Underground palace outside the Forbidden City

The so-called geological park is a park with geological heritage as the main attraction and tourist attraction. The geological heritage sounds strange. In fact, the geological wonders such as stone flowers, stone pillars and stone plaques we see, as well as the mountains and rivers and biological fossils around us, are geological heritages.

Beijing Shihuadong National Geological Park is a large karst cave group. There are more than 30 large and small karst caves in the park, which are distributed along the Dashi River in Fangshan. The most famous park in the park is Shihua Cave. In addition, there is a silver fox cave called “North China Underground Labyrinth”, a deep and thrilling breeze cave, and a hole water hole on the stone wall that has the verses of the Sui and Tang Dynasties. Together with this, there are also the human fairyland around the geological park—Xianqidong, and the caves such as the Yunshui Cave, which is known as the “underground art hall”, which together form the largest karst cave group in the north.

Beijing’s underground pearl
Beijing Shihua Cave and Guilin Reed Flute Cave, Fujian Yuhua Cave, and Hangzhou Yaolin Cave are also known as the four largest karst caves in China. On September 18, 2005, Shihua Cave won the title of “China’s Best Cave Wonders”. In addition, this underground wonder also has many titles such as the National Geological Park, the national 4A-level tourist scenic spot, and the geoscience knowledge science education base.

As a large-scale scenic cave, Shihua Cave is developed in the limestone of the Middle Ordovician Majiagou Formation and is a typical representative of karst caves. There are many types and types of stalactites in the cave. There are dripping, flowing water, stalagmites, stone pillars, stone waterfalls, stone scorpions, moon milkstones, crystal flowers, etc., which are common in caves in southern China. Common capillary water, osmotic water, fissure-bearing water, stone branches formed by splashing water, stone shields, flower-shaped stone flowers and other spectacular landscapes. According to experts’ approval, Beijing Shihua Cave covers almost all types of sediment morphologies described in the karst cave literature.

As time went by, Shihuadong eventually formed the current layered cave structure. At present, seven layers have been discovered in the cave, and the layers are connected and the caves are connected. Among them, 1 to 6 are dry caves, and the 7th is underground dark river. Since it is underground, it must be cooler! Indeed, the Shihua Cave has a constant temperature of 13 °C throughout the year, and it is warm in winter and cool in summer. There are ten wonders in the cave and the most beautiful caves in China. Therefore, geologists call it “the underground pearl of Beijing, the temple of karst art.”

What is more worth mentioning is that the cavernous landscape in the cave records the subtle information of environmental changes in Beijing and even in North China. The study found that the stalagmite microlayer in Shihuadong recorded the summer temperature of Beijing from 2650 BC to 1985 AD, so it was called the “Millennium Thermometer”. Because the stalagmite layer can tell us the age intuitively, it is also called the “natural clock”.

The past and present of Shihuadong

It is said that karst is the most beautiful landscape, such as the landscape of Guilin, the Three Gorges of the Yangtze River and the stone forest of Yunnan are all karst landforms. This also led most people to believe that the beauty of karst is concentrated in the south, and there are few in the north, especially in places like Beijing, and few people associate it with karst scenery. But when we came to Shihua Cave in Beijing, we realized that there are such beautiful caves in the north, which is no worse than the caves in the south.

How is such a beautiful cave formed?

Generally speaking, the formation of a geomorphic landscape requires the following conditions: first, the material of the landscape, that is, the carrier of the geomorphology-rock; the second is the geotectonic region and the natural geographical environment of the landscape, that is, the geology of the landscape And the geographical and climatic background; the third is the driving force for shaping the landscape, that is, the geological dynamics of shaping the landscape; the fourth is the process of forming the scene, that is, what time is the scene we are currently forming, and what is the formation process of it; The fifth is the landscape form, which is the shape of the landscape. The sixth is the example, where is the most representative place of the landscape. Simply put, it is like the shaping of a piece of clothing. Among them, the clothing is a carrier, and the human power is used. People will process the fabric according to the region and time of the season, and produce corresponding clothes. Through the molding of clothing, people have a more accurate judgment.

470 million years ago, the Beijing area was still a vast ocean, and a large amount of carbonates were deposited on the seabed. For more than 400 million years, the oceanic uplift has become land due to crustal movement. About 65 million years ago, due to the influence of the Himalayan orogeny, the Xishan area of ​​Beijing was uplifted. After that, the flowing water melted carbonate along the structural cracks, forming a layered cave of the current Shihua Cave. A simple summary of the formation of the stone flower hole, there are seven processes: shallow sea sedimentation – uplifting into land – sea and land interaction – complex land – fracture deformation – karst initial formation – landform formation.

Enjoy the beauty, visit the stone flower
Entering Shihua Cave, the first landscape we saw was a stalagmite formed by dripping sediment. The scenic spot named it “the lion welcoming guests”. Look closely, its shape is indeed like a lion, the lion’s head, body, tail is very image, and the five senses are full, as if to welcome every visitor.

