What is the order of Permian, Cambrian, Cretaceous and Jurassic?

Precambrian? 570 million years ago

Precambrian began with the formation of the earth about 4.5 billion years ago and ended with the birth of a large number of hard-shelled animals about 542 million years ago. ? Although organisms appeared as early as more than 3 billion years ago, their evolution has long been stagnant at a very low stage, mainly some low-level bacteria and algae.

Palaeozoic Era

Cambrian? Prophase: 564-535, metaphase: 535-5 15, anaphase: 5 15-500.

There are many kinds of invertebrate fossils (arthropods, mollusks, brachiopods, annelids and so on). ) In the Cambrian strata, but there were no animal fossils in the older strata before the Cambrian, which was called the "Cambrian life explosion" by paleontologists.

Ordovician? 500—436

Ordovician is one of the most extensive periods of Shanghai invasion in history, and marine strata are widely distributed in many parts of the world. In the platform area inside the plate, seawater is widely distributed, showing the extensive development of carbonate rocks in coastal shallow sea. In the active geosyncline area on the plate edge, it is a deep-water environment, forming thick shallow and deep-sea clastic deposits and volcanic eruption deposits. There was a large-scale ice age at the end of Ordovician, which was distributed in Africa (especially in North Africa), Argentina and Bolivia in South America, Spain and southern France in Europe.

Silurian? 436—409

Silurian strata are widely distributed in the world, and shallow seas are deposited in most parts of Asia, Europe and America and parts of Australia. Africa and Antarctica are mostly land. Silurian invertebrates are closely related to Ordovician organisms, and many species entered a new recovery stage after the extinction event at the end of Ordovician.

Devonian period: 409-389, Middle Devonian: 389-378, Late Devonian: 378-360.

Devonian period gymnosperms are flourishing. After the middle period, brachiopods and corals developed, and primitive ammonites and insects appeared. In the late stage, primitive amphibians and teeth appeared, and ferns and primitive gymnosperms appeared; The mandible tends to be extinct. Year: 405 million years ago-350 million years ago. In the late Devonian, amphibians appeared. Since Devonian, Hercynian movement has started on the earth. Therefore, during the Devonian period, many areas rose out of the sea and became land, and the paleogeographic features changed greatly in the early Paleozoic. In Devonian, ferns flourished and insects and amphibians increased.

Carboniferous? Prophase: 360-335, anaphase: 335-284.

In Carboniferous, the land area was increasing, and terrestrial organisms were unprecedentedly developed. At that time, the climate was warm and humid, and swamps were everywhere. A large area of forest has appeared on the mainland, which has created favorable conditions for the formation of coal. Carboniferous was a very active period of crustal movement, so great changes have taken place in paleogeography. During this period, the phenomenon of climate differentiation is very obvious. The northern ancient continent is a warm and humid coal-accumulating area, and Gondwana continent is a cold continental glacial sedimentary environment. Climate zoning leads to the formation of geographical zoning of animals and plants.

Mesozoic Era

Triassic? Prophase: 242-237, metaphase: 237-229, anaphase: 229-208.

The typical red sandstone symbolizing Triassic indicates that the climate at that time was warm and dry, and there were no signs of glaciers. It is generally believed that there was no land or ice at the poles. Because there was only one continent on the earth at that time, the coastline at that time was much shorter than today. Six corals appeared at this time, and the earliest angiosperms and the earliest flying vertebrates (pterosaurs) probably appeared at this time. The earliest tortoise in the world, the protognathus, also appeared in the late Triassic. The first ichthyosaurs appeared.

Jurassic? Early and middle stage: 208- 159 and late stage: 159- 140.

Throughout the Jurassic period, it was warm and humid most of the time. At that time, lush forest vegetation formed the rich coal resources in Australia and Antarctica today. Although there were some arid areas at that time, the vast majority of Pangu continent was in lush oases. In many ways, the flora of Lauea and Gondwana in the south is still very unique, and the fauna is more intercontinental. Some important events in the history of biological development have attracted people's attention, such as dinosaurs becoming the rulers of the land, the appearance of pterosaurs and birds, and the development of mammals.

Cretaceous? Early stage: 140-94 Late stage: 94-64

During this period, the mainland was separated by the ocean, and the earth became warm and dry. In the biggest dinosaur period, many new dinosaur species began to appear, dinosaurs still ruled the landing land, pterosaurs glided in the sky, and huge marine reptiles ruled the shallow sea. The earliest snakes, moths, bees and many new small mammals also appeared. Angiosperms also appeared in this period.

Extended data:

The division of geological times is often based on large-scale catastrophic events that affect the global environment. There is a principle in science, that is, don't add entities unless necessary. The reason why we want to draw another human generation above the Holocene is because scientists think that we humans are likely to be the makers of the next earth disaster, and we may have opened Pandora's box for the sixth mass extinction in 4.6 billion years.

In the development of geology, the concept of "geological age" appeared much earlier than the technology that humans really mastered to determine the age of ancient materials. Up to now, all theoretical bases for people to determine the absolute age are nothing more than the simple Rutherford-Soddy decay law, but even this basic understanding of the interior of the nucleus is just a "new thing" that humans realized at the beginning of the 20th century.

