Chapter 1576: Is this a tiankeng?

Chapter 1764: Is this a sinkhole?
After hearing what Zhao Zhongyao said, Feifei said, ‘Okay! Then let's go over and see the situation! ’
So Zhao Zhongyao and Feifei flew to the distant valley again. Soon, they flew into the valley.
It's just that when Zhao Zhongyao and Feifei flew into the valley again while driving the spacecraft, they saw the volcano that originally looked very close to them, but in fact, it was far away from them. They will not be affected by this volcanic eruption in the tiankeng. Even if volcanic lava flows out, it will not flow into the tiankeng.
Because Zhao Zhongyao has already observed this valley again. This valley, although it extends to this tiankeng. But as it leads to this tiankeng, its depth gradually decreases. The closer to the tiankeng, the lower the depth of the valley. When the valley is reached, a gap is formed at the edge of the valley.
Zhao Zhongyao felt that if there was a volcanic eruption in this valley, it would not have much impact on the tiankeng all day. Because the lava flow from the volcanic crater does not flow upwards, only downwards. In other words, these lava flows will only flow below the valley, not above the valley.
Thinking of this, Zhao Zhongyao looked at Feifei and said, ‘Feifei, although this volcano wants to erupt. But we don't have to worry about anything, it will not pose any threat to the sky in front of us, we can just go to that sinkhole. ’
After hearing what Zhao Zhongyao said, Feifei nodded and said, ‘Okay, since this is the case, let’s go to the sinkhole again! Look at Feifei, this volcano will not affect the tiankeng in the distance. He is not so afraid of this volcano. He still wants to see the tiankeng now.
‘Okay, let’s go to the sinkhole! After Zhao Zhongyao finished speaking, he drove the spaceship again and flew towards Tiankeng.
Soon, Zhao Zhongyao piloted the spacecraft and flew over the Tiankeng again. It's just that they are going to land in the sinkhole. They should also discuss it now.
‘Feifei, you said, we should land in the sinkhole now. Zhao Zhongyao looked at his son and asked.
Feifei thought for a while and said, ‘I think we should let the spacecraft land in the center of this sinkhole first! In this way, we can directly understand what the bottom of this tiankeng looks like. ’
Feifei thought, since this is a tiankeng, the middle part of the pit must be the bottom of the tiankeng that day.
After hearing what his son said, Zhao Zhongyao thought for a moment and said, ‘Okay, you are right. The middle part of this tiankeng should be the bottom of the tiankeng. Let's just let the spacecraft land in the middle part of the sinkhole and take a look! ’
As a result, Zhao Zhongyao drove the spacecraft again and flew to the bottom of the Tiankeng.
Although this sinkhole is very large, it is not very deep, only two to three hundred meters deep. In fact, a more accurate term should be called basin. However, from a high altitude, it looks more like a sinkhole. Therefore, Zhao Zhongyao and Feifei are still willing to call this huge basin a tiankeng.
Zhao Zhongyao quickly piloted the spacecraft and flew to the bottom of this sinkhole. After all, the bottom of this tiankeng is not very deep, and the speed of the spacecraft is very fast, just after a while, they flew to the bottom of this tiankeng.
Only when Zhao Zhongyao flew the spacecraft to the bottom of this sinkhole did he realize that the bottom of the sinkhole was not a deep pit. It is a ‘highland’. Of course, to be more precise, it should be a big mountain.
And Zhao Zhongyao's spacecraft could just stop at the top of this mountain. And at the top of this big mountain is a huge rock. The spacecraft can just stop on this huge rock.
After Zhao Zhongyao parked the spacecraft, he looked at Feifei and said, ‘Feifei, our estimate is wrong. The middle part of this tiankeng is not the lowest place at the bottom of the tiankeng. On the contrary, this middle part should be the highest place at the bottom of the entire tiankeng. ’
Zhao Zhongyao can now see the outside of the spacecraft through the porthole of the spacecraft. Although their spacecraft dropped two or three hundred meters. But the area of ​​this tiankeng is huge. Even if they dropped two or three hundred meters, they could still see the surrounding scenery clearly at the bottom of the sinkhole.
