238 resultados para Optimum Currency Area
Resumo:
Carbon isotopes of individual lipids in typical organisms from the Nansha sea area were measured by the GC-IRMS analytical technique. delta(13)C values of saturated fatty acids in different organisms examined are from -25.6parts per thousand to -29.7parts per thousand with the average values ranging from -26.4parts per thousand to -28.2parts per thousand and the variance range of 11.8parts per thousand, between different organisms is also observed. Unsaturated fatty acids have heavy carbon isotopic compositions and the mean differences of 2.9%.9-6.8parts per thousand compared to the same carbon number saturated fatty acids. delta(13)C values of n-alkanes range from -27.5%o to -29.7parts per thousand and their mean values, ranging from -28.6parts per thousand, to -28.9parts per thousand, are very close in different organisms. The mean difference in delta(13)C between the saturated fatty acids and n-alkanes is only 1.5parts per thousand, indicating that they have similar biosynthetic pathways. The carbon isotopic variations between the different carbon-number lipids are mostly within +/-2.0parts per thousand, reflecting that they experienced a biosynthetic process of the carbon chain elongation. At the same time, the carbon isotopic genetic relationships between the biological and sedimentary lipids are established by comparative studies of carbon isotopic compositions of individual lipids in organisms and sediments from the Nansha sea area, which provides scientific basis for carbon isotopic applied research of individual lipids.
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Sinking particulate material collected from Nansha Yongshu reef lagoon and the continental shelf of the East China Sea by sediment traps has been analyzed and studied for the first time using organic geochemical method. The results show that about half of the sinking particulate organic matter in the two study areas are consumed before reaching the depth of 5 m to the sea floor and the degree of this consumption in Yongshu reef lagoon is larger than that in the continental shelf of the East China Sea. The distributions of hydrocarbons and fatty acids indicate that the minor difference of biological sources of sinking particulate organic matter exists between Yongshu reel lagoon and the continental shelf of the East China Sea, but they mainly come from marine plankton. Stronger biological and biochemical transformations of sinking particulate organic matter are also observed and the intensity of this transformation in Yongshu reef lagoon is greater than that in the continental shelf of the East China Sea. It is found that the occurrence of C-25 highly branched isoprenoid (HBI) diene may be related to the composition of diatom species.
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The specific activity concentrations of radionuclides U-238, Th-212, and K-40 of 2300 sampling points in the Qingdao area were measured by an FD-3022 gamma-ray spectrometer. The radioactivity concentrations of U-238, Th-232, and K-40 ranged from 3.3 to 185.3, from 6.9 to 157.2, and from 15.8 to 7834.4 Bq kg(-1), respectively. The air-absorbed dose at I meter above ground, effective annual dose, external hazard index, and radium equivalent activity were also calculated to systematically evaluate the radiological hazards of the natural radioactivity in Qingdao. The air-absorbed dose, effective annual dose, external hazard index, and radium equivalent activity in the study area were 98.6 nGy h(-1), 0.12 mSv, 0.56, 197 Bq kg(-1), respectively. Compared with the worldwide value, the air-absorbed dose is slightly high, but the other factors are all lower than the recommended value. The natural external exposure will not pose significant radiological threat to the population. In conclusion, the Qingdao area is safe with regard to the radiological level and suitable for living.
Resumo:
There are 47 genera and 161 species of Gramineae except the cultivated species in the area of the Karakorum and Kunlun Mountains. The results of research on the distribution of the genera and species of Gramineae in the Karakorum and Kunlun Mountains show that (1) The Gramineae mainly contains elements of North Temperate, rich Old Word Temperate and other Temperate. It is obvious that the floristic nature of Gramineae in the Karakorum and Kunlun Mountains is the North Temperate; (2) All Pantropic genera can stretch to the Temperate Zone in this region, which all parts of the Pantropic type are the Temperate nature to a certain degree. For example, Erianthus ravennae from mediterranean to the Karakorum and Kunlun Mountains through the Central Asia; (3) As most genera of Grasses are the type of Temperate and the Frigid Zone, they have distinct floristic characteristics of mountainous and plateau flora such as Orinus, Alopecurus, Elymus, Trisetum, Littledalea, Elytrigia, Stephanachne and Paracolpodium etc. All of these indicate adaptive phenomenon of alpine specialization and cold-xerophilization on Grasses in this area; (4) Endemic genus of Gramineae is absent due to its nature and history and the endemic species are also rare in the Karakorum and Kunlun Mountains. Most of the genera with one or fewer species have originated from its relative and widespread genera, such as Ptilagrostis from Stipa, Timouria from Achnatherum, and so on; (5) Flora of the Karakorum and Kunlun Mountains is most closely related to the flora of Tibet, and is also extensively to its adjacent areas.
