Tian Limai walked about ten steps, then stopped and said: "Leaders, before starting the tour, I still have a few points to say, or a few precautions to tell the leaders. First, we must do a safe tour during the tour, because our black hole is a scenic spot with very strong geological characteristics, there are many forks in the cave, and there are many dark rivers in the cave, so we must follow the tour line, where there is a warning prompt, we must do it according to the warning prompt. Some places are still relatively slippery, so we must pay attention to our feet at all times, so that we can watch the scenery without moving our feet, and we must not watch the scenery when we move. The second is to do environmental protection tours, in the process of the tour, do not litter confetti and garbage, but also pay attention to if we see a fork in the hole and the Yin River must not throw things into it, including stones and the like. Third, smoking is prohibited in the cave, so please consciously abide by it. ”

After Tian Limai said a few precautions, he led Mr. Wu and them to the black hole, although Tian Limai was walking inside at this time, he really didn't know what the first place that needed to be explained would be? He glanced at Jiang Wenwen for help, Jiang Wenwen smiled and said to Lei Qianqian: "None of the three of them have gone in, I'll go to the front to lead the way!"

Jiang Wenwen said and came to the front of Tian Limai.

Tian Limai whispered: "Thank you, Minister Jiang!"

After walking less than twenty meters into the cave, Jiang Wenwen stopped. Tian Limai will know, take out the card to see, the explanation here is called "General Palace", Tian Limai looked, here is really like a palace, there are large and small stalactites standing in the wide hole, the big one is like a giant pillar in the sky, and the small one is also surrounded by four or five people, very much like many generals standing there.

Tian Limai explained according to the explanation and added his own understanding, Tian Limai found that Mr. Wu didn't see any scene at all, but was concentrating on observing Tian Limai's explanation.

Tian Limai's expression in his heart was stimulated, Tian Limai is such a person, the more people pay attention to him. The more scrappy he became. After staying in the "General's Palace" for a while, Jiang Wenwen walked forward again.

Tian Limai walked as he walked, and he seemed to have something in his mind, and he remembered the scene where the eldest uncle Tian Muzhuang took Liu Junwen and Gu Feifei to explore the altar cave. At that time, Uncle Tian Muzhuang spoke out according to a lot of knowledge he heard from outside experts during the inspection, among them, Uncle Tian Muzhuang seemed to have said that "experts say that the world's karst caves are the same", so can you transplant some of the things that Uncle Tian Muzhuang said?

I walked to a stone waterfall again. Jiang Wenwen stopped, and Tian Limai explained according to the explanation: "The leaders of the world may have seen a lot of waterfalls, but it may be the first time you have seen a waterfall like ours in a black hole, so do you know how the waterfall in this cave is formed?

"As I mentioned earlier, karst caves are an important feature of karst landforms, which are mostly limestone areas. The water containing carbon dioxide in the limestone will dissolve the calcium carbonate in the limestone when it seeps into the crevices of the limestone. The water that dissolves the calcium carbonate gathers together from a certain place in the cave and flows out slowly, because the calcium carbonate is light and heavy, the water is flowing slowly, some of the water evaporates, and the carbon dioxide escapes, so that the dissolved calcium has a solidification process. It becomes solid and stagnant, and in this way, a gradually growing stone waterfall is formed over time. ”

Tian Limai's explanation is not in the explanation. However, the information given to him by Wu Xiaojun was very clear, and Tian Limai carefully read the information and wrote it down, because he thought that it would definitely be tested in the application examination. Because this involves the geological expertise of the scenic explanation, perhaps this is what tourists often ask.

After listening to Tian Limai's explanation, Mr. Wu came over and asked, "Xiao Tian, where did you get this knowledge from?"

Tian Limai glanced at Wu Xiaojun, and didn't know whether he should set it up truthfully, he was afraid that it would affect Wu Xiaojun.

Wu Xiaojun saw Tian Limai's eyes, and hurriedly stepped forward and said: "Mr. Wu, I see that Tian Limai is studious and progressive, I lent him a book of information about our scenic spot, I want him to master more knowledge about our scenic spot, am I doing something wrong, Mr. Wu!"

"Regardless of your rights or wrongs, it's good for young people to cherish each other. Then, Xiao Tian, you can also tell me about the formation of stalactites and stalagmites in the cave!" Mr. Wu said.

