陇西盆地晚第三纪风尘沉积的地层学研究

In Asia, the significant environment changes in Cenozoic include: uplift of Himalayas and Tibetan Plateau, formation Asian monsoon system, Aridification in Central Asia. One of major advances in recent studies of eolian deposit on the Loess Plateau is the verification of the eolian origin for the Late Tertiary Hipparion Red-Earth (also called red-Clay) underlying the Quaternary loess. Thus, the Late Tertiary eolian deposit, which has been proven a nearly continuous terrestrial record and sensitive to climate change, provides us an important archive to understand these above Cenozoic environment events. The deposit in eastern Loess Plateau has been extensively studied, while the property and age of deposit underlying the Quaternary loess in western plateau remains unclear. In this paper, detail investigations were made on the Sedimentology, geochemistry of Longxi section, a typical section in western Loess Plateau, to address its origin, and on micromammalian fossils and magnetostratigraphy to address its age. The main conclusions are presented as following: 1. The sedimentological and geochemical properties in Longxi section are highly similar to typical Quaternary eolian deposit in Loess Plateau. Nearly 100 paleosols are recognized in the field, and the grain size are very fine with the median grain size centered at 4～7μm. There is a good agreement of both major and trace element compositions between Longxi deposit and the Quaternary Loess. The REE distribution patterns of Longxi deposit and the Quaternary loess are remarkably similar in shape, with enrichment LREE and fairly flat HREE profiles and clear negative Eu anomaly. The mangnetic minerals in Longxi deposit are mainly magnetite, hematite and maghematite, which are similar to those of the Hipparion Red-Earth and Quaternary Loess. The major difference among them is that the samples from Longxi section contain more hematite. The characteristics of anisotropy of magnetic susceptibility (AMS) in Longxi deposit is highly consistent with that of Quaternary loess, while values of the major AMS parameters, e.g. anisotropy degree, magnetic foliation and lineation, are significantly lower than those of fluvial and lake deposits. These evidences indicate an eolian origin for the sediment. 2. An investigation of micromammalian fossils was firstly carried out for determining the approximate age of the sequence because of lack of materials for accurate isotope dating. Three fossil assemblages were obtained which indicate a chronological range from the Middle Miocene to Late Miocene. The magnetostratigraphical study suggests that it is a near continuous terrestrial record for the period from 13.23 to 6.23 MaB.P. The obtained chronology is highly consistent with fossils assemblages. This section is the oldest eolian deposit presently known in Loess Plateau. 3. The magnetic susceptibly value is high in paleosols than in surrounded weak-weathered layers, which suggests that it may be a climate index on orbital time scale. While it cannot be used as a proxy to address the long-term, change of climate on tectonic time scale, as content of the magnetic minerals is highly variable in different parts of the section. 4. The appearance of Middle Miocene eolian deposit in the Loess Plateau marks the strengthening of aridification of Central Asia. The high degree of similarity between the geochemical properties of Longxi eolian deposit, Hipparion Red-Earth and Quaternary loess a suggests that a rather similar source provenance. The dust accumulation rate (DAR) of Longxi section, which is widely used as a proxy to document the aridity in source areas in marine and terrestrial record studies, recorded the aridity condition in northwestern China over a period from Middle Miocene to Late Miocene. The DAR of the section shows that the continent aridity remains moderate and relative stable over that period.