“Yaochi Shilian” is the largest spectacle in the cave and the best in the country. It is located in the second hall on the first floor. From a distance, it looks like a lotus pond with blossoming lotus flowers. The blossoming lotus flower in the pool is called “moon milkstone” in geology. Moonstone is a kind of milky white sediment (mainly deposited at the bottom of the pond, and the wall is also attached). It is made up of very fine, multi-component crystals. When wet, the texture is a cheese-like paste. It is powdery at the time. Moonstone is a hydrostatic deposit under cold conditions, and its sedimentary structure is honeycomb, filamentous, filamentous and honeycomb.

Then, we came to the highest point of the second floor of the Xizhi Cave. I saw a lot of strangely shaped stone stalactites, stone swords, and stone flags hanging from the top of the cave. It was as white as jade and its texture was pure, so it was named as Baiyu Tianpeng. “. The most spectacular on the top of the cave is a white jade stone flag, 2.18 meters high and 1.1 meters wide. It is formed by the synergy of dripping and flaky water flowing from the top of the cave. This stone flag of Shihua Cave has less impurities and slow crystallization, so it is transparent, pure as fat, white as jade, hence the name “silver flag”. This is the second wonder in the cave and the second in the country.

In the deepest part of the Xizhi Cave, there is a stone waterfall formed by the deposition of water. The upper part of the water containing calcium carbonate drips down the crack of the cave wall. The waterfall is 10 meters high and more than 20 meters wide. Now it is only 1/3 of the waterfall, and 2/3 is in the cave. This is the largest stone waterfall in the cave. It is named after the water flow. The waterfall is the third wonder in the cave.

Go back to the second main hole and have the largest stone stalactite view in the center hall. It is formed by dripping and flowing water and grows from the top of the cave. This huge stone stalactite is 18 meters high and 3 meters wide. It resembles an overhanging torch burning in the blazing, so the name “torch overhangs” is the fourth wonder in the cave.

Going to the bottom of the second floor, a group of magnificent landscapes come into view, which is the largest group of stone sarcophagus in the cave. Dendrobium is formed by dripping, linear water and flaky water deposited on the wall of the cave. It is 10 meters high and 18 meters wide and has 540 pieces. It is called “Dragon Palace curtain”. Under the light of the light, it was like a large stage curtain that had not been opened. There was a reporter in front of the curtain. You saw that she was wearing a floor-length skirt and holding a microphone, and was reporting for us. This landscape is the fifth wonder in the cave and the third in the country.

Going down, I came to the Dragon Palace. It is 78 meters above the ground and is the deepest part of the second floor. It is also the sixth wonder of the cave. In front of the two, the uniform and majestic stone pillars are formed by stalagmites and stalactites, which are 12.6 meters high and are the tallest two pillars in the cave. They are similar in form, have the same cause, and have similar ages. Therefore, they are collectively called “Qingtianzhu”.

At the entrance to the third floor is a stone shield called “Dragon Lady Embroidery Table”. It is 1.2 meters high and 2.6 meters in diameter. It is the largest stone shield in the cave. It is the seventh largest wonder in the cave and the fourth in the country. There are more than 630 stone shields in the stone flower cave, which is the kingdom of the shield. The stone shield is formed by the pressure-bearing water deposits in the fissures of the cave wall. It starts from the fissures and grows outward in a ring-like layer, forming two upper and lower plates. If the water flow is large, the water flowing out from the cracks at the edge of the stone shield can be Then form a stalactite or a sarcophagus.

“Fire Tree Silver Flower” is the eighth wonder. It is formed by the synergistic action of water and capillary water in the cave wall. This piece of stone flower is distributed in a length of 30 meters and a width of more than 3 meters. Almost all of the stone flowers, stone hair, stone branches and stone chrysanthemums hanging on the wall of the cave form a variety of stone flower landscapes. Because of the beauty of the stone in the cave, the stone flower cave is also named after it.

On the fourth floor of Dongdong, the most famous landscape is the “goose tube”. The goose tube is formed by dripping water. When the water seepage in the top of the hole is in the suspended state, carbon dioxide escapes from the water, calcium carbonate precipitates, and a thin film is formed on the surface of the water droplet, and then the water droplet falls by its own weight, and the crystal film is only in the hole. The top joint is deposited to form a ring with a diameter similar to the diameter of the water droplet. The infiltration water is continuously supplied, and over time, a slender, hollow, white stalactite is formed, which is called a “goose tube.”

In the middle of the fourth layer, there is a cloud basin with a diameter of 9 meters. The cloud basin is formed by a combination of dripping water, splashing water and stagnant water in a hollow pond in the cave. The sediments deposited from the pond are called “pond deposits”. In the vicinity of the water level line of the pond, the border of calcium carbonate precipitated from supersaturated water, called “edge stone”, can indicate the height of the water level in the past pond. A thin piece of borneol-like product floating a few millimeters on the surface of the water is called “water calcium film or acupoint”. Below the water line, crystallized into various forms of calcite clusters and underwater stone grapes, such as acupuncture beads, acupoint cakes, and crystal flowers in the pool. The landscape is the ninth wonder in the cave and the fifth in the country.

The tenth wonder of Shihua Cave is a stalagmite formed by dripping sediment. There are three different stalagmites in the top of the stalagmite. Due to the different impurities contained in the water, a peculiar landscape is formed: the stalagmites with less impurities and slow crystals are transparent. Stalagmites with more impurities and faster crystals in the water are opaque. It’s true: one stone is three things, everything is different.