Tell me the most specific geological age?

The basic concept geologictime refers to a regional or even global stratigraphic sequence system established by dividing and comparing the strata through comprehensive lithologic characteristics, stratigraphic relationship, relative age and absolute age, and each stratum represents the corresponding geological age when it was formed, that is, the era when various geological events occurred on the earth. It contains two meanings: first, it refers to the sequence of geological events, which is called relative geological age; Secondly, it refers to the age before various geological events. Because isotope technology is mainly used, it is called isotope geological age (absolute geological age). The combination of these two aspects constitutes a complete understanding of geological events and crustal evolution age, and the geological year representative is established on this basis. Usually, the division and study of geological times are determined by the history of rocks and fossils. classify

1. relative chronology and absolute chronology relative chronology: refers to the relative old-new relationship between rocks and strata and their chronological order.

Absolute age: Calculate the actual age since the formation of the rock according to the contents of some radioactive elements and metamorphic products in the rock. 2. Geological chronological unit

Period, generation, period and period (corresponding chronostratigraphic units are: stratigraphic expression units: universe, boundary, series, series and stage) have two ways to express geological time series on rocks. One is relative geological age, which uses stratigraphic sequence law, biological sequence law and cutting law to determine the sequence of various geological events; The other is isotopic geological age, that is, the age of rock formation is measured in years by using the transformation law of some radioactive elements in rocks, which is also called absolute geological age. Relativeage Relative age is to determine the rocks formed in various geological historical periods in sequence and the biological combination contained in the rocks, showing the relationship between old and new rocks. Therefore, relative age can only explain the occurrence of geological events sooner or later, and there is no absolute quantitative relationship. The determination of relative age is mainly based on the superposition principle of rock strata, the evolution law of biota and the cutting relationship between geological bodies (rock strata, rock masses, dikes, etc.). ).

The principle of superposition (lawofsuperposition) The original sediments of sedimentary rocks are always superimposed layer by layer, showing the relationship between the old and the new. Unfortunately, the strata in all areas are not complete, some areas are deposited due to crustal decline, and some areas are eroded due to crustal rise. In this case, in order to establish a unified stratigraphic system in a large area or on a global scale, it is necessary to comprehensively study and compare the strata scattered in various places, and finally synthesize a standard stratigraphic sequence (or stratigraphic profile). This method is called stratigraphy. It mainly studies the properties of rocks. The evolution law of biota (evolution law) not only solves the relative newness of rock strata by using the overlapping relationship between lithology and rock strata, but also finds that the biochemical rocks preserved in rock strata also have a clear and determinable order. Moreover, some biological fossils in the lower layer also exist in the upper layer, some have become extinct, but some new species and genera have appeared. This fully shows that there are stages in the process of biological evolution and development. Moreover, species and genera that are extinct in a certain stage will not appear again in the new stage, which is the irreversibility of biological evolution. Therefore, the older the stratum, the more primitive and lower the biological fossils it contains; The newer the stratum, the more advanced and advanced the biological fossils it contains. This is the evolution law of biota that divides the relative age of strata. This method is called paleontology. In particular, the existence and development of organisms always adapt to the environment that changes with time, so there are often different kinds of biological fossils in different strata of different times. Interestingly, some organisms have a narrow vertical distribution (short survival time) but a wide horizontal distribution (large distribution area and large number). This kind of biological fossil is the most significant for dividing and comparing the relative age of strata, and is called index fossil. Therefore, no matter whether the rocks are of the same nature or not and how far apart they are, as long as they contain the same standard fossils or fossil groups, their geological ages are the same or roughly the same. Due to the occurrence of crustal movement, magmatism, sedimentation and denudation, geological bodies (rocks, rock masses and dikes) often cut each other. Obviously, the cut rock layer is older than the cut rock layer; Intrusive rock mass is older than intrusive rock mass or dike. Using this relationship to determine the relative geological age of rock strata is called structural geology method. absolute age

Absolute age refers to the determination of radioactive isotope content in rocks and the calculation of rock age according to its decay law.

Absolute geochronology is a method of expressing geological time in absolute astronomical unit "year", which can be used to determine the time of occurrence, continuation and end of geological events.

