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Speciation of the genus Arthricocephalus Bergeron, 1899 (Trilobita) from the late Early Cambrian and its stratigraphic significance

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Progress in Natural Science:Materials International 2006年第6期16卷 614-623页

作者： YUAN Jinliang, ZHAO Yuanlong and YANG Xinglian (nanjing institute of Geology and Palaeontology, chinese academy of sciences, nanjing 210008, china College of Resource and Environment of Guizhou University, Guiyang 550003, china) [a] nanjing institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China [b] College of Resource and Environment of Guizhou University Guiyang China

The genus Arthricocephalus Bergeron, 1899 is revised, and Halipanktos Balker & Peel, 1997 is suggested here as a senior synonym. The subgenus Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al. , 1974 is considered as a separate genus. Of the 20 previously assigned species of Arthricocephaius (Arthricocephalus) Bergeron, 1899, Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al. , 1974, Arthricocephalus (Euarthricocephalus) Ju, 1983 are lumped into eight species. The speciation trend of Arthricocephalus and Arthricocephalites is demonstrated based on their stratigraphic occurrences. It not only enhances the resolution of the biostatigraphic zonation in the uppermost Lower Cambrian, but also represents a potential candidate to define the Duyunian stage. The base of the stage is suggested at the first appearance datum (FAD) of Arthricocephalus chauveaui Bergeron, 1899 within the evolutionary lineage from Ar. jiangkouensis Yin in Yin & Li, 1978 to Ar. chauveaui in a global scale.

关键词： late Early Cambrian Duyunian stage speciation of Arthricocephalus and Arthricocephalites biostratigraphy.

Criteria for defining and recognizing the various orders of sequences in outcrop sequence stratigraphy

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Science china Earth sciences 2004年第7期47卷 618-629页

作者： WANG Xunlian Faculty of Earth sciences and Mineral Resources, china University of Geosciences, Beijing 100083, china State Key Laboratory of Palaeobiology and Stratigraphy, nanjing institute of Geology and Palaeontology, chinese academy of sciences, nanjing 210008, china 1. Faculty of Earth sciences and Mineral Resources China University of Geosciences 100083 Beijing China 2. State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences 210008 Nanjing China

The regional distribution in different depositional facies belts is here regarded as an important criterion for defining and recognizing the various orders of sequences. The third-order sequence is possibly global in nature, which may be discerned in different depositional facies belts in one continental margin and can be correlated over long distances, sometimes even worldwide. Commonly, correlation of subsequence (fourth-order sequence with time interval of 0.51.5 Ma) is difficult in different facies belts, although some of them may also be worldwide in distribution. A subsequence should be able to discern and correlate within at least one facies belt. The higher-order sequences, including microsequence (fifth-order sequence) and minisequence (sixth-order sequence), are regional or local in distribution. They may reflect the longer and shorter Milankovitch cycles respectively. Sequence and subsequence are usually recognizable in different facies belts, while microsequence and minisequence may be distinguished only in shallow marine deposits, but not in slope and basin facies deposits. A brief discussion is made on the essential conditions for correct identification of sequences, useful methods of study, and problems meriting special attention in outcrop sequence stratigraphy.

关键词： outcrop sequence stratigraphy, facies belt, sequence, subsequence, microsequence, minisequence, meter-scale cyclothem, Milankovitch cycle.

An XPS Study of Nitrogen Structures in Soil Humic Substances

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Pedosphere 2001年第4期11卷 321-326页

作者： WEN QIXIAO, CHENG LILI and CHEN BIYUN institute of Soil Science, the chinese academy of sciences, nanjing 210008 (china) institute of Soil Science the Chinese Academy of Sciences Nanjing 210008 China

X-ray photoelectron spectroscopy (XPS) was applied to examine the N structures of soil humic substances and some of their analogues. It was found that for soil humic substances XPS method gave similar results as those obtained by 15N CPMAS NMR (cross-polarization magic-angle spinning nuclear magnetic resonance) method. 70%～86% of total N in soil humic substances was in the form of amide, and 6%～13% was presented as amines, with the remaining part as heterocyclic N. There was no difference in the distribution of the forms of N between the humic substances from soils formed over hundreds or thousands of years and the newly formed ones. For fulvic acid from weathered coal and benzoqu inone- (N H-4 )-2 S O-4 polymer the XPS results deviated significantly from the 15N CPMAS NMR data.

关键词： distribution of N forms 15N CPMAS NMR soil humic substances XPS.

