What is the geologic time scale?What is it for? These and other questions you will find answers in the article. The geochronological scale (stratigraphic scale) is the time geological scale of the Earth’s history. It is used in paleontology and geology - it is a kind of calendar for colossal time intervals.
You do not know what a geochronological scale is.geologic time? Experts estimate the age of the Earth at 4.6 billion years. Minerals and rocks have been found on our planet that could witness its creation. Extreme old age of the Earth is reduced to the age of the very first solid formations in our planetary system - refractory impregnations rich in aluminum and calcium (CAI) from carbonaceous chondrites.
According to the results of modern testingusing the lead-uranium method, the age of the CAI from the Allende meteor is equal to 4568.5 Ma. Currently, this idea of the age of the solar system is considered the most accurate. The earth could have been formed much later than this period - by several tens and even hundreds of millions of years.
The geologic time scale is prettyentertaining thing. The subsequent period in the history of the Earth is divided into different time intervals. Their boundaries affect the major events that took place.
The boundary between the times of the Phanerozoic appears throughmajor evolutionary phenomena - global extinctions. The Paleozoic is separated from the Mesozoic by the largest Triassic-Perm extinction of species in the history of the Earth. Cenozoic and Mesozoic are separated by Cretaceous-Paleogene elimination.
How was the geologic time scale created?The nomenclature and hierarchy of most of the current geochronological units were adopted in 1881-1900. at the II-VII sessions of the Interethnic Geological Congress. Further, the World Geochronological Scale was continually refined.
Periods were called on various grounds.Most often used geographical names. So, the name of the Devonian period came from the county of Devonshire in England, Jurassic - from the European Jura mountains, Perm - from the city of Perm, and the Cambrian - from the Latin. Cambria, names Wales.
The Vendian, Silurian, and Ordovician stages are namedin honor of the ancient tribes. Names associated with the composition of rocks, used very rarely. The Carboniferous era is so named because of the huge number of coal seams, and the Cretaceous - due to the popularization of writing chalk.
The geologic time scale was created to identify the conditional geognostic age of rocks. Absolute old age, measured in years, is of secondary importance to geologists.
Earth's life is divided into two main periods:cryptosis (Precambrian) and phanerozoa, according to the occurrence of archaic residues in sedimentary rocks. Only soft-bodied organisms existed in the cryptose, which left no traces in the sedimentary rocks. This is the phase of the invisible life.
Phanerozoic began at the moment when the Cambrian and Ediacaria (Vendian) appeared at the turn of the world, forms of mollusks and other organisms, allowing paleontologists to divide the sequences by fossil fauna and flora.
The geologic time scale is a toolnecessary for every geographer. Cryptosis or Precambrian took place 4 billion - 542 million years ago. OO differs in that organisms did not have hard shells and skeletons. Their presence and history is almost impossible to detect, only by rare marks on the stones.
The time frame of the Phanerozoic is 542 million years ago andto the present day. It is determined by solid surface layers of organisms and skeletons, so that the chronicle of the development of life can be traced using fossils. Hidden life passed to the obvious, apparently due to the fact that the atmosphere was saturated with oxygen. Next came the ozone layer, protecting the planet from radiation from space.
Such atmospheric changes were caused by the functioning of organisms. Perhaps this led to the extinction of many species for which oxygen was a poison.
So, we already know what the scale is.geological time phanerozoic. What is Paleozoic? This is the ancient life that existed 542-251 million years ago, “before the dinosaurs”. It is divided into the following periods:
Even children know what a geological scale is.of time. Grade 7, in accordance with the school curriculum, is studying this issue. Pupils know that the Mesozoic is the era of dinosaurs, which existed 251-65.5 million years ago. This phase is known for the following cycles:
Who likes geography?The scale of geological time is one of the most important nuances of this subject. It is known that the Mesozoic and Cenozoic are shared by the most famous, but not the most numerous extinction in the history of our planet. At that time, the entire microfauna disappeared, including the sea one. Experts have found a lot of evidence of catastrophic events of that time, but their details and sequence are still being studied.
The base fall is a huge meteorite with a diameter of 11 km (more than Everest) in the Yucatan zone.
Cenozoic time frame: 65.5 million years ago - our days. This cycle consists of the following periods:
Neocene is called the geological hypotheticalan era which in the future will come in return for the Holocene. Since the future has not yet come, there may be many options for his vision. However, experts can predict some phenomena based on the facts of the current world change: the direction and speed of movement of continents, the approximate slope of the Earth’s axis, the course of ocean currents.
