You live in a new geological era, the Meghalayan

It's official – you live in a new era.

It is called the Meghalayan, and it was officially added this week to the international geological time scale.

The scale divides the Earth's history into eons, epochs, eras, and ages, the way we divide the smallest increments of time into years, months, hours, minutes, and seconds.

The updated geological time scale adds three new ages, subdividing for the first time the present time of the Holocene, into:

• Greenlandic Age ( early Holocene), which began when a sudden warming took place 11,700 years ago and the Pleistocene epoch. 19659006] The age of the Northgrippian (Middle Holocene), which began 8,300 years ago.

• Meghalayan (late Holocene) Age, which begins since the beginning of a "mega drought" 4200 years ago until today

(CBC)

The latest version of the Geological Times Scale was published on July 13 by the International Union of Geological Sciences, which is responsible for setting international standards in geology. The scientific details will be published later this year in the scientific journal Episodes

Unique Human Impact?

The Meghalayan is unique, because it coincides not only with a global climatic event, but also a widespread upheaval among human communities around the Mediterranean, the Middle East and Asia – l & # 39; The collapse of civilizations and human migrations in Egypt, Greece, Syria, Palestine, Mesopotamia, the Indus Valley, and the Yangtze Valley, reports the International Stratigraphy Commission; international geological time scale under the auspices of the Geological Sciences Union.

Mike Walker, who chaired the working group of geologists who proposed the new ages, said that not everyone agrees on the mega drought. history, as there could be other reasons for these, such as socio-economic factors.

"But it is curious that about 4,200 years ago, just at the time when we identified a significantly drier phase … we find signs of the collapse of society that could – and I could say it – reflect the aridification resulting in this collapse, "said Walker, professor emeritus of Quaternary science at the University of Wales.

Sune Olander Rasmussen, Carlsberg Foundation Professor Emeritus at University of Copenhagen, holds the ice core of Greenland which marks the division between the Greenlandic and North-Savoy ages.Rasmussen was a member of the working group that defined the three new ages subdividing the Holocene epoch [19659014] (Sune Olander Rasmussen)

The Meghalayan is named for a stalagmite in a cave of Mawmluh in the northeastern Indian state of Meghalaya which is used as the geological standard that marks e the exact beginning of the age. The stalagmite has been deposited gradually from layers of minerals over the thousands of years that rain water has flowed through the roof of the cave. The layers contain chemical signatures that show how precipitation levels have changed over time.

They show that about 4200 years ago, it suddenly became much drier.

"It's almost as if the monsoon suddenly became less effective. precipitation delivery, "said Walker.

The signing of this "mega-drought" is visible in many other parts of the world, although the climate problem has resulted in additional rainfall rather than drought in some places. For example, in western Canada, an increase in snow caused the reform and rehabilitation of glaciers

The Meghalayan is named after a stalagmite in a cave of Mawmluh in the state of Meghalaya, northeast of India. (International Commission on Stratigraphy)

Similarly, the Greenlandic and North-French ages are named for the Northgrippe Greenland site where ice cores were drilled which clearly show a sudden warming at the beginning of age. the end of the last ice age and a sudden sudden cooling, about 8,300 years ago, caused by an influx of icy ice water from the continental ice sheets in the North Atlantic.

Martin Head, geologist at Brock University in St. Catharines, Ont. , and the chairman of the subcommittee who oversaw Walker's task force said that the geological time scale is used primarily for communication on the calendar of events by a wide range of scientists from geologists to archaeologists. ists. They unofficially divided the Holocene between the beginning, the middle and the late 1970s, but this caused confusion.

"The early Holocene of a person could be the average Holocene of someone else," he said.

Walker sought to solve the problem with a team of 11 other scientists, including two Canadians – the University of New Brunswick's Cwynar ecologist and University geologist Dr. David Fisher. # 39; Ottawa. They spent eight years trying to find exact dates that everyone could hear, based on measurable signatures in specific physical geological features.

Now that their recommendations have been approved, Walker said, "We are relieved."

Another group of activities under the International Commission on Stratigraphy worked over the years to add a new chapter after the Holocene called the Anthropocenemy of the major impacts of men on the technology of the future in the post-industrial era

The group proposed in the journal Science in 2016 that it should begin around 1950 to a limit marked by a layer of fallout from generalized nuclear tests.

If that happened, he would cut off about 70 years the end of the Holocene – and Meghalayan age – but Walker says "he is in no way compromised by the subdivisions we have proposed . "