Walking in the continuous mountains, a huge crater will be revealed in front of you, the cliffs are standing upright like an axe and a knife, and the craters surrounded by the cliffs are like mountains opening their mouths to the sky. This strange natural landscape, commonly known as the "sinkhole", is the mystery of the miraculous creation left by nature to mankind.
"Sinkhole" facing the sky, scientific name karst funnel or karst funnel. In areas where soluble rock is distributed in large areas, abundant surface water leaks downward along vertical fissures in the soluble rock surface, and the fissures continue to expand, thus forming hidden holes shallow from the ground. As the hole expands, the soil above gradually collapses, and finally a funnel is formed. Sinkholes are mainly distributed in China, Russia, Mexico, Slovenia and other places. In recent years, sinkholes have been repeatedly found in mainland China. One sinkhole after another unveiled the mystery, and one surprise after another caused a sensation in the world.
Xiaozhai sinkhole
Fengjie Xinglong Town is located at the junction of Sichuan and Hubei provinces, and the abrupt Shilu Peak stands to the south. To the east of the town, there is a "Sagu Stream" that flows down from an alpine river valley at an altitude of about 2,000 meters. The stream flows through the limestone layer, and after hundreds of millions of years of dissolution and collapse, forming a large typical limestone landform. The world's largest "sinkhole" and the deepest "crack in the ground" are distributed here.
Most of the sinkholes here are only a few feet square, but there are many holes with a diameter of more than 100 meters, and regardless of the size of the holes, all of them are unfathomable. Among them, the most spectacular and mysterious is the Xiaozhai sinkhole. Xiaozhai Sinkhole is located in Xiaozhai Village, Jingzhu Township. Hundreds of meters away, the roar of running water at the bottom of the pit can be heard. Standing at the mouth of the pit, I saw a large pit concave between several peaks, the four walls were vertical, and the depth could not be seen. The upper diameter of the sinkhole is 622 meters, the diameter of the bottom of the pit is 522 meters, the depth is 666.2 meters, and the total volume is about 119 million cubic meters, ranking first in the world in depth and volume. Between the cliffs northeast of the Xiaozhai sinkhole, there is a winding path that goes down the wall and leads to the bottom of the sinkhole. When looking up at the bottom of the sinkhole, the vast sky becomes a small bright hole. From a cave tens of meters high at the bottom of the sinkhole, a dark green river suddenly gushed out. After more than 100 meters of water rushing through the rocks, the river quietly burrowed into another unfathomable stone cave.
Patio Gorge seam
Sagu Creek not only dissolved the world's largest sinkhole, but also cut through a rare feature on Earth, a 37-kilometer-long claw. Also known as the "Tianjing Gap", this gap is composed of canyons, water caves and underground rivers, with cliffs hundreds of meters high on both sides, and Senran ridges stretching parallel and zigzagging. In the valley between the two, a red gap was exposed. The gap is narrow and straight, as if a knife has been cut. Geographically, the cracks in the ground are called "dry valleys" or "blind valleys". In limestone areas, due to funnels and sinkholes in the riverbed, the river is completely cut underground, and the resulting dry riverbed is called "dry valley". Some rivers disappear into caves and become river valleys with no outlets, called "blind valleys".
There are countless sinkholes in the cracks under the Sagu Stream, and all the water of the stream flows into the ground, forming a dry valley. When the gap in the Tianjing Gorge extends to the Chigu Trough, it disappears between the two mountains, and at the end, there is a deep pit in the shape of a pot bottom, which contains green water all year round. In September 1994, British expeditions descended from here and measured a depth of 900 meters, the highest in the world. There is also a large pit under the cliff in the middle of the crevice, called "Black Eye". The walls of the pit are all black shiny stones with strange shapes. Throw a stone down, Tintin dangdang, the sound is endless.
The Xiaozhai Sinkhole and the Tianjing Gorge are ancient and mysterious, majestic and precipitous. Their discovery has extremely important scientific value for the theoretical study of karst landforms in the world.
Leye sinkhole
There is a Leye County in western Guangxi, which belongs to the Baise region, adjacent to Guizhou Province, and is located in the southern part of the Yunnan-Guizhou Plateau. Here, there is the largest sinkhole complex in the world. The Leye sinkhole group consists of the Dashiwei sinkhole and dozens of nearby sinkholes, densely arranged in a radius of more than 20 square kilometers, like huge shafts, and the wells are connected. Experts measured the accurate data of the big stone circumference through GPS earth satellite surveys: the depth is 613 meters, the crater mouth is 600 meters long from east to west, the width from north to south is 420 meters, and the volume is about 80 million cubic meters. Its vertical height and volume are second only to Xiaozhai sinkhole, ranking second in the world.