Because this sinkhole is not on the back of Mercury, but on the front of Mercury. The front of Mercury is always daylight. There will always be plenty of sunshine. Even at the bottom of this tiankeng, you can clearly see the surrounding scenery.
It's just that when Zhao Zhongyao and Feifei were above the tiankeng just now, when they looked at the scenery below, they felt that they couldn't see clearly. This is because the light above the tiankeng is very strong. This strong light affects the scenery you see in other places.
It was possible to see things clearly under this tiankeng. Just because the spacecraft was above the tiankeng before, it was not so easy to see the situation inside the tiankeng. And now, Zhao Zhongyao and Feifei have reached the bottom of the tiankeng. They can now clearly see the scenery at the bottom of the tiankeng.
Now Zhao Zhongyao and Feifei have Qu Yuqian and Tiantian. The family curiously began to look outside through the porthole of the spacecraft. When they saw it, their eyes widened in surprise.
Because the whole situation outside is completely beyond everyone's expectations. They thought just now that there might not be anything magical at the bottom of this tiankeng. It might be something like rocks.
But when they got to the bottom of this tiankeng, they saw that the bottom of the tiankeng was aquamarine everywhere, and the whole was an undulating prairie. Because of the lush grass growing at the bottom of the whole tiankeng.
‘Dad, under this is a prairie! Feifei said very excitedly.
Of course Zhao Zhongyao saw all this, he also felt very surprised, and he didn't understand how there was such a magical place at the bottom of this sinkhole.
‘Yes, this is an underground prairie. Zhao Zhongyao also looked surprised.
At first glance, the outside world turned out to be a prairie. Feifei would be happy. He immediately looked at Zhao Zhongyao and said, ‘Dad, what are you waiting for then. Since it's a prairie outside, should we hurry up and have a look on the prairie. ’
After hearing what Feifei said, Zhao Zhongyao thought for a moment and said, ‘Feifei, don’t worry. Let's observe the outside situation first. This is Mercury. We don’t know much about this planet. It’s amazing that such a prairie suddenly appeared here. We still have to be careful. ’
After hearing what my father said, Feifei said, ‘Okay, let’s take a look at the outside situation first. Feifei also felt that Dad was right. They just got to the bottom of this sinkhole and they couldn't act rashly. They still had to observe for a while.
‘Okay, let’s take a look at the situation outside. See if there is anything dangerous outside. Said Zhao Zhongyao.
Feifei just watched it all day and felt that there was nothing special in it. Just some grass. There is nothing left except the grass. Not even a big tree seems to be seen.
Feifei looked at it for a while, and it didn't feel interesting. So he looked at Zhao Zhongyao again and said, ‘Dad, there seems to be nothing outside here! It seems that there are no more animals on this prairie. We can go to the prairie outside to play. Feifei wants to go out and play now!
But Zhao Zhongyao heard Feifei’s words and said again, ‘Feifei, don’t worry. We are now in a sinkhole. We have to think of going outside. Still need to learn more about Tiankeng. ’
After hearing what Zhao Zhongyao said, Feifei said, ‘Okay then! Dad first tell us some knowledge about Tiankeng! ’
Everyday now, I am very happy to see the prairie outside. I also want to go out and play. It's just that she also wants to learn about Tiankeng. So I looked at Zhao Zhongyao and said, ‘Dad, then you can quickly tell us some knowledge about Tiankeng! I also want to learn about this knowledge. ’
‘Okay, since that’s the case, let me tell you something about tiankeng first! After Zhao Zhongyao finished speaking, he thought about it. Then, I told my son some knowledge about Tiankeng.
Tiankeng is a kind of negative karst terrain with steep walls and hundreds of meters in depth and diameter developed in carbonate karst areas. It has a huge volume and is connected to an underground river at the bottom. This karst landform was later named "tiankeng" by scholars.
