辽西南票地区早二叠世山西组孢子花粉组合

辽西南票地区山西组,共发现孢粉２１个属４７种。组合特征是蕨类植物孢子占优势,为孢粉总量的９７．４％;裸子植物花粉含量很少,仅占２．６％。根据孢粉含量及其在垂直方向上的变化,本组合自下向上划分成两个组合带：Ｓｉｍｏｚｏｎｏｔｒｉｌｅｔｅｓ－Ｓｉｎｕｌａｔｉｓｐｏｒｉｔｅｓ;Ｓｉｎｕｌａｔｉｓｐｏｒｉｔｅｓ－Ｌａｅｖｉｇａｔｏｓｐｏｒｉｔｅｓ。     

鲁西地区早二叠世早、中期孢粉组合特征

为解决鲁西地区二叠系内部划分和煤层对比问题，笔者先后对鲁西诸煤田二叠系进行了大量的孢粉分析工作，采集处理300多块样品，经系统研究，建立了本区二叠纪的4个孢粉组合，本文重点讨论早二叠世早、中期的两个孢粉组合，自下而上为：Thymospora thiessenii-Laevigatosporites vulgaris-Densosprites组合；Gulisporites cochlearius-Laevigatosposporites组合。根据所建立的各孢粉组合特征并与华北各地二叠纪孢粉组合广泛对比，进一步阐述了各孢粉组合的地质时代。     

东北地区早二叠世岩相古地理研究

利用野外地质剖面、关键钻井剖面和区域地质资料,在地层划分对比和构造格局研究基础上,运用沉积相分析的方法,探讨了东北地区早二叠世岩相古地理特征,将早二叠世分为阿瑟尔期-亚丁斯克期、空谷期两个编图单元进行岩相古地理编图,恢复了东北地区早二叠世的岩相古地理面貌。研究表明,早二叠世东北地区主要发育半深海沉积体系、浅海陆棚沉积体系、碳酸盐台地沉积体系、无障壁海岸沉积体系、障壁海岸沉积体系及河流沉积体系;阿瑟尔期-亚丁斯克期存在漠河古陆、松辽古陆、佳木斯古陆及华北北缘高地四个古陆,物源区碎屑物质供应充分,研究区为浅海、海陆交互及河流沉积区,周边古陆的格局;至空谷期,松辽古陆消失,研究区为浅海-半深海沉积,周边古陆的格局。     

300-Myr-old magmatic CO2 in natural gas reservoirs of the west Texas Permian basin

Except in regions of recent crustal extension, the dominant origin of carbon dioxide in fluids in sedimentary basins has been assumed to be from crustal organic matter or mineral reactions. Here we show, by contrast, that Rayleigh fractionation caused by partial degassing of a magma body can explain the CO2/3He ratios and delta13C(CO2) values observed in CO2-rich natural gases in the west Texas Val Verde basin and also the mantle 3He/22Ne ratios observed in other basin systems. Regional changes in CO2/3He and CO2/CH4 ratios can be explained if the CO2 input pre-dates methane generation in the basin, which occurred about 280 Myr ago. Uplift to the north of the Val Verde basin between 310 and 280 Myr ago appears to be the only tectonic event with appropriate timing and location to be the source of the magmatic CO2. Our identification of magmatic CO2 in a foreland basin indicates that the origin of CO2 in other mid-continent basin systems should be re-evaluated. Also, the inferred closed-system preservation of natural gas in a trapping structure for approximately 300 Myr is far longer than the residence time predicted by diffusion models.     

广州地区二叠纪双壳类动物

记述的双壳动物化石采自广州市郊嘉禾地区的二叠系中,共计25属、53种,其中3个新种.可分为两个双壳类组合,即下部的Palaeonilo-Pernopecten 组合和上部的Euchondria-Permoperna 组合.下部组合以古栉齿类及股海扇最繁盛,特点是个体小,属种单调,分异度较低,装饰简单;上部组合以海扇超科及二叠股蛤占主要地位,特点是个体大小不一,装饰复杂,壳刺发育,分异度高.当前双壳动物群的面貌基本上与湖南斗岭组上段的双壳动物群相似,因此,这一双壳动物群的时代无疑属早二叠世晚期.     