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The alpine meadow ecosystem on the Qinghai-Tibetan Plateau is characterized by low temperatures because of its high elevation. The low-temperature environment may limit both ecosystem photosynthetic CO2 uptake and ecosystem respiration, and thus affect the net ecosystem CO2 exchange (NEE). We clarified the low-temperature constraint on photosynthesis and respiration in an alpine meadow ecosystem on the northern edge of the plateau using flux measurements obtained by the eddy covariance technique in two growing seasons. When we compared NEE during the two periods, during which the leaf area index and other environmental parameters were similar but the mean temperature differed, we found that NEE from 9 August to 10 September 2001, when the average temperature was low, was greater than that during the same period in 2002, when the average temperature was high, but the ecosystem gross primary production was similar during the two periods. Further analysis showed that ecosystem respiration was significantly higher in 2002 than in 2001 during the study period, as estimated from the relationship between temperature and nighttime ecosystem respiration. The results suggest that low temperature controlled the NEE mainly through its influence on ecosystem respiration. The annual NEE, estimated from 15 January 2002 to 14 January 2003, was about 290 g CO2 m(-2) year(-1). The optimum temperature for ecosystem NEE under light-saturated conditions was estimated to be around 15 degrees C.
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The Study carried out in Xueshan Township, Guoluo prefecture, Qinghai Province, P. R. China from 1997 to 1999 on 1) Growth regulation of yak from born to adult and 1/4 wild yak from born to one and half year; 2) The effect of nursing or not on the growth and development of dam; 3) Meat performance of local yak; 4)Milk productivity of female yak. It can be served as the theory basis from which crossbreed improvement of yak and government decision could be drawn.
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(1) I research on the relationship between elastic parameters, lithology and liquid. It is a physical base for pre-stack seismic inversion. I research all kinds of approximate expressions of Zoeppritz function. Then the relation of all kinds of approximate expressions can be confirmed. The geological model of water sand and gas sand in different depth was designed. Moreover I research on precision of all kinds of approximate expressions. (2) In process of seismic data which aim at amplitude recovery and apply in pre-stack seismic inversion, I advance to adopt double flow chart for different aim. Pre-stack noise elimination, real amplitude recovery and NMO correction of long offset are the key taches. (3) I made a systemic expatiate for the thinking and applicability about all kinds of expressions of elastic impedance. And mathematical model was applied to compare the precision with all kinds of expressions of elastic impedance. I propose a new pre-stack simultaneous inversion which is based on the Zoppritz function and simulated annealing algorithm. This method can ensure calculation precision of reflection coefficient from different incident angle and get a global optimum solution. Therefore this method improves the precision of pre-stack seismic inversion. (4) The object function of P-S wave pre-stack simultaneous inversion was established. I compared the precision and convergence between simultaneous inversion and P-wave inversion. And the results show that simultaneous inversion is superior to P-wave inversion. Through the study of AVO event of transformed wave, AVO characters of different kinds of gas sand were analyzed. (5) I carried out the study work of pre-stack seismic inversion for carbonate reservoir in middle of Tarim basin and sand shale reservoir in Sulige Area of Erdos Basin. The method and technology in this paper was applied to practical work. And I made a prediction for heterogeneous reservoir. Moreover it acquires a good application effect. Key Word: reflection coefficient, amplitude recovery, pre-stack seismic inversion, Heterogeneous reservoir,prediction.
Resumo:
As a kind of strategic resource,petroleum play an very important role in current social stability, economic development and state safety. Since 1993 China has turned from a net oil exporter into a net oil importer, the figure of imported oil increased from then on. In 2004 China's total energy consumption exceeded Japan’s, and ranked in the second place, just inferior to America. Today China is the world’s third-largest importing nation, accounting for 6% of world imports and 8% of world consumption. Comparing with other strategic petroleum reserve schemes, underground oil storage possess many advantages, such as security, economy, less pollution, save land, suited for strategic reserve and so on, so it is the most ideal form for strategic petroleum reserve. In the background of China Strategic Petroleum Reserve Program started just now, this paper choose Circum-Bo sea region as a study area, and do some system study on the underground oil storage caverns constructed in inter-large granite rock masses in Circum-Bo sea region. On the foundation of a great amount of information come from both home and abroad, firstly this paper analysed the principle, economy, cavern shape, profile dimension, and gain some cognizances and logos, as follows: ①Hard rock mass such as granite is the major rock, in which underground oil storage are constructed; ②Unlined underground oil storage caverns had been wide spread used as a sort of oil storage form abroad, there already exist a suit of skilled experience and technologies to prevent oil product from leaking; ③Compared with surface tanks, underground oil storage cavern possess predominance in economy clearly. In general, it will be more economical when the storage capacity exceed 50000m3. The quality of rock mass is the most important factor for underground storage cost, however such as hydrogeology, storage capacity, the number of storage galleries, the length, storage product, mechanical equipments, geographic location also influent the cost. In designed depth of the underground storage, the rock mass of Jinzhou mainly belong to class Ⅱ, but parts with dykes, clayization alteration, and dense