| Chongqing is located in the second stage landscape step edges. Karst landform is well developed, is a typical subtropical karst type appearance. In-depth study on it can provide the basis for karst areas of information and scientific evidence for territorial control planning, agricultural zoning and other related production, teaching, scientific research institutes in Chongqing, and has important practical and theoretical value.Through the field investigation, a typical regional mapping, geological, topographic map interpretation, verification, and previous methods of data analysis and chronology of karst in Chongqing were studied. Preliminary conclusions are:(1) Karst landscape is a comprehensive reflection of karst forms. It is the same as other landforms and the result of internal and external product of geological forces. Therefore, this article classifies karst landscape with the combination of cause and landform as the basic principles of morphology. We will classify three karst landforms. The first stage, formation classification, which depends on the formation of the landform types of the dominant operator in strength and composition of the different geological material basis for a different type. Morphological classification is of the second stage. Form combinations (combination of positive and negative terrain) are characterized by specific targets, divided into two types. The last stage is formed by a variety of karst individual forms. Their small sizes, spatial distribution were discrete dot, line or shape in the form of a small facet, not for regional distribution.(2) The combination of karst landscape features in Chongqing: First, complex and diverse combination of karst landforms are dominate with mountains and hills. Second, karst geological structure and surface composition discrepancy are controlled significantly, regional variation as well.(3) Analysis of the study area by geological structure, lithology, altitude, etc. on the development of karst topography and field investigation, in this paper, Chongqing is divided into four karst landform areas, are:northwest non-karst landform (I), Middle typical valley karst mountain landform (II), Southeast typical gorge karst mountain landform(III), Northeast layered structure karst mountain landform(IV).(4) Karst landscape evolution:â‘ Yanshan movement from the Cretaceous to early Quaternary, ranging from the amount due to intermittent uplift of the crust results, Daba and the development of the Three Gorges area has four planation surface, the other three areas;â‘¡On the new tectonic movement in terms of the rate of increase to the maximum Daba, followed by a Qiyao Jinfo Mountain and the Three Gorges area, Yangtze River valley to the tilt;â‘¢the left side of the Yangtze River region, the third stage after the formation of planation surface, the right bank of the Yangtze River region syncline area vertical and horizontal along the river and the valley is still abnormal development of the secondary, strong erosion, so a mountain anticline, syncline valley for the hills, white and orderly arranged to form a parallel combination of Ridge Valley landscape. The right side of the Yangtze River region, mostly planation surface like inverted step mountains, mainly because of planation surface tension crack development, leading to the back Xiegu Capture views into the valley of water increases, erosion strengthened, so the formation of syncline platform or mountain the inversion. |
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