Xia Shang Zhou Qin Han, Tang Song Yuan Ming Qing, this is our China's historical era, but to say the historical chronology of the earth, it is estimated that many people do not know. From the time the Earth became an independent planetary body to the beginning of written records of human history, there is a considerable period of rock formation recording in the history of the Earth, according to the isotopic age value of the oldest strata on the Earth that has been discovered so far, which is about 4.6 billion years, and the academic community generally divides the history of the Earth into two major stages, the stage before 4.6 billion years is called the "astronomical period", and the stage after 4.6 billion years is called the "geological period". The real-time geohistory refers to the geological period of 4.6 billion years.
From the time The Earth became an independent planetary body until the beginning of written records in human history, there was a considerable period of rock formation recording in the history of the Earth.
Geological periods are divided into "epochs" by geologists, just like the dynasties and dynasties in Chinese history, but because the 4.6 billion years of earth history is too long, and the natural features of each stage are very different, and there are also great differences in biological species, so in order to subdivide, geologists have established a set of geological era system, from large to small divided into zeus, generation, era, epoch, period and other units.
Each zeus, era, epoch, epoch, epoch, period or epoch in the geological chronology has its own name, which is used to describe the degree of development of organisms in different geological time and space.
The largest geological dating unit of "Zeus" has 4 Pluto, Archaic, Proterozoic and Psynesian. The first three periods are collectively known as the "Cryptozoic" or "Precambrian", because life at that time was still very primitive, and there were no multicellular organisms that were obviously visible to the naked eye until the late Proterozoic period. The Cambrian explosion of life, 541 million years ago, marked the advent of the "Ezoogenous".
The Chengjiang biota of China, the Burgess biota of Canada and the Kaili biota constitute the world's three largest shale-type biota, providing evidence for the Cambrian explosion of life
"Generations" are the various major periods under each "Zeus", which can last up to hundreds of millions of years. Often said Paleozoic, Mesozoic, Cenozoic, is the three major periods of the Eminozoic, of which the Paleozoic means "ancient biological age", starting with the isotopic age of 542±0.3 billion years, ending in 251 ±0.4 billion years, lasting about 300 million years; the Mesozoic means "middle" + "biological" era, between the Paleozoic and Cenozoic, The time span is 252 million years ago to 66 million years ago, starting from the Permian-Triassic extinction event and ending with the Cretaceous-Tertiary mass extinction event, spanning 180 million before and after; as for the Cenozoic is the latest geological era in the history of the Earth, from the extinction of dinosaurs about 65 million years ago to the present, it is in the Cenozoic.
"Ji" is a further subdivision of each "generation", which generally spans tens of millions to more than 100 million years.
"Ji" is a further subdivision of each "generation", which generally spans tens of millions to more than 100 million years. For example, the Paleozoic Is divided into the Cambrian (about 542 million years ago - 485 million years ago), the Ordovician (480 million years ago - 440 million years ago, which lasted 42 million years), the Silurian Period (440 million years ago - 410 million years ago), the Devonian Period (410 million years ago - 359 million years ago), the Carboniferous Period (359 million years ago - 295 million years ago, continued about 65 million years), and the Permian (299 million years ago - 250 million years ago, after 45 million years);
In the Permian, the continents of the world gradually came together, and the animals and plants withstood unprecedented severe tests, and also burst out to lay the foundation for the birth of dinosaurs.
The Mesozoic Is divided into the Triassic (250 million years ago – 200 million years ago), the Jurassic (199.6 million – 145.5 million years ago) and the Cretaceous (145 million – 66 million years ago, 79 million years); the Cenozoic is divided into paleogenesis (65 million to 23.3 million years ago), Neogene (23 million to 2.58 million years ago), and the Quaternary Period, all of which are in the Quaternary period, from about 2.58 million years ago when the Earth entered the ice age.
Mammoths were widely distributed in the Quaternary Pleistocene in the boreal regions of the Northern Hemisphere, including northeastern China.
Since the biological fossils of each "era" are very different, and fossils are the number one indicator of identifying strata, "eras" are the most commonly used units of first-class geological epoch, especially in the Phanerozoic. Each epoch has a different natural environment, as well as unique biological species: trilobites in the Cambrian, fern forests in the Carboniferous, dinosaurs in the Jurassic and Cretaceous....
The Cretaceous asteroid impact on Earth 65 million years ago led directly to the extinction of the dinosaurs that dominated the world's terrestrial ecosystems for more than 160 million years.
The forces behind these lives are the geological activity of each epoch, climate change, or an asteroid that has come to stir up trouble. The evolutionary development of eventual life and the order of formation of rocks eventually divide earth's history into natural stages corresponding to the development of life, that is, relative geological age. It can represent the sequence of geological events, the natural phases of geological history, and the stages of crustal development.
Some natural substances present in nature grow or deposit according to the year or season, known as the "clock of nature".
This is due to the fact that in nature, there are some natural substances that grow or deposit according to the year or season, the former such as trees and corals, and the latter such as lake sedimentation, ice and snow accumulation and the deposition of stalactites in caves, so that the rings or layers of the earth's historical time can be seen. Based on these rings or layers, geologists can accurately count when they grow or are deposited, so these natural substances are figuratively called "natural clocks."
It is alternately deposited from layers of limestone and mud shale in the prehistoric ocean, like a new Zealand "pancake rock" on a page. ”。
At the same time, during the growth or deposition of these "natural clocks", with their sensitivity to climate change, past climate or environmental changes will be recorded, such as ice cores, tree wheels, mud, stalagmites and corals. These "high-resolution" natural recorders are our windows to understanding the changes in the Earth's climate and environment 100,000, millions, tens of millions or even hundreds of millions of years ago, and are also one of the core bases for compiling geological year representatives.
Stalagmites, which are mainly composed of carbonates, sulfates, phosphates, etc., and have been deposited over a long period of time, are high-resolution natural recorders.
Of course, compared with the "natural clock" for the determination of relative geological age, there is also an "absolute geological dating" method, that is, according to the content of radioactive isotope decay products in the rock layer, to determine the formation of the formation and the age of geological events.
Different historical epochs of prehistoric Earth have different styles. The picture shows the Earth before the Cenozoic Era
In the earth's 4.6 billion years of long geological age, there have been cold ice ages, there have been warm interglacial periods; there have been Cambrian explosions of life that laid the foundation for biological evolution, there have been Ordovician species extinctions where 85% of species have been extinct; there have been "Penstone Age" Silurian, there have been "Fish Age" Devonians, there have been coal-formed Devonians, and there have been "Insect Age" Permians...
It turns out that in different historical periods, the earth has different styles.
Review of the previous issue: Civilization is the gift of climate (Part 2): During the warm period of the Ice Age, why does the earth switch between cold and summer?
Remarks: This article is only a word, welcome to share and correct. In addition, the picture in the article is quoted from the Internet, if there is a copyright private link, please delete.