Macross invites you to break the case and break the dinosaur "fans" together

The dinosaurs that once dominated the earth are always one of the focus of people's curiosity, but they have long been extinct for 66 million years. It is not easy to understand them. However, the geologists are like detectives, and they will peel the cocoons from each dinosaur fossil to detect the "mystery."

Among them, the form of dinosaurs, food properties, reproduction methods, etc., can be directly used to study with the help of dinosaur skeletal fossils, but what is the living environment of the dinosaurs and the living environment, it is difficult to get it directly from the dinosaur skeletal fossils and other information. Essence

At this time, the key evidence is not the bone fossils of the dinosaur, but something that the average person thinks of inconspicuous — such as the rock layer, dinosaur egg fossils, feces fossils, and footprint fossils.

Dinosaur bone fossils are the focus of all museums. They can help us directly understand the body structure of the dinosaur, but they are not all. To restore the living environment of the dinosaur, more materials are needed. Image source: wikipedia

Where are the dinosaurs?

To explore the above content, we have to go to a place -Shandong Zhucheng. Shandong Zhucheng is a well -known dinosaur fossil output place in China. In recent years, scientists have discovered duckbill dragons, and for the first time outside North America, large -scale horn dragons -Zhucheng Chinese corner dragons, Jialong, virtual bone dragon, and virtual bone dragons, and as well as, as well as, as well as, and as well as bone bone dragons, and as well as, and as well as, as well as bone bone dragons, as well as, and bone dragons, and as well as, and bone dragons, as well as,, and bone dragons, and bone dragons, and as well as,,, as well as One of Asia's largest tyrannosaurus -a large number of dinosaur fossils such as giant city tyrannosaurus. In addition to these dinosaur fossils, Zhucheng also found large -scale dinosaur foot -trace fossils.

Zhucheng is an important place for dinosaur fossil production in China.

These footprint fossils are mainly preserved in the three areas of Zhang Zhuhe Bay, Tangxun Gezhuang area and the Huanglonggou area south. Footprint fossils preserve the wonderful moment of dinosaurs in daily life, and provide information about the types, size, quantity, walking direction and speed of dinosaurs, while dinosaur skeletal fossils reflect the buried environment after their death.

Among them, the dinosaur footprint fossils of Huanglonggou are the largest and most famous in the world. It is located in the Dashan community in Huanghua Town, the south of Zhucheng. It has been proven about 5,000 square meters here. Different types of beasts and wolverine foot dinosaur footprints have been found. Geological wonders.

The dense dinosaur footprints here are located on a 50 ° steep slope. The entire slope consists of a hard rock formation. Within nearly 5,000 square meters, more than 11,000 different forms, different sizes, and different depths are arranged densely. At the level of the same rock layer, it is exists in yellow -green fine sandstone, which is accompanied by cracks and ripples.

Mud refers to the traces of dry and cracking after the dry season of the shore, and they will be saved into the rocks after the sun is exposed; the wave marks are the same. Water fluctuations leave ripples, and they are also saved into rocks.

Emperor Longgou Dinosaur Fossil Fossils Follower Picture Source: Author provides

These footprints are well preserved, and the toes, feet, and heels of each dinosaur fossil are clear and clear, as natural and realistic as the footprints left on the soft soil.

Dinosaur footprint comes from a variety of dinosaurs such as large beasts, sub -large beasts, small beast feet (like dragon), and saurop, including small beast footsteps. Between these dinosaur fossil footprints, between these dinosaur fossil footprints,, between these dinosaur fossil footprints. Occasionally, the traces of the turtle swimming can be seen.

Huanglonggou footprint fossil (large round pit is a footprint footprint, a small beast foot footprint) picture source: author provided

The fossils of Tangxuan Gezhuang and Zhang Zhuhe Bay Dinosaur Fossils are located in the north of Zhucheng City, about 100 million years ago, and the distance between the two places is 1 kilometer.

