Ulmus harutoriensis Oishi et Huzioka角质层特征及古环境意义

根据大量室内实验分析，对产于云南腾冲的植物化石Ulmus harutorensis Oishi et Huzioka的角质层进行了细致研究，揭示了Ulmus harutoriensis叶的表皮构造，其主要特征为：上表皮厚1．1μm，下表皮厚小于1μm，上表皮细胞大于下表皮细胞、毛基少、气孔器很小、只在下表皮发育、无规则型、散生、下陷较浅，在此基础上结合其他资料推测了古气候变化，并与现生Umlus pumila L。同时进行了气孔密度和气孔指数的统计，用生物学的方法推测了古大气CO2浓度，讨论了Berner的碳平衡模型。     

兰州地区古气候变化的奇怪吸引子研究

利用兰州九洲台黄土剖面磁化率资料分析了古气候变化的混沌特性。结果表明，该地区．４Ｍａ以来的古气候具有有限个自由工的复杂系统，吸引子的关联维数为４．３，饱和度嵌入维数为１２。．     

Thermally unstable maghaemite and its palaeoclimatic significance in Chinese loess

Magnetite and maghaemite are the two main contributors to magnetic susceptibility in the Chinese loess/palaeosol sequence. Due to the close similarity in physical properties, early investigators treated them together as "magnetite". Utilising the property of thermally instability of maghaemite, we have been able to separate it from magnetite in loess and palaeosol samples from the upper parts of the Xifeng and Luochuan sections on the central Chinese Loess Plateau and compare its variation with depth and horizon. Our results indicate that thermally unstable maghaemite is relatively enriched in both 1) weakly weathered loess units and 2) towards the west, the direction of dust supply, suggesting that maghaemite is at least partially (coarse grains) of detrital aeolian origin while some pedogenic maghaemite (extra fine grains) occurs in the palaeosols. The physical meaning of magnetic susceptibility, therefore, needs to be reconsidered as a synthetic indicator reflecting the palaeoenvironment for both source area and deposition area. Thermally unstable goethite is a minor magnetic component of palaeosol samples, but it may play a significant role in determining characteristic magnetic remanence of weakly weathered loess samples, especially when one applies alternating-field cleaning.     

A method for calculating palaeoclimate index in quaternary pollen－spore analysis

Ａｍｅｔｈｏｄｆｏｒｃａｌｃｕｌａｔｉｎｇｐａｌａｅｏｃｌｉｍａｔｅｉｎｄｅｘｉｎｑｕａｔｅｒｎａｒｙｐｏｌｌｅｎ－ｓｐｏｒｅａｎａｌｙｓｉｓＬｕｏＬｕｎｄｅ（ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏｇｒａｐｈｙ，ＳｏｕｔｈｗｅｓｔＣｈｉｎａＮｏｒｍａｌＵｎｉ...     

Preliminary study on LGM climate simulation and the diagnosis for East Asia

LGM climate study is a hot topic in international fields on global changes. Climate simulation in this study applies both common designs of 21 kaBP boundary conditions from the Paleoclimate Modeling Intercomparison Project (PMIP), including insolation, glaciation, sea surface temperature and atmospheric CO₂ concentration, and land surface conditions from Eurasia continent by compilation of geological evidence. The simulation outputs are in agreement with climate spatial patterns reconstructed by observation records. Sensitive experiment on land surface conditions shows that changes in vegetation would make significant impacts on temperature and precipitation. Particularly in the Tibetan Plateau, this change would increase in differences of winter and summer temperature, precipitation and P-E.     

东胜煤田侏罗系延安组植物群及古气候分析

应用放大镜观察的方法对东胜煤田侏罗系延安组中保存的大量植物化石进行分析,共鉴定出24属64种.在此基础上,对侏罗系延安组植物群组合特征及其所反映的古气候进行研究.结果表明:该植物群可分为有继承性的Coniopteris szeiana-Nilssonia pterophylloides-Eboracia lobifolia与Neocalalamites hoerensis-Podozamites lanceolatus上下两个组合;该植物群与北京门头沟植物群、豫西义马植物群主要属种相同,都是银杏纲、真蕨纲占优势,并以蚌壳蕨科的繁盛为特征,均属于我国北方地区早、中侏罗世Coniopteris-Phoenicopsis植物群,可进行对比;植物群组合特征反映东胜煤田延安组时期为季节分明、偏潮湿的温带-暖温带气候.     

共存分析法在兰州盆地渐新世哺乳动物化石研究中的应用

运用共存分析法对甘肃兰州盆地渐新统韩家井组的23种哺乳动物化石进行了分析,重建了该地区渐新世古气候各参数:年均温为-2.8～14.4℃(中值5.8℃),最热月均温为8.0～27.5℃(中值17.75℃),最冷月均温为-4.4～-14.6℃(中值-9.5℃),年较差为23.1～26.2℃(中值24.65℃),年均降水量为...     

云南大理点苍山地区晚更新世以来的古植被和古气候

根据云南大理点苍山地区晚更新世沉积地层中的古植被的孢粉化石鉴定，结合孢粉图示的综合分析以及孢粉组合带的划分，探讨了该地区自晚更新世以来古植被的演替过程，并在此基础之上对古气候的波动过程进行了初步推测，结论显示自122-118Ka.BP的湿热气候期之后，该地区的气候演变经历了7次从冷-湿热的气候波动旋回。     

Carbon and nitrogen stable isotope analyses of mammal bone fossils from the Zhongba site in the Three Gorges Reservoir region of the Yangtze River,China

Based on AMS ¹⁴C dating data, carbon and nitrogen isotope analyses were conducted on mammal bone collagen of deer, cattle and pigs from the Zhongba site in the Three Gorges Reservoir region of the Yangtze River. These analyses were conducted to reconstruct palaeodiets of mammals, palaeoecology, palaeoenviroment and previous human activities in the study area. Results show that the collagen loss of bone did not change the in vivo isotopic composition of carbon and nitrogen stable isotopes, and most of the bone fossils were well preserved. The bone collagen of samples from deer had a mean δ¹³C of -23.1‰ and a mean δ¹⁵N of 4.7‰, suggesting that deer subsisted in a closed habitat and fed on branches and leaves. The bone collagen of cattle had a mean δ¹³C of –19.6‰ and a mean δ¹⁵N of 5.2‰, which indicates that cattle subsisted in an open habitat and fed on grasses and stems. The δ¹³C values show that both deer and cattle fed on C₃ plants and lived in the same ecosystem, but the t-test results show that deer δ¹³C and δ¹⁵N values were both more negative than those of cattle, indicating that they inhabited different niches. The δ¹³C and δ¹⁵N values of cattle partially overlapped those of deer, suggesting some competition in diets between them. The t-tests show that the δ¹³C and δ¹⁵N values of pigs were more positive than those of cattle and deer, which signifies that pigs occupied a higher trophic level compared to cattle and deer. The wide range of pig δ¹³C values demonstrates that pig trading had been taking place from early Neolithic Age to late Bronze Age. There were no significant differences in deer δ¹³C and δ¹⁵N values among different archaeological periods, making it clear that climatic, ecological and environmental conditions were kept relatively stable from 2200 to 4200 a BP. This stability may have been responsible for the extensive and complete cultural layers at the Zhongba site. The minimum number of samples required to estimate the mean δ¹³C values of deer, pigs and cattle are 8, 73 and 16, respectively, and for mean δ¹⁵N values of deer, pigs and cattle, the minimum numbers are 4, 5 and 6, respectively.