Types of fossils
In the last issue, we learned about the formation process of fossils
Do you also wonder
What are the types of fossils?
This time, I will take you to find out!
The size of the fossils varies greatly, from tens of meters to a few hundredths of a sesame seed.
According to their preservation characteristics, the fossils in the strata can be roughly divided into four categories: solid fossils, molded fossils, relic fossils and molecular fossils.
Let's introduce them one by one!
1. Solid fossils
Solid fossils are fossils that have been preserved from the remains of living organisms. Under particularly suitable circumstances, biological remains avoid the oxidation of the air and the corrosion of microorganisms, and their hardware and software can be preserved relatively intact without significant changes.
Common solid fossils include: animal bones, tree trunks, shells, etc.
2. Molded fossils
Molded fossils are impressions or replicas left by biological remains in rocks, which are divided into imprinted fossils and impression fossils.
Imprinted fossils are generally the remains of organisms that do not have a hard shell that have fallen into sediments, such as plant leaves.
Imprint fossils are traces of the contour structure of the biological shell imprinted on the surrounding rock, including the outer and inner molds.
3. Relic fossils
Relic fossils refer to the traces or relics of paleontological life or activity preserved in rock formations.
The most common relic fossils are footprint fossils, in addition to animal crawl marks, burrowings, and drilling, which can form relic fossils.
Relic often refers to animal excrement or eggs, which form dung fossils and eggs become egg fossils.
4. Chemical fossils
These fossils cannot be seen or touched, but under certain conditions, the organic substances such as amino acids and fatty acids formed by the decomposition of the organic components that make up the organism can still be retained in the rock formations. For this reason, scientists refer to this type of organic matter as chemical fossils.
In addition, there is a special type of fossil, such as amber, which can also be called resin fossils.
Expanding Knowledge: The "Best" of Fossils
■ Smallest dinosaur egg fossil: weighs only 10 grams
According to a report by Xinhua News Agency on June 24, 2020, scientists have found the world's smallest known fossilized dinosaur egg, which is about 2 centimeters wide, less than 5 centimeters long and weighs only 10 grams in an early Cretaceous formation in western Japan. What is this concept? It looks like a quail egg.
■ Largest dinosaur fossil: 77 tons
On May 17, 2014, the fossil was found in the desert of the Patagonia region of Argentina. This titanosaur dinosaur fossil was pieced together and measured, and it was found to be 40 meters long and about 20 meters tall. According to biologists' estimates, the dinosaur should have weighed more than 77 tons.