Geomorphology is to study the morphological characteristics, causes, distribution andevolutionDiscipline of laws, also known asTopography。
Geomorphology isgeographyA branch ofgeologyPart of.The English Geomorphology of geomorphology is derived from Greek and consists of three words: Geo (earth), Morphe (appearance) and Logos (discussion), that is, the discussion on the appearance of the earth.
Geomorphology is gradually differentiated from geography and geology, and its development history can be divided into three stages:
Embryonic stage
Geomorphology
In the Western Zhou Dynasty of ChinaThe Book of Songs Daya Dugong LiuThere are descriptions of "hillock" (hill), "tableland" (plain) and "valley" (low wetland).In the late 11th century (Northern Song Dynasty)Meng Xi Bi TanIn the middle, Shen Kuo's invasion, transportation andAccumulationThere is a clear concept of the relationship between the three, andNorth China PlainIt is the result of river accumulation.
Early Qing DynastySun LanLiu Ting's "Theory of Geomancy" proposed that the geomorphic function "changes with time, changes with time, and changes with people", which has involved the evolution of geomorphology and noted the impact of human activities on geomorphology.British JHuttonIn the Theory of the Earth (1788)changeIt is regarded as an integral part of the development of earth geology.[1]
Formation stage
From the end of the 19th century to the middle of the 20th century, geomorphology began to become an independent discipline.United States WM. Davis and W. Penk of Germany played an important role in this.Davis put forward the theory of geographical (geomorphic) cycle in 1899, and believed that geomorphology was a function of structure, agent and time (erosion stage).tectonic movementThe rising mountains caused byExternal force actionUnder the erosion of flowing waterManhoodAnd old age.In old age, the ground is flattened“Peneplain”。
Penck Of《Geomorphologic analysis》(1924) proposed that the landform is the product of the simultaneous interaction of internal and external forces, and noted that the denudation process and the crustVertical movementThe relationship between（Convex slope、Concave slope, straight slope) depends on the structural (ascending) movement andDenudationThe quantity comparison relationship between.These views have long been the theoretical basis of geomorphology.
Development stage
Since the middle of the 20th century,Plate tectonic theoryThe rise oflandforms, including the study of marine geomorphology.River dynamics、Ocean dynamicsThe introduction of glacier dynamics has strengthened thequantitative study 。Physical detection andremote sensing techniqueIt provides macro data in depth for geomorphological research.The establishment of various geomorphological observation stations will help to understand the dynamics and trends of modern geomorphological processes.The theory of geomorphology has also made new progress.
After 1949, China's geomorphology developed rapidly.We have systematically studied theFluvial landformandQinghai Tibet PlateauLandform provides scientific data for water conservancy and road construction, and also provides scientific information for the unique loess in northwest China and southwest ChinaKarstThrough in-depth research, the author puts forward the relevant theory of cause of formation.
The development of geomorphology can be roughly divided into the following three stages.
Initial stage
Geomorphology
Geomorphology germinated very early in China.Written in the Warring States Period"Pipe · Ground Staff"DistinguishedProfane farmland(Plain), grave extension (sloping land), hills, mountain forests and rivers. In the hills, 14 types can be subdivided according to the terrain and other conditions.Northern Wei DynastyLi DaoyuanOn《Water injection》The Yellow River, Yangtze RiverXijiang RiverRiver bank topography.Shen Kuozhai of the Northern Song Dynasty《Mengxi Writing》The river erosion, transportation andAccumulation, and believes thatNorth China PlainIt is formed by river accumulation.the Ming dynastyXu XiakeFor Southwest ChinaKarst sceneryThe classification, distribution and cause of formation of are all incisively discussed.
In Europe, the United States and other countries, geomorphology was initially subordinate to geology.British JHuttonIn the book Earth Theory published in the 1880ssedimentary rockThe process of rising to form mountains and then being eroded by flowing water to become lowlands.UK CRyleOn《Principles of Geology》It indicates that the rock is disintegrated on the surface, and the rock debris generated is washed, transported and deposited by the flowing waterlowlandProcess.