Before that, people didn't know the secret inside the nucleus at all, let alone calculate the exact age of its host substance through the decay rate of the nucleus. Although people don't even know the age of an ordinary stone for a long time, a simple view of nature is rooted in human consciousness, that is, ordinary rock formations everywhere on the surface seem to be the remains of the earth for a long time.

They are composed of rolling mountains, rugged coastlines, steep barriers and steep cliffs ... In these prehistoric remains, we can often find some unknown biological remains, which are very different from today's biological appearance. 17 and 18 centuries, with the spread of scientific revolution in various disciplines, the cognition of earth history, like other disciplines, began to be included in the track of modern scientific methodology.

In that era when the exact age of rocks was unknown, all attempts made by people could only go to such a seemingly compromise end, that is, sorting out the relative old and new order between strata. I don't care when you were born, but at least I know that you are older than me and that's all people can do.

/kloc-in the 7th century, Danish doctor Nicola Stena put forward the famous three laws of stratigraphy, which laid the initial foundation for the birth of stratigraphic chronology. Its first rule is that the original strata are always superimposed horizontally without disturbance, which is the "original horizontal law"; Secondly, in these overlapping strata, the age of the lower strata must be older than that of the upper strata, which is the "stratigraphic sequence law"; Thirdly, strata are the product of sedimentary environment, and vertically uninterrupted sedimentary strata represent horizontally uninterrupted sedimentary environment, which is the "original continuity law".

Although these three laws are simple and intuitive, they even use "primitive level; Alternation between old and new; The short twelve words "horizontal continuity" can be completely summarized, but it is undoubtedly a guiding logical starting point for those who try to sort out the relationship between the old and new classes.

Just then, that era caught up with another geological melee-the famous war of water and fire. Siniu's three laws of strata are perfectly consistent with the core theoretical framework of Neptune's theory (the embryonic form of sedimentology), "All rocks are formed in water", so it has received a positive response from its flag bearer A.G. Weiner. Wei took the lead in trying to divide the evolution history of the earth's geology into four eras, corresponding to the alluvial events of four "great floods" respectively. His name is straightforward, and they are called Phase I, Phase II, Phase III and Phase IV respectively.

Naturally, such a division scheme is only symbolic. In addition to Weiner's actual contact with the area, just refer to a set of strata anywhere else, and no one may be able to tell which age it is. Although the three laws are intuitive, they have subtext after all, and are only applicable to strata with very continuous superposition relationship in space. Back to the actual situation, the emergence of the mainland in the region is actually highly discontinuous.

To really overcome this problem, we should benefit from the rapid development of paleontology. The progress of fossil cognition finally gave birth to the core methodology of stratigraphy: stratigraphic correlation. As the name implies, the essence of stratigraphic correlation is "to establish the correlation between different strata".

If there is a kind of fossil, which only develops in a certain layer in both places, but can't be found in the upper and lower layers, then the strata in the two places have strong correlation, so it can be classified as the product of the same era. In this way, under the idea of stratigraphic correlation, people can gradually establish a comprehensive stratigraphic evolution context as long as they expand the investigation area.

In fact, the extensive study of the three laws of stratigraphy and relative chronology has in turn promoted the development of paleontology and even biology-under the logic of the old and new strata, people began to realize that the Paleozoic era in which trilobites lived was much earlier than the Mesozoic era in which dinosaurs lived, and a stratum with ichthyosaurs should never be the place where a new generation of saber-toothed tigers should appear. In this way, in a step-by-step attempt, an increasingly fine and continuous stratigraphic relationship framework is gradually established.

Trilobites first appeared in Cambrian, peaked in Early Paleozoic and disappeared at the end of Permian. The strata with trilobite fossils must have been formed in this time range. Photo: Bohemia Center System designed by Balland.

The Anthropocene has inherited the naming methods of the seven worlds of the Cenozoic era in etymology, all of which take "-Neocene,' recent'" as the root. As mentioned above, after 2004, the Cenozoic is divided into Paleogene, Neogene and Quaternary. These three periods can be subdivided into seven eras-Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene and Holocene. In the traditional scheme, the Holocene refers to the whole period from 1 1700 to the present, while the Anthropocene is defined as the next generation after the Holocene, meaning "the latest era of mankind".

Leaving aside the Anthropocene, the latest geological period in the traditional view, the Holocene, must be counted at least 10 thousand years ago. In the conventional understanding, as a geological chronological unit, it must be at least "10,000", which is the most basic span requirement. So, when did the new world begin? Learn from humans to drill wood for fire? Or not to hunt from farming? The emergence of cities? No, neither. This time it is literally "people are new but not ancient".

At present, there are two relatively mainstream voices in academic circles. One voice thinks that the starting point should be1610-look, not to mention the old, even the beginning of Modernus in the humanistic sense; Another voice is "more modern", which holds that the Neogene began at1964-in this way, anyone around us may be "born in the last geological age".

References:

Baidu encyclopedia? Geological generation