joints are Ⅲ, Ⅳ; ④Now, there are few underground oil storages span more than 25m in both abroad and home. The examples of some ancient underground works and modern underground excavation with wide span surely give us many precious elicitations to construct more great unlined storage caverns, when the rock mass quality is good, cavern shape and construction method also are proper, it is quite possible to construct underground oil storage cavern with span more than 30m . The main axis orientation of Jinzhou underground oil storage cavern is NW direction, the cavern's elevation locate between -53msl and -76msl. The storage's total volume is about 3×106m3, composed of 8 parallel galleries with 950m length, the pillars between them are 45m, and every two of galleries form one unit, which can deposit 75×104m3 for each unit. The product will be stored are Saudi light and Saudi medium crude oil, the main cavern's section is 411.5m2, with 23m height and 19m width. According to the principle and technique of engineering geomechanics, this study supply a sort of system scientific thinking and method for sitting location of underground oil storage in granite region: ① On the foundation of the earth crust stability sub-zone appraise of Circum-Bo sea region, farther research concerning granite distribution, genesis, geological period and fault structure are conducted in stable areas, generally, this paper select Liaoxi, east shore of Liaotung peninsula and Jiaotung peninsula as target areas for underground oil storage regions, where Mesozoic granite is magnitude; ②After roundly comparison in facts of geologic structure, engineering geology, hydrogeology, topography, transportation and so on of three granite distributed areas, at last, selecting Jingzhou granite zone in Liaoxi out as an ideal construction area; ③ Detailed investigation is conducted in the southeast of Baimashi in Jingzhou development district, the final field. Ultrasonic Borehole Television, as a major way to collect original information of borehole rock mass were used, which is very effective to appraise the quality of deep rock mass; ④ According to the field data of tectonic stress, rock mass quality, the spatial distribution of fracture water, some optimum designs in cross section, axial direction and cavern span have been designed for the underground oil storage cavern layout in Jinzhou. To understand the characteristics of swelling alteration rock in Jinzhou granite mass, collected abundant swelling alteration rock engineering examples in granite, which study them in detail, concluded the swelling alteration rock distribute nearly everywhere in China, intruded medium-basic dykes alteration, along discontinuities and mineral hydrothermal alteration with genesis of granite are three main forms clayization alteration rock in granite rock mass. In Jinzhou field, from macro to micro studied the swelling rock which induced by mid-basic dyke intrusion, with weak swelling. In conclusion, this paper conclude the distribution rule and features of expansion alteration rock in filed, and advise some technical suggestions for excavation at swelling alteration rock part. The main features of this paper: ①In the process of site selection, investigation and design, a suit of technique and method of engineering geomechanics metasynthesis were formed, which is significative to guide the large scale underground oil storage cavern sitting location, investigation and design in granite rock mass; ②The detailed discussion on the engineering geology problems in granite mass, such as weathering crust, faults, dykes and clayization alteration rock, are useful for other projects in aspects of site selection, engineering geology evaluation and stability estimation; ③The summary and integration of the genesis, type, countermeasure relate to swelling alteration rock, also is likely to be used for other underground oil storage caverns constructed in swelling alteration granite. In conclusion, this study is meaningful for guiding the large scale underground oil storage for site selection, investigation and design in granite rock mass.
Resumo:
In this paper, the detailed analysis of fundamental seismic data and theoretical method are given, and the tests of some new technologies are performed. For seismic data processing assembly, some key technologies are developed and applied, such as global static correction, amplitude consistency processing, wavelet consistency shaping, fine velocity model establishing and prestack time migration. These technologies can efficiently settle the problems during the course of multiple- block– jointed prestack time migration processing, and it is highly significant for holding the oil output of 40,000,000 tons for Daqing oilfield. Through the research of this dissertation, the following important contributions are shown: (1) The combination of near-surface model method and refraction static correction method is developed, and is applied to solve global static correction for the whole merging area. (2) Prestack amplitude normalization processing method based on fold is developed. The method eliminates the effects of fold on amplitude uniformity, and solves the problem of energy uniformity for tie-area prestack migration processing. (3) Wavelet consistency is investigated. For multiple survey blocks existing in the area, the optimum method of wavelet shaping is developed, which removes the waveform variance between two adjacent blocks. (4) Controlled velocity inversion (CVI) technique is used to establish migration velocity field. It can largely shorten the period of velocity modeling, and improve velocity analysis precision. (5) Float datum level technique is employed, and is able to guarantee prestack migration results of subsurface shallow layers. (6) The static partition of seismic data volume relating to migration aperture is firstly developed. And the precious imaging for huge data volume by prestack time migration is realized. (7) The numerical forward simulation and prestack migration processing is primarily combined to discuss the migration technique for a complex geology structure from practical field information. The combination of numerical simulation and prestack migration is a feasible way to solve the fine imaging of complex volcanic structure. And the combination approach can help to select appropriate migration parameters.