Before humans find a suitable dating method, it is more about the estimation of the age of the earth and the time of geological events. For example, seasonal-climatic method, sedimentation method, paleontology method and seawater salinity method are used. Different scholars will get different results by using these methods, and these results are also very different from the actual age of the earth. At present, the more common and accurate dating method is radioisotope method. Among them, there are mainly U-Pb method, K-Ar method, Ar-Ar method, Rb-Sr method, SM-ND method, carbon method, fission track method and so on. According to the different geological conditions and the half-life of radioisotopes, the ideal results can be obtained by choosing appropriate methods.

The largest rock age on the earth obtained by radioisotopes is 4.5 billion years, the moon rock age is 4.6-4.7 billion years, and the meteorite age is 4.6-4.7 billion years. So the age of the earth should be more than 4.6 billion years. Before humans find a suitable dating method, it is more about the estimation of the age of the earth and the time of geological events. For example, seasonal-climatic method, sedimentation method, paleontology method and seawater salinity method are used. Different scholars will get different results by using these methods, and these results are also very different from the actual age of the earth. Detailed stratigraphic system

The earth's crust consists of rock layers. This kind of layered rocks (including loose sediments) formed in the process of crustal development and the non-layered rocks between them are called stratigraphic system. "Yu", "boundary", "series" and "series" refer to the first, second, third and fourth levels of stratigraphic system classification. The first level of stratigraphic system classification is "Yu", which can be divided into cryptogenic space (now it should be called Archean space and Yuanguyu space) and epiphytic space. Geochronology, that is, the composition and structure of the crust. According to the sequence of biological development and stratigraphic formation, several natural stages divided by the history of crustal development are called geological ages. "Zhou", "Dai", "Ji" and "history" refer to the first, second, third and fourth grades of geological age. The first stage of geological age division is Phanerozoic, which is divided into cryptozoic (now it should be called Archean and Proterozoic) and Phanerozoic. Tàigǔyǔ Taikooli

The first universe of stratigraphic classification. Stratigraphic system formed in Archean. Formerly known as Archaean, it belongs to hidden space (hidden space is no longer used, renamed Archaean space and Yuangu language). Archaean tiger ǔzh?u

The first stage of geological chronology. It started about 4 billion years ago and ended 2.5 billion years ago. During this period, the earth's surface is very unstable, and the earth's crust has undergone tremendous changes, forming the oldest land foundation. The rocks are mainly gneiss with complex composition, and there are no biological fossils in sedimentary rocks. There are fungi and lower algae in the later period, but there are not many reliable fossil records due to many crustal changes and magmatic activities. Formerly known as Archean, it belongs to cryptozoic generation (cryptozoic generation is no longer used, but renamed Archean and Proterozoic). Yuanren

The second dimension of stratigraphic classification. Stratigraphic system formed in Proterozoic. Formerly known as Proterozoic, it belongs to the hidden space (the hidden space is no longer used, but renamed Taikoo Space and Yuan Guyu). Proterozoic yuángǔzhòu

The second stage of geological age division. It started about 2.5 billion years ago and ended 570 million years ago. During this period, the crust continued to undergo drastic changes, some parts were relatively stable, and a large number of carbonaceous rocks appeared. Algae and fungi began to flourish, and late invertebrates occasionally appeared. There are fossils of lower organisms in the stratum. Formerly known as Proterozoic, it was originally cryptozoic (cryptozoic is no longer used, but renamed Archean and Proterozoic). xiǎnshēngyǔ·Xi·ǔ

The third dimension of stratigraphic classification. Stratigraphic system formed in Phanerozoic. Yu Xiansheng can be divided into Paleozoic, Mesozoic and Cenozoic. Phanerozoic Xi

The third stage of geological age division. Phanerozoic can be divided into Paleozoic, Mesozoic and Cenozoic. Paleozoic gǔshēngjiè

Yu Xiansheng's first border. Stratigraphic system formed in Paleozoic. It can be divided into CAMBRIAN, Ordovician, SILURIAN, Devonian, Carboniferous and Permian. Paleozoic gǔshēngdài

The first generation of Phanerozoic. It started about 570 million years ago and ended 250 million years ago. It is divided into CAMBRIAN, Ordovician, SILURIAN, Devonian, Carboniferous and Permian. During this period, the biological world began to prosper. Animals are mainly marine invertebrates, and vertebrates include fish and amphibians. Plants include ferns and Lycopodium, and conifers and cypresses also appeared during this period. Therefore, the fauna at that time showed an ancient look, hence the name. Cambrian háNWψxυ

The first part of Paleozoic. Stratigraphic system formed in CAMBRIAN. Cambrian há NW τ j √.

