Due to the uplift of Qinghai-Tibet Plateau （QTP）, the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on ...Due to the uplift of Qinghai-Tibet Plateau （QTP）, the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on the QTP experienced repeated expansion and degradation. Based on the remains and cross-correlation with other proxy records such as those from glacial landforms, ice-core and paleogeography, the evolution and changes of permafrost and environmental changes on the QTP during the past 150,000 years were deduced and are presented in this paper.At least four obvious cycles of the extensive and intensive development, expansion and decay of permafrost occurred during the periods of 150-130, 80-50, 30-14 and after 10.8 ka B.P.. Ehiring the Holocene, fluctuating climatic environ-ments affected the permafrost on the QTP, and the peripheral mountains experienced six periods of discernible permafrost changes： （1） Stable development of permafrost in the early Holocene （10.8 to 8.5-7.0 ka B.P.）; （2） Intensive permafrost degradation during the Holocene Megathermal Period （HMP, from 8.5-7.0 to 4.0-3.0 ka B.P.）; （3） Permafrost expansion during the early Neoglacial period （ca. 4,000-3,000 to 1,000 a B.P.）; （4） Relative degradation during the Medieval Warm Period （MWP,from 1,000 to 500 a B.R）; （5） Expansion of permafrost during the Little Ice Age （LIA,from 500 to 10.a B.P.）; （6） Observed and predicted degradation of permafrost during the 20th and 21st century. Each period differed greatly in paleoclimate, paleoenvironment, and permafrost distribution, thickness, areal extent, and ground temperatures, as well as in the development of periglacial phenomena. Statistically, closer dating of the onset permafrost formation, more identi-fication of permafrost remains with richer proxy information about paleoenvironment, and more dating information enable higher resolution for paleo-permafrost reconstruction. Based on the scenarios of persistent climate warming of 2 2 -2 .6 °C 展开更多
Using five group dating of the fossil by Uranium series age method shows that the age of Nanjing Homo Erectus is between 280－ 430 ka B. P. Combining with the analysis of fossil mammalian form Stegodon, Sus.Lydekkeri ...Using five group dating of the fossil by Uranium series age method shows that the age of Nanjing Homo Erectus is between 280－ 430 ka B. P. Combining with the analysis of fossil mammalian form Stegodon, Sus.Lydekkeri Zdansly, M.pachyosteus Young, P.grayi Zdansky and E.SanmeniensisTeilhard et Pive teau, which are located in the same stratum, the authors thinks that the Nanjing Homo Erectus may have lived in the late Mid Pleistocene (about 350 ka B.P.). Based upon the spores and pollen in the cave sediments of the area, we can find that most of spores and pollen are subtropical and warm temperature types. For instance, broad leaf trees which are fond of warm climate, including Cunning hamia, Jsuga and Pinus ,as well as Morus, Carpinus and Ptendium. Among the above spores and pollen, only Tsuga,Liquidambar, Betula,Ulmus and Salix are the remainders of Humid hot environment from the Tertiary period. Above evidences illustrate that the living environment of the Nanjing Homo Erectus not only was not cloder but also was not drier than the Peking Man’s. It could be said that dry climate and the ice age of the Mid Pleistocene didn’t undergo this area.As for the manner of the Homo Erectus’s making stone artifact and using fire, because now we have not found the evidence of the stone artifact and the ash, the futher excavation to the talus of the Huludong cave should be needed.展开更多