西江流域环境河水地球化学研究

River is a major component of the global surface water and CO2 cycles. The chemistry of river waters reveals the nature of weathering on a basin-wide scale and helps us understand the exogenic cycles of elements in the continent-river-ocean system. In particular, geochemical investigation of large river gives important information on the biogeochemical cycles of the elements, chemical weathering rates, physical erosion rates and CO2 consumption during the weathering of the rocks within the drainage basin. Its importance has led to a number of detailed geochemical studies on some of the world's large and medium-size river systems. Flowing in the south of China, the Xijiang River is the second largest river in the China with respect to its discharge, after the Yangtze River. Its headwaters drain the YunGui Plateau, where altitude is approximately 2000 meters. Geologically, the carbonate rocks are widely spread in the river drainage basin, which covers an area of about 0.17xl06 km2, i.e., 39% of the whole drainage basin. This study focuses on the chemistry of the Xijiang river system and constitutes the first geochemical investigation into major and trace elements concentrations for both suspended and dissolved loads of this river and its main tributaries, and Sr isotopic composition of the dissolved load is also investigated, in order to determine both chemical weathering and mechanical erosion rates. As compared with the other large rivers of the world, the Xijiang River is characterized by higher major element concentration. The dissolved major cations average 1.17, 0.33, 0.15, and 0.04 mmol I"1 for Ca, Mg, Na, and K, respectively. The total cation concentrations (TZ+) in these rivers vary between 2.2 and 4.4 meq I'1. The high concentration of Ca and Mg, high (Ca+Mg)/(Na+K) ratio (7.9), enormous alkalinity and low dissolved SiO2/HCO3 ratio (0.05) in river waters reveal the importance of carbonate weathering and relatively weak silicate weathering over the river drainage basin. The major elements in river water, such as the alkalis and alkaline-earths, are of different origins: from rain water, silicate weathering, carbonate and evaporite weathering. A mixing model based on mass budget equation is used in this study, which allows the proportions of each element derived from the different source to be calculated. The carbonate weathering is the main source of these elements in the Xijiang drainage basin. The contribution of rainwater, especially for Na, reaches to approximately 50% in some tributaries. Dissolved elemental concentration of the river waters are corrected for rain inputs (mainly oceanic salts), the elemental concentrations derived from the different rock weathering are calculated. As a consequence, silicate, carbonate and total rock weathering rates, together with the consumption rates of atmospheric CO2 by weathering of each of these lithologies have been estimated. They provide specific chemical erosion rates varying between 5.1~17.8 t/km2/yr for silicate, 95.5~157.2 t/km2/yr for carbonate, and 100.6-169.1 t/km2/yr for total rock, respectively. CO2 consumptions by silicate and carbonate weathering approach 13><109and 270.5x10 mol/yr. Mechanical denudation rates deduced from the multi-year average of suspended load concentrations range from 92-874 t/km2/yr. The high denudation rates are mainly attributable to high relief and heavy rainfall, and acid rain is very frequent in the drainage basin, may exceed 50% and the pH value of rainwater may be <4.0, result from SO2 pollution in the atmosphere, results in the dissolution of carbonates and aluminosilicates and hence accelerates the chemical erosion rate. The compositions of minerals and elements of suspended particulate matter are also investigated. The most soluble elements (e.g. Ca, Na, Sr, Mg) are strongly depleted in the suspended phase with respect to upper continent crust, which reflects the high intensity of rock weathering in the drainage basin. Some elements (e.g. Pb, Cu, Co, Cr) show positive anomalies, Pb/Th ratios in suspended matter approach 7 times (Liu Jiang) to 10 times (Nanpan Jiang) the crustal value. The enrichment of these elements in suspended matter reflects the intensity both of anthropogenic pollution and adsorption processes onto particles. The contents of the soluble fraction of rare earth elements (REE) in the river are low, and REE mainly reside in particulate phase. In dissolved phase, the PAAS-normalized distribution patterns show significant HREE enrichment with (La/Yb) SN=0.26~0.94 and Ce depletion with (Ce/Ce*) SN=0.31-0.98, and the most pronounced negative Ce anomalies occur in rivers of high pH. In the suspended phase, the rivers have LREE-enriched patterns relative to PAAS, with (La/Yb) SN=1 -00-1 .40. The results suggest that pH is a major factor controlling both the absolute abundances of REE in solution and the fractionation of REE of dissolved phase. Ce depletion in river waters with high pH values results probably from both preferential removal of Ce onto Fe-Mn oxide coating of particles and CeC^ sedimentation. This process is known to occur in the marine environment and may also occur in high pH rivers. Positive correlations are also observed between La/Yb ratio and DOC, HCO3", PO4", suggesting that colloids and (or) adsorption processes play an important role in the control of these elements.