The first period of Paleozoic started about 570 million years ago and ended 565.438 billion years ago. During this period, the land sank and most of the northern hemisphere was submerged by seawater. The biota is dominated by invertebrates, especially trilobites and lower brachiopods, and red algae and green algae in plants begin to flourish. Cambrian is the Latin name of Wales, England, where the strata of this period were first discovered. Ordovician period

Palaeozoic secondary system. Stratigraphic system formed in Ordovician. Ordovician Otá oj √.

The second phase of Paleozoic began about 565.438 billion years ago and ended 438 million years ago. During this period, the rocks were composed of limestone and shale. The biota is dominated by trilobites, graptolites and brachiopods, as well as platypus and corals. Algae are thriving. The Ordovician was named after the ancient Ordovician in northern Wales, England. Siluric

The first part of Paleozoic. The stratigraphic system was formed in Silurian. Zhilijiro

The third stage of Paleozoic started about 438 million years ago and ended 4. 1 100 million years ago. During this period, the crust was quite stable, but there was a strong orogeny at the end. Brachiopods and corals flourish in the biota, while trilobites and graptolites still flourish, with no jaw development. Primitive fish appeared in the late stage, and primitive terrestrial plants gymnosperms appeared in the late stage. The Silurian was named after the Silurian people who lived in southwest Wales, England in ancient times. Devonian Period

Quaternary system of Paleozoic. Stratigraphic system formed in Devonian. Devonian Period

The fourth stage of Paleozoic started about 4,654,380+0 million years ago and ended 355 million years ago. At the beginning of this period, the seawater receded everywhere and accumulated sediments in later layers. In the later stage, seawater flooded the land and formed sediments containing a lot of organic matter, so the rocks were mostly sandstone and shale. Brachiopods and corals developed in biota. Besides primitive chrysanthemum worms, insects and primitive amphibians were also found. Fish developed, ferns and primitive gymnosperms appeared. Devonian is named after Devonian county in England. Carboniferous.

Palaeozoic fifth system. Stratigraphic system formed in Carboniferous. carboniferous period

The Paleogene started about 355 million years ago and ended 290 million years ago. During this period, the climate was warm and humid, and tall and dense plants were buried underground and carbonized to form coal seams, hence the name. Most rocks are limestone, shale and sandstone. Amphibians appear in animals, ferns and conifers appear in plants. Permian è rdié x √

Palaeozoic Paleogene. Stratigraphic system formed in Permian. Pamia è rdié j √.

The sixth and last period of Paleozoic. It started about 290 million years ago and ended 250 million years ago. During this period, strong tectonic movement took place in the crust. In Germany, the dichotomy of Paleogene strata is obvious, hence the name. During this period, ammonites in animals, primitive reptiles, conifers and cycads in plants all developed. Zhang surname in Mesozoic

Yu Xiansheng's second border. Stratigraphic system formed in Mesozoic. It is divided into Triassic, Jurassic and Cretaceous. Mesozoic zhongsh ngdáI

Phanerozoic second generation. Divided into Triassic, Jurassic and Cretaceous. It started about 250 million years ago and ended 65 million years ago. The main animals in this period were reptiles, dinosaurs flourished, and mammals and birds began to appear. Invertebrates are mainly ammonites and arrowstones. Plants are mainly ginkgo, cycads and conifers. Triassic sandier

The first part of Mesozoic. Stratigraphic system formed in Triassic. Triassic s ā ndié j √.

The first period of Mesozoic began about 250 million years ago and ended 205 million years ago. During this period, the geological structure changed little, and the rocks were mostly sandstone and limestone. Because the stratum in this period was originally divided into upper, middle and lower parts in Germany, it was named. Most animals are cephalopods, crustaceans, fish, amphibians and reptiles. The plants are mainly cycads, conifers, ginkgo, equisetum and ferns. Jurassic zh Zhuóx

The second line of Mesozoic. Stratigraphic system formed in Jurassic. Jurassic zh zh Luój

The second phase of Mesozoic began about 205 million years ago and ended 65.438+35 million years ago. During this period, there were orogenic movements and violent volcanic activities. Named after Jura Mountain on the border between France and Switzerland. Reptiles are very developed, including giant dinosaurs, dragons and archaeopteryx, among which cycads and ginkgo are the most prosperous. Cretaceous bay

The third line of Mesozoic. Stratigraphic system formed in Cretaceous. Cretaceous báI' j√.

