Table of Content

    15 November 1995, Volume 50 Issue 6 Previous Issue    Next Issue
    Xu Shiyuan, ChenZhongyuan
    1995, 50 (6):  481-490.  doi: 10.11821/xb199506001
    Abstract ( )   PDF (608KB) ( )   Save
    For the past over 15 years, active investigation was carried out, mainly using coring and sonar profiling, to study the sedimentological/geomorphologic processes of the major late Quaternary deltas, such as Ruan River delta, Yellow River delta, Yangtze River delta, Han River delta and Pearl River delta, distributed along the eastern coast of China. It is found that there obviously exist many respects of similarity and discrepancy in delta formation, reflecting that the late Quaternary delta processes influenced by eustasy, isostasy and climatic fluctuation are extensively comparable, even though different backgrounds of physiographic zonations along the eastern coast of China played an important role in affecting the delta development. Similarity of late Quaternary delta processes includes l) the tectonic subsidence inducing delta depocenter shift in space and river channel migration, 2) late Pleistocene basal stiff muds, which reflect alluvial sedimentation during the lower stand of sea level, 3) Holocene transgressive sands which is progressively combined with the fluvial sediment landward, 4) mid to late Holocene delta sediment sequences, which are primarily composed of three sections, i. e. from bottom upward, the pro-delta, delta front and delta plain, 5) changes of coastal environmental facies which coincides with the vertical changes of the Holocene facies. and 6) Holocene delta initiation. which started from~7 000 aBP, tested by many radiocarbon isotopes. These respects can be believed as worldwide as the research on Nile and Mississippi deltas were recently finished. In addition to the above-mentioned similarities, it is evident that vital discrepancies exist in the delta construction, resulted from deferential physiographic backgrounds, for instance the sediment input and hydrodynamic features around delta estuary. These features can be regarded as the direct factors in causing the dissimilar configuration of delta geomorphology, such as the fluvio-dominated type, fluvial-tide-dominated type and wave-dominated type. Sedimentary facies assemblages response to these types are distinct sand facies systems, i. e. the alluvial crevasse to sand bar system, tidal berm to sand shoal system and sand ridge to lagoon system. It is demonstrated that these delta sand facies systems are related to the oil-bearing unit in petroleum exploration.
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    Li Chunfen
    1995, 50 (6):  491-496.  doi: 10.11821/xb199506002
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    This paper is intended to discuss the research frontier of regional geography. A brief review of the main defects ever present in the discipline is made with a view to revealing the crux responsible for the decline of the discipline since late fifties. From the standpoint of development of the discipline, it is critical of its satisfaction merely with the uniqueness of the region and their areal differentiation which were regarded as the ultimate goal of research. This is tantamount to a tacit consent to the status quo of the field as a closed system. There in lies the crux of the problem that prevents it from seeking a research frontier. Today it has become known that a region is an open system. ’External, relations are often seen as more important than ’internal’ relations. i. e. relations between the components of the regional system. Since fifties numerous geographers became much interested in spatial relations and sought to establish a new concept of regions based primarily on interregional connections. This is the concept of functional regions which suggests a dynamic picture as against the static one of formal regions. As regional economic development involves not only the internal relations but the interregional relations as well, the latter are often seen as more omportant. The causal. historical and morphological approaches of regions were replaced by functional ones. In a large spatial organization of areas or regions the component parts with their own respective advantages and resources are mutually complementary, thereby promoting development separately and jointly and contributing their share to the overall interests of the whole spatial organization. Therein lies the research frontier of regional geography. It is, therefore, imperative to shift our emphasis of research to interregional relationship and connectivity, which involves theoretical and pratical significance. indispensable for healthy and promising development. The shift from emphasis on uniqueness of regions to that on areal differentiation and recently to that on interregional relationships is an inexorable trend.