塔里木陆块周缘的新元古界地层记录了涉及Rodinia聚合和裂解的构造热事件,但塔里木在Rodinia超大陆中的位置以及在Rodinia裂解后如何运动尚无定论。采用收集的古地磁数据,并结合塔里木西北缘阿克苏地区的野外工作以及塔里木周缘代表性...塔里木陆块周缘的新元古界地层记录了涉及Rodinia聚合和裂解的构造热事件,但塔里木在Rodinia超大陆中的位置以及在Rodinia裂解后如何运动尚无定论。采用收集的古地磁数据,并结合塔里木西北缘阿克苏地区的野外工作以及塔里木周缘代表性岩石如A型花岗岩、基性岩墙群、大陆溢流玄武岩和双峰式火山岩等的同位素年代学数据,将塔里木陆块从Rodinia超大陆中裂解的时间限制在830～700 Ma BP。之后,塔里木陆块随澳洲板块一起加入冈瓦纳大陆。约在450Ma BP,塔里木陆块和澳洲板块发生分离,并快速北漂,最终在晚古生代加入劳亚大陆。新元古代—早古生代,塔里木陆块整体上从北半球较高纬度向南半球漂移,并在奥陶纪向北半球快速回返。展开更多
【研究目的】越来越多的高分辨率古气候记录证实全新世存在一系列数十年至百年尺度的快速波动,而这种突然的气候变化与人类社会经济发展有着非常密切的关系。4.2 ka BP气候突变事件在亚洲、非洲、北美洲以及地中海和南欧等地均有记录,...【研究目的】越来越多的高分辨率古气候记录证实全新世存在一系列数十年至百年尺度的快速波动,而这种突然的气候变化与人类社会经济发展有着非常密切的关系。4.2 ka BP气候突变事件在亚洲、非洲、北美洲以及地中海和南欧等地均有记录,表明了它的全球性特征。但在海陆交互的海岸带、特别是中国北方泥质海岸带地区,该事件的记录迄今未得到充分证实。【研究方法】本文以渤海湾西北岸相距1~6 km的岭头、罾口河及俵口南部3处埋藏牡蛎礁体及其上覆泥层为研究对象,通过硅藻分析(83个样品)、加速器^(14)C测年(32个数据)与沉积学研究,重建了礁体及上覆泥层所记录的古环境信息,同时探索了可能存在的“4.2 ka BP事件”在海岸带的印记。【研究结果】全新世以来,研究区依次经历了早全新世潮上带盐沼至潮间带→中全新世潮下带—潮间带中下部—潮间带中上部→晚全新世沼泽-盐沼低地沉积环境演变的海进-海退.过程。在约7 ka cal BP以来,3处礁体先后出现,气候温暖。随着礁体的向上建造,海水影响减弱,在5~4.3 ka cal BP时,3处礁体进入潮间带中下部,气候相对寒冷,致使3处礁体同时在4.2~4 ka cal BP时停止建礁,随即被上覆泥层覆盖。【研究结论】研究区在5~4 ka cal BP发生了一次气候波动过程:5~4.3 ka cal BP期间相对寒冷,4.3 ka cal BP后逐渐转暖,气候变化事件的转折点发生于约4.3 ka cal BP。这一明显的环境变化是中国北方泥质海岸带地区对“4.2 ka BP事件”的响应。展开更多
基金supported by the Subproject No.XDA05120302(Permafrost Extent in China during the Last Glaciation Maximum and Megathermal)Strategic Pilot Science and Technology Program of the Chinese Academy of Sciences(Identification of Carbon Budgets for Adaptation to Changing Climate and the Associated Issues)(Grant No.XDA05000000)+1 种基金Open Fund of State Key Laboratory of Frozen Soil Engineering(Grant No.SKLFSE201505)under the auspices of the International Permafrost Association(IPA)Working Group on"Last Permafrost Maximum and Minimum(LPMM)on the Eurasian Continent."
文摘Due to the uplift of Qinghai-Tibet Plateau （QTP）, the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on the QTP experienced repeated expansion and degradation. Based on the remains and cross-correlation with other proxy records such as those from glacial landforms, ice-core and paleogeography, the evolution and changes of permafrost and environmental changes on the QTP during the past 150,000 years were deduced and are presented in this paper.At least four obvious cycles of the extensive and intensive development, expansion and decay of permafrost occurred during the periods of 150-130, 80-50, 30-14 and after 10.8 ka B.P.. Ehiring the Holocene, fluctuating climatic environ-ments affected the permafrost on the QTP, and the peripheral mountains experienced six periods of discernible permafrost changes： （1） Stable development of permafrost in the early Holocene （10.8 to 8.5-7.0 ka B.P.）; （2） Intensive permafrost degradation during the Holocene Megathermal Period （HMP, from 8.5-7.0 to 4.0-3.0 ka B.P.）; （3） Permafrost expansion during the early Neoglacial period （ca. 4,000-3,000 to 1,000 a B.P.）; （4） Relative