Resumo:
The dynamic environments of mineralization in Mesozoic Jiaodong gold mine concentrated area can be devided into two types, compressive environment which related to intracontinental collision and extensional environment which related to intracontinental volcanic rift. The altered rock type (Jiaojia type) and quartz vein type (Linglong type) which related to the former one, were discovered for several years, and became the main types of gold deposits in recent years. A new type gold deposit, syn-detachment altered tectonic breccia type gold deposit, such as Pengjiakuang gold deposit and Songjiagou gold deposit has been discovered on the northeastern margin of Jiaolai Basin. In this paper, the new type of gold deposit has been studied in detail. The study area is located at the northeastern boundaries of Jiaolai Basin, and between the Taocun-Jimo Fault and Wji-Haiyang Fault, in the eastern part of the Jiaodong Block. Pengjiakuang gold deposit and Songjiagou gold deposit occur in a arc-shape detachment fault zone between conglomerate of Lower Cretaceous Laiyang Formation and metamorphic complex of Lower Proterozoic Jingshan Group. Regional geological studies show that Kunyuanshan and Queshan granite intrusions and Qingshanian volcanism were formed in different period of lithospheric thinning of East China in Mesozoic. Granite intrusions were formed in compressive environment, while Qingshanian volcanism were formed in extensional environment. They are all related to the detachment of Sulu Orogenic Belt and the sinistral motion of Tanlu Fault. The Pengjiakuang detachment systems which were formed in the the sinistral motion of Tanlu Fault are the important ore-controlling and ore-containing structure. The Pengjiakuang type gold deposit, controlled by detachment structure, was formed before Yanshanian volcanic period concerning with mixture of meteoric water and magmatic water found in fluid inclusions of gold ores. The minerogenetic epoch has been proposed in 90~120Ma. the host rocks have been extensively subjected to pyritization, silicification, sericitization and carbonatization. Individual ore-body has maximum length of 800m, oblique extension of 500~700m and gold grade of 1~43 * 10~(-6). Native gold is disseminated in silicified, phyllic or carbonatized tectonic breccia. Sulfur, carbon and lead isotope studies on gold ores and wall rocks show that the sulfur come from the metamorphic complex of Lower Proterozoic Jingshan Group, carbon comes from the marble in Jingshan Group, while a part of lead comes from the mantle. The mineralizing fluid is rich in Na~+ and Cl~-, but relatively impoverished in K~+ and F~-. According to the date from hydrogen and oxygen isotopic compositions (δ~(18)OH_2O = 0.59%~4.03%, δDH_2O = -89.5%~97.9%), the conclusion can be reached that the mineralizing fluid of Pengjiakuang gold deposit was a kind of mixed hydrothermal solution which was mainly composed of meteoric water and magmatic water. A genetical model has been formulated. Some apparent anomaly features which show low in the central part and high in the both sides corresponding to the gold-bearing structure, were sum up after analying a vast amount of date by prospecting the orebodies using gamma-ray spectrometer, electrogeochemical parameter technique, controlled source audio magnetic telluric (CSAMT) and shallow surface thermometry in Pengjiakuang gold deposit. The location forecasting problem of buried orebodies has been solved according to these features, and the successful rate is very high in well-drilling. The structural geological-geophysical-geochemical prospecting model has been formulated on the base of the study of geological, geophysical and geochemical characteristics of Pengjiakuang type gold deposit, and the optimum combinational process of geophysical and geochemical prospecting techniques has been summed up. A comparative study shows that the Pengjiakuang type gold deposit, the syn-detachment altered tectonic breccia type gold deposit, is different from Jiaojia type gold deposits and Linglong type gold deposits, in Jiaodong Block. In general, if formed under an extensional tectonic condition and located at detachment fault zone along the margin of Mesozoic Jiaolai basin, and the gold mineralization has also close genetic relationship with alkaline magamtism. Being a new type of gold deposit in Jiaodong gold mine concentrated area, it could be potential to explore in the same regions which processed the same ore-forming geological conditions and mineralization informations.
