There are many introductions of dinosaur fossils!

After the death of dinosaurs, the soft tissues in the body disappeared due to decay, and hard tissues such as bones and teeth sank into the sand and were in an anaerobic environment. After tens of millions of years of precipitation, these bones have completely turned into fossils and have been preserved. In addition, the remains of dinosaur life, such as footprints and dinosaur eggs, can be turned into fossils and preserved when there is time.

1, Petrochemical and Burying

The fossilization process began when dinosaurs died and were soon covered with sediments or underwater sediments. These deposits contain fine particles, which will form a soft covering on the surface of the corpse. This "blanket" can protect animal carcasses from scavengers, isolate oxygen and inhibit the decomposition of microorganisms.

2. Petrochemical process

Hard parts such as bones and teeth of dinosaurs were made of minerals. Minerals often decompose and recrystallize underground and become harder. This process is called "petrochemical process". With the continuous thickening of the sediments above, the remains were buried deeper and deeper, and finally became fossils. The surrounding sediments also turned into hard rocks. This process is extremely slow.

Step 3 get back to the ground

There are still many dangers in the process of petrochemical returning to the surface. In the process of thousands of fossils, the surrounding rocks may bend and deform, so the fossils will be squashed. In addition, the high temperature at the bottom of the crust may also melt fossils. After avoiding these disasters, someone must find the fossils before they are separated from the surrounding rocks, otherwise they will break and disappear.

4. Types of dinosaur fossils

Dinosaur remains such as teeth and bone fossils are the most common fossils, called body fossils; As for the remains of dinosaurs (including footprints, nests, feces or foraging marks), they may also be preserved as fossils, which are called scar fossils. These fossils are the main basis for our study of dinosaurs, from which we can infer the species, quantity and size of dinosaurs.

The burial place of dinosaur fossils

Only a few rather special geological environments can preserve fossils well, and the most common one is fine-grained sedimentary rocks. But dinosaur fossils are more difficult to preserve because of their age. At present, the burial places of dinosaur fossils mainly include German Sorenhorn Mountain, Mongolian Gobi Desert Flame Cliff and China Yunnan Lufeng.

Sorenhofen 1

Dinosaurs lived in the Sorenhorn quarry in Germany, which is a tropical shallow sea. There were scattered islands. The fine limestone layer in Sorenhorn preserves the fossils of the genus monitor lizard, as well as the slender remains of fish and the remains of early birds, archaeopteryx and other island animals.

2. Flame Cliff

Many late Cretaceous animal fossils, including protoceratops, egg sneakers and raptors, have been preserved in the flame cliffs of Gobi Desert in Mongolia. Since the discovery of fossils in Flame Cliff in the 1920s, many world-famous dinosaur specimens have been excavated here.

3.como cliff

During the period of 65438+1970s, scientists found many dinosaur bones on the cliff of Como, Wyoming, USA, most of which were sauropods. Scientists from the American Museum of Natural History have been digging here since 65438+1990s, and hundreds of specimens have been found so far.

3. Moon Valley

Moon Valley is a barren canyon in western Argentina. People didn't know about dinosaurs until fossils were found here. Fossils found in Moon Valley include corals and other reptiles in the Late Triassic, including early theropod dinosaurs, protosaurus and Lei Long. This remote place was discovered in the 1950s, but it was not until the late 1980s that people realized that the fossils here were very rich.

4. Lufeng

The Fiona Fang of Dinosaur Mountain in Lufeng County, Yunnan Province, China covers an area of 10 square kilometers, which is the world-famous hometown of dinosaurs. Archaeologists first discovered a complete dinosaur fossil here in 1938, and then unearthed dozens of dinosaur fossils one after another. It has been identified that there are 24 genera and more than 30 species of dinosaurs, which are the most primitive, oldest, richest and most complete vertebrate fossils in the world.

Discovery of dinosaur fossils

The discovery of dinosaur fossils is the most critical step in the study of dinosaurs. Most fossils are preserved in sedimentary rocks, and their exposure is regular. Therefore, when looking for fossils, we need to know all kinds of sedimentary rocks and their geological ages first. The adoption of new technology can also help us find dinosaur fossils.

1. Preservation of dinosaur fossils

Many fossils are preserved in sedimentary rocks. In addition, the fossil footprints on the cooled karst rock surface may also be preserved. Fossils that are permanently frozen on the ground, such as permafrost in Siberia, can also be well preserved.

2. Sedimentary rocks

Sedimentary rock is a kind of rock consolidated by sediments deposited in rivers, oceans, basins or land. According to its origin and material composition, it can be divided into conglomerate, sandstone and mudstone. Because the sand grains that make up sedimentary rocks are very small and can well preserve fossils, they also contain round stones called nodules. Tuberculosis is produced by chemical changes, and the reason for its formation is the existence of fossils.