A. Surrell of France studiedThe AlpsOfRiver profileIn 1841, it was pointed out that the longitudinal profile of a river, regardless of its size, tended to be a balanced profile, and the profile slope became slower from upstream to downstream.Meanwhile, GK. Gilbert is here《Bonneville Lake》The paper also puts forward the concept of balance in geomorphic development.
Formation stage
From the end of the 19th century to the middle of the 20th century, geomorphology became an independent discipline.The main representative of this period is the United StatesW. M. DavisAnd GermanyW. PunkThey made valuable theoretical discussions on the long-term evolution of landforms.Davis has a famous saying that "landform is a function of structure, process and stage", that is to say, the landform status of a region depends on the geological structure of that region (includingrock stratumPhysicalchemical propertyAnd rock stratumOccurrenceAnd structure), the geomorphic shaping effect (such as flowing water, glacier, wave, etcErosionandAccumulationAnd the stage of landform development.He proposedErosion cycle theory, considered byEarth internal forceCaused by tectonic movementDenudationWill eventually be razed intoPeneplain；The tectonic movement is spasmodic (that is, a sudden, followed by long-term stability). Under the long-term water erosion, the rising mountain will go through three stages of development: infancy, manhood and old age.
Punk was the founder of geomorphology at the same time as Davis《Geomorphologic analysis》(1924), etc.He believed that the slopes in the arid area were denuded and retreated in parallel, rather than the top-down denudation and erosion that Davis said was growing in the foothillsDenudation plain。He called this process the piedmont leveling process, and the formed leveling terrain is the piedmontPlanation planeReplace withPeneplain。(SeeTheory of parallel retreat of mountain slope、Piedmont step）
Germany also made important contributions during this periodF. Von RichthofenAt the end of the 19th century, he made a lot of field investigations in China and proposedLoess aeolian theory；France EM. P.M.J. de Margerie and de la Noe analyzedRock occurrenceAnd make these differencesOccurrenceOfTectonic stressThe impact on landform evolution has createdTectonic geomorphologyResearch direction of.
There are also many new developments in theoretical research.As for denudationPlanation planeThe cause of formation, JK. Biddle believes that the structure is stablechemical weathering PrevailingHumid hot climateExtensive planation surface can be formed in the area.Its formation process is: extremely thickWeathering crustAs the surface is scoured, it develops to the depth, so that the terrain is leveled. This kind of planation surface is called etching plain.
FranceJ. - L. - F. TricarthinkPeriglacialThe alternative action of thawing and freezing of the environment and the thawing and freezing mud flow on the slope can also level the terrain.This planation surface can be formed at the top of the mountain, and its function is called highPlanation。Therefore, the planation surface at the top of high mountains and plateaus may not be formed at the lower part first, and then uplifted to the top by tectonic movement.
The study of the relationship between tectonic movement, geological structure and geomorphology.narrow senseTectonic geomorphologyIt refers to the formed geological structure (such asanticline、syncline , monoclinic), external forceErosionVarious landforms formed under, also known asGeological structure and landform；The generalized tectonic geomorphology also includesNeotectonic movementLandforms directly caused and not significantly transformed by external erosion, such as newly uplifted mountains and plateaus, newly subsided plains and basins, newly arched anticlines anddepressionSyncline, also calledActive structurelandforms.
yesGeological structure and landform, mainly studied inExternal force actionNext, the specific performance of the overall landform of various geological structures, and the specific performance of various strata composed of different rocks in the landform.Main research on active tectonic landformEarth internal forceGeomorphic deformation caused byGeotectonicsandGeodynamicsTo analyze the force source of deformation.
Climatic geomorphology
To study the characteristics of the surface morphology controlled by climate and the rules of its occurrence and development.DifferentClimatic zoneThere are different dominant external forces, as well as differences in strength and combination of external forces, which will form differentClimatic geomorphologyType.asGlacial GeomorphologyandPeriglacial landformThe distribution boundary of is controlled by climatic conditions. However, different glacier landforms and periglacial landforms will be shaped due to the differences in precipitation and temperature conditions in the same glacier or freeze-thaw interaction area;The geomorphic effects of wind and water are common on land, but they are differentClimatic zoneThe landforms are very different;be otherwise similarlimestoneReceiving watercorrosionThe formed karst landform will have different performances under different water and heat conditions in different climatic regions.