The karst tiankeng caused by the collapse is currently the most important type discovered, and it has an absolute advantage in quantity, such as Xiaozhai Tiankeng, Dashiwei Tiankeng Group, Xiaoyanwan Tiankeng, Longgang Tiankeng, etc.
The collapsed tiankeng is formed by the continuous collapse of rock formations and reaching the surface due to the strong erosion of the underground river. Its development goes from underground to ground, and has experienced several major stages: underground river tunnels, underground collapse halls, and surface tiankengs. The formation of a collapsed tiankeng should meet the following necessary conditions: there are continuous deposits, a thick carbonate rock layer, and a wide range of continuous exposure and distribution; the level of the rock layer is gentle to a gentle occurrence, especially a wide and flat anticline The axis is the most advantageous; the relatively low drainage base level and the thickness of the aeration zone of the aquifer are above 50-200m; the tropical to subtropical climate conditions with warm, humid and rainy conditions; the aquifer has strong material and energy input and output functions Power system.
Erosion tiankeng is a sinkhole or blind valley tiankeng formed under special geological, geomorphic and hydrological conditions. Only two cases have been found so far. The development conditions should be met: the upper and lower parts should have a huge layered structure of non-karstized and karstized rocks, and be widely exposed in the upstream and downstream respectively.
The rock formations are horizontal to gentle as a whole; there is a 100-200-meter-thick aquifer aeration zone in the lower karstized rock formations; tropical to subtropical climatic conditions with warm, humid and rainy conditions; there is a history of continuous crust ascent for more than hundreds of thousands of years. Tiankeng is one of the largest individual forms formed by karst. It was formed through internal and external dynamic geological processes in the long geological history. It is scarce and non-renewable.
It has great scientific value in karst and related scientific research. The formation of tiankengs is particularly closely related to karst hydrogeological processes and the evolution of aquifers. Research on the formation mechanism, distribution and evolution of tiankengs may lead to a huge leap in people's understanding of the nature and evolution of aquifers.
The study of tiankeng will help to deepen and develop the understanding of the basic mechanism of karst, especially the mechanism of dissolution, erosion and collapse and their relationship. Tiankeng is a natural wonder and unique to karst. It has a series of special tourism value and sensory attributes such as rare, steep, peculiar, magnificent, magnificent, and unique ecological environment.
Looking at Feifei and Tiantian, Zhao Zhongyao talked about what he knew about Tiankeng. After Feifei and Tiantian listened to the knowledge his father said, they felt very curious. I don't understand how this huge tiankeng was formed.
Tiantian also watched Dad naively asking, ‘Dad, is this huge sinkhole also a karst cave? ’
After hearing what Tiantian said, Zhao Zhongyao wanted to speak. But Feifei looked at her sister and said wisely, ‘Sister, what you asked is not nonsense. Since this huge deep pit is also a tiankeng, the cause of this tiankeng must be the same as that of the tiankeng on our planet. ’
After hearing what Feifei said, Zhao Zhongnian smiled and said, ‘This is not necessarily true. This is Mercury. This is not the earth. The deep hole on Mercury may not necessarily be the same as the one on Earth. ’
Feifei heard what Dad said, and said in confusion, ‘Dad, what are you talking about. You just said that this deep pit is a sinkhole. What do you say now, the reason for the formation of this tiankeng is different from the tiankeng on our planet. ’
After hearing what his son said, Zhao Zhongyao smiled again and said, ‘this is Mercury, not the earth. The deep hole formed here may be different from the sinkhole on our planet. I call him Tiankeng because it looks like a Tiankeng. But in fact, it cannot be a sinkhole. ’
‘Dad, then I don’t understand. Since this deep pit is not a tiankeng, why do you call him a tiankeng? Feifei can’t understand what Dad said now.
Zhao Zhongyao had to look at Feifei again and said, ‘That’s right, the reason I call this huge pit is Tiankeng. Just because it looks more like a tiankeng. But in fact it is unlikely to be a sinkhole. ’