We explain what the Precambrian was, the stages into which it is divided and how the Earth was formed. In addition, its characteristics, flora and fauna.
The Precambrian lasted about 4,027 million years , ending about 542 million years ago, with the beginning of the Phanerozoic eon and its first Era, the Paleozoic , and its first period, the Cambrian. Logically, everything that came before the Cambrian Period is considered part of the Precambrian.
In this period of time the planet was formed, the first geological events began and life on Earth originated. Despite its importance, the study of the Precambrian is difficult, since there are almost no fossil records and the rocks formed in those times have changed greatly over billions of years of transformation.
Each contains several Eras which are further divided into different periods.
The classification is given as follows:
Hadean Eon . The oldest, begins with the formation of the Earth and the Moon about 4,600 million years ago. It is also called Azoic, and there are no definitive agreements regarding its limits. Does not include eras or periods.
According to this theory, known as the Nebular Hypothesis, our planet formed, as we have seen some others form in distant regions of space, from a cloud of dust and gases that began to attract each other due to their gravity .
With due passage of time, these balls of gas and dust would have condensed enough to have a firm existence and a definite shape. Thus it came into existence as what we normally call a planet .
Tea hit Earth about 4.533 million years ago , merging its core with our planet's and leaving a ring of debris from both bodies floating around.
This ring would have given rise to two satellites , one of which ended up crashing against the planet again, at that time little more than a broth of molten or vaporized rock at 4,000 ° C, while the rest, which we call today the Moon, remained at a distance necessary to orbit the planet for millennia.
More in: Moon
As the planet cooled, the first cratons, precontinental cores, emerged . Due to their collisions, the first mountains were formed , since they were found in a hot mantle of molten rock.
During the Proterozoic the convergence of these cratons into a single continent occurred , on three separate occasions. Thus, the earth's crust and the first shields, the core of the current continents, cooled. The oldest of all are those of Africa and Greenland, formed 3,500 million years ago.
Only then did liquid water begin to form and give rise to proto-oceans. Thus began the cooling of the entire planet , until eventually significant drops in temperature occurred: the first ice ages, which froze the primitive ocean . This was especially common in the Cryogenic period.
Finally, when oxygen made its appearance thanks to life, a new element began to appear in the atmosphere : ozone . Its atmospheric layer began to filter much of the solar radiation and allowed the planet's internal climate to stabilize.
Thanks to this process, part of the heat emitted by the Sun stopped penetrating towards the Earth's surface. This happened about 1.8 billion years ago and was very important for the origin of life .
Thus, the atmosphere gained weight, density and new elements . As the Precambrian neared its end, these eruptions began to become more sporadic and the planet to stabilize more and more.
Exactly how life got its start is hard to figure out, but somehow microscopic bubbles containing certain chemical elements that had affinity for each other formed in the oceans.
More complex and functional structures were created from these bubbles , which even managed to replicate themselves. Thus the first proto-cells emerged, thus setting evolution in motion.
Thus, from the Sideric period to the beginning of the Paleoproterozoic, about 2.4 billion years ago, the atmosphere was awash with oxygen . The proliferation of this gas had notorious impacts on the climate and on planetary chemical reactions. It led to a world more similar to the one needed by oxygen-consuming life forms.
In other cases they used solar radiation (photosynthesis) for the same purposes. Later, more complex life forms arose, but their soft bodies did not leave much to fossilize and it is difficult to know of their existence.
Later, around the Ediacaran period, the first complex forms of multicellular life appeared , consisting of soft corals, primitive jellyfish, annelids, and other small, soft-bodied animal life forms.
The above content published at Collaborative Research Group is for informational and educational purposes only and has been developed by referring reliable sources and recommendations from technology experts. We do not have any contact with official entities nor do we intend to replace the information that they emit.