At the bottom of the Leye sinkhole group, a dense primeval forest grows. There are thousands of species of plants in the forest, most of which are very different from the plants outside the pit. Primitive shady plants abound under the sinkhole in Tai Shek Wai, mostly algae and ferns. Among them, more than 60 trees have been identified as living fossils of the dinosaur era and first-class protected plants, rare plants such as fir and blood and tear vine trees, Chinese medicinal materials such as beautiful horse-leaf flowers, small clusters of rock yellow lichen, and delicate seven sisters, as well as anon-famous orchids with slender stems and light green flowers. In addition, many rare plants from the prehistoric period such as clover, wild plantain, wild taro, etc. have been found in the closed environment of the sinkhole. The many sinkholes where various primitive plants live are essentially plant gene pools.
In the dark river at the bottom of the sinkhole in Tai Shek Wai there is a rare fish - blind fish. The blind fish is transparent throughout, the red blood, colored internal organs, and white bones in the body are clearly visible, but the eyes are small and small, which is obviously due to the dark environment of long-term life. The blind shrimp in the dark river have no eyes, and their limbs and antennae are two or three times longer than their bodies. The Leye sinkhole also found a national second-class protected animal called "Flying Tiger" by locals. The flying tiger is shaped like a bat, the face is like a fox, the mouth is like a mouse, the ears are like a rabbit, the duck foot claws, the long tail, the limbs are connected by leather wings, can glide between the jungle and the cliff, the posture is beautiful and the landing point is accurate, and it has the reputation of "excellent jungle glider".
In the spring of 2001, a huge underground palace was discovered in the Leye Dacao Sinkhole. According to investigations, the underground palace is about 300 meters long, about 200 meters wide, the highest point is 260 meters, and the volume is about 1.5 million cubic meters, which is enough to fit the next Beijing Workers' Stadium. Since the sinkhole is connected to the underground dark river, it is not uncommon for a cave to appear under the sinkhole, but such a huge underground palace is extremely rare. What is particularly striking is that the top of this underground hall, just 20 meters above the ground, is a sinkhole in the making. The discovery of the underground palace provides the most intuitive scientific basis for studying the origin and structure of sinkhole caves.
There is also a difficult mystery in the underground palace: at the entrance of the underground palace, there is a field of charcoal ash several meters square, and the ashes are stacked neatly, indicating that someone once roasted a fire here. Experts carefully studied the ashes and found that most of them were calcified, and based on the degree of calcification, they were at least a few hundred years old. In other words, someone discovered this rare underground palace hundreds of years ago and lived in it for a while. So, who was the first to enter the underground palace? Why break into the underground palace? Where did it go then? Obviously, the underground palace contains many unknown secrets.
Why are there so many sinkholes within a radius of thousands of meters? Chinese geologists deduce that this is related to the special geological structure of Leye County. The strata in Leye County have an S-shaped twist structure, and the area distributed by the sinkhole is in the middle of this twist structure, that is, the connecting line of two reverse arcs. This is the area where the tension occurs most during crustal oscillations, resulting in numerous tensile fissures, known as sinkhole groups. This inference also explains why there are no sinkholes in Lingyun, Tianyang, Xilin and other counties with the same geological conditions as Leye.
For the time of the formation of the sinkhole group, experts believe that it was about 3 million ~ 4 million years ago in the Cenozoic Quaternary, during which the famous Himalayan orogeny occurred, and the Yunnan-Guizhou Plateau was also formed during this period. Due to the hot and humid weather, abundant rainfall, and large limestone formations in the Tai Shek Wai Tin Leye area, these are necessary conditions for building sinkholes like Tai Shek Wai. The opening to the underground palace at the bottom of the sinkhole is unusually narrow, and it is a dangerous place created by nature. In the primeval forest at the bottom of the pit, there are plants that are contemporary to dinosaurs, so some people trace the formation of the Leye sinkhole back to 65 million years ago. If this is the case, then in the tens of millions of years of crustal changes, what role do these sinkholes rely on to maintain their original appearance? It's a mystery. In addition, is there still an unknown sinkhole in Leye County? Underneath this magical mountain, is there a cave that is forming that will one day suddenly collapse and become a new sinkhole?
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