检索结果-南通市图书馆

Science china Earth Sciences 2008年第2期51卷 294-299页

作者： li yongxiang1 & xue xiangxu1,2.1 {2. key Laboratory of continental dynamics, department of geology, northwest university, institute of cenozoic geology and environment, xi’an 710069, china 2.institute of Earth {12., {2. key Laboratory of Loess and Quaternary geology, Chinese Academy of Sciences, xi’an 710075, china 1. state key Laboratory of {2. dynamics Department of Geology Northwest University Institute of Cenozoic Geology and Environment Xi’an 710069 China 2. institute of Earth environment State Key Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an 710075 China

Three microtine species are recovered from the Zhangping Caves of the Qingling Mountains, namely Microtus oeconomus, Caryomys inez and Caryomys eva. They are climate-sensitive ones with different ecological habits, therefore their distribution well corresponds to {2.al variations. Statistical comparison of the distribution of fossil microtines and their counterparts nowadays displays that the climate variation of the studied area and its contiguity since the middle Pleistocene are: warm and humid at 493 ka ago, cool and humid at 2.9 ka ago―cold and humid at 2.5 ka ago―cool and humid at 2. ka ago, and warm and dry at present.

关键词： environmental variation since Middle Pleistocene microtine fossils Zhangping Caves of the Qinling Mountains

Paleoenvironments indicated by the fossil mammalian assemblages from red clay-loess sequence in the Chinese Loess Plateau since 8.0 Ma B.P.

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第5期49卷 518-530页

作者： xue xiangxu1,2. ZHANG Yunxiang1,2.& YUE Leping1,{2.. state key Laboratory of Continent dynamics (northwest university), institute of cenozoic geology and environment, De- partment of geology, northwest university, xi’an 710069,{12. 2. institute of Earth environment, state key Laboratory of Loess and Quaternary geology, Chinese Academy of Sciences, xi’an 710075,{12. 1. state key Laboratory of Continent {2. (northwest university) Institute of Cenozoic Geology and Environment Department of Geology Northwest University Xi’an 710069 China 2. institute of Earth environment State Key Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an 710075 China

Information from eleven profiles of eolian earthy red silty clay and loess of the middle of the Late Miocene to Holocene age have been studied and correlated. A complete summary profile with projected isotopic ages and fossil-bearing beds has been assembled. The profile is subdivided into 12.stratigraphic units proceeding from the lower (older) to the upper (younger) one. The character of mammalian assemblages contained in each unit was analyzed and the corresponding pa- leo-climatic environments were deduced. The environmental character of each period and the change from the middle of the Late Miocene at about 8.0 Ma B.P. up to the Holocene progressed from the hot semiarid and semi-moist, warmer-moist, warm-moister of the Late Miocene. To slightly less warm moist, cool-dry, slight-warmer-moister of the Pliocene; later the cool to cold dry periods alternated frequently with the mild semiarid and semi-moist periods of the Quaternary. Vegetation progressed from the grasslands with sparse woods, wooded shrub-grasslands and subtropical forest-grasslands of the Late Miocene age to sparse grasslands and dry grasslands of the Pliocene; and to sparse grasslands, dry grasslands and tundras of the Quaternary. The climate changes in the Neogene were of low-amplitute in a generally warm-humid background. Those of the Quaternary were of higher am- plitude with a longer phase. Cool or cold dry and slightly warm semiarid and semi-moist climates al- ternated on a generally cool-dry background. The tendency since the start of the Quaternary was the change to more northern and western shift in the Loess Plateau, with progressively cooler and dryer conditions. The dramatic uplift of the Qinghai-xizang (Tibet) Plateau and the forming and expansion of the Arctic ice sheet might be the main reasons of the more pronounced changes in the Quaternary.

关键词： paleoenvironment, mammalian fossils, eolian red clay-loess sequence, Loess Plateau.

