A Carbon Isotopic Stratigraphic Pattern of the Late Palaeozoic Coals in the North China Platform and Its Palaeoclimatic Implications

This paper gives the stable carbon isotopic data in coals from the Late Namurian to Kazanian stages inthe Serteng Mt., Xishan and Huainan coalfields of the North China Platform. Its stratigraphic pattern shows that sev-eral isotopic shifts are apparent, and the large δ~(13)C negative shifts (approximately 2.5 to 3.0‰) occurred during theStephanian, Artinskian and Kazanian are observed in three Permo-Carboniferous coalfields. Those negative shifts areneither related to the coal rank and coal macerals, nor caused by the variety of peat-forming plants. The general de-crease in the δ~(13)C values of the Stephanian, Artinskian and Kazanian coals is consistent with an overall decrease inthe δ~(13)C values of ambient atmospheric CO_2 and/or a relative increase in atmospheric P_(CO2) during the coal-forming pe-riods. Therefore the authors postulate that the oxidation of peat, and the δ~(13)C-depleted CO_2 flux into the atmosphereduring the above stages may have contributed to coeval palaeoclimatic warming by way of the greenhouse effect.     

现代砗磲壳的碳、氧、锶同位素的变化

本文测定了西沙群岛永乐环礁现代鳞砗磲壳的碳,氧,锶同位素组成。碳,锶同位素组成呈现以年为周期的规律性变化。     

Climatic and Anthropogenic Influences on Radial Growth of Scots Pine at Hanvedsmossen, a Raised Peat Bog, in South Central Sweden

Past studies of the climatic influence on tree growth at peat bogs in northern latitudes have shown weak correlation between annual tree-ring widths and climatic parameters during the growing season. At Hanvedsmossen, a raised peat bog in south central Sweden, tree-ring width chronologies from one drained and one undrained growth site, as well as one dry site outside the bog, were compared to meteorological records. Low temperatures, which means less evaporation, as well as high precipitation appear to be inhibiting pine growth at the undisturbed bog site as the trees are sensitive to changes in the local water table. Drainage causes an instant increase in annual tree growth for approximately 10 years. If draining is maintained, the response to climate of the pines resembles that of pines growing on mineral soils. The variance in annual tree-ring growth explained by temperature/precipitation or both was low for the entire lengths of all chronologies, but high for some analysed subperiods; the significant months changed with time. The reason for this seems to be that pines at Hanvedsmossen are growing in a region where precipitation and temperature are less limiting to tree growth than at higher and lower latitudes.     

Palaeoclimatic record from a loess–soil profile in northeastern Bulgaria—II. Correlation with global climatic events during the Pleistocene

Magnetic susceptibility ( χ ) variations and the behaviour of the ratio of susceptibility to saturation magnetization ( χ/J _s ) along the loess/palaeosol section at Koriten (NE Bulgaria) are used to deduce climatic changes during the Pleistocene in southeastern Europe. A good correlation of susceptibility variations with the astronomically tuned oxygen isotope record from ODP site 677 enables us to propose a more precise dating of the upper part of the Bulgarian loess complex. Close correspondence between susceptibility and δ ^{1 8} O records demonstrates the global significance of the palaeoclimatic signal recorded, although differences in relative amplitudes of χ and χ/J _s and δ ^{1 8} O create difficulties in making quantitative estimates of the climatic humidity in the past. The role of local factors affecting the palaeoclimatic mineral magnetic record deduced from the profile studied in Bulgaria is discussed.     

Evidence of the Pan-Lake Stage in the Period of 40-28 ka B.P. on the Qinghai-Tibet Plateau

The Qinghai-Tibet plateau is one of major saline lake regions in China, where saline lakes are widespread and constitute an important object of researches on the palaeoclimatic change in the region. On the basis of comprehensive investigations of the evolution of the lake's surface and sediments on the plateau, the authors have further demonstrated the existence of a pan-lake stage (river and lake flooding stage) on the Qinghai-Tibet plateau during the period of about 40+-28 ka B.P. and analyzed the palaeoclimatic characteristics of the pan-lake period and relationships between the ancient monsoons and the uplift of the plateau since the beginning of the Quaternary.     

闽中地区金矿地质特征及找矿方向

闽中地区德化、尤溪、永泰一带发现的金矿点构成福建金矿床金三角,按成矿类型可划分为石英脉型、破碎带蚀变岩型、多充化物型和火山－次火山岩型金矿。在分析金矿成矿地质背景、构造、地层及岩浆活动基础上,进一步探索找矿方向。     

澳大利亚的第三纪及第三纪-第四纪过渡期

第三纪的板块运动驱动着澳大利亚的气候和植被进行演化。广布的湿润森林区是澳大利亚早第三纪的特征。一直到始新世,生物多样性都在不断地提高。毫无疑问,这是澳大利亚由高南纬区向北部中纬区运移的结果。从始新世到上新世,澳大利亚的气候总体上要比现在湿润,但降水量季节性变化的增强推动了中新世以后硬叶植物和旱生植物的发展。上新世晚期似乎与第四纪一样,都出现过周期性干旱。这种干旱与冰期条件有关,至少由南澳大利亚晚第四纪的记录可以认识到这一点,澳大利亚的这段历史与东亚的气候变迁是同步发生的。在东亚,印一澳板块的运动致使青藏高原抬升,从而引发了区内乃至全球气候的巨变。穿越赤道区的季风和信风的环流格局致使晚第三纪和第四纪中国与澳大利亚的气候系统的相关性更强。     

Automatic recognition of freight car number

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云南地区强震前的应变扰动异常

计算和分析了云南地区5次M_L ≥ 6.5强震前的应变扰动ε_i值.结果表明,地震前5~8年,归一化为4级的地震的ε_i出现明显的高值异常;未来震中区域ε_i值变小,周围地区增大,形成空区;ε_i值有由零星分布逐渐向震中区收缩、集中并增强的趋势.     

进化序列系统学——以二叠纪瓦岗珊瑚类为例

进化序列系统学是古生物学中研究物种间和类别间的系统发育关系为目的的学科, 包括研究物种或类别间的亲缘关系, 并确定它们形成的先后序列.表型-分支系统学是该系统学的基础.分支系统学的许多重要概念在该系统学中加入了时间的含义, 例如, 认为最亲近的姐妹种之间的时间间隔不会超过它们母种的生存期.姐妹群和性状镶嵌分析是进化序列研究的主要方法, 而理解性状镶嵌分布是关键.这些分析可由计算机程序实现.以二叠纪瓦岗珊瑚类作为研究进化序列系统学的实例, 该类在特提斯地区广泛分布.通过对瓦岗珊瑚类的特征分析确定了17个性状用于研究, 并且每一性状确定了几个变化状态.根据最广布的性状状态、化石记录和个体发生等原则分辨出近祖性状状态, 并根据性状在系统发育中的重要性确定性状分级.然后, 确定了姐妹群间的关系和物种间的进化序列.在姐妹群与进化序列分析相互检验中可发现性状退化、平行演化和多向分支等古生物学重要现象, 并分辨出物种的异常顺序.在检验生物地层学首次出现事件讨论中推测了一些化石首次出现的可能层位.