Meghalayan Age: The Newest Chapter In Earth’s History Named After Indian State Meghalaya

International Chronostratigraphic Chart, the diagram depicting the earth's history is being updated by the International Commission of Stratigraphy (ICS) , BBC has reported. ICS is the official keeper of geologic time and had proposed three phases to the Holocene epoch denoting major climate events.

The Chronostratigraphic chart divides the earth's history into eons, eras, periods, epochs and ages. The last 4200 years are being called the 'Meghalayan Age' which marked the death of several civilisations due to a severe drought. Egypt, Greece, Syria, Palestine, Mesopotamia, the Indus Valley, and the Yangtze River Valley civilisations were disrupted during the 'Meghalayan Age'.

To win a nomination for a separate age, a slice of geological time should reflect an event with global impact. This event should associated with a geological formation (rock or sediment type) that is unambiguous.

For the Meghalayan, change in oxygen isotope concentration in layers of a stalagmite growing from the floor of Meghalaya’s Mawmluh Cave, reflects 20-30 percent decrease in monsoon rainfall according to Mike Walker of the University of Wales.

The idea of a separate age was pitched in a scholarly paper six years ago. The Meghalayan Age is being inserted into the Holocene epoch. The other two ages inserted into the epoch are Northgrippian and Greenlandian.

Greenlandian age refers to the period of the ice age. Northgrippian age spans from the end of ice age to the filling of oceans and modification of ocean currents. Changes during the Northgrippian age might have led to the droughts in Meghalayan age.

"The Meghalayan Age is unique among the many intervals of the geologic timescale in that its beginning coincides with a global cultural event produced by a global climatic event", Secretary-General of the International Union of Geological Sciences (IUGS) Stanley Finney told the BBC.

However, questions have been raised by some scientists regarding the "global impact" of the changes during this "new ages" .