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Frontiers of Earth Science 2014年第4期8卷 540-546页

作者： Zongli WANG Hui ZHAO Guanghui DONG Aifeng ZHOU Jianbao LIU Dongju ZHANG MOE Key Laboratory of West China's Environmental System Lanzhou University Lanzhou 730000 China Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

The accurate radiocarbon dating of loess-soil sequences plays an essential role in the reconstruction of the environmental and climatic changes in continental settings during the last glaciation and Holocene. However, our knowledge about the reliability of radiocarbon ages of various fractions of soil and loess samples is still insufficient. Here, we present our study results on radio- carbon ages based on bulk organic matter, humin fraction, and carbonate of samples collected from a loess-paleosol section in the western Chinese Loess Plateau. We compare these observations with the optically stimulated luminescence ages and charcoal radiocarbon ages to evaluate the reliability of these fractions. We observed that the radio- carbon ages of humin fraction are very close to those of charcoal and are consistent with the optically stimulated luminescence ages within the experimental errors. We observed a significant deviation in the radiocarbon ages of carbonate and bulk organic matter from those of charcoal and optically stimulated luminescence ages, likely due to the dilution of these fractions during the pedogenetic process. Our results reveal that, except for charcoal, the humin fraction may yield reliable laC ages for the Chinese loess-soil sequence.

关键词： loess-soil sequence humin fraction charcoal,organic matter radiocarbon dating

Spatiotemporal distribution of regional landslides and erosion rates in Southeastern Tibet

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Journal of Mountain Science 2023年第6期20卷 1650-1659页

作者： WANG Xue-liang SUN Juan-juan WANG Shan-shan QI Sheng-wen ZHAO Hai-jun GUO Song-feng WANG Xin-hui Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Sciences Chinese Academy of SciencesBejing 100029China University of Chinese Academy of Sciences Bejing 100049China China Aero Geophysical Survey and Remote Sensing Center for Natural Resources Bejing 100083China Beijing North-Star Technology Development Company LTDBejing 100120China

The difficulty in estimating ages of regional landslides hampers to assess frequency of landslides and hence to quantitatively assess regional landslide hazard.In this study,we used radiocarbon dating of organic sediment on boulder rock varnish to estimate landslide ages in Langxian(LX)arid region in southeastern Tibet.Samples of rock varnish with organic sediment were collected on site for radiocarbon dating,leading to landslide ages from 1880±30 to 18,430±30 yr B.P.To measure surface roughness characteristics of 109 remotely-mapped large bedrock landslide deposits,we estimated average standard deviation of slope(SDS)over an area of~640 km^(2) by calculating the slope gradient of each raster cell and using a rectangular moving window method in Arc Map from a 5 m-resolution Digital Elevation Model generated from helicopterobtained photographs.Combing estimated landslide ages(t)with average surface roughness of mapped landslide deposits(R)quantified by SDS,we fit an exponential landslide deposits surface roughness-age function(t=1.47×10^(6)×e^(-1).46R,r2=0.63)that was used to estimate regional landslide ages in LX.We conclude that three periods with clusters of regional landslides in LX were revealed by different surface roughness of landslide deposits combing roughness-age function,with the values of 5563-7455 yr B.P.,1724-4151 yr B.P.,and 960-1287 yr B.P..Furthermore,we used our estimates of landslide ages to quantify landslide erosion rates of three corresponding hillslopes in LX ranging from 0.50 to 2.42 mm yr-1.Although rock varnish radiocarbon dating provides us a feasible option for timing regional landslides of arid regions,the epistemic uncertainty in the dating method should arouse our attention,which could be reduced by increasing the number of samples.

关键词： Landslide Spatiotemporal distribution radiocarbon dating Rock varnish Southeastern Tibet

Once upon a time biomass burning in the western Alps: Nesting effects of climate and local drivers on long-term subalpine fires

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Forest Ecosystems 2022年第2期9卷 257-266页

作者： Christopher Carcaillet Benjamin Boulley Frederique Carcaillet Univ Lyon Universite Claude Bernard Lyon 1CNRSENTPE(UMR LEHNA)F-69622VilleurbanneFrance Paris Sciences&Lettres University(PSL) Ecole Pratique des Hautes Etudes(EPHE)F-75014ParisFrance NaturCom Chair Universite de MontpellierF-34000MontpellierFrance MARBEC(Universite de Montpellier CNRSIfremerIRD)F-34000MontpellierFrance