Early-Mid Ordovician brachiopod diversification in South china

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Science china Earth sciences 2005年第5期48卷 662-675页

作者： ZHAN Renbin, RONG Jiayu, CHENG Jinhui & CHEN Pengfei nanjing institute of Geology and Palaeontology, chinese academy of sciences State Key Laboratory of Palaeobiology and Stratigraphy, nanjing 210008, china 1. nanjing institute of Geology and Palaeontology Chinese Academy of Sciences State Key Laboratory of Palaeobiology and Stratigraphy 210008 Nanjing China

Affected by paleogeographic position, paleoclimatic condition and depositional environments, the increase of the Early-Mid Ordovician brachiopod diversity of South china commenced at the beginning of the Ordovician (early Tremadoc), accelerated from the Tetra- graptus approximatus Biozone (base of Arenig), and reached its first acme in the Didymograptus eobifidus Biozone (mid early Arenig) when the number of brachiopod genera was over 7 times as great as that at the start of the Ordovician. This was the first radiation in the history of brachiopod macroevolution in South china, which occurred nearly 5 graptolitic biozones earlier than the global trend of the great Ordovician biodiversification (in the lower part of the Undulograptus austrodentatus Biozone). It is also characterized by (1) the origination or first occurrences of some major groups, such as the punctate dalmanelloids and the pseudopunctate stro- phomenoids including Plectambonitoidea (cardinal process simple or absent) and Stro- phomenoidea (cardinal process bilobed) in South china; (2) niche expansion, particularly in the first occupation of deeper water benthic regimes by the Euorthisina-Nocturnellia Association developed at Houping, Chengkou, northern Chongqing; and (3) the differentiation of brachiopod faunas under different environmental conditions. The gradual and increasing separation from Gondwana may have been one of the factors responsible for the radiation in South china.

关键词： biodiversity, evolutionary radiation, brachiopods, Early-Mid Ordovician, South china.

Two new species of Vestrogothia (Phosphatocopina, Crustacea) of Orsten-type preservation from the Upper Cambrian in western Hunan, South china

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Science china Earth sciences 2009年第6期52卷 784-796页

作者： ZHANG HuaQiao1,2 & DONG XiPing1,2 1 School of Earth and Space sciences,Peking University,Beijing 100871,china 2 State Key Laboratory of Palaeobiology and Stratigraphy,nanjing institute of Geology and Palaeontology,chinese academy of sciences,nanjing 210008,china School of Earth and Space sciences Peking University Beijing 100871 China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China

Although fossils of Orsten-type preservation represented by Skaracarida and Phosphatocopina were first reported from the Middle and Upper Cambrian in western Hunan, South china in 2005, diversified phosphatocopine species have never been appropriately described and elucidated in terms of their evolutionary relationships. Here, we described two new species of Phosphatocopina, Vestrogothia anterispinata sp. nov. and V. bispinata sp. nov. The evolutionary relationship among all the valid species of Phosphatocopina is discussed and the phylogeny of Phosphatocopina is reestablished using cladistic analysis. Accordingly, phosphatocopines primitively evolved along two lineages: one evolved towards the emergence of lobes; the other evolved towards the emergence of dorsal spines. Respectively, lobes originated independently three times, and dorsal spines originated only once. With regard to the dorsal rims, interdorsum originated first, whereas dorsal furrow originated independently twice on the basis of interdorsum. Probably Hesslandona may represent a polyphyletic group, whereas Vestrogothia a monophyletic group.

关键词： fossils of Orsten-type preservation Vestrogothia Phosphatocopina Crustacea evolution phylogeny Cambrian Hunan

A Simulation Study on Effect of Surface Film-Forming Material on Water Evaporation

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Pedosphere 2001年第1期11卷 67-72页

作者： ZHUANG SHUNYAO, YIN BIN and ZHU ZHAOLIANG (institute of Soil Science, the chinese academy of sciences, nanjing 210008 (china)) 中科院南京土壤所江苏南京 210008

A greenhouse experiment was conducted to investigate the effect of surface film-forming material (SFFM), a mixture of 16-18-octadecanols by emulsification, on water evaporation. Air-dried soil with distilled water was incubated firstly for 7 days to reestablish soil biological activity and then for another 7 days after treated with SFFM at rates of 0, 1, 2, 4, 6 and 8 g m-2, respectively. Everyday during the 7-day incubation after addition of SFFM, water losses due to evaporation were ~measured by an electronic balance. The rate of water evaporation with the addition of SFFM was reduced significantly compared with the control treatment and the effectiveness of SFFM on water evaporation reduced with time. According to the equation expressions of the effect of SFFM on water evaporation, the half-life of electiveness of SFFM on water evaporation was introduced and calculated to analyze quantitative relationship between the effectiveness of SFFM on water evaporation and the addition rate of SFFM. The calculated half-life increased with the addition rate of SFFM and the confidence of the calculated values of the half-life was high, suggesting that the half-life of effectiveness of SFFM on water evaporation could be described quantitatively and may be helpful for ameliorating application method of SFFM and screening surface-film forming materials in order to improve nitrogen fertilizer use efficiency in flooded rice fields.