Resumo:
The formation of civilization, one of great marks in the history of human's society development, has been remained one of the hottest topics in the world. Many theories have been put ford to explain its causes and mechanisms. Although more attentions have been paid to its development, the role of environmental change should not be ignored. In this paper, the level of ancient farming productivity was analyzed, the mechanisms and the process of Chinese ancient civilization formation was explored, and some causes why Chinese ancient civilization shows many different features from other 5 ancient civilizations of the world was analyzed. The main results and conclusions are presented as followed. 1. Compared with the productivity level of other five ancient civilizations, the productivity of ancient China characterized by a feature of extensive not intensive cultivation was lower than that of other five ancient civilizations whose agriculture were based on irrigation. 2. The 5 5000 a B.P. cold event may have facilitated the formation of Egypt and Mesopotamian ancient civilizations and also have had an influence on the development of Neolithic culture in China. 3. The 4 000 a B.P. cold event, which may be the coldest period since the Younger Dryas cold event and signifies the changes from the early Holocene Climate Optimum to late Holocene in many regions of the world, resulted in the great migration of the Indo-European peoples from north Europe to other part of the World and the collapses of ancient civilizations in Egypt, Indus and the Mesopotamian and the collapse of five Neolithic cultures around central China. More important than that is the emergence of Chinese civilization during the same period. Many theories have been put ford to explain why it was in Zhongyuan area not other places whose Neolithic cultures seem more advanced that gave rise to civilization. For now no theory could explain it satisfiedly. Archaeological evidence clearly demonstrate that war was prevailed the whole China especially during the late Longshan culture period, so it seemed war has played a very important role in the emergence of China ancient civilization. Carneiro sees two conditions as essential to the formation of complex societies in concert with warfare, i.e. population growth and environmental circumscription. It was generally through that China couldn't evolved into the environmental circumscription and population pressure because China has extensive areas to live, but that depends on situations. The environmental circumscription area was formed due to the 4000a B.P. cold event and companied flooding disasters, while the population pressure is formed due to three factors; 1) population grow rapidly because of the suitable environment provided by the Holocene Optimum and thus laid its foundations for the ancient human population; 2) population pressure is also related to the primitive agricultural level characterized by extensive not intensive cultivation; 3) population pressure was mainly related to the great migrations of people to the same areas; 4) population pressure was also related to productivity decrease due to the 4 000a B.P. cold event. 4. When population pressure is formed, war is the most possible way to solve the intensions between population and the limited cultivated land and then resulted in the formation of civilization. In this way the climate change during the 4 000a B.P. cold event may have facilitated the emergence of Chinese ancient civilization. Their detailed relations could also be further understood in this way: The first birth places of China ancient civilization could be in Changjiang areas or (and) Daihai area, Shandong province rather than in central China and the emergence time of ancient civilization formed in central China should be delayed if the 4 000a B.P. cold event and companied flooding disasters didn't occurred.
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The past two decades have witnessed an unprecedented growth of interest in the palaeoenvironmental significance of the Pleistocene loess deposits in northern China. However, it is only several years ago that the Tertiary red clay sequence underlying Pleistocene loess attracted much attention. One of the major advances in recent studies of eolian deposits on the Loess Plateau is the verification of the eolian origin for the Tertiary red clay sediments. The evidence of the eolian origin for the red clay is mainly from geochemical and sedimentological studies. However, sedimentological studies of the red clay deposits are still few compared with those of the overlying loess sediments. To date, the red clay sections located near Xifeng, Baoji, Lantian, Jiaxian, and Lingtai have been studied, with an emphasis on magnetostratigraphy. These sections have a basal age ranging from ~4.3 Ma to ~7.0 Ma. The thickness of the sections varies significantly, depending perhaps on the development of local geomorphological conditions and the drainage system. Although the stratigraphy of the red clay sections has been recorded in some detail, correlation of the red clay sequences has not yet been undertaken. Geological records (Sun J. et al., 1998) have shown that during glacial periods of the Quaternary the deserts in northem China were greatly expanded compared with modern desert distribution. During interglacial periods, desert areas contracted and retreated mostly to northwestern China because of the increase in inland penetration of monsoonal precipitation. According to pedogenic characteristics of the red clay deposits, the climatic conditions of the Loess Plateau is warmer and wetter generally in the Neogene than in the late Pleistocene. Panicle analyses show that grain size distribution of the red clay sequence is similar to that of the paleosols in the Pleistocene loess record, thus implying a relatively remote provenance of the red clay materials. However, the quantitative or semiquantitative estimates of the distance from the source region to the Loess Plateau during the red clay development remains to be investigated. In this study, magnetostratigraphic and sedimentological studies are conducted at two thick red clay sequences-Jingchuan