Background:The present article questions the relative importance of local-and large-scale processes on the long-term dynamics of fire in the subalpine belt in the western Alps.The study is based on soil charcoal dating and identification,several study sites in contrasting environmental conditions,and sampling of soil charcoal along the elevation gradient of each site.Based on local differences in biomass combustion,we hypothesize that local-scale or landscape-scale processes have driven the fire history,while combustion homogeneity supports the hypothesis of the importance of large-scale or macro-ecological processes,especially climate.Results:Biomass burning during the Holocene resulted from the nesting effects of climate,land use,and altitude,but was little influenced by slope exposure(north versus south),soil(dryness,pH,depth),and vegetation.The mid-Holocene(6500–2700 cal BP)was an important period for climate-driven biomass burning in the subalpine ecosystems of the western Alps,while fires over the last 2500 years appear much more episodic,prompting us to speculate that human activity has played a vital role in their occurrence.Conclusion:Our working hypothesis that the strength of local drivers should offset the effects of regional climate is not validated.The homogeneity of the fire regime between sites thus underscores that climate was the main driver during the Holocene of the western Alps.Long-term subalpine fires are controlled by climate at the millennial scale.Local conditions matter for little in determining variability at the century scale.The mid-Holocene was a chief period for climatic biomass burning in the subalpine zone,while fires during the late Holocene appear much more episodic,suggesting that social drivers has exercised key function on their control.

关键词： Biomass burning Subalpine forest Climate Landscape Pedoanthracology radiocarbon dating Pyrogenic carbon

Prehistoric agriculture development in the Yunnan-Guizhou Plateau, southwest China： Archaeobotanical evidence

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Science China Earth Sciences 2016年第8期59卷 1562-1573页

作者： LI HaiMing ZUO XinXin KANG LiHong REN LeLe LIU FengWen LIU HongGao ZHANG NaiMeng MIN Rui LIU Xu DONG GuangHui Key Laboratory of Western China’s Environmental Systems (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University Lanzhou 730000 China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Yunnan Province Institute of Cultural Relics and Archaeology Kunming 650118 China College of Agronomy and Biotechnology Yunnan Agricultural University Kunming 650201 China

The origin, development and expansion of prehistoric agriculture in East Asia have been widely investigated over the past two decades using archaeobotanical analysis from excavated Neolithic and Bronze Age sites. Research on prehistoric agriculture has predominantly focused in the valleys of the Yellow River and the Yangtze River. Agricultural development during the Neolithic and Bronze Age periods in the Yunnan-Guizhou Plateau of southwest China, an important passageway for human migration into Southeast Asia, still remains unclear. In this paper, based on macrofossil and microfossil analysis and radiocarbon dating at the Shilinggang site, we investigate plant subsistence strategies in the Nujiang River valley during the Bronze Age period. Combined with previous archaeobotanical studies in the Yunnan-Guizhou Plateau, we explore agricultural development processes in this area during the Neolithic and Bronze Age. Our results indicate that rice and foxtail millet were cultivated in Shilinggang around 2500 cal a BP. Three phases of prehistoric agricultural development in the Yunnan-Guizhou Plateau can be identified: rice cultivation from 4800–3900 cal a BP, mixed rice and millet crop(foxtail millet and broomcorn millet) cultivation from 3900–3400 cal a BP, and mixed rice, millet crop and wheat cultivation from 3400–2300 cal a BP. The development of agriculture in the Yunnan-Guizhou Plateau during the Neolithic and Bronze Age periods was primarily promoted by prehistoric agriculture expansion across Eurasia, agricultural expansion which was also affected by the topographic and hydrological characteristics of the area.

关键词： Nujiang River valley Yunnan-Guizhou Plateau Neolithic Bronze Age Macrofossil analysis Phytolith analysis radiocarbon dating

Emergence of ancient cities in relation to geopolitical circumstances and climate change during late Holocene in northeastern Tibetan Plateau, China

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Frontiers of Earth Science 2016年第4期10卷 669-682页

作者： Guanghui DONG Honggao LIU Yishi YANG Ying YANG Aifeng ZHOU Zhongxin WANG XiaoyanREN Fahu CHEN Key Laboratory of Western China's Environmental Systems (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University Lanzhou 730000 China College of Agronomy and Biotechnology Yunnan Agricultural University Kunming 650201 China Qinghai Provincial Institute of Cultural Relics and Archaeology Xining 810007 China

The study of the history of human activities in ancient cities has provided valuable evidences for under- standing the evolution of human-land relations during the late Holocene. Numerous ancient cities were discovered through archaeological surveys of the east Qinghai Province, located on the northeastern border of the Tibetan Plateau, China; however, the mystery of when or why these cities were built remains unsolved. As recorded in this paper, we sampled reliable dating materials from 47 ancient cities in the area, determined their ages by radiocarbon dating, and compared the dating results with historical documents and high resolution paleoclimate records to explore the influencing factors for the develop- ment of these ancient cities. The 54 radiocarbon dates indicated that most of these cities were built or repaired during the Han Dynasty （202 BC-AD 220）, Tang Dynasty （AD 618-AD 907）, the Five Dynasties and Ten Kingdoms period （AD 907-AD 960）, the Song dynasty （AD 960-AD 1279）, and the Ming Dynasty （AD 1368-AD 1644）. The radiocarbon dates correspond well with historical records of the area. Our work suggests the ancient cities in east Qinghai Province were likely built primarily for military defense, and may have also have been affected by climate change.

