The reconstruction of the facts and events passed on Earth before the appearance of man has long led scientists to incredible discoveries. This is how recently a team of researchers discovered that in the past, chains of mountains three times larger than the Himalayas would have existed. Analysis of the minerals present on these rocks could tell more about these ancient supermountains.
In reality, these are analyzes relating mainly to zircons (recent minerals on the super mountains). According to experts, the creation and the destruction of these two giant ranges could have fueled two of the biggest booms in history of our planet. Finally, these phenomena would have dumped huge amounts of nutrients into the sea.
Many researchers participated in the research. Ziyi Zhua postdoctoral student at the Australian National University (ANU) in Canberra and main author of a new study of the majesties of the mountains were one of them.
Zircon, revealing the age of mountain ranges
Indeed, twice in the history of the Earth, colossal mountain ranges have raised over thousands of kilometers dividing ancient supercontinents. Geologists have called them the “great mountains”.
Today, scientists can piece together the history of Earth’s mountains by studying the minerals that these peaks leave in the crust earthly. The analysis of zircon crystals gives information detailed on the rock from which they come. In addition, the precise elemental composition of each of these grains can reveal the conditions of the crust.
Separately, in their new study, the scientists examined zircons containing traces of lutetium, a rare earth element from high peaks. The data revealed two “spikes” of formation of super mountains : one of about 2 billion to 1,8 billion yearsand the second of there is 650million to 500million years old.
Super mountains at the origin of life
As these two mountains eroded, they would have poured enormous amounts of nutrients as the iron and the phosphorus in the sea through the water cycle. According to scientists, these nutrients could have considerably speed up the rounds organic in the oceanleading evolution to greater complexity.
In addition to this nutrient overflow, eroding mountains may also have released oxygen into the atmospheremaking the Earth again more hospitable to life.
“The Transgondwanan supermountain coincides with the appearance of the first large animals 575 million years ago and the Cambrian explosion 45 million years later, when the majority of animals appeared in the fossil record. »
ZiyiZhu postdoctoral student at the Australian National University (ANU)