Early period of early Permian tubular cyanobacteria reef in the eastern part of south Qinling Mountains

A typical reef occurs in the eastern part of south Qinling Mountains in Sanlixia, Xunyang, Shaanxi Province. The reef, extending in north-south direction, was built up by various kinds of calcareous tubes including Girvanella, tubular cyanobacteria and problem microbials. The bioclastic bank, built up by algal clasts, foraminiferous, and fusulinids, formed the reef basement, on which dasyclads baffle bioclasts formed the original bafflestone at a small scale on the reef basement, and then a mass of bindstone was made up by all kinds of calcareous tubes and algae. On lateral part the reef is cryptalgal mudstone. The reef that occurred in the geosynclinal area is so familiar with one of the platforms in many respects, such as in reef structure, morphology and building mold. This indicates that building organisms have amazing adaptability and identity for building capacity in the two kinds of geotectonic background mentioned above.     

远程耦合视角下的土地利用/覆被变化解释

传统的土地利用覆被/变化驱动力研究在很大程度上并未充分考虑远距离相互作用的影响,对全球化世界中由远距离相互作用驱动的土地利用/覆被变化日益缺乏解释力。鉴于此,本文旨在将远程耦合（Telecoupling）理论框架引入到土地利用/覆被变化的动力机制研究中来。在概述土地利用/覆被变化驱动力研究的基础上,从驱动力背景的变化出发,切入远程耦合框架的介绍,并基于此给出远距离相互作用驱动土地利用/覆被变化的经验证据;认为远程连接、全球化和城市化是远距离相互作用驱动土地利用/覆被变化的3种主要形式;进而提出建立“时—空—事”三位一体的土地利用/覆被变化解析路径、土地利用/覆被变化的近远程驱动力分解和基于网络的跨系统综合研究是土地利用覆被/变化驱动力研究中应用远程耦合框架的重点内容。     

辽西下白垩统义县组湖相碳酸盐岩碳氧稳定同位素组成及其沉积环境

通过辽西义县盆地上白垩统义县组湖相碳酸盐岩碳氧稳定同位素组成,分析了赋存热河生物群的义县盆地湖湘沉积环境.该地层序列中碳酸盐岩的δ13C值在-4.825‰～6.870‰之间;δ18O值在-16.190‰～-7.143‰之间,均呈负值,这表明当时水文特征趋于封闭,气候炎热干燥,湖水温度和盐度均较高,火山活动可能是影响义县...     

THE APPLICATION OF REMOTE SENSING TECHNIQUE ON GEOLOGICAL INVESTIGATION OF PLACER DEPOSIT

The practice has proved that it is an economic and effective method to investigate placer gold deposit by using multi-level information sources of remote sensing and multi-variate analysis methods, especially for the area with a sparse population and difficult condition like the Da Hinggan Mountains, China.The information sources used in our work includes Landsat TM, aerial infrared photography and their mosaic image maps and enlarged photos with different scales. According to statistic data, in the study area the gold-bearing rocks are mainly granite, alaskite, granodiorite and some old metamorphic rocks. On gold-bearing geological structures, the fault zones in the four directions (NE, NNE, NW and EW) are obvious, in which NNE and EW are the most key fault zones. On fluvial geomorphology the flow courses stored placer are in the tributaries of the 4th and 5th levels, especially in straight or slight curve reaches. On the basis of analysis the interpretative signs were set up, and the interpretative wo     

基于RAPD的SCAR分子标记技术鉴定虎纹蛙及引进种

为了对引进种泰国虎纹蛙加强种质监测,本文对泰国虎纹蛙和中国虎纹蛙进行了SCAR标记研究。在对2种蛙随机扩增多态DNA(RAPD)标记研究的基础上,选用随机引物OPP5和OPZ19对2种蛙进行扩增,将2个特异性扩增片段OPP5-471bp和OPZ19-512bp回收、克隆和测序,并根据序列信息设计两对SCAR引物SP5和SZ19。利用两对SCAR引物对2种蛙基因组DNA扩增的结果显示:SP5显示了其特异性,在对中国虎纹蛙的扩增中出现了单一SP5-388bp特异片段,而在泰国虎纹蛙中没有扩增产物;SZ19在对2种虎纹蛙的扩增中出均出现了单一条带,但片段大小不同,在中国虎纹蛙中为SZ19-456bp,在泰国虎纹蛙中为SZ19-497bp。3个分子标记都可作为基于RAPD成功转化后的SCAR分子标记对2种虎纹蛙进行鉴定。     

Enantiornithine Bird with Diapsidian Skull and Its Dental Development in the Early Cretaceous in Liaoning, China

A Iarge number of enantiornithine birds are discovered from the Early Cretaceous Jiufutang Formation in western Liaoning, China. They are all small-sized birds with a few small teeth. The enantiornithine bird from the Jiufutang Formation in the Shangheshou area, Chaoyang, Liaoning Province reported in this paper is the largest individual known in all enantiornithine birds of the Early Cretaceous. However, its teeth possess a feature of pseudoheterodont. Some different development stages of the new teeth substitute the earlier stages and the stages of development are preserved in this specimen. This development pattern is similar to that of Archaeopteryx and alligator but not dinosaur. A well-developed postorbital was also preserved in the skull, which was a diapsidian skull like that of Confuciusornis. Additionally, the distinctive preservation of its prefrontal distinguishes it from other enantiornithine birds of the Early Cretaceous.     