Geomorphologic evidence of phased uplift of the northeastern Qinghai-Tibet Plateau since 14 million years ago

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2004年第9期47卷 822-833页

作者： LU Huayu1, WANG xiaoyong1, AN Zhisheng1, MIAO xiaodong1, ZHU Rixiang3, MA Haizhou2. li Zhen4, TAN Hongbing2.& WANG xianyan1 1. state {2. Laboratory of Loess and Quaternary geology, institute of Earth environment, Chinese Academy of Sciences, xi’an 710075 china 2. Qinghai institute of Salt Lakes, Chinese Academy of Sciences. xining 810008, china 3. institute of geology and Geophysics, Chinese Academy of Sciences, Beijing 10002., china 4. {12. of Geography, Qinghai Normal university, xining 810008, china Chinese Acad Sci Inst Earth Environm State Key Lab Loess & Quaternary Geol Xian 710075 Peoples R China Chinese Acad Sci Qinghai Inst Salt Lakes Xining 810008 Peoples R China Chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China Qinghai Normal Univ Dept Geog Xining 810008 Peoples R China

A typical sequence of fluvial terraces and aeolian deposits overlying these ter- races were multidisciplinary investigated. New evidences for uplift process of the northeastern Qinghai-Tibetan Plateau in the past 14 million years were obtained. At least 11 river terraces along Huangshui, the first-class tributary of Yellow River, at the xining-Huzhu region are identi- fied. While the first one (T1) is classified as an accumulation terrace, the others are all basement river terraces, which consist of the Tertiary sandstone and siltstone bedrock, fluvial gravel and pebbles and the overlying aeolian loess-Red Clay deposit. Samples from the aeolian deposits were examined for paleomagnetic stratigraphic reconstruction (1030 samples), luminescence dating (16 samples), magnetic susceptibility and grain-size distribution (more than 4000 sam- ples). The luminescence dating and stratigraphic correlation suggest that terraces of Tll, T10, T8, T7, T3, T2. T1 were formed at 14, 11.3, 1.55, 1.2. 0.15, 0.07 and 0.01 million years ago, re- spectively. Sedimentological analysis and geomorphological observation indicate that formation and evolution of these terraces were mainly driven by tectonic uplift. Therefore, the terrace se- quence provides an ideal geological record, of the uplift process of the northeastern during the past 14 million years, and the timings of the terraces formation are regarded as the timings of tectonic uplift. The significant uplifting events took place at 14, 11.3, 1.2.and 0.15 mil- lion years ago, respectively. The fluvial incision at the xining-Huzhu region is less than 100 m during a period of ~12.million years in the Miocene era (between the Tll and T9), while the Huangshui River had incised 432.m during the past 1.2.million years (from T7 to the present floodplain). The river incision process clearly demonstrates that accelerated rising of the north- eastern Qinghai-Tibet Plateau during the late cenozoic, and provides new evidence of previous thoughts

关键词： river terrace, tectonic uplift, loess-Red Clay, the past 14 million years, northeastern Qinghai-Tibet Plateau.

New fossils of the Early Pleistocene Equus huanghoensis(Equidae,Perissodactyla)from Nihewan in Hebei Province of china

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2016年第10期59卷 83-94页

作者： li yongxiang ZHANG Yunxiang SUN BoYang AO Hong {2. xiangxu state key Laboratory of {2. dynamics Department of GeologyNorthwest UniversityXi'an 710069China state key Laboratory of Loess and Quaternary {2. Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China Tianjin Museum of Natural History Tianjin 300201China

This paper describes new fossils of Equus huanghoensis from an Early Pleistocene bed in Nihewan, Hebei Province, which confirms the classification of E. huanghoensis by Chinese researchers. The new fossils include a relatively complete male skull and mandible with all upper and lower dentition, a broken female skull with fragment of mandible and a broken Mc III of Equus sp. The fossils were collected from the Yangshuizhan site of Nihewan. The age of the formation is about 1.6 Ma. The new materials verify some classification characteristics based on teeth published in previous descriptions. These characteristics include large teeth size, short protocone, and tilted protoloph and metaloph. We have added to these characteristics of large skull size, a developed protuberantia supramagna, pentagonal nuchal side, weak Pli cabaline, simple enamel plications; a series of new characteristics strikingly different from the other Equus horses. The broken Mc III is similar to Equus qingyangensis from Qingyang, Gansu.