and Lingtai section. The objectives of these studies are focused on further sedimentological evidence for the eolian origin of the red clay, correlation of red clay sequences, provenance of the red clay, and the palaeoclimate reconstruction in the Neogene. Paleomagnetic studies show that the Jingchuan red clay has a basal age of 8.0 Ma, which is 1 million years older than the previously studied Lingtai section. The Lingtai red clay sequence was divided into five units on the basis of pedogenica characteristics (Ding et al., 1999a). The Jingchuan red clay sequence, however, can be lithologically divided into six units according to field observations. The upper five units of the Jingchuan red clay can generally correlate well with the five units of the Lingtai red clay. Comparison of magnetic susceptibility and color reflectance records of four red clay sections suggests that the Lingtai red clay sequence can be the type-section of the Neogene red clay deposits in northern China. Pleistocene loess and modem dust deposits have a unimodal grain-size distribution. The red clay sediments at Jingchuan and Lingtai also have a unimodal grain-size distribution especially similar to the paleosols in the Pleistocene loess record. Sedimentological studies of a north-south transect of loess deposits above S2 on the Loess Plateau show that loess deposits had distinct temporal and spatial sedimentary differentiation. The characteristics of such sedimentary differentiation can be well presented in a triangular diagram of normalized median grain size, normalized skewness, and normalized kurtosis. The triangular diagrams of the red clay-loess sequence at Lingtai and Jingchuan indicate that loess-paleosol-red clay may be transported and sorted by the same agent wind, thus extending the eolian record in the Loess Plateau from 2.6 Ma back to about 8.0 Ma. It has been recognized that during the last glacial maximum (LGM) the deserts in northern China had a distribution similar to the present, whereas during the Holocene Optimum the deserts retreated to the area west of the Helan Mountains. Advance-retreat cycles of the deserts will lead to changes in the distance of the Loess Plateau to the dust source regions, thereby controlling changes in grain size of the loess deposited in a specific site. To observe spatial changes in sedimentological characteristics of loess during the last glacial-interglacial cycle, the texture of loess was measured along the north-south transect of the Loess Plateau. Since the southern margin of the Mu Us desert during the LGM is already known, several models of grain size parameters versus the minimum distance from the source region to depositional areas were developed. According to these semiquantitative models, the minimum distance from the source region to Lingtai and Jingchuan areas is about 600 km during the Neogene. Therefore the estimated provenance of the Tertiary red clay deposits is the areas now occupied by the Badain Jaran desert and arid regions west of it. The ratio of the free iron to total iron concentration attests to being a good proxy indicator for the summer monsoon evolution. The Lingtai Fe_20_3 ratio record shows high values over three time intervals: 4.8-4.1 Ma, 3.4-2.6 Ma, and during the interglacial periods of the past 0.5 Ma. The increase in summer monsoon intensity over the three intervals also coincides with the well-developed soil characteristics. It is therefore concluded that the East-Asia summer monsoon has experienced a non-linear evolution since the late Miocene. In general, the East Asia summer monsoon was stronger in Neogene than in Quaternary and the strongest East Asia summer monsoon may occur between 4.1 and 4.8 Ma. The relatively small ice volume and high global temperature may be responsible for the strong summer monsoon during the early Pliocene.
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In the engineering reinforcement of-rock and soil mass, engineers must consider how to obtain better reinforcing effect at the cost of less reinforcing expense, which, in fact, is the aim of reinforcement design. In order to accomplish the purpose, they require not only researching the material used to reinforce and its structure, but also taking into account of several important geological factors, such as the structure and property of rock and soil mass. How to improve the reinforcing effect according to engineering geomechanical principle at the respect of the reinforcement of engineering soil and rock mass is studied and discussed in this paper. The author studies the theory, technology and practice of geotechnical reinforcement based on engineering geomechanics, taking example for the soil treatment of Zhengzhou Airport, the effect analysis of reinforcement to the slope on the left bank of Wuqiangxi Hydropower Station and the reinforcing design of the No. 102 Landslide and unique sand-slide slope on the Sichuan-Tibet Highway. The paper is comprised of two parts for the convenience of discussion. In the first part, from the first chapter to the fifth chapter, trying to perform the relevant research and application at the viewpoint of soil mass engineering geomechanics, the author mainly discusses the study of reinforcing soft ground soil through dynamical consolidation and its application. Then, in the second part, from the sixth chapter to the eleventh chapter, the study of new technologies in the rock slope reinforcement and their application are discussed. The author finds that not only better reinforcing effect can be gained in the research where the principle and method of rock mass engineering geomechanics is adopted, but also new reinforcing technologies can be put forward. Zhengzhou Airport is an important one in central plains. It lies on Yellow River alluvial deposit and the structure of stratum is complex and heterogeneous. The area of airport is very large, which can result in differential settlement easily, damage of airport and aircraft accident, whereas, there are no similar experiences to dispose the foundation, so the foundation treatment become a principal problem. During the process of treatment, the method of dynamic compaction was adopted after compared