A core named Nanyong-1 was obtained at the flat of Yongshu Reef which is situated at 9°32'-9°42/N, 112°52'-113°04'E,in Nansha Islands.The core depth is 152.07m.It is loose bioclastic gravel layer from 0 m to 17.3m and reef limestone beneath 17.30m.According to the coral genera and species(Lobophyllia and Merullia in the lower Stratum, the age of strata dated by uranium-disequilibrium series that is 875000 a B.P.and the result from Paleomagnetic methoed that is 900 000-970 000 a B.P., the strata of all the core are defined to be Quaternary sediments.Based on the analytical results of peleomagnetic dating,uranium series dating,14C dating, and amino acid dating with the eroded surfaces and the changes of diagenesis,the line of demarcation between the Eaxly Pleistocene and Middle Pleistocene is estimated at the depth of 90m.But the line of demarcation between Middle pleistocene and Epipleistocene is difficult to detsrmine according to the existing information.The line of demarcation of the Epipleistocene and Holocene is at the depth of 17.3m.Therefore,the strata of core Nanyong-1 can be divided into two groups: the strstum at depth of 0-17.3m is Nanhai group, Holocene, and the stratum at the depth of 17.3-152.07m(not reaching the base surface) is Nansha group, Pleistocene.
The main stream estuary of the Nandujiang River is that of wave and river interactions,where runoff and wave field have obvious seasonal changes.There are three basic forms of estuary sediment byeeing: downstream bypasssing, outer for bypassing the shoreward bypassing.During flood season runoff flows outside the estuary in efflux form at a velocity of 1.5～3.0 m/s, the sediments is deposited on both sides of the river-mouth and near the estuary,forming marginal linear bars and bar shoal, respectively.Outflow mainly westward diffuses because it is affected by waveinduced shorward and alongshore radiation stress and east-west oriented tidal current.During low water season although out flow is small, incident waves are impeded and broken at the depths greater than the normal.Westward radiation stress causes littoral drift over bar shoal and its periphery, shoreward radiation stress results in shoreward migration of swash bare over bar shoal.According to compartive analysis of the historical ocean map, it is revealed that a net erosive quantity of subsqueous accumulations of the main stream estuary is more than 40 000m3/a, 0m, and 5m contours gradually seaward accrete, but 2m contour shoreward regresses.
The poor limestone mountain regions in Guangdong are situated in subtropical zone with plentiful sunshine and rainfall.But poverty in natural resources, degrsdation of ecological envirment and low bearing capacity of land have limited the development of the rations which are the poorest in Guangdong.In recent years,for mitigating the population pressure on the land parts of the people have been moved to other places from the regions.The author considers that after moving people out,vegetation on the mountain should be recovered throush closing hillsides to facilitate afforsetation so as to approve ecological environment;a large area of limestone mountains can be built into natural forest park or natural reservesl then some scenic spots with necessary fundamental facilities can be built for tourism.
Guangdong,located at low latitudes, has warm climate and is rich in solar energy in winter.The climatic resources in winter ought to be made full use of.The heat condition can meet the demands of three crops a year in Guangdong, which has large population and insufficient land.We should not only develop tropical and subtropical economic plants,but also increase the production of rice and extend the sreen manure-growing areas for development of the system of three crops a year,in order to increase the land productivity.Cold wave often occurs during winter in Guangdong,and makes damages to the winter crops, overwinter crops, fruit trees, domestic animals and pond fishes.Synthetical measures of preventing cold damages are proposed in this peper based on the analysis of the materials of cold damage on agricultural production in recent two years.
It is found that the slack-seasons of vegetable supply in spring and summer-autumn are obvious in Guangzhou owing to the limitation of climatic condition, and the problem has not been effectively solved for a long time because of the over-concentration of vegetable production bases near the urban area.The experience in vegetable production and supply in many developed contries and some cities in China shows that it is the key to distribute the production reasonably for the balance of vegetable supply.Based on the analysis of climatic resources in Guangdong Province,it is proposed that the slack-spring bases and slack-autumn bases be established respectively in Southwest and North Guangdong in order to increase vesetable supply to Guangzhou in slack-seasons.
Based on the census data of 1991,the population structure in 91 blocks of Guangzhou and their characteristics on space distribution are discussed.Compered with that in 1982,the basic characteristics on space changes are indicated.1) The urban population density is variously high.In central part of the city,31.35% of the people live in 6.7% of the area.In spite of the situation like this,the density of the central part tends to decrease, but that of the marginal districts tends to increase.Additionally, the increasing speed of population in the central pert is lower than that in the marginal ones.2)The population average age in the central pet is larger than that in the marginal.The communities of Core Family appear in the newly-built residential parts around the city border.From the structure of reseneration ages,the percentages of age from 0 to 14, from 15 to 49 and over 50 in central part are 16.1%, 59.4% and 24.5%,respectively.But those in the marginal districts are 14.9%,68.2% and 16.8%.In Guangzhou Economic and Technical Development Zone which rose in recent years, the Percentase of young people is above 90%.3)The sex ratio varies greatly(95.63-274.03).The further it is away from the central part, the higher the sex ratio is.This relates to the difference of occupation's space distribution, age structure and historical male immigrants.4)The distribution of occupation smicture matches the industrial structure.The 3rd industrial area is located at the northeast.The fixture of the 1st and 2nd stand at southwest.In the middle, the mixture of the 2nd and 3rd industries.5)The average education level is 9.35 years.It is high in the east, low in the west.This matches the space structure of occupation types.6) Muslin, Zhuang, Man are the main minority nationalities.Their percentages to the total population are 0.21%, 0.13% and 0.13% respectively.Although their population is small, their space distributions are relatively concentrated with lucrative businesses.General speaking, the space distribution of population structure is quite disbalanced.It is the combinative consequence of natural and historic background,city functions arrangment,industrial structure and urban planning.