关键词： Nihewan Early Pleistocene Equus huanghoensis New fossils

同方期刊数据库

Chemical characteristics of haze particles in xi＇an during Chinese Spring Festival： Impact of fireworks burning

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2018年第9期30卷 179-187页

作者： Can Wu Gehui Wang Jiayuan Wang Jianjun li Yanqin Ren Lu Zhang Cong Cao Jin li Shuagshuang Ge Yuning xie xinpei Wang Guoyan {2. state key Laboratory of Loess and Quaternary {2. Key Lab of Aerosol Chemistry and Physics Institute of Earth Environment Chinese Academy of Sciences Xi' an 710061 China key Laboratory of Geographic Information Science of the Ministry of Education School of Geographic Sciences East China Normal University Shanghai 210062 China Center for Excellence in Regional Atmospheric environment Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China university of Chinese Academy of Sciences Beijin9 100049 China state key Laboratory of {2.al Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing 100012 China

Fireworks burning releases massive fine particles and gaseous pollutants, significantly deteriorating air quality during Chinese Lunar New Year （LNY） period. To investigate the impact of the fireworks burning on the atmospheric aerosol chemistry, 1-hr time resolution of PM2.5 samples in xi＇an during the winter of 2.16 including the LNY were collected and detected for inorganic ions, acidity and liquid water content （LWC） of the fine aerosols. PM2.5 during the LNY was 167 ± 87 μg/m^3, two times higher than the china National Ambient Air Quality Standard （75 μg/m^3）. K^＋（2. wt.% of the total ion mass） was the most abundant ion in the LNY period, followed by SO^2.4 （2. wt.%） and C1^- （18 wt.%）. In contrast, NO^-3 （34 wt.%） was the most abundant species in the haze periods （hourly PM2.5 〉 75 μg/m^3）, followed by SO^2.4 （2..2.wt.%） and NH^＋4 （16.3 wt.%）, while SC94 （35 wt.%） was the most abundant species in the clean periods （hourly PM2.5 〈 75 μg/m^3）, followed by NO^-3 （2..1 wt.%） and NH^＋4 （11 wt.%）. Being different from the acidic nature in the non-LNY periods, aerosol in the LNY period presented an alkaline nature with a pH value of 7.8 ± 1.3. LWC during the LNY period showed a robust linear correlation with K2.O4 and KC1, suggesting that aerosol hygroscopicity was dominated by inorganic salts derived from fireworks burning. Analysis of correlations between the ratios of NO^-3/SO^2.4 and NH^＋4/SO^2.4 indicated that heterogeneous reaction of HNO3 with NH3 was an important formation pathway of particulate nitrate and ammonium during the LNY period.

关键词： Inorganic ions Aerosol acidity liquid water content Composition and source Nitrate formation

在线全文

学校读者我要写书评

暂无评论

土壤生态系统微生物多样性技术研究进展

地球与环境 2018年第2期46卷 204-209页

作者：陈慧清李晓晨于学峰马瑜柯杨朱海云薛静陕西师范大学西安710119 中国科学院地球环境研究所黄土与第四纪地质国家重点实验室西安710061 陕西省微生物研究所西安710043

土壤微生物多样性主要研究土壤环境中微生物种群的类别、丰度、分布、结构变化及微生物群落功能的多样性,是土壤生物多样性研究的主体部分。19世纪末,传统的微生物分离培养方法应用于土壤微生物多样性解析。至2.世纪70年代,建立了以磷... 详细信息

土壤微生物多样性主要研究土壤环境中微生物种群的类别、丰度、分布、结构变化及微生物群落功能的多样性,是土壤生物多样性研究的主体部分。19世纪末,传统的微生物分离培养方法应用于土壤微生物多样性解析。至2.世纪70年代,建立了以磷脂脂肪酸图谱分析法（PLFA）和BIOLOG微量分析法为代表的对土壤微生物群落多样性评价的生物化学方法。2.世纪90年代后期,随着分子生物学技术的快速发展,建立了变性梯度凝胶电泳（DGGE）、末端限制性片段长度多样性（TRFLP）、克隆文库和高通量测序等土壤微生物多样性研究方法。本文综述了土壤微生物多样性研究技术的原理、进展,并对不同技术的优缺点及应用进行探讨,并对相关领域研究提出思考。

关键词：微生物多样性土壤生态系统微生物群落研究进展

Olivine-norite rock detected by the lunar rover Yutu-2.likely crystallized from the SPA-impact melt pool