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    Huang Suiliang
    1995, 50 (6):  497-505.  doi: 10.11821/xb199506003
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    Heavy-metal pollutants entering into natural rivers can be adsorbed by suspended solids in water. and will be mainly adsorbed by sediment particles. This is a major way by which heavy-metal pollutants change into a solid phase from an unsaturated liquid phase. and the water takes place selfpurification. On the other hand, sediment particles adsoring heavy-metal pollutants, namely, sediment particles comtaminated by heavy-metal pollutants may release heavy-metal pollutants to make the water polluted secondarily under certain apuatic environment conditions. For example. sediment contaminated by heavy-metals enters a "clean" water, or bed mud polluted by heavy-metals turns into a suspended load (Aquatic environmental chemistry conditions also take place changes.). For another example. while dredging in revers. sediment on bed will be disturbed to suspend upwords. It is founded frequently that heavy-metal pollutant concentration in water phase increases a lot during the dredging. This phenomenon was studied by several pioneers through changing artificially environmental, chemical conditions in reactions. For example, acid is added to change the value of PH or a great quantiy of other metalions are added to change total ionic concentration of the aqueous solution to observe the variation of heavy-meal concentration in water phase . Grain size of sediments in natural rivers is non-uniform, and adsorption-desorption capacities of the sediments with different grain sizes are quite different. Laboratorial experiments of desorption by sediments with different grain sizes are conducted in the paoer by modelling sediment contaminated by Cd. Kinetics characteristics of desorption by sediments with different grain sizes (in the light of uniform sediment) is studied and discussed at first, and then kinetics model of desorption by sediments with different grain sizes is studied and discussed- Main conclusions are as follows.(l) Combining the adsorption reaction Kinetics equation with the mass conservation equation,formulae used to calculate residual adsorption content of specific weight sediment and heavy-metal pollutant concentration in water phase are deduced in the case of desorption by sediment. Experimental data agree with them fairly well. Furthermore, formulae for calculating equilibrium residual adsorption content of specific weight sediment and equilibrium heavy-metal pollutant concentration in water phase are also obtained. These can be treated as the basis for further quantitaively studying characteristics of desorption by sediments.(2) Generally speaking, coarse sediment particles have weak adsorption abilities and strong desorption abilities, So in the study of the release of heavy-metal pollutants by sediments in rivers,great attention should be paid to the coarse sediment particles with high content of heavy-metal pollutants. Moreover, the higher the sediment concentration, the higher the concentration of heavy-metal pollutants in water phase. Therefore, When dredging sediments polluted by heavy-metal pollutants, attention must ha paid to the control of the sediment concentration during the operation.(3) Concurrent desorption kinetics model by sediments with different grain sizes is Eq. (4-4).It indicates that there is no competition or interference among different grain sizes its residual adsorption content of specific weight of sediments is the sum of the residual adsorption contents of each grain size.
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    Zhang Renshun
    1995, 50 (6):  506-513.  doi: 10.11821/xb199506004
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    The tidal inlet in mud coast is of a special type. which was not studied in detail before. The paper studies the development of tidal inlet in mud coast, with the special reference to coast of Yellow River Delta. The studies show that the tidal inlet of this type has evolved from abandoned river mouth. The outer coast of the tidal inlet is shell sand bar created in higher sea level period and is reformed by current hydrodynamical processes. The global rise of mean sea level and the earth subsidence of the delta are important factors leading to the creation of tidal basin of the tidal inlet. The abandoned river channel changes into the main tidal creek in the basin. The scour against the creek system enlarges the drainage areas because the adjacent coast retreats at a greater rate after a river mouth is abandoned. Once the height of the shell sand bar is lower than that of mean sea level, tidal inlets of this type will start to decline. The present Disokou and Shenxiangou outlets are at a formation stage of the tidal inlet. Dakouhe and Taoerhe oulets are at a mature stage. The old Caofeidan oulet is declining.The paper points out another type of the declined tidal inlet in mud coast, which is because of depositon of tidal basin. Tlhe old Qikou outlet belongs to this type. The tidal inlet around nowdays Yellow River Dalta is compared with that of the abandoned Yellow River Dalta in North Jiangsu Province in this paper . It shows that along northern Jiangsu Coast, there doesn’t exist the welldeveloped tidal inlet because of human activity and the lower sea level.
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    Chen Zhongxiang
    1995, 50 (6):  514-520.  doi: 10.11821/xb199506005
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    The original "Diao Zhuang" village was a traditional temporery dwelling place in the hilly area. Because of a low population density and special natural conditions , some pieces of the farming lands were far away from farmer’s homes, so simple dwellings were built near these lands. The simple dwellings . which were called "Diao Zhuang" village. were usually straw sheds or small caves. They were only temporarily used during the planting and harvesting seasons. The new "Diao Zhuang" villages are real villages. They are newly built houses in the nearly developed irrigated areas for the migrants mainly from the poor hilly areas. At the beginning . in the first two or three years. the new houses are used seasonally like the old "Diao Zhang"villages.After three years. the migrants will settle down in the new homeland . Today, the "Diao Zhuang" village has developed a new meaning:a newly established residential area in a newly developed irrigated area for the migrants from other places. In the article "Diao Zhuang" village is used to describe a model of regional development and population relocation. To solve poverty problems in the Southern hilly areas and to develop the Northern irrigated areas, Ningxia Autouomous Region successfully develops the model of "Diao Zhuang" villages for immigrants. From 1983 to 1992, more than 20 :Diao Zhuang" villages were built, more than 200 000 people were moved from the overpopulated Southern hilly areas to the Northern newly irrigated areas. This is a great achievement in the history of population relocation and regional development .This paper discusses its theoretical foundation, main specialities, and restristive factors.