As a system, population,land,grain and disasters are interrelated,but attention has not been focused on the coordination of the factors in the system for a lons time.The excessive growth of the population has added detrimental effects to the national economy and livelihood:decrease and degradation of land resources,statution of grain production and increase of natural disasters.As the 21st century is approaching, it is a very important task for people to take effective measures to solve the problems above.In this paper, the relationship among population,land, grain and disasters is analysed according to the conditions in China f and some suggestions are put forward.
Resemblance of industrial structure in different regions has turned into the main problem of industrisl development in Hunan Province, but differences of the structure exist in different-departments, including force typical aspects:1)the comprehensive capacity of specialization which represents the scale of the departments 2)the smicture within the department which includes the connection of the constitution of product and technology;3)the economic benefit of each department and of all departments as a whole.In order to realize the adjustment and optimization of the structure, a modle for the reasonable allocation of the industrial productivity is established, and the allocation of sixteen industrial depotments in Hunan Province is valuated.The author sugsesta to adjust 1)the regional structure of industrial allocation,2)the depotment structure,3)the enterprise structure,and 4)the product structure.
The establishment of System Dynamics has made it possible for sociologists, strategists,and policpoaters to have tried out experiments in a laboratory like sciefitists do before a significant stratesital decision is made so that they are able to see the practical results in coming years, cornpare the differences among various plans, choose the mest satisfactory plan and abolish the unhealthy, even harmful ones.Taking Yongding County of Fujian Provice as an example, this paper tries to set up a strategical and tactical laboratory of planning for general coordinative development of science, technology, economics and society by using method of System Dynamics.Through experiments,three developing plans(low, middle and high) with the main environmental suppeitions needed for attaining the Soals and some results of decision analyses are chosen to give policymakers the powerful quantitative supports in making macroscopic development planning.
Based on the application of experimental technology in geographical research and teaching,the characteristics of geographical experimental technology are explored in this paper.(1)The types of experiments are different and the technological system is sophisticated,including all-control experiment, semi-control experiment and non-contral expectment according to the methods and conditions of experiments,and they can also be divided into observation experiment, analysis experiment and research experiment in view of the direct goal of experiments.(2)Observation is the primary characteristic of geographical experiment.(3)The indirectness and non-control lingness are the reticular advantages of geographical experiment.(4)Because of the Limitations of technology, the conclusion only has shoilarity, the experitment cannot create the peicular environment and conditions that scientific research needs.From the development trend of modern geography and the limitations of geographical experimental technology, the authors propose some ideas: strengthening the cultivation of experimental technology experts, actively carrying out scientific experiment, creating batter experimental conditions, exploring and improving comprehensive experimental technology, and developing reticular geographical expertriment technology system.
The 1500-meter contour line is of distinct importance as the dividing line between the subtemperate zone and the subtropical zone at the Ailao Mountain in Yunnan Province.The area below the 1500-meter contour line has been opened up and planted to rice,while that above it still preserves a dense temperate forest.These two are combined into a wonderful complementary and conjugate realationship.The dense forest may not only conserve water but also accumulate a lot of humus,which can meet the large demand of rice agriculture for moisture content and fertilizer.The Hani nationality mainly inhabits around the 1500-meter contour line area,chiefly because of the requirements of the terrace of rice agriculture.Even though it is no doubt also for the purpose of avoiding the damp and hot and epidemic environment.Because it is far from enough natural fertilizer and it is tripossible to fertilize the terraced rice fields in the high mountain and deep valley areas as people in plains do.The only way is to make use of the natural manure flushed by running water and so the source of the manure should be above the terraced field.Moreover, the Hani nationality that settles around this altitude can easily hunt in the woods.Because of all those, the terraced field landscape is gradually internalized into a cultural morphology unique to the Hani nationality.Natural, economic and human factors constitute a highly coordinated relationship which enables the Ailao Mountalous Area to become one of the typical areas for studying the man-land relationship of geography.
Fuzhou is a distingushed cultural city with a history of more than 2100 years, and is one of the fourteen open coastal cities in China.The city is rich in tourism resoures.Fine mountains with grotesque rocks and quiet valleys hold the city in their heart.The islets and ragged reefs asterisk the vast sea, presenting an eye-opening view.More than 100 scenic spots,such as hills, islands, caves, rocks, lakes, temples, nunneries and pagodas, are distributed in/around the city.It is assumed that Fuzhou will be one of the most favorable tourist regions in East Asia by 2000.To realize the above magnificant goal, the following measures should be adopted:1)investigating and evaluating tourism resources, and making regional tourist development planning;2)adjusting tourist product structure and designing up-to-now types of tourist products;3)protecting tourism resources and environment,and improving the tourism facilities;4)constructing tourist commodity production bases and developing purchase tourism.