关键词： radiocarbon dating ancient city historicrecords war climate change

A study of the construction times of the ancient cities in Ganjia Basin,Gansu Province,China

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Journal of Geographical Sciences 2020年第9期30卷 1467-1480页

作者： XIA Huan ZHANG Dongju WANG Qiang WU Duo DUAN Yanwu CHEN Fahu Key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth Environmental SciencesLanzhou UniversityLanzhou 730000China Key Laboratory of Alpine Ecology Institute of Tibetan Plateau ResearchCASBeijing 100101China Center for Excellence in Tibetan Plateau Earth Sciences CASBeijing 100101China

The Ganjia Basin in Xiahe County,Gansu Province,China,is located on the northeastern edge of the Tibetan Plateau.The area lies in the transitional zone between the Plateau ethnic groups dominated by ancestral Tibetans,and the Central Plains dynasties dominated by ancestral Han in history.The Ganjia Basin is therefore well suited to studying the history of the intermixing of the Han and Tibetan peoples.In this study,we collected samples of organic materials from two ancient cities,Bajiaocheng(BJC) and Sirougucheng(SRGC),in the Ganjia Basin,which were used for radiocarbon dating.Our aims were to determine the construction times and function of the cities,based on the radiocarbon ages,Bayesian age modeling,and the analysis of relevant historical records.The results are used to discuss the role of the Ganjia Basin in the conflicts between and the integration of the two ethnic groups during the historical period.We conclude that BJC was established during 663–732 CE(Common Era);its early occupation history can be divided into an initial establishment phase(670–780 CE) and a phase of regeneration(880–1030 CE).SRGC was probably built at the time of the transition between the Song and Yuan dynasties(~1271 CE).Combining the dating results with an analysis of the architectural styles and historical records,we conclude that BJC was originally built by the Tubo Kingdom as a military stronghold,and its major functions were military,economic and religious,and to support the major eastward expansion of the Tubo.SRGC was most likely a temple-focused city intended to promote Tibetan Buddhism which was a major political and religious leadership for the Tibetans at that time,reflecting changes in the status of different religions in the Ganjia Basin.In addition,the intermixing and blending of the Han and Tibetan groups,reflected by the human activities in the Ganjia Basin,was an important demographic and cultural foundation for the formation of the culturally-diverse but spiritually-united modern Chinese people.

关键词： Ganjia Basin radiocarbon dating Bajiaocheng Sirougucheng ethnic amalgamation Tubo

Evolution of sedimentary environments of the middle Jiangsu coast, South Yellow Sea since late MIS 3

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Journal of Geographical Sciences 2013年第5期23卷 883-914页

作者： XIA Fei ZHANG Yongzhan WANG Qiang YIN Yong Karl W. WEGMANN J. Paul LIU Department of Coastal Ocean Science School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China The Key Laboratory of Coastal and Island Development Ministry of Education Nanjing University Nanjing 210093 China Department of Marine Earth and Atmospheric Sciences North Carolina State University Raleigh NC 27695 USA Tianjin Institute of Geology and Mineral Resources China Geological Survey Bureau Tianjin 300170 China

An evolutionary model of sedimentary environments since late Marine Isotope Stage 3 （late MIS 3, i.e., ca. 39 cal ka BP） along the middle Jiangsu coast is presented based upon a reinterpretation of core 07SR01, new correlations between adjacent published cores, and shallow seismic profiles recovered in the Xiyang tidal channel and adjacent northern sea areas. Geomorphology, sedimentology, radiocarbon dating and seismic and sequence stratigraphy are combined to confirm that environmental changes since late MIS 3 in the study area were controlled primarily by sea-level fluctuations, sediment discharge of paleo-rivers into the South Yellow Sea （SYS）, and minor tectonic subsidence, all of which impacted the progression of regional geomorphic and sedimentary environments （Le., coastal barrier island freshwater lacustrine swamp, river floodplain, coastal marsh, tidal sand ridge, and tidal channel）. This resulted in the formation of a fifth-order sequence stratigraphy, comprised of the parasequence of the late stage of the last interstadial （Para-Sq2）, including the highstand and forced regressive wedge system tracts （HST and FRWST）, and the parasequence of the postglacial period （Para-Sql）, including the transgressive and highstand system tracts （TST and HST）. The tidal sand ridges likely began to develop during the postglacial transgression as sea-level rise covered the middle Jiangsu coast at ca. 9.0 cal ka BP. These initially submerged tidal sand ridges were constantly migrating until the southward migration of the Yellow River mouth to the northern Jiangsu coast during AD 1128 to 1855. The paleo-Xiyang tidal channel that was determined by the paleo-tidal current field and significantly different from the modern one, was in existence during the Holocene transgressive maxima and lasted until AD 1128. Following the capture of the Huaihe River in AD 1128 by the Yellow River, the paleo-Xiyang tidal channel was infilled with a large amount of river-derived sediments from AD 1128 to 1855, causing the emergence of some of

关键词： Marine Isotope Stage 3 （MIS 3） South Yellow Sea middle Jiangsu coast tidal sand ridge tidal channel sedimentary environment radiocarbon dating seismic stratigraphy sequence stratigraphy