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    Lei Xiangyi
    1995, 50 (6):  521-533.  doi: 10.11821/xb199506006
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    The Thickest loess deposits in the world are observed at the Chaoxian village, Jingyuan, Gansu, China. Developed on the 6th terrace of Yellow River and having a typical loess-paleosol sequence. this loess section is about 505 m thick. with 33 layers of paleosols. According to the paleomagnetic data, the Jingyuan section contains Brunhes Normal Polority Zone and Matsuyama Reversal Polority Zone. BIM boundary is located in L8 (8th layer of loess from top downward). The Jaramillo (J) Normal Polority Subchron corresponds to the interval from L11 to S12 Jingyuan loess began to form at 1. 40 MaBP. The rate of loess deposition in Jingyuan loess section is about 36 cm/ka.The component particles of loess in Jingyuan are less than 0. 25 mm. with about 65%-68% silts (0. 050 0.01 mm). The average quantity of particles which are less than 0. 002 mm is about 7. 0%. Its main chemical composition is SiO2 and Al2O3 the contents of which are about 57. 21% and 11. 90% respectively. A obvious characteristic of the chemical component is that content of Fe2O3 is smaller (2. 87%). while the content of CaO is higher (more than 8. 31 %). The above-mentioned fact shows that the paleo-conditions in Jingyuan may be arid-cold during the formation of loess.Under the scanning electron microscope (SEM). the microfabrics of the loess in Jingyuan change from the top to the bottom gradually from the weak-cementation fabric group to the semi-cementation one, and then to the cementation fabric group, and correspondingly, the loess engineering properties are also getting better. For instance, coefficients of collapsibility obviously diminish,while initial pressure of collapsing gradually increases. It indicates that the mechanical properties of loess are closely related to the microfabric characteristics.The Jingyuan section has been correlated with a composite oxygen isotope (δ18O) record. In the past 0. 9 Ma, 9 loess-paleosol groups coincide with 9 climatic cycles of oxygen isotope record. which fluctuate within a wide range and a long-period, and from 1. 38 Ma to 0. 9MaBP, the climatic cycles of δ18O record fluctuated within a narrow range and a short-period, being coincidence with the thin loess and closely bedded paleosols in the Jingyuan section.
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    Mu Chongru, Wang Jinghua
    1995, 50 (6):  534-541.  doi: 10.11821/xb199506007
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    The so-called "Jing-Shan-Mon borderland" energy industrial area is situated between Shanxi and Shaanxi Provinces and Inner Mongolia Autonomous Region. The middle reaches of the Yellow River are located in the region. With an total area of 54 000km2, it is one of the major energy industrial bases in China. Coal. oil, natural gas and other natural resources are distributed widely in this borderland area. Yet, owing to the misuse of these resources, the environmental pollution is quite serious recently. In this paper, air. water and waste solid pollution and its control planning are discussed. The control of the concentration of pollutants in atmosphere and in river water by 2000 and 2010 years are also discussed.Discharge of waste water in 1990 amounted to 1700?104 tons. of which 44. 8% was by electrical power industry. 17. 0% by chemical industry and 12. 7% by textile industry. The water of the Yellow River is seriously polluted. The major pollutants are suspended substances. oxygen-consuming organic matter and oils. The content of suspended substances is over 100% more than national standard, and is rising. The oil pollutant exceeds the standard by 60% - 100% and mercury is over 5. 7%.The emission of waste gases from various plants and urban areas are the main source of air pollution. The annual amout of waste gases is 132. 4?104m3. The electrical power industry has a high emission of waste gases which accounts for 34. 7% of the total, and chemical industry has 14. 4% .In residential and industrial areas. the average suspended particles are different. The concentration of total suspended particles is 0. 69 mg/m3 in residential areas 0. 947 mg/m3 in industrial areas. but only 0. 202 mg/m3 in clean areas. The quantity of industrial solid waste directly released is 370?104t, of which 75% is from coal mineral wastes. This amout reaches 17% of the total of the Country.The selection of the targets for environmental improvement is concentrated in the areas with major resources and for the main pollutants. The COD in the water and SO2 in the air are chosen as main pollutants. The treatment of industrial waste water should reach 45% - 50%, and the recycling amount of industrial used water should make up more than 50% - 50%. 70% of urban used water should be treated.In the past, the atmospheric pollution in the area was not strictly controlled. The reduction of waste gases and SO2 emission will have great effects. It is required that the concentration of SO2 in atmosphere in most parts of this area should be kept at a lavel of national third standard.