The scale of Tangxun Gezhuang Dinosaur footprint is relatively small, and those who have important scientific significance are on the same rock formation. Here the scientific examiners discovered the dinosaur turning footprints composed of 28 lizard dinosaur footprints. 30 cm, the whole trace is semi -circularly distributed, which exactly preserves the entire process of dinosaur steering. It is currently the first discovered dinosaur 180 ° steering.

These footprints are concentrated on the same level with an inclination angle of about 45 °, existing in purple -red fine sandstones, and accompanied by mud, staggered layers, and rain marks.

Tangxun Gezhuang Dinosaur Fossil Fossil Picture Source: Author provides provided by the author

Zhang Zhu Hewan Dinosaur Fossil Point is located on the east bank of the East River in Zhangzhuhewan Village, Shiqiaozi Town. It consists of 4 lizards and 1 ancient bird footprint. Among them, the ancient bird footprints are particularly precious. At the level of the level.

Zhang Zhu Hewan Dinosaur Fat Fossil Picture Source: Author provides

How to reason the living environment of dinosaurs?

The above descriptions seem to be a bit boring, but just as detectives can solve the case through the scene of the crime, geologists can infer the environment of dinosaurs at that time from the information of these rock formations and fossils-drought-semi-arid lakeside.

This judgment is naturally not made at will. Below we follow the ideas of geologists to analyze the cocoon:

1. Fine sand rocks are produced from the surroundings of water and other water bodies such as rivers, lakes, lakes.

Fine sandstone, as the name implies, is a rock formed by the delicate sand and dehydration long ago. As most of the beaches we see today appear near the sea, lakes, rivers, etc., fine sand in the geological period also appears in these places.

In addition, the wave marks on the fine sandstone layer can also confirm that this is the beach by the water. Based on the analysis of the local geological maps and other information, it can be further concluded that it is a lakeside instead of river or seaside. Sandstone is composed of sand, and its formation of the environment as modern beach picture Source: wikipedia

2. Dinosaur once lived on the shore of the lake.

The footprints of the three fossils of Zhucheng are existing in fine sandstones, accompanied by horizontal layers and rain marks and mud. This indicates that the dinosaurs of the three locations are left on the beach on the shore of the lake before leaving footprints.

The emergence of a large number of dinosaur footprints and bird footprints also proves that these three locations have existed in water bodies during the early white cymbal period. Dinosaurs and birds take the lake here as water sources and regularly come to drink water.

Moreover, here should be their long -term and fixed venues. After all, the conditions for preserving fossils are very harsh. Not all footprints can be left into fossils. Only when they are frequent enough and the number is enough can they increase the probability of turning fossils.

3. Lake south and deep.

The mud cracks in the Huanglonggou formation (in the arid season, the shallow water areas are often dry up first, and the sediment under the water is exposed to form mud). The south/southwest, while the northeast is the lake shore.

The wave mark picture source at the level of Huanglonggou footprint: The author provided

4. It was once a dry-semi-arid environment.

It is very rare to keep so many dinosaur footprints. First of all, the beach on the shore of the lake naturally requires that the beach on the shore of the lake is delicate enough, and the humidity, viscosity, and particle size are just moderate in order to leave intact and exquisite footprints. Moreover, even if the beach conditions are met, it is necessary to meet specific environmental conditions.

After the dinosaur footprint is formed, if it rains immediately or is drowned by the water, the footprint that has not been dry will soon be melted in the water. Therefore, after the footprint is formed on the humid ground, it takes a certain amount of dryness. After the surface of the footprint is dry and hardened, it is buried by the later sediment to form fossils.

Therefore, the possibility of saving footprints in the sedimentary environment of lakes, seaside, and riverside in the arid areas is greater.

5. The mud crack itself reflects a drought-semi-drought environment.

The mud in the sandstone is also a sign of indicating the climate environment. Mud cracks, also known as dry or cracks, are commonly existed in short -accumulating water areas or low -lying water in the sea, lakes, rivers, etc., and people with rural life experience can often see this phenomenon.