To study the role of various external forces in the formation of landform and the morphological characteristics of the formed landform.External forces include water, glacier, wave, wind, dissolution, thermal freezing and thawing, etc.It uses the methods of physics (mainly mechanics) and chemistry to studyGeomorphic processTo reveal the internal mechanism in the process of geomorphic occurrence and development, and then establish its physical or mathematical model.
Dynamic geomorphologyHas becomemodern geomorphology Important development direction.An important theoretical basis of dynamic geomorphology is the idea of dynamic balance.After long-term interaction between various external forces and the surface, they can be adjusted to a relatively balanced state. At this time, energy consumption and material distribution are in the most reasonable state, that is, the maximum "entropy" value is reached, and the landform is relatively stable.Equilibrium profile of mountain slopeRiver equilibrium profile、Coastal isostatic profileAnd the balance of ice and snow accumulation and melting are the embodiment of this idea.Nature tends to be balanced, and can also reach a transient equilibrium state.However, the early geomorphology overemphasized the role of balance, and regarded the occurrence and development of geomorphology as a process ofClosed systemEnergy (various agents) and material (destruction and transportation) can only move within the system, so it is believed that when the whole system reaches equilibrium, the development of landform will stop or start a new cycle later.
modernDynamic geomorphologyChanged this view and believed thatGeomorphic processIt is an open system, in which energy and matter can enter and exit freely, and the equilibrium state can be reached in a certain period of time or a certain space in advance, not necessarily the equilibrium of the whole system.In fact, the energy flow of nature andMaterial flowIn a random state, it is ever-changing.Therefore, there is a trend of equilibrium and it is in a state of being broken at any time.On the other hand, there is also a problem of scale, which may have reached equilibrium in a long time and on a large scale, but may not reach equilibrium in a short time or in a local scope.Like a rivertime scale If there is no significant change in the average elevation, average sediment discharge and other characteristic values of its longitudinal profile, it can be considered that it has achieved equilibrium.However, from the perspective of different hydrological years and different seasons in the year, there are changes in erosion and deposition, sometimes even quite large, which is in an unbalanced state.According to this idea to study the occurrence and development of geomorphology, geomorphology research is closer to the actual situation of nature.
Study some catastrophesGeomorphic process, such asLandslide, landslideDebris flowTo predict and propose protective measures;Study erosion, transportAccumulationAnd provide basis for water and soil conservation, channel regulation, port site selection, bank and slope protection and other engineering construction;Study the law of sand movement, take measures to prevent wind and fix sand, and protect farmland, grassland and roads;The selection and construction of many tourist spots and areas characterized by natural scenery also need the knowledge of geomorphology.
research method
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Since the 1950s, geomorphologicalresearch methodAnd means have made great progress.
① The research and application of geomorphology is not only based on qualitative description methods, but must use quantitative methodsGeomorphic processExplain the relationship between landform and its formation factors.17. Quantitative methods were used in the study of river geomorphology in the 18th century, but were widely used in 1945 by RE.HortonProposedRiver length, number and level.Most of them are used for the measurement of geomorphic morphological elements, such as river length, drainage area, terrain height and slope. These parameters are used to carry out mathematical statisticsFluvial landformCharacteristics, slope characteristics, etc.Because many geomorphic processes are very slow, some sudden factors are difficult to monitor, and the influencing factors are too complex to be quantitatively expressed one by one, the application of metrological methods in geomorphological research is not enough.
④ Radioactivity is applied to the formation age of many geomorphic eventsisotope、Thermoluminescence、PaleomagnetismThe development history of landform can be reconstructed more accurately from time and influence factors, and then its macro development trend can be predicted.
⑤ Geomorphologic mapping technology has made great progress,Geomorphic mapIt is developing towards quantification, standardization and legend standardization.