河流-三角洲储层剩余油分布模式及预测

Aim at the variousness and complexity of the spatial distribution of Remaining Oil in the fluvial and delta facies reservoir in paper. For example, in the La-Sa-Xing oilfield of Daqing, based on the research of the control factor and formation mechanization of block, single layer, interlayer and micromechanism, synthesizing the theories and methods of geology, well logging, reservoir engineering, artificial intelligence, physical simulation test , and computer multidisciplinary; Fully utilizing the material of geology, well logging, core well, dynamic monitor of oil and water well, and experimental analysis, from macro to micro, from quality to quantity, from indoor to workplace, we predicted the potentiality and distribution according to the four levels of Block, single layer, interlayer and micromechanism, and comprehensively summarized the different distribution pattern of remaining oil in the fluvial and delta facies reservoir This paper puts forward an efficient method to predict the remaining recoverable reserves by using the water flooding characteristic curve differential method and neutral network; for the first time utilizes multilevel fuzzy comprehensive judgment method and expert neutral network technology to predict the remaining oil distribution in the single layer? comprehensively takes advantage of reservoir flowing unit, indoor physical simulation test, inspection well core analysis and well-logging watered-out layer interpretation to efficiently predict the distribution of remaining oil; makes use of core analysis of different periods and indoor water driving oil test to study the micro distribution of remaining oil and the parameters varying law of reservoir substance properties, rock properties, wetting properties. Based on above, the remaining oil distribution predicting software is developed, which contains four levels of block, single layer, interlayer and micromechanism. This achievement has been used inLa-Sa-Xing oil field of Daqing and good results have been received.

流动单元四维模型和剩余油预测以濮城油田为例

This study is aimed to reveal macroscopic and microscopic anisotropism by using new theories, new methods and new technology. In order to reveal the forming mechanism and distribution pattern of remaining oil, flow units 4-dimension model and realistic model was established according the data over 20 years development of the Pucheng Oil field. Based on theories of multi-discipline subject, methods and technologies, by using correspondent 4-D data body and computer, combining quantity and quality study, static and development data, macroscopic and microscopic data, the two different geneses' reservoir, eg., braided delta and lake delta, are studied. The two different geneses' reservoir flow units models were established. Main achievement of this thesis are summarized as following: The standard of parameter optimization, identification and appreciation of two different geneses' reservoir were established. Based on the standard, the reservoir were classed into four flow units class as G,E,F and P. The flow unit static models of two different geneses' reservoir were established, and the relation of geometric shape, space distribution and macroscopic remaining oil was revealed. the flow units microscopic model were established, which tells that the changes of all the microscopic factor in the development. (4) Accordig BP arithmetic method, an adapt arithmetic method were designed, and the reservoir flow units were simulated based on the new method. (5) Reservoir realistic model of flow unit were established. Based on the model the microscopic development is simulated, which reveals the oil and water seepage in the reservoir and the mechanism of the microscopic oil formation. (6) The spatial residual oil distribution patterns were summarized. The remaided oil is mainly in the places as not being affected by the injected water, high part of the structures and the place near the sealed faults. There are 3 kinds and 9 distribution modes of microscopic remaining oil. The forming mechanism and distribution rule were pointed out. The study has developed a set of theories, technology and methods for flow units study, including flow units description, characterization and prediction. The study is also an improvement of the development geology theory in continental fault depression lake basin.