with other methods using the theory of synthetic integration. Dynamic compaction is an important method to consolidate foundation, which was successfully used in the foundation of Zhengzhou Airport. For fill foundation, controlling the thickness of fill so as to make the foundation treatment can reach the design demand and optimum thickness of the fill is a difficult problem. Considering this problem, the author proposed a calculation method to evaluate the thickness of fill. The method can consider not only the self-settlement of fill but also the settlement of the ground surface under applied load so as to ensure the settlement occurred during the using period can satisfy the design demand. It is proved that the method is correct after using it to choose reasonable energy of dynamic compaction to treat foundation. At the same time, in order to examine the effect of dynamic compaction, many monitor methods were adopted in the test such as static loading test, modulus of resilience test, deep pore pressure -test, static cone penetration test and the variation of the pore volume measurement. Through the tests, the author summarized the discipline of the accumulation and dissipation of pore pressure in Yellow River alluvial deposit under the action of dynamic compaction, gave a correct division of the property change of silt and clay under dynamic compaction, determined the bearing capacity of foundation after treatment and weighted the reinforcing effect of dynamic consolidation from the variation of the soil particle in microcosmic and the parameter of soil mass' density. It can be considered that the compactness of soil is in proportion to the energy of dynamic compaction. This conclusion provided a reference to the research of the "Problem of Soil Structure-the Central Problem of Soil Mechanics in 21 Century ". It is also important to strengthen rock mass for water conservancy and electric power engineering. Slip-resistance pile and anchoring adit full of reinforced concrete are usually adopted in engineering experience to strengthen rock mass and very important for engineering. But there also some deficiency such as the weakest section can't be highlighted, the monitor is inconvenient and the diameter of pile and adit is very large etc. The author and his supervisor professor Yangzhifa invented prestressed slip-resistance pile and prestressed anchoring adit full of reinforced concrete, utilizing the advantage that the prestressed structure has better anti-tensile characteristic (this invention is to be published). These inventions overcome the disadvantages of general slip-resistance pile and anchoring adit full of reinforced concrete and have the functions of engineering prospecting, strengthening, drainage and monitor simultaneous, so they have better strengthened effect and be more convenient for monitor and more economical than traditional methods. Drainage is an important factor in treatments of rock mass and slop. In view of the traditional drainage method that drainage pore often be clogged so as to resulted in incident, professor Yangzhifa invented the method and setting of guide penetration by fiber bundle. It would take good effect to use it in prestressed slip-resistance pile and anchoring adit full of reinforced concrete. In this paper, the author took example for anchoring adit full of reinforced concrete used to strengthen Wuqiangxi left bank to simulate the strengthened effect after consolidated by prestressed slip-resistance pile, took example for 102 landslide occurred along Sichuan-Tibet highway to simulate the application of slip-resistance pile and the new technology of drainage. At the same time the author proposed the treatment method of flowing sand in Sichuan-Tibet highway, which will benefit the study on strengthening similar engineering. There are five novelties in the paper with the author's theoretical study and engineering practice: 1. Summarizing the role of pore water pressure accumulation and dissipation of the Yellow River alluvial and diluvial soil under the action of dynamical consolidation, which has instructive significance in the engineering construction under the analogical engineering geological conditions in the future. It has not been researched by the predecessors. 2. Putting forward the concept of density D in microcosmic based on the microcosmical structure study of the soil sample. Adopting D to weight the reinforcing effect of dynamic consolidation is considered to be appropriate by the means of comparing the D values of Zhengzhou Airport's ground soil before with after dynamically consolidating reinforcement, so a more convenient balancing method can be provided for engineering practice. 3. According to the deep research into the soil mass engineering geology, engineering rock and soil science, soil mechanics, as well as considerable field experiments, improving the consolidating method in airport construction, from the conventional method, which is dynamically compactmg original ground surface firstly, then filling soil and dynamically layer-consolidating or layer-compacting at last to the upgraded method, which is performing dynamical consolidation after filling soil to place totally at the extent of the certain earth-filling depth. The result of the dynamical consolidation not only complies with the specifications, but also reduces the soil treatment investment by 10 million RMB. 4. Proposing the method for calculating the height of the filled soil by the means of estimating the potential displacement produced in the original ground surface and the filled earth soil under the possible load, selecting the appropriate dynamically-compacting power and determining the virtual height of the filled earth soil. The method is proved to be effective and scientific. 5. According to the thought of Engineering Geomechanics Metal-Synthetic Methodology (EGMS), patenting two inventions (to the stage of roclamation, with Professor Yang Zhi-fa, the cooperative tutor, and etc.) in which multi-functions, engineering geological investigation, reinforcement, drainage and strength remedy, are integrated all over in one body at the viewpoint of the breakage mechanism of the rock slope.