3. Fossil exposure

Water, wind or human activities can lead to the exposure of rocks containing fossils. Erosion cliffs and river banks are good places to look for fossils. Sites where fossils are exposed due to human activities usually include quarries, roadsides and construction sites.

4. Tools for finding dinosaur fossils

Geological maps are often used to find places where dinosaurs may be buried. Geological maps can show different types of rocks or different units exposed on the surface. Aerial photography and satellite photography can also be used with geological maps to determine the exact location of exposed rocks.

Excavation of dinosaur fossils

After discovering the burial place of dinosaur fossils, archaeologists must dig them up. It may only take a few minutes for a person to pick up the scattered small fossils, but it may take many people weeks or months to pick up the big fossils from the hard rocks. Erosion of cliffs and river banks is a good place to look for fossils, which is done by various mechanical tools. In this process, measuring and recording operation details are equally important.

1, excavation location

The best place to explore dinosaurs is on or near the surface of Mesozoic sedimentary rocks. Mountain roads, quarries, coasts, cliffs, river banks and even coal mines may be places to explore. However, the areas with the widest area and the most dinosaur deposits exposed to the surface are mostly located in rugged and barren land or distant deserts.

2, the method of mining

In the excavation of dinosaur fossils, the staff will adopt different excavation methods according to different excavation sites. For example, in some desert areas, they can select bones by removing sand from them. However, to dig the big skeleton buried in hard rock, they must use explosives, road openers or powerful drills.

3, surveying and mapping excavation site

Before removing anything from the dinosaur excavation site, people will use the network to partition it. The fossils found in different areas should be clearly marked, photographed and accurately mapped, so that an accurate and complete site map will be obtained in the end. This process is almost as important as the fossil itself. Recording the exact location of the excavation site and its relative location will help to reveal the cause of death of specimen dinosaurs at that time and why they were preserved.

4. Disposal of fossils

Fossils should be stable before moving. Sometimes it is only necessary to brush the exposed part with glue or resin, and sometimes it is necessary to wrap it with a bandage made of hot gypsum soaked in burlap. Small fossils can be wrapped in paper or kept in sample bags to avoid damage. Large fossils can be wrapped in gypsum or protected by polyurethane foam in the most vulnerable parts. Some big stones containing fossils must be split before transportation.

Reconstruction and restoration of dinosaur fossils

Searching and digging is only the first step to understand dinosaur fossils, and then pieced together fossil bones to rebuild a skeleton. The repair work is to add muscles to the bones to make them look like they were before they died. So sometimes paleontologists spend more time in the laboratory than in the wild.

1, clean up fossils

Be especially careful when taking out dinosaur fossils in the laboratory. It takes a lot of time to remove rocks and expose the subtle details of fossils. The tools used can be determined according to the number of rocks to be removed. After removing the rocks around the fossils, glue and resin should be coated on the fossils for protection.

2, acid preparation work

Dilute acetic acid or formic acid can be used to dissolve the rocks around the fossils without harming the fossils themselves. However, the whole operation process must be carefully monitored, because sometimes acids decompose fossils from the inside. Moreover, some acidic agents are quite dangerous and may burn the skin, so users must wear safety masks, gloves and protective clothing.

3. Academic description and nomenclature

When the fossil is fully prepared, paleontologists can describe the structure of the fossil and compare it with related or similar dinosaurs. If it is possible to be a new genus or species, a new scientific name should be given to dinosaur fossils. By comparing the characteristics of new fossils with other fossils, new fossils can be brought into the phylogenetic relationship.

4. Graphic depiction

The process of graphic depiction is the key to describe the actual appearance of dinosaurs. There are many graphical ways, some are accurate sketches of fossils buried in rocks, and some are reconstructed and restored bone maps with complete structure and clear labels. For accuracy, scientists usually use photographic plotters. Although sketches are not as accurate as photographs, they are still very useful because sketches can combine features that may appear on a single fossil at the same time.

5. manuscript review and paper publication

After the fossil research is completed, the research results can be published in the paper. The content of the paper may be a description of a new dinosaur, or it may be a re-evaluation of a long-known dinosaur species. It can be assisted by charts and photos. Because all papers need to be reviewed by peers before they are officially published, most of them are reliable.

Step 6 reorganize

After figuring out the structure of a dinosaur skeleton, we will reorganize the skeleton as much as possible. The lost skeleton was replaced by a model made of glass fiber. Most of the large display skeletons we can see now are replaced by a lightweight fiberglass model, in which thin metal strips are hidden to support the structure.

Step 7 transform

The reconstructed skeleton is the basic basis for reshaping the appearance of dinosaurs before their death. The existing body structures of reptiles, birds and mammals can also be used for reference. They help to point out the size, shape and position of dinosaur viscera and the muscles that make up the abdomen. Skin structure refers to the skin imprint on fossils.