鄂西二叠纪孤峰组碳酸盐结核的成因研究

通过对研究区孤峰组碳酸盐结核的岩石学和地球化学特征的研究,认为碳酸盐结核是一种成岩结核,在成岩的早中期形成,结核的形成是不同期次的。结合正常浅海型综合生物地球化学响应成岩模式分析碳酸盐结核形成于滞留贫氧还原的环境,主要在硫酸盐还原带形成,其为透入性生长模式,碳酸盐胶结物在整个结核中同时成核结晶生长。     

青藏高原东部玉树隆宝蛇绿混杂岩中早二叠世放射虫的发现及其地质意义

报道了采自青藏高原东部玉树隆宝蛇绿混杂岩硅质岩岩块中的放射虫化石.该放射虫组合包括Latentifistula crux Nazarov et Ormiston,Pseudoalbaillella scalprata scalprata Holdsworth et Jones,Pseudoalbaillella scalprata rhombothoracata Ishiga,Pseudoalbaillella sakmarensis(Kozur)等.该放射虫组合属于Pseudoalbaillella scalprata rhombothoracata带,该带可以进行全球对比,地质时代为早二叠世.放射虫动物群与可可西里、滇西等地的古特提斯放射虫组合一致,它指示了玉树早二叠世存在深水沉积盆地.     

福建晚石炭世及早二叠世四射珊瑚新属种的发现

记述了福建西部龙岩、宁化等地晚石炭世及早二叠世地层中发现的四射珊瑚５个新属及其典型种。它们分别是：黄龙组的Ｙｉｎｏｐｈｙｌｌｕｍ ｃｒａｓｓｕｓ，Ｎｉｎｇｈｕａｐｈｙｌｌｕｍ ｔｙｐｉｃｕｍ，马平阶的Ｐｓｅｕｄｏｂｏｔｈｒｏｐｈｙｌｌｕｍ ｆｕｊｉａｎｅｎｓｅ，Ｐａｒａａｎｔｈｅｒｉａ ｉｒｒｅｇｕｌａｒｉｓ，Ｊｉｎｇｙａｎｇｏｐｈｙｌｌｕｍ。     

A eudicot from the Early Cretaceous of China

The current molecular systematics of angiosperms recognizes the basal angiosperms and five major angiosperm lineages: the Chloranthaceae, the magnoliids, the monocots, Ceratophyllum and the eudicots, which consist of the basal eudicots and the core eudicots. The eudicots form the majority of the angiosperms in the world today. The flowering plants are of exceptional evolutionary interest because of their diversity of over 250,000 species and their abundance as the dominant vegetation in most terrestrial ecosystems, but little is known of their very early history. In this report we document an early presence of eudicots during the Early Cretaceous Period. Diagnostic characters of the eudicot fossil Leefructus gen. nov. include simple and deeply trilobate leaves clustered at the nodes in threes or fours, basal palinactinodromous primary venation, pinnate secondary venation, and a long axillary reproductive axis terminating in a flattened receptacle bearing five long, narrow pseudo-syncarpous carpels. These morphological characters suggest that its affinities are with the Ranunculaceae, a basal eudicot family. The fossil co-occurs with Archaefructus sinensis and Hyrcantha decussata whereas Archaefructus liaoningensis comes from more ancient sediments. Multiple radiometric dates of the Lower Cretaceous Yixian Formation place the bed yielding this fossil at 122.6-125.8 million years old. The earliest fossil records of eudicots are 127 to 125 million years old, on the basis of pollen. Thus, Leefructus gen. nov. suggests that the basal eudicots were already present and diverse by the latest Barremian and earliest Aptian.     

A Middle Jurassic 'sphenosuchian' from China and the origin of the crocodylian skull

The skull of living crocodylians is highly solidified and the jaw closing muscles are enlarged, allowing for prey capture by prolonged crushing between the jaws. Living species are all semi-aquatic, with sprawling limbs and a broad body that moves mainly from side-to-side; however, fossils indicate that they evolved from terrestrial forms. The most cursorial of these fossils are small, gracile forms often grouped together as the Sphenosuchia, with fully erect, slender limbs; their relationships, however, are poorly understood. A new crocodylomorph from deposits in northwestern China of the poorly known Middle Jurassic epoch possesses a skull with several adaptations typical of living crocodylians. Postcranially it is similar to sphenosuchians but with even greater adaptations for cursoriality in the forelimb. Here we show, through phylogenetic analysis, that it is the closest relative of the large group Crocodyliformes, including living crocodylians. Thus, important features of the modern crocodylian skull evolved during a phase when the postcranial skeleton was evolving towards greater cursoriality, rather than towards their current semi-aquatic habitus.     

中国蛙类原虫与棘头虫名录

为了解我国蛙类原虫与棘头虫的种类与地理分布,收集了报道我国蛙类原虫与棘头虫的相关文献,依据较新的原虫与棘头虫分类系统整理成名录.共记录在中国31种蛙体内检出原虫61种,隶属于7门、11纲、12目、14科、23属;棘头虫8种,隶属于1门、2纲、2目、2科、3属.列出了每种原虫和棘头虫的中文名称、拉丁文名称、命名人与命名年、宿主与寄生部位、地理分布及文献来源等信息,为较全面了解我国蛙类原虫与棘头虫的种类情况提供了基础材料.     