Resumo:
Daihai Lake, a graben-type closed lake, lies ca. 10 km east of Liangcheng County, Inner Mongolia, north-central China. For its location at the transition of semi-humid and semi-arid areas, and in the north edge of the East Asian monsoon, the lake is sensitive to changes in climate and environment. Based on analyses of total inorganic carbon (TIC), total organic carbon (TOC) and the ratio of total organic carbon to total nitrogen (C/N ratio) of DH99a core sediments recovered in the central part of Daihai Lake, the data suggest Holocene climatic history of the lake region is reconstructed. In this paper, the TIC and TOC contents of the lake sediments are closely related to climate changes. 1) Changes in TIC content of the lake sediments is closely related to climate, which directly reflect changes of temperature in the lake region, i.e., higher TIC content is linked with warmer temperature and stronger evaporation; 2) Changes in TOC and C/N ratio reflect the regional precipitation, i.e., relatively higher TOC content and C/N ratio indicate higher rainfall which results in stronger river flow and more organic matter entering into the lake. Data of the TIC content, TOC content and C/N ratio of DH99a core sediments suggest that climatic history of the Daihai Lake region is characterized by 4 stages. During the interval of ca. 11200-7500 a BP, higher TIC content, relatively lower TOC content and C/N ratio value indicate a warmer and slight dry condition over the lake area. From ca. 7500 to 4500 a BP, high values of TIC content, with an increase in TOC content and C/N ratio suggest the climate was warm and humid. Changes of TIC content, TOC content show that both temperature and precipitation displayed obvious fluctuations during the period, i.e., slightly cool and humid ca. 7500-6700 a BP, warm and moist ca. 6700-5300a BP, mild and comparatively humid ca. 5300-4500a BP. Between ca. 4500 and 2900 a BP, TIC content and TOC content decreased gradually while fluctuating, C/N ratio displayed a decreasing trend. These data imply that the climate generally became cooler and drier than the preceding period. The lowest values of TIC content, TOC content and C/N ratio during the interval of ca. 2900-0 a BP, demonstrate that the climate was severe, and became cool and dry. However the relative higher values of TIC content, TOC content and C/N ratio between ca. 1700 and 1300 a BP may denote an increase both in temperature and in precipitation. Data of TIC content, TOC content and C/N ratio in Daihai DH99a core sediments indicate that the warm period was asynchronous with the humid time, the warm interval began in ca. 11200 a BP, and ended in ca. 2900 a BP. The humid period was ca. 7500-2900 a BP. During ca. 7500^500 a BP, the climate was warm and humid, which was the climatic optimum of the Holocene Epoch in the Daihai Lake region. Data of TIC content, TOC content and C/N ratio in Daihai DH99a core sediments imply that the Holocene climate was unstable, the fluctuating events happened occasionally. Such as the cold and dry climate in ca. 4400-4200a BP, the warm and humid climatic condition in the period between ca.1700 and 1300a BP.
Resumo:
Based on the study of the combined flooding test block of Guantao formation in Third faulted block of Yangsanmu oil field, this paper carries out the integration of reservoir precise characterization for very high water cut reservoir, establishes precise 3D geologic model for high water cut development period and states the changing law of the reservoir architecture dtiring development by combined flooding. Then, by subdivided the thick oil reservoir, the study of remaining oil saturation monitoring in fiber glass cased well and tracer monitoring is developed. According the study of multiple constrained combined flooding reservoir numerical simulation, remaining oil distribution are predicted, the methods architecture of predicting remaining oil distribution are established for fluvial facies reservoir at late development stage, develops plan is designed and adjustment associating technologies for enhancing oil recovery. On these base, related measures for tapping the potential are given, it is verified and optimized through the field former test and the good economic effect is achieved . The major achievements of this paper are as follows. The changing law of the reservoir architecture and it's property parameters is revealed, The result indicates that the temperature-pressure of the injecting material and the interaction effect of the injecting material and reservoir petrography are the main factors of the dynamic changes of the reservoir architecture. The quantitative reservoir geologic model, which is tallied with dynamic reservoir parameters of the study area, is established. Subdivided the thick oil reservoir is very important for the study of the remaining oil distribution within the thick oil reservoir. Subdivided the thick oil reservoir technology, which consists of six technologies as follow: micro-cyclic divided, flow unit method, architectural element method, high resolution log technology, high resolution-process technology for normal logging data and using the production data is presented. 3. It is established dynamic monitoring system of remaining oil saturation quantitative research which are inner and interlayer remaining oil saturation from time-lapse logging in fiber glass cased well, inter-well remaining oil saturation from the technology of isotopic tracer monitoring technology, and 4d remaining oil saturation distribution from combined flooding numerical modeling integrated by production datao The forming mechanism of remaining oil for polymer flooding and alkali/polymer combined flooding is clarified, and the plane and vertical distribution law of remaining oil after combined flooding is revealed. Predicting methods and technologies for the combined flooding reservoir of fluvial facies is developed. Combined flooding has been achieved good displacement result in the pilot of Third fault block in Yangsanmu oil field, and accumulated types of important parameters and optimum plans, this technology of combined flooding is expected to increase recovery ratio by 4.77%.