This is due to the fine -grained sediments (clay, powder, or mud) or the fine -grained sediments of the surface after the water deployed underwater deposition. Caused by dehydration and contraction.

Mud cracks in modern environment Source: Jonathan Wilkins

Although mud cracking in modern environment is common, it is easily affected by weathering and erosion after the formation of mud in the geological period. It is difficult to save on the surface. It is generally believed that the emergence of mud in the geological period indicates that the drought or dry and dry environment is alternated.

During the geological period, the dry cracks are formed in the low -lying area of ​​the drought -semi -arid area, and the short -term precipitation makes the low -lying area accumulate water. Due to the large evaporation, the water quickly evaporates, and it is easy to form mud. The mud fissure formed in this environment has been on the surface for a long time, and the water flooding time is short and the preservation time is longer.

According to the large amount of dinosaur footprint fossils in the Zhucheng Baiya layer, the appear on the mud cracking structure. It can be inferred that the dinosaur lives in the lakeside environment and has intermittent drought.

6. Holured footprints mostly appear in semi -drought environments.

From a worldwide perspective, the footprints of lizards are always common in the semi -arid inland basin environment or coastal deposition of coasts in the dry areas of low latitudes. The three fossils of Zhucheng found the footprints of lizard, indicating that the city of the city was already drought at the time. The sedimen exposed in the air appears mud due to evaporation and dehydration.

7. The drought here has intensified over time.

The Huanglonggou dinosaur footprint fossil group was existed in the sandstone in the Longwangzhuang group of the Laiyang Group in the middle of the early mid -Baiji World. The analysis of the sedimentary sedimentation of the measured section of the large ratio was shifted. Over time, the environment of the shallow lake gradually evolved to the lake environment. Gradually, the climate is drought.

At the footprint level, the mud cracks are mostly sandwiched in the middle sandstone with a thin layer, indicating that the flood flooded to the panta of mud, and the floods were retreated in the short term. Its climate environment should be seasonal semi -drought -drought climate.

Compared with the footprint layer of mud, the size and range of the layer of layer of the formation of the formation significantly expanded indicating that the degree of climate drought is intensified.

H-Huanglonggou footprint layer later formed a mud crack on the layer; I-footprint layer mud cracking picture source: Journal of Ancient Garden

The above reasoning process is just a small example in geological research. Over the past few hundred years, geologists have been doing this kind of work like time -like detectives, which have continuously enriched our awareness of the history of the earth.

Now just finding a science book can tell us about the magnificent evolutionary history of the earth authentic, but in fact, behind each story, there is a seemingly small and interesting reasoning process.

Produced: Popular Science China

Author: Sun Jiafeng

Producer: China Science Popularization Expo

references:

[1] Xing Lida, Gereide D. Harris, Wang Kobai, waiting for. 201c. The non-bird dinosaur and bird footprint fossil combination of the Baiji Tong Laiyang group in Zhucheng basin in Shandong [J]. Geological report, 29 (8): 1105-1112. [2] Liu Yongqing, Guang Hongwei, Peng Nan, etc., etc. 2011. 2011. Shandong Jiaolei Basin Baiji Period Dinosaur Foot Trail and Bone Fossils Flowing and Ancient Geographical Environment [J].-twenty four.

[3] Wang Baohong, Liu Yongqing, Kang Hongwei, Wang Kubai, Chen Shuqing, Zhang Yanxia, Peng Nan, Xu Huan, Chen Jun, Liu Hai, Xu Jialin, Wang Mingwei.[J].

[4] Xu Huan, Liu Yongqing, Kang Hongwei, Wang Kobai, Chen Shuqing, Zhang Yanxia, Peng Nan, Chen Jun, Wang Mingwei, Wang Baohong. Wang Baohong.Journal of Palace, 2013,15 (04): 467-488.

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