在线全文

学校读者我要写书评

暂无评论

National Science Review 2020年第5期7卷 913-920页

作者： Honglei lin Zhiping He Wei Yang Yangting lin Rui Xu Chi Zhang Meng-Hua Zhu Rui Chang Jinhai Zhang Chunlai li Hongyu lin Yang liu Sheng Gou Yong Wei Sen Hu Changbin xue Jianfeng Yang Jie Zhong xiaohui Fu Weixing Wan Yongliao Zou key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences key Laboratory of Space Active Opto-Electronics Technology Shanghai Institute of Technical Physics Chinese Academy of Sciences state key Laboratory of Lunar and Planetary Sciences Macau University of Science and Technology Beijing institute of Space Mechanics and Electricity state key Laboratory of Space Weather National Space Science CenterChinese Academy of Sciences state key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences key Laboratory of Electronics and Information Technology for Space System National Space Science Center Chinese Academy of Sciences xi'an institute of Optics and Precision Mechanics Chinese Academy of Sciences institute of Optics and Electronics Chinese Academy of Sciences Shandong Provincial key Laboratory of Optical Astronomy and Solar-Terrestrial environment Institute of Space SciencesShandong University

Chang’E-4 landed in the South Pole-Aitken (SPA) basin,providing a unique chance to probe the composition of the lunar *** landing site is located on ejecta strips in Von Karman crater that possibly originate from the neighboring Finsen crater.A surface rock and the lunar regolith at 10 sites along the rover Yutu-2.track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission *** situ spectra of the regolith have peak band positions at 1and 2.m,similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper,which confirms that the regolith’s composition of the landing area is mostly similar to that of Finsen *** rock spectrum shows similar band peak positions,but stronger absorptions,suggesting relatively fresh *** rock may consist of 38.1±5.4%low-Ca pyroxene,13.9±5.1%olivine and 48.0±3.1%plagioclase,referred to as *** plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle,but representative of the lunar lower ***,the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle *** scenario is consistent with fast-cooling thermal conditions of a shallow melt pool,indicated by the fine to medium-sized texture (2.12.2.0:730-43].

关键词： impact basin lunar interior composition visible and near-infrared spectra lunar rover Yutu-2 Chang’E-4 mission

南海北部白垩纪-渐新世早期沉积环境演变及构造控制

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

古地理学报 2022年第1期24卷 73-84页

作者：吴哲张丽丽朱伟林邵磊杨学奇中海石油(中国)有限公司深圳分公司广东深圳518054 同济大学海洋地质国家重点实验室上海200092

南海北部珠江口—琼东南盆地白垩系—下渐新统记录了华南大陆边缘从主动陆缘向被动陆缘的转换过程。基于盆地构造-地层、单井相、地震相等特征的综合分析,结合南海中南部的沉积环境和区域构造演化,探讨南海北部白垩纪—渐新世早期的沉... 详细信息

南海北部珠江口—琼东南盆地白垩系—下渐新统记录了华南大陆边缘从主动陆缘向被动陆缘的转换过程。基于盆地构造-地层、单井相、地震相等特征的综合分析,结合南海中南部的沉积环境和区域构造演化,探讨南海北部白垩纪—渐新世早期的沉积环境演变及构造控制背景。研究发现:(1)南海北部白垩系广泛分布,古新统分布极为有限;始新世早-中期,琼东南盆地只在部分凹陷深部发育了小规模的滨浅湖相和扇三角洲相沉积,珠江口盆地白云凹陷以大规模发育的湖泊相为特征;始新世晚期—渐新世早期,琼东南盆地和珠江口盆地白云凹陷都受到海侵作用的影响,以海岸平原相和滨浅海相为主。(2.构造演变包括5期:包括白垩纪安第斯型大陆边缘的“弧—盆”体系发育期,古新世区域隆升剥蚀山间盆地发育期,始新世早-中期裂陷发育,始新世晚期—渐新世早期陆缘破裂期,渐新世晚期东部海盆稳定扩张期。最后,探讨了南海盆地中生代末/新生代初的动力学转换过程及特征。

关键词：南海珠江口盆地琼东南盆地沉积环境构造古地理

山东半岛石笋记录的倒数第二次冰消期δ18O变化特征及其气候环境意义

在线全文

学校读者我要写书评

暂无评论

第四纪研究 2019年第4期39卷 812-824页

作者：薛刚蔡演军马乐成星李东卫莹莹中国科学院地球环境研究所黄土与第四纪地质国家重点实验室陕西西安710061 中国科学院大学北京100049 中国科学院第四纪科学与全球变化卓越创新中心陕西西安710061 青岛海洋科学与技术试点国家实验室海陆气候环境变化开放工作室山东青岛266061 西安交通大学全球环境变化研究院陕西西安710054

