The occurrence and significance of C25HBI in Cenozoic saline lacustrine source rocks from the Western Qaidam Basin,NW China

The saline lacustrine deposit of the Oligocene Lower Ganchaigou Formation is the main source rock for the Western Qaidam Basin,NW China.In this study,abundant highly branched isoprenoids with 25 carbon atoms (C25HBI) were detected in the upper section of the Lower Ganchaigou Formation.C25HBI is a biomarker for diatoms,and can provide information regarding biogeochemical processes during production and preservation of sedimentary organic matter.The carbon isotopic values of C25HBI in these source rocks were in the range of-18‰ to-20‰.The relative enrichment in 13C of C25HBI suggests that these isoprenoids were derived from diatom blooms.In this case,the diatoms used HCO3-as an additional carbon source to dissolved CO2 in water column due to their high biological productivity.Conversely,the diatom blooms indicated an abundant nutrient supply to the environment and high primary productivity.Thus,the occurrence of 13C-enriched C25HBI could be an ideal marker for good source rocks.The decreased concentration of CO2(aq) in the water column induced by diatom blooms can result in an enrichment in 13C of organic matter synthesized by primary producers.This may be a possible reason for the occurrence of 13C-enriched organic matter in the Cenozoic source rocks of the Western Qaidam Basin.Previous studies have shown that the high carbon number n-alkanes sourced from diatoms have no carbon preference.Hence,the sources of n-alkanes in regional source rocks are complex,and should be considered when discussing the sources of organic matter in future studies.     

木化石连续切片方法

初步结果表明,一些保存较好的木化石材料(或渗矿化材料),可先经过酸浸解,使其矿质杂屑离解并暴落出原实体材料,然后用金属刀进行连续切片。     

用离析法研究化石木材

本文首次报道用离析方法研究湖北省新洲县的被子植物化石木材的情况.实验证明,经该方法处理后的木化石、导管、木射线、纤维等清晰可见,这对化石木材的研究是有意义的,并提供了一种新的辅助手段.     

贵阳乌当古生代腕足动物化石壳质成份的初步研究

通过对乌当古生代五组腕足动物化石壳和围岩的光谱半定量及红外光谱测试扫描,发现化石壳的化学成份、矿物成份和围岩关系密切,说明石化过程中,置换、交代作用进行得比较完全,这种研究有明显意义。     

文化冲突与《圣经》话语的戏剧化——对张资平小说《冲积期化石》的考察

张资平的“文字”能力一直被文人所称道。从《冲积期化石》中可以看出，在张资平独具魔力的文字背后，隐含着其独特的文化心理。中国传统文化和西方基督教文化对他都有一定的影响，他在坚持欲望自由的道德立场时，对两种文化规范都有一定程度的抗拒。他在批评社会现实时广泛借用《圣经》话语，而传统文化美学又不时地影响他的审美心理，两种文化美学规范的潜在作用使他的话语表达取得了戏剧性的效果。     

杉科化石植物角质层的研究

化石角质层是地质史上真正生活过的植物活体上的原物，其表皮细胞和气孔的特征以及气孔的分布与排列可作为杉科植物属种分类的依据．本文简要讨论了角质层在杉科化石植物研究上的重要性．     

Bdelloid rotifers in Dominican amber: Evidence for parthenogenetic continuity

Recently discovered representatives of the Class Bdelloidea from Tertiary amber from the Dominican Republic represent the oldest known fossils of the Phylum Rotifera. Assuming that the fossil bdelloids had a similar mode of reproduction as present day members of the Class (apomictic thelytoky), then contrary to current thought, some lines of parthenogenetic organisms are not doomed to an early extinction and have evolved built-in mechanisms for genetic diversity.     

中国大别山双子叶植物化石木材（Ⅱ）：橄榄科,山茱萸科

湖北省新州县大别山下阳逻镇双子叶植物硅化木系列报道之二，在前文里我们描述了樟科一种化石木。本文增加二科进行描述，它们是橄榄科植物化石新种小节橄榄木和山茱萸科植物化石新种湖北山茱萸木。这些木化石的解剖学特征都显示了大别山地区在第三纪时气候更倾温暖湿润。     

Fitting of growth curves over time when the data are obtained from a single realization

This paper focuses on the general problem of forecasting the maximum value of a time series which by the nature of the data must approach an asymptotic value. Examples of such series include the growth of organisms, the concentration of a chemical reagent during a reaction occurring over time or the amount of a fossil fuel resource which has been discovered or produced as a function of time. The approach taken below differs from the usual models for this type of data in that it assumes that an unobserved time series is actually driving the process, and that the observed data series is a function of the unobserved process. In the case of fossil fuels the unobserved series might be a measure of the exploratory drilling, the number of production days in a given time period or even the amount of fiscal resources devoted to exploratory activities. A maximum likelihood method is developed for estimating the parameters of the process, especially the maximum S, and the covariance structure of the estimators is developed. The methodology is illustrated on an example of oil production. Finally, methods are developed for forecasting the data into the near future.