Zircon U-Pb age,geochemical, and Sr-Nd-O isotopic constraints on the origin of the youngest Mesozoic adakitic dikes in Jiaodong peninsula,North China Craton: implications for Early Cretaceous crustal evolution

ABSTRACT

The adakitic dikes with zircon ages of ~120–118 Ma are identified in the Xiejiagou gold deposit, Jiaobei terrain. The Early Cretaceous intermediate-acidic dikes include monzonite, quartz monzonite, and monzogranite, which have SiO₂, Al₂O₃, K₂O, Na₂O contents ranging from 61.01 to 74.72 wt. %, 14.42 to 17.28 wt.%, 2.55 to 4.45 wt.%, and 3.09 to 4.64 wt.%, respectively. The dikes are enriched in large ion lithophile elements (LILEs) (e.g., Rb, Sr, and Ba) and light rare earth elements (LREEs), but are depleted in high field strength elements (HFSEs) (e.g., Nb, Ta) and heavy rare earth elements (HREEs). They are also characterized by continental crust-like isotopic compositions: whole-rock δ¹⁸O = 7.6–9.9‰, (⁸⁷Sr/⁸⁶Sr)_i = 0.70893–0.71036, and ε_Nd(t) = ?13.16 to ?17.06. Assimilation and fractional crystallization are limited, and partial melting of source rock is the main mechanism in controlling the compositional variation. The high Sr/Y (41.51–93.25) and (La/Yb)_N (22.9–44.7) ratios imply that the dikes have affinities similar to adakitic rocks. The regional geological setting, coupled with the geochemical and isotopic data, indicate that the adakitic dikes were unlikely produced by partial melting of a subducted oceanic slab or a thickened/delaminated lower crust, or AFC processes of mantle-derived magmas. We conclude that the adakitic dikes are generated by partial melting of lower crust which was triggered and modified by underplating of the lithospheric mantle. We also propose that the eastern part of the North China Craton experienced severe thinning in the Early Cretaceous (~135–120 Ma), and the lithospheric thinning is related to delamination of the lower crust.     

Study on model for remote sensing estimation of maize yield

ＳＴＵＤＹＯＮＭＯＤＥＬＦＯＲＲＥＭＯＴＥＳＥＮＳＩＮＧＥＳＴＩＭＡＴＩＯＮＯＦＭＡＩＺＥＹＩＥＬＤＬｉｕＺｈａｏｌｉ（刘兆礼）ＨｕａｎｇＴｉｅｑｉｎｇ（黄铁青）ＷａｎＥｎｐｕ（万恩璞）ＺｈａｎｇＹａｎｇｚｈｅｎ（张养贞）ＣｈａｎｇｃｈｕｎＩｎｓｔｉ...     

辽西地区早白垩世义县组大康堡层沉积特征及沉积环境演化

辽西义县盆地下白垩统义县组大康堡沉积层分布范围广,为"热河生物群"的重要产出层位。通过对王家沟西山典型剖面的沉积学研究,识别出11种岩相类型,包括基质支撑砾岩相、凝灰质中-粗粒砂岩相、平行层理中-细砂岩相等,并将该时期的湖泊沉积划分为滨浅湖和深-半深湖环境。分析大康堡层垂向序列特征及纹泥特征,将该时期的湖泊演化划分为4个阶段:早期浅水湖泊沉积,见大量浅水生物化石;中期深-半深湖沉积,处于相对封闭-半封闭的状态,盐度增加;晚期湖泊水体变浅,水文动力条件增强,盐度降低;末期深-半深湖环境,纹泥指示陆源碎屑供给极少,降水较少。湖泊的演化过程受古气候控制明显。     

辽东半岛震旦系甘井子组叠层石生长机制研究

辽南半岛新元古界震旦系甘井子组叠层石出露完好,宏观形态完整,微观构造清晰,是研究新元古代微生物碳酸盐岩建造的理想对象,对恢复古环境和古生态研究具有重要意义。本文选择甘井子组地层为研究对象,根据岩性特征该组自上而下可分成3段。叠层石出露于下段的底部和上段的顶部,底部叠层石为透镜状,顶部叠层石呈大规模层状。下段叠层石呈现波纹状—柱状—丘状的形态组合,上段叠层石呈现波纹状—柱状—长柱状的形态组合,均为水深不断增加的结果。本文通过对比现代叠层石生长机制,确定甘井子组叠层石纹层的3层构造和形成顺序,分析硬质基底对于叠层石定殖和叠层石密集生长的控制,厘定环境变化从微观到宏观对于柱体形态和叠层石规模的影响,揭示了甘井子组叠层石的形成机制。