[ad_1]
The Official History of the Earth Has a New Chapter
Geologists have just ranked the last 4,200 years as a definite age in the history of our planet.
The new geological age called Megalaya Megalaya or Megalayense and began when a great drought affected many civilizations.
The new clbadification means that the famous International Chronostratigraphic Charter, the famous geological history of the Earth that is taught to schoolchildren around the world, must be updated
. But the decision announced this week by the International Stratigraphy Commission of the International Union of Geological Sciences has caused surprise and controversy in the scientific community.
Several researchers claim that there was not enough debate since a study raised the possibility of Megalayense. seven years.
Drought of 200 years
Geologists they divide the 4,600 million years of the history of the Earth in time bands
Each corresponds to a significant event, such as the separation of continents, dramatic changes in climate or the emergence of certain species of plants or animals
. We are currently living in the Holocene geological epoch, which includes everything that happened 11,700 years ago, when a great warming ended the last ice age. .
But the Holocene itself was now divided into several centuries by the International Commission on Stratigraphy
The ages mark dramatic changes in the climate of the planet. The most recent, Megalayense, dates back to 4200 years ago and began with a drought whose effects were felt for 200 years
Drought caused the collapse of civilizations and migrations in Egypt, Greece, Syria, Palestine , Mesopotamia.
Scientists believe that this devastating drought was probably caused by changes in ocean and atmospheric circulation.
In addition to the Megalayense, the other two subdivisions of the Holocene are Greenlandic (11,700 -8,300 years before the present) and Norgripian (8,300-4,200 years old).
These phases were defined by global climatic changes recorded by isotopic markers on ice cores taken from two different wells in central Greenland at 1,492 and 1228 meters, respectively
The other name, Norgripiense, refers to one of those Greenland surveys called NGRIP1 (North Green Basic Ground Ice Project No. 1).
Megalaya, a state in India
For a phase to be considered distinct, it must reflect a change in overall impact and be badociated with rock. or sediment that clearly shows it.
The limit, for example, that 66 million years ago marked the pbadage from Cretaceous to Tertiary can be observed in traces of the element iridium in sediments.
the planet after the impact of the asteroid that annihilated the dinosaurs
In the case of Megalayense, the best record can be seen in the layers of stalagmites or mineral deposits in the caves of Megalaya, a state in northeastern India. "Now it's official"
Some scientists question the impact of climate change used in the new clbadification and claim that it is premature.
Several geologists also questioned the approval of the new clbadification. New subdivisions while discussing a possible new phase that reflects the impact of human beings on the planet.
This phase was provisionally called Anthropocene and we are currently studying its precise definition and initiation.
"After the study seven years ago and the review by several committees, they make a sudden announcement and change the chart," said Mark Maslin, professor of geography at the University College of London and one of the leading scientists in the debate on the Anthropocene.
"Now it's official, we're in a new era – who would say it?" We now have definitions that (…) may go against what most scientists consider the most important change on Earth over the last 10,000 years. " (BBC World)
[ad_2]
Source link