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    Wang Liangjian, Li Xianming, Lin Zhiyuan
    1995, 50 (6):  542-551.  doi: 10.11821/xb199506008
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    This paper takes the soils below dark coniferous forests on the east slope of Gongga Mountains and in the Jiuzhaigou natural protection regions as an example. Studies on the soil genetic properties were conducted and a new attempt on the soil classification with the method of Chinese soil taxonomic classification was taken. The result shows that these soils have chelation, eluviation and illuviation of organic acids and the peats gather together obviously to the surface horizon. They have histic evidence and diagnostic subsurface horizons──the spodic horizon and albic horizon. Therefore,they belong to spodosol order, orthic spodosol suborder. podzol group, peatic podzol subgroup.
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    Kang Ersi
    1995, 50 (6):  552-561.  doi: 10.11821/xb199506009
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    Based on the field measurement on energy and water fluxes in a Tianshan glacierized basin. this paper is aimed at simulating the runoff formation and transformation processes by using an energy and water balance model taking the standard meteorological elements as the foremost inputs. The purpose is to understand the processes of energy and water exchange between mountain glacierized areas and atmosphere and their relation to the runoff formation.The glacierized basin which is chosen for runoff simulation in this paper is situated at the sourcearea of the Urumqi River. The basin is located at 43°06’N and 86°50’E. Its catchment area is 28. 9km2, of which 5. 74km2 is covered by glaciers. The altitude of the basin ranges from 3408m to 4479m.The runoff consists mainly of the water from melted ices and snows, and of some efficient liquid precipitation. A glacierized basin can be divided into glacierized area and non-glacierized area. Snow cover is approximated to the solid precipitation. The precipitation of the basin is determined by the systematic error corrected precipitation and its altitude gradient. The ratio of solid precipitation to the total precipitation is determined by the temperature criteria for precipitation to form, the daily maximum and minimum temperatures and the daily mean temperature. The runoff from the ice and snow covered area is calculated by an energy and water balance model, while that from the ice and snow free area is obtained by a water balance model. The calculated results indicate that the runoff coefficient of the glacierized basin is 0- 72, and the runoff from melted glaciers is 13/00, the melted snows from the non-glacierized area makes up 57/60, and liquid precipitation accounts for only 8/00.The total amount of melted snows and ices from the glacierized area makes up 35/00.Under the climate conditions on the Tianshan Mountain, the ablation season can be divided into the weak melting period and intense melting period. The weak melting period is mainly for the melt of seasonal snow cover- and the runoff transformation occurs mainly on the surface. The intense melting period is mainly for glacier to melt, and a large amount of water is produced during this period. The intra-and subglacial drainage system and the active layer of the permafrost develop welland play an important role in the runoff transformation. The runoff transformation processes are simulated by a tank model, which is constructed with two vertically connected tanks. The simulation shows that, during the weak melting period, the runoff transformation processes are rather unitary with the characteristics of a linear reservoir, while during the intense melting period, the discharge increases with the water storage which has the nonlinear characteristics.The present study links the climate variables to the energy and water balance, and to the runoff formation in a glacierized basin. The discharge hydrographs at the basin outlet are well simulated.This is significant in the studies on the relationship of the changes of mountain glaciers, permafrost.snow cover and runoff to the climate change and its simulation.
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    Shi Zhong, Chen Jiyu
    1995, 50 (6):  562-567.  doi: 10.11821/xb199506010
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    Saltmarshes plants are recognized to have their ability to damp waves, modify flow currents,promote sediment deposition and provide habitats for coastal organisms. "This paper reviews the advances in the research into the erosion, deposition and sediment dynamics on the coastal saltmarshes (1982-1994). These include field short-term accretion/erosion measurement, laboratory physical modeling, and numerical modeling. These studies have broadened our understanding of the reponses of saltmarshes to the changes in wind-wave climate, tidal regime, global sea level and plants. A combination of field and laboratory based researches is essential to solve major interpretative ambiguities arising from practical limits to field measurements. Numerical modeling provides and alternative way to obtain an insight into the growth and the response to main external factors of saltmarshes.Further research is needed on the detailed monitoring of instantaneous sedimentation processes on saltmarsh surface and on the effects of saltmarsh vegetation on the saltmarsh sedimentation. A full understanding of fundamental hydrodynamic processes in saltmarsh canopies is also required.
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