Archean, Proterozoic, Paleozoic, Mesozoic and Cenozoic.

1, Archaean

It is the oldest period in the history of geological development, and the strata formed in this period are called Archean. This period is as long as/kloc-0.5 billion years, which is the initial stage of clear geological records in the history of earth evolution.

Due to the age, the geological records preserved in Archean are very scattered. However, Archean is also a crucial period for the evolution of the earth. The formation of the earth's lithosphere, hydrosphere, atmosphere and life all took place in this important and long period. About 3.9 billion years ago, the earth formed its first permanent crust, and by 3.5 billion years ago, the atmosphere and seawater began to form.

2. Proterozoic

The strata formed in this period are called Proterozoic, and the representative symbol is "Pt". Proterozoic in English means "early life". "Proterozoic" means primitive times.

During the long period from 2.5 billion to 800 million years ago, the biological world evolved from prokaryotes to eukaryotes, dominated by fungi and algae, so Proterozoic was also called the era of bacteria and algae.

Compared with Archean, Proterozoic magmatism was obviously reduced, the scope of silicon-aluminum continental crust was expanded, and the thickness of crust was increased, which indicated that crustal activity was obviously weakened, forming the prototype of North China plate and Yangtze plate-primitive platform.

3. Paleozoic. Originally known as PRIMARY

Paleozoic (symbol PZ) is an era in geological age, which started at 542 0.3 million years (Ma) and ended at 2510.4 Ma. Paleozoic belongs to Phanerozoic, the last generation is Neoproterozoic, and the next generation is Mesozoic.

Paleozoic is the first generation of Phanerozoic, the last generation is Proterozoic Neoproterozoic, and the next generation is Mesozoic. Paleozoic includes Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. Among them, Cambrian, Ordovician and Silurian are collectively referred to as Early Paleozoic, while Devonian, Carboniferous and Permian are collectively referred to as Late Paleozoic.

4. Mesozoic

In Greek, Mesozoic means "middle"+"living things". Mesozoic is between Paleozoic and Cenozoic. Because the dominant animals in this period are reptiles, especially dinosaurs, it is also called the reptile era.

Mesozoic is also an era of great changes in plate, climate and biological evolution. At the beginning of Mesozoic, all continents were connected into a supercontinent-Pangea. Pangea was later divided into two parts: North America and Eurasia, and South America, Africa, India and Madagascar, Australia and Antarctica. Only Australia is not completely separated from Antarctica.

The Mesozoic climate was very warm, which had an impact on the evolution of animals. At the end of Mesozoic, the embryonic form of modern biota has been seen.

5. Cenozoic era

Cenozoic era (65 million years ago, Cenozoic era) is the latest geological era in the history of the earth. With the extinction of dinosaurs, Mesozoic ended and Cenozoic began. The Cenozoic is divided into three periods: Paleogene, Neogene and Quaternary. It includes seven eras: Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene and Holocene.

The strata formed in this period are called Cenozoic. The Cenozoic era is characterized by the high prosperity of mammals and angiosperms. Because the biological world gradually presents a modern look, it is named the Cenozoic era, that is, the era of modern biology.

Baidu encyclopedia-Archaean

Baidu encyclopedia-Proterozoic

Baidu encyclopedia-Paleozoic