港西地区河流相砂岩油藏剩余油分布研究

The Gangxi oil field has reached a stage of high water production. The reservoir parameters, such as reservoir physical characteristics, pore structure, fluid, have obviously changed. This thesis therefore carries out a study of these parameters that control reservoir characteristics, physical and chemical actions that have taken place within the reservoirs due to fluid injection, subsequent variations of reservoir macroscopic physical features, microscopic pore structures, seepages, and formation fluid properties. This study rebuilds a geologic model for this oil field, establishes a log-interpreting model, proposes a methodology for dealing with large pore channels and remnant oil distribution, and offers a basis for effective excavation of potential oil, recovery planning, and improvement of water-injection techniques. To resolve some concurrent key problems in the process of exploration of the Gangxi area, this thesis carries out a multidisciplinary research into reservoir geology, physical geography, reservoir engineering, and oil-water well testing. Taking sandstone and flow unit as objects, this study establishes a fine geologic model by a quantificational or semi-quantificational approach in order to understand the remnant oil distribution and the reservoir potential, and accordingly proposes a plan for further exploration. By rebuilding a geological model and applying reservoir-engineering methods, such as numerical simulation, this thesis studies the oil-water movement patterns and remnant-oil distribution, and further advances a deployment plan for the necessary adjustments and increase of recoverable reserves. Main achievements of this study are as follows: 1. The Minghazhen Formation in the Gangxi area is featured by medium-sinuosity river deposits, manifesting themselves as a transitional type between typical meandering and braided rivers. The main microfacies are products of main and branch channels, levee, inter-channel overflows and crevasse-splay floodplains. The Guantao Group is dominantly braided river deposit, and microfacies are mainly formed in channel bar, braided channel and overbank. Main lithofacies include conglomerate, sandstone, siltstone and shale, with sandstone facies being the principal type of the reservoir. 2. The reservoir flow unit of the Gangxi area can be divided into three types: Type I is a high-quality heterogeneous seepage unit, mainly distributed in main channel; Type II is a moderate-quality semi-heterogeneous seepage unit, mainly distributed in both main and branch channels, and partly seen within inter-channel overflow microfacies; Type III is a low-quality, relatively strong heterogeneous seepage unit, mainly distributed in inter-channel overflow microfacies and channel flanks. 3. Flow units and sedimentary microfacies have exerted relatively strong controls on the flowing of underground oil-water: (1) injection-production is often effective in the float units of Type I and II, whilst in the same group of injection-production wells, impellent velocity depends on flow unit types and injection-production spacing; (2) The injection-production of Type III flow unit between the injection-production wells of Type I and II flow units, however, are little effective; (3) there can form a seepage shield in composite channels between channels, leading to inefficient injection and production. 4. Mainly types of large-scale remnant-oil distribution are as follows: (1) remnant oil reservoir of Type III flow unit; (2) injection-production well group of remnant oil area of Type III flow unit; (3) remnant oil reservoirs that cannot be controlled by well network, including reservoir featured by injection without production, reservoir characterized by production without injection, and oil reservoir at which no well can arrive; (4) remnant oil area where injection-production system is not complete. 5. Utilizing different methods to deal with different sedimentary types, sub-dividing the columns of up to 900 wells into 76 chronostratigraphic units. Four transitional sandstone types are recognized, and contrast modes of different sandstone facies are summarized Analyzing in details the reservoirs of different quality by deciphering densely spaced well patterns, dividing microscopic facies and flow units, analyzing remnant oil distribution and its effect on injection-production pattern, and the heterogeneity. Theory foundation is therefore provided for further excavation of remnant oil. Re-evaluating well-log data. The understanding of water-flood layers and conductive formations in the Gangxi area have been considerably improved, and the original interpretations of 233 wells have changed by means of double checking. Variations of the reservoirs and the fluid and formation pressures after water injection are analyzed and summarized Studies are carried out of close elements of the reservoirs, fine reservoir types, oil-water distribution patterns, as well as factors controlling oil-gas enrichment. A static geological model and a prediction model of important tracts are established. Remaining recoverable reserves are calculated of all the oil wells and oil-sandstones. It is proposed that injection-production patterns of 348 oil-sandstones should be adjusted according to the analysis of adaptability of all kinds of sandstones in the injection-production wells.

汉语韵律短语切分及语调降阶和下倾研究

Firstly, prosodic boundaries of 1991 common sentences were labeled based on speech perception experiment, relation between prosodic structure and syntactic structure was examined after immediate constituent analysis, an example of prosodic phrasing from text sentences was provided using CART. Then, using designed sentences, phenomena of downstep and declination in pitch downtrend of Chinese declarative sentences were examined, commonness and speciality of Chinese intonation were discussed. The main results of the study are: 1 The distribution patterns of prosodic phrase boundaries for different syntactic structures are different, and there is great freedom in prosodic chunking. The relation between syntactic structure and prosodic structure can only be discussed in statistical sense. 2 Besides of syntactic relation, the second most important factor which influences prosodic phrase boundaries is length. The distances to the front boundary and the back boundary are more important than the lengths of the left syntactic contituent and the right one. In our corpus, the length distributions of prosodic phrases are 5±3 syllables. 3 Automatic downstep can lower intonation linearly, but is affected by stress easily. Non-automatic downstep lowers the higher part of pitch contours and has no effect on the lower one of the intonation. 4 The downtrend reason of low point is declination. The extent of declination relates to not only tones of low points, but also their positions in prosodic words, the baselines decline much faster when low point are in the initial position of a prosodic word. In long sentences, the baselines of prosodic phrases are the basic declination units, and the whole declination pattern of a sentence is related to syntactic relations between two neighboring prosodic phrases.