关键词： half-life of effectiveness surface film-forming material water evaporation

Paddy Soil Stability and Mechanical Properties as Affected by Long-Term Application of Chemical Fertilizer and Animal Manure in Subtropical china

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Pedosphere 2007年第5期17卷 568-579页

作者： LI Jiang-Tao ZHANG Bin School of Geographic and Oceanographic sciences Nanjing University Nanjing 210093 （China） institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）

Wet stability, penetration resistance （PR）, and tensile strength （TS） of paddy soils under a fertilization experiment for 22 years were determined to elucidate the function of soil organic matter in paddy soil stabilization. The treatments included no fertilization （CK）, normal chemical fertilization （NPK）, double the NPK application rates （2NPK）, and NPK mixed with organic manure （NPK＋OM）. Compared with CK, Fertilization increased soil organic carbon （SOC） and soil porosity. The results of soil aggregate fragmentation degree （SAFD） showed that fast wetting by water was the key fragmentation mechanism. Among the treatments, the NPK＋OM treatment had the largest size of water-stable aggregates and greatest normal mean weight diameter （NMWD）（P ≤ 0.05）, but the lowest PR and TS in both cultivated horizon （Ap） and plow pan. The CK and 2NPK treatments were measured with PR 〉 2.0 MPa and friability index 〈 0.20, respectively, in the Ap horizon, suggesting that the soils was mechanically unfavourable to root growth and tillage. In the plow pan, the fertilization treatments had greater TS and PR than in CK. TS and PR of the tested soil aggregates were negatively correlated to SOC content and soil porosity. This study suggested that chemical fertilization could cause deterioration of mechanical properties while application of organic manure could improve soil stability and mechanical properties.

关键词： soil aggregate stability chemical fertilization organic matter penetration resistance tensile strength

Hispanic Corridor formed as early as Hettangian: On the basis of bivalve fossils

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chinese Science Bulletin 2002年第5期47卷 414-417页

作者： SHAJingengnanjing institute of Geology and Palaeontology, chinese academy of sciences, nanjing 210008, china (e-mail: jgsha @***) nanjing institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

After tracking the historical distribution of the pectinids being very capable of dispersion, it is easy to be found that the bivalves Chlamys (Chlamys) valoniensis (Defrance), Camptonectes (Camptonectes) auritus (von Schlo-theim) and Chlamys (Chlamys) textoria (von Schlotheim) first occurred in the Late Rhaetian, the end of the Triassic, or the earliest Hettangian, the earliest Jurassic of western Europe, and subsequently they spread into the southeastern coast of Palaeo-pacific through the Hispanic Corridor during the Hettangian or a little later. It has demonstrated that the Hispanic epicontinental seaway became established along the rifting area between North America and South America and Africa of the Pangaean supercontinent as early as Hettangian or even earlier, connecting western Tethys and eastern Palaeo-pacific and providing a corridor for migration and exchange of creatures between Tethys and Palaeo-pacific.

关键词： Hispanic Corridor form Hettangian.

Applicability of Fractal Models in Estimating Soil Water Retention Characteristics from Particle-Size Distribution Data

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Pedosphere 2002年第4期12卷 301-308页

作者： LIU JIANLI and XU SHAOHUIinstitute of Soil Science, the chinese academy of sciences, nanjing 210008 (china) institute of Soil Science the Chinese Academy of Sciences Nanjing 210008

Soil water retention characteristics are the key information required in hydrological modeling. Frac-tal models provide a practical alternative for indirectly estimating soil water retention characteristics fromparticle-size distribution data. Predictive capabilities of three fractal models, i.e, Tyler-Wheatcraft model,Rieu-Sposito model, and Brooks-Corey model, were fully evaluated in this work using experimental datafrom an international database and literature. Particle-size distribution data were firstly interpolated into20 classes using a van Genuchten-type equation. Fractal dimensions of the tortuous pore wall and the poresurface were then calculated from the detailed particle-size distribution and incorporated as a parameter infractal water retention models. Comparisons between measured and model-estimated water retention cha-racteristics indicated that these three models were applicable to relatively different soil textures and pressurehead ranges. Tyler-Wheatcraft and Brooks-Corey models led to reasonable agreements for both coarse- andmedium-textured soils, while the latter showed applicability to a broader texture range. In contrast, Rieu-Sposito model was more suitable for fine-textured soils. Fractal models produced a better estimation of watercontents at low pressure heads than at high pressure heads.

关键词： fractal model particle-size distribution soil water retention characteristics