Our planet is thought to have been born approximately 4.500 billion years ago. Its appearance back then is nothing like what we know today. It was simply a conglomeration of rocks whose interior heated up, causing all the elements to fuse. As it cooled, the outer layers became solid, and the heat coming from the planet's center melted them again. Once the planet had a certain stability, what we know as you were geological.
In this article we are going to tell you everything you need to know about the main geological eras.
Origin of the planet
It is important to know that to take into account geological eras, the scale of geological time. When the Earth was nothing more than a conglomeration of molten rocks, it could not be treated as a planet. The process of cooling and heating of the rocks continued until the temperature dropped at the surface to such a point that a Earth crust stable. This happened around 3.800 billion years ago.. At this time, the atmosphere as we know it had not yet formed and the Earth was hit by a large number of meteorites.
In addition, we must add that the volcanoes were fully active so that the lava flowed over the surface in large masses and caused the temperature to be high. Science has tried to study all the geological eras that are those that mark how our planet evolves throughout the long period of time. These investigations have been possible thanks to the study of the rocks and fossils that are contained in some.
After studying the rocks you can know different information such as:
- How old our planet is.
- The temperatures that existed in the different eras through which we have passed.
- Movements that are recorded in the earth's crust and that have given rise to the formation of mountains and depressions.
- The variation in the distribution of land and sea on the planet's surface. These have not been stable during all periods.
The age of the earth has been calculated thanks to the constitution of radioactive materials present in the rocks. Uranium atoms are changing into lead atoms at a constant rate. If you compare the amount of lead in a rock within a uranium ore, you can calculate when the rock that contains it was formed. This is how information from the past is obtained.
Studies of geological ages
Various fossils found in sedimentary rocks are also studied. Thanks to these fossils, we have been able to identify the different animal and plant species that lived during these periods. Furthermore, we can learn about the climate in different regions thanks to the existence of certain animal and plant species through the study of their biology.
Fossils abound in sedimentary rocks. A fossil is simply a remnant of animal or plant origin preserved beneath the Earth's crust as sedimentary rocks form. Throughout each era of our planet, certain typical animal and plant species have lived, not prevalent in others. This is how geologists can determine the period in which a particular rock was formed. The elevations of typical fossils allow us to determine the age of the rock.
The evolution of our planet has been reconstructed thanks to geology. Sedimentary rocks are those deposited at the bottom of seas and lakes for millions and millions of years. Rocks provide us with information like pages in a book. Thus, it has been established that the evolution of planet Earth has consisted of four major stages, which have been called geological eras. These geological eras are: Proterozoic, Paleozoic, Mesozoic, and Cenozoic.
It was proterozoic
This era is divided into two stages known as the Archean and the Precambrian. The Archean period marks the beginning of history, when the Earth was a sphere of incandescent gases resembling the shape of the sun. During this stage, oceans formed and the first signs of life emerged. The rocks that formed the surface continued to cool and the atmosphere formed.
In the Precambrian, the earth's crust was quite weak and made up mostly of granites and basalts. At this stage, many areas of the Earth were attacked by different external agents such as rain, wind and differences in temperature that resulted in a moderate terrain. The forms of life manifested in the form of unicellular organisms similar to today's bacteria. These organisms could not leave fossil footprints.
Paleozoic era
In this era, the lands that were already energized possessed powerful sedimentation mantles. The rocks were also already limestone, marble and quartzite types. It is in this era that carbon-rich rocks were formed. There was a great purification of the atmosphere thanks to the propagation of continental plants.
This age is considered to be the age of the fish and the great ferns. For a long period of time there were no major shocks on Earth. It is considered one of the most stable geological eras. Erosion is intensely reducing the relief of the areas emerging from the oceans.
Mesozoic era
In the It was Mesozoic it is produced the great rupture of the super continent called Pangea. This is where the theory of Tectonic plates. The climate of our planet changed several times from humid to desert. It is here where animals underwent constant transformations and adaptations to a changing environment. The formation of oil also began.
Cenozoic era
During this era spanning the last 60 million years It is where the first man-like beings have emerged. From the cessation of the last glaciations is when men have begun their slow march to civilization.