文章基于山东半岛岩溶洞穴(上小峰洞)一根长约41 cm的石笋SD1的铀系测年和稳定同位素组成分析,获得138. 0~12.. 8 ka B. P.平均分辨率为30年的石笋δ18O 和δ13C时间序列,并据此讨论了倒数第二次冰消期区域气候和环境变化的特征及与全... 详细信息

文章基于山东半岛岩溶洞穴(上小峰洞)一根长约41 cm的石笋SD1的铀系测年和稳定同位素组成分析,获得138. 0~12.. 8 ka B. P.平均分辨率为30年的石笋δ18O 和δ13C时间序列,并据此讨论了倒数第二次冰消期区域气候和环境变化的特征及与全球变化的联系.在倒数第二次冰消期,上小峰洞石笋( SD1)δ18O的变化与中国南方石笋δ18O的变化具有类似的阶段变化特征,进一步确认了冰消期北大西洋气候对亚洲季风的重要影响.通过对山东石笋高分辨δ18O记录进行时间序列分析,发现该记录存在显著的约60年、 75年和162.年周期,表明太阳活动和北大西洋涛动与该地区气候变化有紧密的联系.同时,通过对比东亚季风区高分辨率石笋记录,认为在倒数第二次冰消期为"两步冰消"的变化特征.除此之外,上小峰洞石笋碳酸盐δ18O冰期和间冰期平均值的差异仅为0. 7‰,远小于内陆洞穴石笋碳酸盐δ18O冰期和间冰期平均值的差异(羊口洞约为1. 4‰,董哥洞约为2. 2.,三宝洞约为2. 4‰).这一显著差异可能主要源于海岸线迁移造成的海陆格局的变化对区域季风降水及降水氧同位素组成的重要影响;并且冰期-间冰期海平面变化对近海环境记录、大陆架下垫面、海洋沉积物气候指标等都可能产生影响.

关键词：石笋氧同位素倒二冰消期弱季风期海岸线移动

在线全文

学校读者我要写书评

暂无评论

基于文献计量的自然湿地研究态势分析

环境生态学 2023年第2期5卷 32-37,50页

作者：李悦王雪王巍于炜瑞李金鹏盛连喜东北师范大学环境学院国家环境保护湿地生态与植被恢复重点实验室吉林长春130117 吉林龙湾国家级自然保护区管理局吉林通化135102

自然湿地因具有重要的生态功能而受到全球科学研究者的广泛关注。为全面了解自然湿地领域的研究现状及发展趋势,选取Web of Science数据库,利用VOSviewer可视化分析软件对2.09—2.18年自然湿地研究领域发表的SCI论文进行文献计量分析。... 详细信息

自然湿地因具有重要的生态功能而受到全球科学研究者的广泛关注。为全面了解自然湿地领域的研究现状及发展趋势,选取Web of Science数据库,利用VOSviewer可视化分析软件对2.09—2.18年自然湿地研究领域发表的SCI论文进行文献计量分析。结果表明:(1)自然湿地研究在全球的受重视程度越来越高,近10年发文量呈波动式增长趋势,中国和美国在该领域进行了大量研究,是发文数量最多的两个国家;(2.中国科学院在自然湿地领域的发文数量和总被引频次都位居首位;(3)《Ecological Engineering》《Wetlands》《Science of the Total environment》是该领域刊载论文量排名前3的期刊;(4)自然湿地领域发展涉及环境科学与生态学、水资源学、工程学、地质学、海洋和淡水生物学等多学科协作,学科交叉融合趋势明显;(5)研究热点主要集中在湿地生物多样性与湿地管理、植被恢复、泥炭地碳排放、湿地水文特征等方面。文献计量学分析能够为自然湿地范畴的研究工作提供一定参考,增进国际、各研究机构交流合作,推动学科交叉融合,加强机理性研究等应是未来一段时间自然湿地领域的重点方向。

关键词：自然湿地 Web of Science 文献计量分析可视化分析研究热点