The third period of Mesozoic began about 65.438+0.35 billion years ago and ended about 65 million years ago. It is named because the Cretaceous strata in western Europe are mainly chalk. During this period, the orogeny was very strong, and many mountains in China were formed at this time. Dinosaurs are the most abundant animals, but eventually they gradually became extinct. Fish and birds are very developed, and mammals begin to appear. Angiosperms appear. Among plants, flowering plants are very prosperous, and tropical plants and broad-leaved trees have also appeared. Cenozoic X: and xī nshē ngjiè

Yu Xiansheng's Third Border. Stratigraphic system formed in Cenozoic. It is divided into Paleogene (Lower Tertiary), Neogene (Upper Tertiary) and Quaternary. Cenozoic xρnshüngdàI

Phanerozoic third generation. It can be divided into Paleogene, Neogene and Quaternary. About 65 million years ago to now. During this period, strong orogeny occurred in the crust, reptiles disappeared in Mesozoic, mammals flourished, and biology reached a highly developed stage, close to modern times. Humans appeared in the later period. Paleogene ǔ j ǔ nx ǔ

Cenozoic Eogene (formerly known as Paleogene and Eogene). Stratigraphic system formed in Paleogene. It can be divided into Paleocene, Eocene and Oligocene. Paleogene g incarnation j incarnation

The first period of Cenozoic (formerly known as Paleogene and Eogene). It started about 65 million years ago and ended 23 million years ago. During this period, mammals not only lived on land, but also bats flying in the air and whales swimming in the water. Angiosperms flourish. Paleogene can be divided into Paleocene, Eocene and Oligocene, and the corresponding strata are called Paleocene, Eocene and Oligocene. Neogene x and NJ NX

The second line of Cenozoic (formerly Neogene and Neogene). Stratigraphic system formed in Neogene. It can be divided into Miocene system and Pliocene system. Neogene x: and NJ: NJ:

The second period of Cenozoic era (before Neogene and Late Tertiary). It started about 23 million years ago and ended 6.5438+0.6 million years ago. During this period, mammals continued to develop, their bodies gradually became bigger and some ancient types became extinct. There is little difference between higher plants and modern plants, and diatoms are more common in lower plants. Neogene can be divided into Miocene and Pliocene, and the corresponding strata are called Miocene and Pliocene. Quaternary system d √ s √ x √.

The third sector of the new generation. Stratigraphic system formed in Quaternary. It is the last system of Cenozoic and the last system of stratigraphic system. It can be divided into Pleistocene series (lower Pleistocene series, middle Pleistocene series and upper Pleistocene series) and Holocene series. Four yuan d √ s √ j √.

The third period of Cenozoic, the last period of Cenozoic, is also the last period of geological age division. It started about 6.5438+600,000 years ago and has been up to today. During this period, there were many glaciation, the crust, animals and plants became modern, and human ancestors (such as Beijingers and Neanderthals) began to appear in the early days. Quaternary can be divided into Pleistocene (early Pleistocene, middle Pleistocene and late Pleistocene) and Holocene, and the corresponding strata are called Pleistocene (lower Pleistocene, middle Pleistocene and upper Pleistocene) and Holocene. Attachment: the origin of Quaternary name. At first, people divided the history of crustal development into three stages: the first stage (roughly equivalent to Precambrian, that is, Archean Proterozoic), the second stage (roughly equivalent to Paleozoic and Mesozoic) and the tertiary. The corresponding strata are called primary system, secondary system and tertiary system respectively. 1829, when French scholar Denoyer studied the strata in the Parisian basin, he divided the loose sediments in the upper tertiary into Quaternary, which was called Quaternary. With the development of geological science, the first and second phases were abandoned because they were subdivided into several phases, and only the names of Paleogene and Quaternary were retained, which were collectively called Cenozoic. Now the Tertiary has been divided into Paleogene and Neogene, so only the name Quaternary is left. The geological year of China represents marine and continental facies.