saudi Arabia (i.e., southern Gondwana), hence reflecting the early geographical proximity of the two palaeocontinents. The increasing quantity and diversity of trilete spores point to the rapid evolution of early vascular plants in Indo-China terrane during the early Ludlow. This work was funded by Strategic Priority Research Program (B) of the Chinese Academy of Sciences and the National Natural Science Foundation of China. Article information: Liu, F., Wang Y., Zhu, H.C., Ouyang, S. (2016): Palynomorphs from massive metamorphosed rocks in Lvchun, Yunnan, Southwest China: evidence from the Ludlow Age and its geological implications. Review of Palaeobotany and Palynology, 233. 146-160.
Pollen fossils extracted from Huguangyan Maar Lake sediment The Earth’s climate changed from cold to warm through a succession of abrupt climate fluctuations over the past 30 000 years, including three important periods, i.e. the Last Glaciation, the Last Deglaciation and the Holocene, which casted great influence on the formation of human civilization and the development of early agriculture. Huguangyan Maar Lake in Zhanjiang, Guangdong Province is rarely affected by the outside disturbance because its supply is limited to a volcano formed ring dyke. The long time of water retention, simple lake system, and deep underground dyke make the Maar Lake sediments one of the valuable sites in the past global change study, which is comparable with deep sea sediments, polar ice cores and loess deposits. Huguangyan is located in the Leizhou Peninsula at the southernmost tip of Chinese Mainland, and adjacent to the South China Sea. It is under the inference of East Asian summer monsoon and southwest India monsoon, becoming a most important link between the South China Sea, the water vapor sources for the summer monsoon rainfall and the inland area. It is also a connection of the low latitude tropical climate system and the mid latitude monsoon climate. In recent years, a research team combined by Prof. WANG Weiming and his postgraduate students MENG Yuting et al. from Nanjing Institute of Geology and palaeontology, Chinese Academy of Sciences, and Prof. HU Jianfang from Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, carried out a systematic study of a drilling core from Huguangyan Maar Lake in Guangdong Province, South China. They reconstructed vegetation and climate changes over the last 30 000 years based on a relatively high-resolution pollen record. Pollen assemblages are well comparable with the results from ice-core, loess, stalagmites, lake and deep sea sediment records, reflecting that the tropical land system is very sensitive to both climate change on the solar orbit scale, and rapid climate events on the non solar orbit scales. This results provide a new scientific evidence for a better understanding of the interaction among the sea, the land and the plateau snow cover, the evolution of the monsoon, and the regional response of the global climate change in the low latitude region. The pollen assemblages show a succession of vegetation and climate changes from 30 cal. ka BP. During the Last Glaciations, 30-15.8 cal. ka BP, the Huguangyan area was dominated by subtropical evergreen-deciduous forest with grassland surrounding the lake, reflecting a colder and drier climate than today. During the Last Deglaciation, 15.8–11 cal. ka BP, the content of evergreen and deciduous broad-leaved plants displayed a mutual growth and decline, indicating the study area was experiencing several climatic fluctuations. In the Holocene from 11 cal. ka BP, the tropical rain forest was common with the climate shifted to warmer and wetter conditions.
A comparison of the pollen assemblage with summer mean insolation, NGRIP ice-core, EPICA Dome C ice-core and Guliya ice-core records During the Last glacial maximum (LGM), pollen assemblage showed no distinct millennial climate change recorded in some East Asia and high latitude regions. A clear warming event in about 21-18.5 cal. ka BP, might indicate a gradually warming climate in the Huguangyan area which was earlier than the high latitude area, but similar to the warming pattern revealed by the oxygen isotope records from the Antarctic and the Guliya Ice cores. In addition, the climate warming was synchronous with the increasing amount of sunshine at 33 ° north latitude, reflecting a highly responsible terrestrial vegetation system in the tropical area to the solar orbital scale changes. Frequent climate fluctuations were recognized in the pollen assemblages during the Last Deglaciation, with a changing process from warm, to colder, warmer and cold climate. The evergreen broad-leaved forest expanded during 15.8-14 cal. ka BP, corresponding to B？lling-early Aller？d warm period, while the subtropical deciduous broadleaved trees and grassland became re-established during 14-11 cal. ka BP, implying a cold period, possibly including the Younger Dryas. The tropical rain forest got rapidly expanded during 11-6 cal. ka BP, which was consistent with that the arrival of Holocene climatic optimum with warm and humid climate condition. Tropical rain forest had a rapid decline in 8.5 cal. ka BP, implying a strong cooling event. The ratio of woody and herbaceous plants decreased in the middle and late Holocene, indicating a possible climate decay, which may be related to a weakening summer monsoon. The sediment record of the last 2 cal. ka BP cannot be used to interpret natural palaeoclimate changes due to the intense anthropogenic influences. The article was published online on February 15, 2017 in Boreas. This research was funded by the CAS Strategic Priority Research Program and National Natural Science Foundation of China. Article information: Yuting Meng, Weiming Wang*, Jianfang Hu, Jixiao Zhang, Yangjun Lai, 2017. Vegetation and climate changes over the last 30 000 years on the Leizhou Peninsula, southern China, inferred from the pollen record of Huguangyan Maar Lake. Boreas, doi/10.1111/bor.12229.