Kinetic theory for particle concentration distribution in two phase flow

The results of experiments in open channels and closed pipelines show two kinds of patterns for the vertical distribution of particle concentration (i.e., pattern I and pattern II). The former shows a pattern of maximum concentration at some location above the bottom and the downward decay of the concentration below the location. The latter always shows an increase of the particle concentration downward over the whole vertical, with the maximum value at the bottom. Many investigations were made on the pattern II, but few were made on pattern I. In this paper, a particle velocity distribution function is first obtained in the equilibrium state or in dilute steady state for the particle in two-phase flows, then a theoretical model for the particle concentration distribution is derived from the kinetic theory. More attention is paid to the predictions of the concentration distribution of pattern I and comparisons of the present model are made with the data measured by means of laser doppler anemometry (LDA). Very good agreements are obtained between the measured and calculated results.

Y-chromosome haplotype distribution in Han Chinese populations and modern human origin in East Asians

We investigated the distribution of Y-chromosome haplotype using 19 Y-SNPs in Han Chinese populations from 22 provinces of China. Our data indicate distinctive patterns of Y chromosome between southern and northern Han Chinese populations. The southern po

Altitudinal Ranging of Black-Crested Gibbons at Mt. Wuliang, Yunnan: Effects of Food Distribution, Temperature and Human Disturbance

We studied the altitudinal ranging of one habituated group of black-crested gibbons (Nomascus concolor) at Dazhaizi, Mt. Wuliang, Yunnan, China, between March 2005 and April 2006. The group ranged from 1,900 to 2,680 m above sea level. Food distribution was the driving force behind the altitudinal ranging patterns of the study group. They spent 83.2% of their time ranging between 2,100 and 2,400 m, where 75.8% of important food patches occurred. They avoided using the area above 2,500 m despite a lack of human disturbance there, apparently because there were few food resources. Temperature had a limited effect on seasonal altitudinal ranging but probably explained the diel altitudinal ranging of the group, which tended to use the lower zone in the cold morning and the higher zone in the warm afternoon. Grazing goats, the main disturbance, were limited to below 2,100 m, which was defined as the high-disturbance area (HDA). Gibbons spent less time in the HDA and, when ranging there, spent more time feeding and travelling and less time resting and singing. Human activities directly influenced gibbon behaviour, might cause forest degradation and create dispersal barriers between populations. Copyright (C) 2010 S. Karger AG, Basel

Predominant expression and cellular distribution of fish Agr2 in renal collecting system

Anterior gradient 2 (Agr2) genes encode secretory proteins, and play significant roles in anterior-posterior patterning and tumor metastasis. Agr2 transcripts were shown to display quite diverse tissue distribution in different species, and little was known about the cellular localization of Agr2 proteins. In this study, we identified an Agr2 homologue from gibe[ carp (Carassius auratus gibelio), and revealed the expression patterns and cellular localization during embryogenesis and in adult tissues. The full-length cDNA of CagAgr2 is 803 nucleotides (nt) with an open reading frame of 510 nt encoding 169 amino acids. The Agr2 C-terminus matches to the class I PDZ-interacting motif, suggesting that it might be a PDZ-binding protein. During embryogenesis, CagAgr2 was found to be transcribed in the mucus-secreting hatching gland from tailbud stage and later in the pharynx region, swim bladder and pronephric duct as revealed by RT-PCR and whole mount in situ hybridization. In the adult fish, its transcription was predominantly confined to the kidney, and lower transcription levels were also found in the intestine, ovary and gills. To further localize the Agr2 protein, the anti-CagAgr2 polyclonal antibody was produced and used for immunofluorescence observation. In agreement with mRNA expression data, the Agr2 protein was localized in the pronephric duct of 3dph larvae. In adult fish, Agr2 protein expression is confined to the renal collecting system with asymmetric distribution along the apical-basolateral axis. The data provided suggestive evidence that fish Agr2 might be involved in differentiation and secretory functions of kidney epithelium. (C) 2009 Elsevier Inc. All rights reserved.