"Okay, Mr. Wu, then I will briefly explain the formation process of stone pillars, stalactites and stalagmites.

"Just now, when introducing the stone waterfall, I have already said that the underground karst caves are distributed in the underground composed of limestone, the main component of limestone is calcium carbonate, when it encounters water dissolved with carbon dioxide, it will react to generate calcium bicarbonate with greater solubility; When the water at the top of the cave is slowly leaking downward, the calcium bicarbonate in the water will undergo the above reaction, some are deposited on the top of the cave, some are deposited at the bottom of the cave, the stalactites on the top of the cave are formed over time, the stalagmites are formed at the bottom of the cave, and the stone pillars are formed when the stalactites are connected with the stalagmites. This is the stone pillar we see.

"In the karst landform, many limestone areas, its main component is limestone, and it is for this reason that strange peaks and caves are formed, and stalactites and stalagmites are grown.

"Next, let's talk about stalactites, stalactites are very different from stalagmites, one is like icicles under the eaves of a winter house, hanging down from above, and the other is like bamboo shoots that 'emerge' from under the ground in spring.

"There are many fissures in the roof of the cave, and in each of them there are water droplets seeping out, and whenever the water evaporates, some calcareous precipitation is left there. One, two, three...... The water appears and evaporates, and the limestone on the roof of the cave accumulates more and more, until a milky house is formed – this is the "childhood" of stalactites. Later, the outside of the house was covered with layers of limestone, so that the drooping longer and longer this formed stalactites. The length of stalactites can reach up to 10 meters long.

"Next, let's talk about stalagmites, which are pointed cones that stand upright at the bottom of a cave in a karst cave. It is formed on the same principle as the formation of stone pillars and stalactites. Water saturated with calcium carbonate passes through the cracks in the roof of the cave or drips from the stalactites to the bottom of the cave. On the one hand, due to the evaporation of water, and on the other hand, due to the sometimes high temperature in the cave, the amount of carbon dioxide dissolved in the water decreases, so the calcium precipitates and deposits at the bottom of the cave. Over time, it will grow from the bottom up to produce a bamboo shoot-like calcium carbonate stone, which is a stalagmite.

"Stalagmites are stalactites' intimate companions. When water drops from the roof of the cave, limestone is also deposited on the ground. That's it. The stalagmites grow upwards against the stalactites. It can be said that stalactites are 'sir' and stalagmites are 'postlife'. However, the stalagmite has a large chassis and is relatively stable and not easy to break. Therefore, it often 'grows' faster than stalactites. The stalagmites can reach a maximum height of 30 meters, and sometimes they grow like a 'stone tower' that looks like a treasure. ”

Tian Limai paused at this point, and it should be said that the formation of stone pillars, stalactites, and stalagmites in the cave was clearly explained. Unexpectedly, Mr. Wu said again: "Xiao Tian, can you tell me about the formation of the cave?"

Tian Limai looked at Lei Qianqian. I feel like I'm being taken too seriously, as if I know everything.

Wu Xiaojun next to him walked over and whispered to Tian Limai: "I recognize that the information is also there, as if when talking about the formation of the cave, he talked about the formation principle, geomorphological characteristics, etc., you think about it!"

Tian Limai smiled, it's not that he doesn't know, it's not that he doesn't remember, the key is that Tian Limai wants to leave this part for Yang to talk about. Because, once you've covered everything. I'm afraid that Yang Cuo and Wang Yin'e in the back will not be easy to talk about, because the leaders of the scenic spot will listen to it like chewing buns, and who will listen to it without fresh content!

Tian Limai had no choice, since Mr. Wu had ordered it, he had no choice but to speak.

Tian Limai then said: "The formation of the cave is the result of the long-term dissolution of groundwater in the limestone area, and the insoluble calcium carbonate in the limestone can be converted into slightly soluble calcium bicarbonate by the action of water and carbon dioxide. Because the limestone layer contains different amounts of calcareous and is eroded differently, it is gradually dissolved and divided into karst caves that are not interdependent, diverse, steep and beautiful peaks and strange landscapes, and the resulting landform is generally called karst landform.

