Surface karst landform 1. Gullies and stone buds
Karst groove refers to the rock groove formed by the continuous dissolution and erosion of rocks by surface water flowing along the rock surface and cracks; Stone bud refers to the protruding stone ridge between gullies, which is actually the residue during the formation of gullies. Yunnan Shilin is a well-developed tall stone bud group, and its formation conditions are thick layer, pure quality, gentle occurrence, sparse vertical joints and humid climate and environment.
2. Tiankeng and Shaft
Mainly due to the continuous depression of karst ground, funnel-shaped circular depressions or vertical holes are formed, which are widely distributed in Chongqing and southern Sichuan. They are formed on both sides of steep slopes, depressions and the bottom of basins. Because flowing water erodes strongly along cracks in rocks, sinkholes or shafts are tens to hundreds of meters deep.
3. Dissolved depressions and valleys
Dissolved depression is a kind of closed karst depression, with a wide range and approximate circle, surrounded by low mountains and peaks, with a flat bottom, which is prone to waterlogging in rainy season and drying in dry season. The area ranges from half a square kilometer to more than ten square kilometers. The dissolution valley is formed by the further expansion or integration of the dissolution depression, which is greatly influenced by the structure and has a wide area. Generally, it is tens of square kilometers to hundreds of square kilometers, distributed in a plane strip, dozens of kilometers long and flat at the bottom. For example, there is a dissolved valley in Duan, Guangxi, which is one kilometer wide and ten kilometers long. This karst terrain is widely distributed in Yunnan-Guizhou Plateau in China, and the locals call it "bazi".
4. dry valley
Dry valley is a valley left over from the disappearance of surface runoff in karst area. The reason for its formation is that a certain section of river water flows into the ground along the shaft or water tunnel at the bottom of the river, forming underground runoff. This phenomenon that surface runoff becomes underground runoff is called undercurrent. Another reason is the result of river cutting and straightening. This landform type is common in North China and Northeast China.
5. Peak forest, peak cluster, butte and Tiansheng Bridge
"Guilin's landscape is the best in the world, and Yangshuo's landscape is the best in the world." China and Guangxi have unique scenery, and karst is the main reason for this natural barrier.
Peak cluster is a collection of peaks formed by strong dissolution of soluble rocks. Peak forest is formed by the further evolution of peak cluster. Of course, under the action of neotectonic movement, the peak forest will be transformed into peak cluster with the rise of the crust. The peak is pointed like a cone, tower and column, with stone buds and karst ditches on the surface, and there are often caves and shafts between the peaks. The peak cluster landform can be said to be a museum of karst landform.
Gu Feng is an isolated limestone peak in karst area, which needs long-term stability of the earth's crust without much geological movement. The strange and beautiful scenery of Guilin will tell you your love for nature.
Tianshengqiao is an arched landform formed by the dissolution of the lower part of soluble rock by running water.
6. Surface travertine accumulation
This is a typical karst landform on the surface, mainly including waterfall flowers, travertine dams and karst spring flowers.
Waterfall bloom refers to the sudden increase of water velocity, decrease of internal force, and the escape of carbon dioxide in the water, forming waterfall bloom. The famous Huangguoshu Waterfall in Guizhou, China belongs to this kind.
The formation of travertine dam is that the alpine snow and ice dissolved water containing a lot of CaCO3 and the underground seepage karst water containing a lot of CaCO3, after a certain distance of underground runoff, are discharged from the surface in the form of spring water. With the increase of water temperature, the acceleration of water flow speed and the action of a large number of algae, a large number of travertine deposits are formed. Travertine contains many impurities and many different elements, and is influenced by aquatic plants, which makes travertine show many colors. This landform is widely distributed in the first generation Huanglong Temple in Sichuan, China, and the development of tourism in Huanglong Temple is closely related to this unique karst landform.
Karst spring flower is a kind of spring water, in which a large amount of CaCO3 is dissolved and gushes out from the surface. Due to the increase of temperature and the decrease of pressure, CaCO3 forms travertine deposits at the spring mouth, and the long-term accumulation makes the spring flowers form different shapes, which is also a beautiful scenery endowed by nature to human beings. This karst landform is very common in Yunnan, China. Underground karst 1. General situation of karst caves
Karst caves are underground caves formed by the dissolution and expansion of groundwater along the cracks of soluble rocks, with different scales, which can accommodate more than 1000 people. There are many strange landscapes in the cave, such as stalagmites, stone pillars, stalactites and stone curtains. It's too small to pass a person. Caves are the result of water dissolution, flowing water erosion and gravity for a long time. Cave landscape is widely distributed in Hunan, Sichuan, Guizhou, Yunnan, Guangxi and other provinces in China.
2. Dissolved landform-stone pot and side ditch
If a local place at the top of the karst cave is subjected to strong turbulence, with the increase of water pressure, the dissolution ability is enhanced, and the dissolution in these places is greater than that in the surrounding area, thus forming an arc surface concave to the top side. This landform is called stone pot. Side ditch refers to the trough-shaped landform in which the side wall of karst cave forms a cave-oriented depression under the action of water solution. These two karst landforms are very common in karst caves.
3. Accumulation landform
Accumulation landform is the essence of karst cave landscape, and you can enjoy the magical cave world in southwest karst caves. The accumulation of gravity water is the main formation mode of karst cave accumulation landform. Water drops with a large number of soluble rocks fall intermittently from the top of the cave and accumulate continuously, thus forming colorful stalactites, stalagmites, stone pillars, stone curtains, marginal stone dikes and so on.
Stalactite is an inverted cone-shaped karst deposit, which can reach several meters in size and only a few centimeters in size. It is mainly caused by karst water seeping out along the tiny cracks at the top of the cave and continuously precipitating at the dripping place. It is closely connected with the top of the cave and extends to the bottom of the cave.
Stalagmite is a karst deposit extending upward from the bottom of the cave, which is mainly the product of continuous deposition of karst water dripping to the bottom of the cave. Compared with stalactites, it generally appears in the form of bamboo shoots, towers and cones.
The cross sections of stalactites and stalagmites are concentric circles.
Stalactites and stalagmites grow relatively and gradually combine into a whole. With the continuous deposition of karst water, they gradually form thick stone pillars.
Stone curtain is the product of CaCO3 _ 3 gradually deposited in the process of karst water flowing along the cave wall in the form of thin film. It is generally flaky and layered, with curved streamline and tens of meters high, which is very spectacular.
Edge stone wall refers to the rock wall-like deposits on both sides of the bottom of the cave, which are several centimeters to several tens of centimeters high, arc-shaped and stepped.
In addition, there are many grotesque landscapes in the cave, some like lotus flowers, some like branches stretching, and some stone grapes, stone corals and so on.