8. Color of dinosaur skin

We can recover and infer the shape and life form of dinosaurs from the fossils found, but we can't find the fossil basis for the skin color of dinosaurs, so we can only speculate based on our understanding of existing animals. According to paleontologists, large dinosaurs may have stripes or spots as protective colors, and the colors will be more vivid. During mating, some areas of the male dinosaur's head and skin may show bright colors like modern birds, which is more likely to win the favor of the opposite sex.

9. Treasure in stock

The dinosaurs we can see in the museum are actually only a small part of the fossils in stock. For example, the Earth Science Museum of Brigham Young University in Provo, Utah, stores nearly 65,438+000 tons of fossils that have not been stripped of gypsum shells. The shelves or drawers in the basements of many museums are full of tagged dinosaur bones, most of which will remain intact for several years, waiting for scientists to study. Some paleontologists will identify brand-new dinosaurs from bones unearthed one or two hundred years ago, which have not been studied or identified incorrectly.

Study on dinosaur fossils

The study of dinosaurs is basically based on fossils that have been discovered. Nowadays, paleontologists can see the inside of dinosaurs without destroying fossils through advanced instruments, and they can also see the fine internal structure that could not be inspected in the past. This can help us understand the lifestyle, food, growth and behavior of dinosaurs, and understand the evolutionary pedigree of dinosaurs.

1, dinosaur fossil anatomy

The anatomy of dinosaur fossils can provide us with information about the possible lifestyle or structure of dinosaurs themselves, and also provide information about the evolution of the groups to which dinosaurs belong. Paleontologists can also compare the bones of an animal with similar bones, thus expounding the evolutionary pedigree relationship between species. Although the muscles, organs and other soft tissues of dinosaur fossils can not be preserved as fossils, they can also be inferred by comparing the anatomical structure of modern animals with dinosaur fossils.

2. Dinosaur control system

The sympathetic nervous system and hormone system coordinated the functions of dinosaurs. Most sauropods have small brains, while some small theropods have large and complicated brains. Tyrannosaurus Rex is one of the large theropods. It has a brain dedicated to controlling limb movements and processing visual and olfactory information, but its brain is very small.

3. Cardiopulmonary system of dinosaurs

Theropod dinosaurs may have an efficient heart to keep their body temperature high. The huge bodies of sauropods can store enough solar heat to keep them warm all night. The heart and lung system of dinosaurs may be similar to the warm-blooded system of human beings or the cold-blooded system of reptiles.

4. Soft tissue of dinosaurs

The soft tissues of dinosaurs mainly include muscles and digestive system. Their bones are connected by ligaments. Pairs of competing muscles are usually attached to the bones through tendons, making the limbs move back and forth in a contracted and relaxed way. The digestive system of dinosaurs consists of spiraling intestines. The digestive tract of carnivorous dinosaurs is quite short and simple, while herbivorous dinosaurs need long and complicated intestines to decompose plant fibers, body wastes and so on. Sperm and eggs are also excreted through cloaca.

5. dinosaur bones

The main function of dinosaur bones is to support muscles used for exercise, protect the brain, heart and lung organs, and place hematopoietic bone marrow. Different groups of dinosaurs have special bones, such as the huge temporal hole on the big head of theropod dinosaurs, which can reduce unnecessary weight.

6. Skull and teeth

By observing the eyeballs, nose tissues and ears of dinosaur fossils, we can understand the sensory organs of dinosaurs. Teeth show the lifestyle of fossil dinosaurs. For example, the teeth of carnivorous dinosaurs usually had sharp edges or conical teeth, while the teeth of herbivorous dinosaurs had leaflike or flat chewing teeth. The dentition patterns in different dinosaur mouths can also provide information about dinosaur eating patterns.

7. Paleopathology

Paleontologists have discovered that Edmund ToLuo Long will suffer from cancer like humans. The study of ancient diseases and injuries is called paleopathology, and this kind of research is mainly carried out through preserved bones. For example, if the bones of a fossil animal have pathological changes or special growth, it means that the animal may have been sick or injured before its death. If many individuals of a fossil species often show certain characteristics, people can infer their lives from some aspects.

8. Computed tomography

Computed tomography can see the internal structure of fossil skulls without destroying specimens. Now, detailed structures that usually need to be examined by cutting fossils can be easily completed by computerized tomography. Traditional X-rays compress objects into a single plane, while computerized tomography can generate three-dimensional computer models and manipulate them in multi-dimensional space.

9, the use of the microscope

Paleontologists have been able to study various fossil microorganisms by observing fossils under a microscope. Scanning electron microscope (SEM) is a powerful tool, which can magnify objects millions of times and see the details of fossil bones are far more delicate than in the past. This instrument reveals the microbial structure of fossils for the first time, which helps paleontologists to understand the living environment of dinosaurs more deeply.

Is that enough?