"Of course. It is also because the sea recedes due to the continuous movement of the earth's crust, and a continuous stream of limestone peaks of karst landforms appears. These exposed stone mountains have been washed by rain and wind and frost for a long time. The top has become a sword mountain. Due to the long-term dissolution of groundwater and the long-term impact of river water in the geohistorical period, a karst cave was gradually formed. ”

Speaking of which, the cave can be regarded as clear.

Tian Limai didn't expect it again, and Mr. Wu asked again: "How can there be so many postures in the cave?"

Tian Limai suddenly felt. Wu was always deliberately examining himself, and the various postures in the cave were not composed of stone pillars, stalactites, stalagmites, etc.? However, Mr. Wu said, who would raise objections? Tian Limai had no choice but to continue to explain, but this time Tian Limai changed slightly:

"Well, in the formation of the cave, the cave continues to be dissolved and expanded, and the limestone solution dissolved in the water drops down from the top of the cave, or even flows downward, promoting the further diffusion of carbon dioxide, and at the same time the solution is evaporated, forming saturation, and the remaining calcium bicarbonate precipitation forms stalactites growing from top to bottom. Water droplets drip at the bottom of the cave, forming stalagmites in turn. Those stone pillars like Ganoderma lucidum that stand up to the sky and the earth are formed after stalagmites and stalactites are docked. It is said that stalactite stones and stalagmites only grow one centimeter tall and one meter long every hundred years, which is 10,000 years.

"We already know that the stalactites that grow down and the stalagmites that grow up are stalagmites, and sometimes the stalactites are joined together with the stalagmites that grow up, joining together to form a stone pillar, thick at both ends and thin in the middle. In many limestone caves, stalactites and stalagmites are mostly not connected, so what is the reason, because logically speaking, they should be connected, is it that the stalactites are broken? No, it is too much limestone that blocks the passage of the water droplets, and the water droplets are forced to change their path and move to another place, and a new stalactite grows in other places. In this way, stalactites and stalagmites are not connected.

"Groundwater plays a decisive role in the formation of stalactites and stalagmites. Wherever it flows, it leaves a trace, either a ditch or a hole, or a stalactite, or a stalagmite, or a stone pillar, and when combined they become a 'forest', a 'beaded curtain', and so on.

In fact, we often encounter this phenomenon in our daily lives: for example, the bottom of the kettle used to boil water often has a layer of limescale. If you take some out and add some vinegar, you will see that there are a lot of bubbles produced. This is because tap water contains calcium bicarbonate, magnesium bicarbonate, etc., and some components of limescale are the products of their decomposition when heated, such as calcium carbonate and magnesium hydroxide.

"Of course, the temperature in nature is by no means as high as boiling water, so stalactites and stalagmites are not formed so quickly, and they are formed after tens of thousands of years of long-term sedimentation and continuous change. ”

After Tian Limai finished speaking, Mr. Wu said happily: "Come, we applaud Xiao Tian's wonderful explanation!" Mr. Wu took the lead in applauding after speaking.

As soon as Mr. Wu applauded, everyone applauded.

Lei Qianqian walked up to Tian Limai and said to Tian Limai: "Tian Limai, congratulations!"

Lei Qianqian's meaning is obvious, that is, Tian Li Maitong guò gave an on-site trial lecture by Mr. Wu and others, and achieved good results.

Tian Limai looked at Jiang Wenwen, Jiang Wenwen said with a smile: "Tian Limai, I didn't expect you to explain so well, okay, our explanation department will have a talent like you in the future, and I will be a little more relaxed then!"

"Mr. Wu, there is not much time, Tian Limai will not talk about it, let Yang Cuo and Wang Yin'e continue to talk!?" Lei Qianqian asked Mr. Wu.

"Okay," Mr. Wu then said to Tian Limai: "Xiao Tian, it's the first time you have come to the cave, and it's already very good to be able to explain this way, so we all applauded you." However, your explanations are too dull and dogmatic, and although you try to be as colloquial as possible, you still lack a sense of humor and cheerfulness!"

"Yes, Mr. Wu!" Tian Limai agreed.

Tian Limai also thought about mobilizing the atmosphere to be a little more cheerful, but he didn't dare, especially when he entered the black hole for the first time, his understanding of the black hole was unfamiliar, and he was afraid of messing up, so he preferred to be dull.

(To be continued.) )