degradation during the Medieval Warm Period （MWP,from 1,000 to 500 a B.R）; （5） Expansion of permafrost during the Little Ice Age （LIA,from 500 to 10.a B.P.）; （6） Observed and predicted degradation of permafrost during the 20th and 21st century. Each period differed greatly in paleoclimate, paleoenvironment, and permafrost distribution, thickness, areal extent, and ground temperatures, as well as in the development of periglacial phenomena. Statistically, closer dating of the onset permafrost formation, more identi-fication of permafrost remains with richer proxy information about paleoenvironment, and more dating information enable higher resolution for paleo-permafrost reconstruction. Based on the scenarios of persistent climate warming of 2 2 -2 .6 °C
基金Under the auspices of the National Natural Science Foundation of China (49771075) and Testing Foundation by the Modern Analysis
文摘Using five group dating of the fossil by Uranium series age method shows that the age of Nanjing Homo Erectus is between 280－ 430 ka B. P. Combining with the analysis of fossil mammalian form Stegodon, Sus.Lydekkeri Zdansly, M.pachyosteus Young, P.grayi Zdansky and E.SanmeniensisTeilhard et Pive teau, which are located in the same stratum, the authors thinks that the Nanjing Homo Erectus may have lived in the late Mid Pleistocene (about 350 ka B.P.). Based upon the spores and pollen in the cave sediments of the area, we can find that most of spores and pollen are subtropical and warm temperature types. For instance, broad leaf trees which are fond of warm climate, including Cunning hamia, Jsuga and Pinus ,as well as Morus, Carpinus and Ptendium. Among the above spores and pollen, only Tsuga,Liquidambar, Betula,Ulmus and Salix are the remainders of Humid hot environment from the Tertiary period. Above evidences illustrate that the living environment of the Nanjing Homo Erectus not only was not cloder but also was not drier than the Peking Man’s. It could be said that dry climate and the ice age of the Mid Pleistocene didn’t undergo this area.As for the manner of the Homo Erectus’s making stone artifact and using fire, because now we have not found the evidence of the stone artifact and the ash, the futher excavation to the talus of the Huludong cave should be needed.
文摘塔里木陆块周缘的新元古界地层记录了涉及Rodinia聚合和裂解的构造热事件,但塔里木在Rodinia超大陆中的位置以及在Rodinia裂解后如何运动尚无定论。采用收集的古地磁数据,并结合塔里木西北缘阿克苏地区的野外工作以及塔里木周缘代表性岩石如A型花岗岩、基性岩墙群、大陆溢流玄武岩和双峰式火山岩等的同位素年代学数据,将塔里木陆块从Rodinia超大陆中裂解的时间限制在830～700 Ma BP。之后,塔里木陆块随澳洲板块一起加入冈瓦纳大陆。约在450Ma BP,塔里木陆块和澳洲板块发生分离,并快速北漂,最终在晚古生代加入劳亚大陆。新元古代—早古生代,塔里木陆块整体上从北半球较高纬度向南半球漂移,并在奥陶纪向北半球快速回返。
文摘【研究目的】越来越多的高分辨率古气候记录证实全新世存在一系列数十年至百年尺度的快速波动,而这种突然的气候变化与人类社会经济发展有着非常密切的关系。4.2 ka BP气候突变事件在亚洲、非洲、北美洲以及地中海和南欧等地均有记录,表明了它的全球性特征。但在海陆交互的海岸带、特别是中国北方泥质海岸带地区,该事件的记录迄今未得到充分证实。【研究方法】本文以渤海湾西北岸相距1~6 km的岭头、罾口河及俵口南部3处埋藏牡蛎礁体及其上覆泥层为研究对象,通过硅藻分析(83个样品)、加速器^(14)C测年(32个数据)与沉积学研究,重建了礁体及上覆泥层所记录的古环境信息,同时探索了可能存在的“4.2 ka BP事件”在海岸带的印记。【研究结果】全新世以来,研究区依次经历了早全新世潮上带盐沼至潮间带→中全新世潮下带—潮间带中下部—潮间带中上部→晚全新世沼泽-盐沼低地沉积环境演变的海进-海退.过程。在约7 ka cal BP以来,3处礁体先后出现,气候温暖。随着礁体的向上建造,海水影响减弱,在5~4.3 ka cal BP时,3处礁体进入潮间带中下部,气候相对寒冷,致使3处礁体同时在4.2~4 ka cal BP时停止建礁,随即被上覆泥层覆盖。【研究结论】研究区在5~4 ka cal BP发生了一次气候波动过程:5~4.3 ka cal BP期间相对寒冷,4.3 ka cal BP后逐渐转暖,气候变化事件的转折点发生于约4.3 ka cal BP。这一明显的环境变化是中国北方泥质海岸带地区对“4.2 ka BP事件”的响应。
