The first part of the history of the Earth has been deprived of oxygen during this period, it had no life. There is still debate as to who were the main players in the biological oxygen-free world, but most researchers are looking for the roots of the issue in ancient sedimentary rocks.
Most scientists believe that the amount of oxygen on Earth was very small about 2.4 billion years ago, while the atmosphere is not napolnilas oxygen. This sharp increase in the oxygen content in the atmosphere was due to cyanobacteria — photosynthetic microbe that breathes oxygen.
How and when there were microbes, breathe out oxygen, has not yet been determined due to the fact that the oxygen content of the atmosphere is a complex mix of global cold snap, the origin of mineral rocks, as well as the emergence of new species.
"We are not yet able to determine what is cause and what is the result," — said Dominic Papineau, an expert of the Carnegie Institution in Washington. "A lot of things happened almost simultaneously, so it's a lot of uncertainties." In order to help understand the geological study of the issue Papineau range of iron formations and sedimentary rocks, which are formed on the bottom of ancient seas.
Papineau study focused on specific minerals that are contained in the formations of iron, and that may be associated with the occurrence of the life and death of ancient microbes. Iron minerals, which are deep in the bottom of the sea, is the largest source of iron ore. However, this source is about more than just the material for the manufacture of steel. Geologists exploring them, since they have a rich history associated with the emergence of life on Earth.
However, their origin — it is a very big mystery. The most recent conclusion arrived at by the majority of scholars, is that their formation requires special help trace elements, unfortunately, has not yet revealed which ones. These simple one-celled sea creatures do not leave anything that could help researchers to reconstruct their image and understand what they are like.
It is possible that the builder of the iron minerals were cyanobacteria, and oxygen from the bacteria and caused the oxidation of iron in the seas and oceans of oxygen before the great explosion. Then why, if cyanobacteria actually began long before the accumulation of oxygen on Earth, it took several hundred million years before the atmosphere was filled with oxygen?
Perhaps Papin and his colleagues have found the answer to a question from a complex interplay of biology and geology. Oxygen from the cyanobacteria can be broken methane. The interaction of these two gases produces carbon dioxide and water. They also noted that oxygen can not accumulate in the methane-rich environment.
Methane emerged from bacteria called methanogens, resulting in uptake of the bacteria carbon dioxide and hydrogen, and the emergence of methane. In this case scenario, methanogens and cyanobacteria overrule in ancient seas and oceans, but the number of methanogens was more so when they produce methane, it overlaps the path of oxygen accumulation, and warmed the planet due to the greenhouse effect. But once the earth has become "oxygen", the number of these organisms has decreased dramatically, allowing the atmosphere to fill the gas.
See also: The latest archaeological findings, ancient civilization of Antarctica.