Noeggerathiales as coal-forming plants in Cathaysia: conclusions from an Early Permian vegetational Pompeii in Inner Mongolia

Noeggerathiales are an extinct group of sporebearing plants of uncertain systematic position that are known from Carboniferous and Permian age Euramerican and Cathaysian floras that occurred in presentday Europe, North America, and East Asia. The order Noeggerathiales includes over 50 species of more than 20 fossil genera, but their paleoecology is not well understood yet. Previously this group had been found only in extrabasinal floras or those inhabiting clastic wetlands. Noeggerathiales have never been recorded in coal ball floras. Thus, it is up to now uncertain whether this group has contributed to the formation of coal. Recent investigations of an Early Permian peatforming flora of the Taiyuan Formation near Wuda, Inner Mongolia, which was preserved in a volcanic ash fall has provided evidence that noeggerathialean plants not only existed in the peatforming vegetation but could even be the dominant group in some areas of the coal swamp. The Noeggerathiales in this particular peatforming forest include Tingia unita, Paratingia wudensis, and a new species of Paratingia. Exceptionally well-preserved specimens indicate that these noeggerathialean plants are small trees with a canopy of compound leaves and strobili near the top of an unbranched （monocaulous） stem.     

间质干细胞来源、鉴定、可塑性和应用前景(综述)

间质干细胞(MSCs)存在于骨髓、肌肉、骨、软骨等部位,可分化为中胚层的细胞,如成骨细胞、成软骨细胞、成脂肪细胞等,亦可分化为内胚层、外胚层的细胞,如神经细胞、肝脏细胞、肾脏细胞等,同时由于来源广、易于分离扩增和基因转染,在临床、科研上有很大的潜在应用价值。     

山东淄博煤田晚石炭世——早二叠世植物群落特征

山东淄博煤田晚石炭世—早二叠世植物化石经鉴定,共计37属104种,其中包括11个新种。分析了本区植物化石的埋藏类型,根据各类植物的生活习性和生境,将晚石炭世—早二叠世植物群划分为五个植物群落,讨论了它们的多度、成分、结构和生活型等特征,并采用信息函数数理统计方法,应用电子计算机对各植物群落的分异度和均衡度进行了计算。     

A basal troodontid from the Early Cretaceous of China

Troodontid dinosaurs form one of the most avian-like dinosaur groups. Their phylogenetic position is hotly debated, and they have been allied with almost all principal coelurosaurian lineages. Here we report a basal troodontid dinosaur, Sinovenator changii gen. et sp. nov., from the lower Yixian Formation of China. This taxon has several features that are not found in more derived troodontids, but that occur in dromaeosaurids and avialans. The discovery of Sinovenator and the examination of character distributions along the maniraptoran lineage indicate that principal structural modifications toward avians were acquired in the early stages of maniraptoran evolution.     

Early gas stripping as the origin of the darkest galaxies in the Universe

The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early.     

A tentative study on the ultrastructure of the Middle Permian AcritarchMicrhystridium from western Yunnan, China

A preliminary study on the ultrastructure of Middle Permian AcritarchMicrhystridium from western Yunnan has been made using laser scanning confocal microscope (LSCM). Some quite new features about the texture and ultrastructure of this kind of Acritarch has been detected for the first time, which opens up a new application of this advanced technique to microfossil study.     

福建永安晚二叠世双壳类

根据系统采集的地层化石．记述了福建永安晚二叠世地层中发现的四个双亮类新种．它们分别是ＣＩａｒａｉａ？ｐｒａｅｃｕｒｓｏｒ　ｓｐ．，Ｔｏｗａｐｔｅｒｉａ　ｉｎｔｅｒｍｅｄｉａ　ｓｐ．ｎｏｖ．，Ｌｏｐｈａ　ｆｕｊｉａｅｎｓｉｓｓｐ．ｎｏｖ，Ｔａｉｍｉｒｉａ　ｍｉｎｉｍａ　ｓｐ．ｎｏｖ，建立了二个双壳类组合．     

淮北青东井田早二叠世浅水三角洲沉积特征及模式研究

利用研究区内162口钻孔岩芯精细观察资料及100多个薄片粒度分析样,系统地分析了研究区内沉积特征,建立了淮北青东井田早二叠世山西组、下石盒子组地层的浅水三角洲沉积模式.研究认为研究区是浅水三角洲沉积体系由东南入海而成,山西组主要发育前三角洲、三角洲前缘、三角洲平原亚相,可细分为远砂坝、河口砂坝、分流河道、分流间湾等微相.下石盒子组主要发育上三角洲平原,可细分为分流河道、分流间湾等微相.研究发现,浅水三角洲发育于台地背景下,水体浅,水深一般小于100 m,主要由三角洲平原亚相组成,分流河道是其主要的沉积微相,三角洲前缘亚相和前三角洲亚相的沉积厚度较薄.在上述研究基础上,建立了整个研究区的浅水三角洲沉积模式.