Spatial distribution of benthic algae in the Gangqu River, Shangrila, China

This study consisted of sampling benthic algae at 32 sites in the Gangqu River, an important upstream tributary of the Yangtze River. Our aims were to characterize the benthic algae communities and relationships with environmental variables. Among the 162 taxa observed, Achnanthes linearis and Achnanthes lanceolata var. elliptica were the dominant species (17.10% and 14.30% of the total relative abundance, respectively). Major gradients and principal patterns of variation within the environmental variables were detected by principal component analysis (PCA). Then non-metric multidimensional scaling (NMS) divided all the sites into three groups, which were validated by multi-response permutation procedures (MRPP). Canonical correspondence analysis (CCA) indicated that three environmental variables (TN, TDS, and TP) significantly affected the distribution of benthic algae. Weighted averaging regression and cross-calibration produced strong models for predicting TN and TDS concentration, which enabled selection of algae taxa as potentially sensitive indicators of certain TN and TDS levels: for TN, Achnanthes lanceolata, Achnanthes lanceolata var. elliptica, and Cymbella ventricosa var. semicircularis; for TDS, Cocconeis placentula, Cymbella alpina var. minuta, and Fragilaria virescens. The present study represents an early step in establishing baseline conditions. Further monitoring is suggested to gain a better understanding of this region.

Vertical distribution and migration of planktonic rotifers in Xiangxi Bay of the three Gorges Reservoir, China

We investigated diel vertical migrations (DVM) and distributions of rotifers in summer, 2004 and spring, 2005, in Xiangxi Bay of the Three Gorges Reservoir, China. Water temperature, pH, conductivity, and phytoplankton were closely related to rotifer vertical distribution, while dissolved oxygen had no relationship with the vertical distribution of rotifers. The species composition and population density of rotifers changed significantly between seasons. However, rotifer vertical distributions in both seasons were similar. They aggregated at specific depths in the water column. All the rotifer species inhabited the surface layers (0.5-5 m). Generally, the rotifers did not display DVM except for Polyarthra vulgaris (in summer), which performed reverse migration. The reason that rotifers did not perform DVM may be explained by the low abundance of competitors and predators and the high density of food resources at the surface strata.

Geographic distribution of Pelteobagrus fulvidraco and Pelteobagrus vachelli in the Yangtze River based on mitochondrial DNA markers

Three populations of Pelteobagrus vachelli and Pelteobagrus fulvidraco of the Yangtze River were examined by PCR-RFLP analysis of mitochondrial DNA fragments. ND5/6 and D-loop fragments were digested by 10 restriction endonucleases. Significant geographic variations between upstream and mid-downstream populations in the haplotype frequencies and restriction patterns were revealed. This suggested that the diversity of P. vachelli was high; 11 haplotypes were obtained from all the samples. The upstream population shared seven haplotypes and the middle and downstream populations shared another four haplotypes. Among all of the haplotypes, one haplotype was shared in 30 samples of the populations from middle and downstream, but it was not found in the upstream population. Any haplotype found in the upstream population was not detected in the middle and downstream populations. Genetic diversity of P. fulvidraco was low and only five haplotyes were detected from all 60 samples. Phylogenic relationships also indicated that the fishes from upstream and mid-downstream were apparently divided into two populations.

Distribution of the meiofaunal community in a eutrophic shallow lake of China

In a Chinese eutrophic shallow lake, the spatial, temporal and vertical distributions of meiofauna in different lake zones along a eutrophic gradient were analyzed. The spatial distribution of meiofauna among sampling stations changed with nutrient levels. Nematoda were most abundant at the majority of sampling stations comprising 70.6 - 93.2 % meiofaunal abundance except for a hypereutrophic station. The seasonal patterns in abundance of nematodes, oligochaetes, rotifers, chironomids and different nematode feeding groups differed among stations, which revealed that the temporal variations of these meiofaunal groups and the nematode feeding groups may vary with different nutrient loadings. The vertical distributions of meiofaunal groups, nematode species, and nematode trophic groups in the upper and lower sediment layers were similar, suggesting a consistent vertical distribution pattern across different trophic conditions. Nematode species richness, Shannon-Wiener species diversity index, trophic diversity and Maturity Index were significantly correlated with nutrient levels (total phosphorus and nitrogen in lake water and total phosphorus in sediment). Our results suggest the importance of nematode community analyses in the assessment of freshwater eutrophication.