By Daiaphira Kharsati
SOHBAR/MAWMLUH: The Geological Survey of India (GSI) on Monday took a step forward towards popularising two sites as tourist destinations, and one of them also for declaration in future as geological monument, at Sohbar and Mawmluh in East Khasi Hills district.
The GSI, North Eastern Region (NER) installed two geo-scientific information boards at the two important geological sites.
The Additional Director General and Head of Department, North Eastern Region, GSI, Mulkh Raj Jarngal, unveiled the two boards at Mawmluh cave and Therriaghat, Sohbar in the presence of officials, local residents and students.
Mawmluh cave is a Global Stratotype Section and Point (GSSP) site for Meghalayan Age while Therriaghat marks the Cretaceous (K)-Palaeogene (Pg) mass extinction event.
The Um-Sohryngkew (Wahrew) river section at Therriaghat is known for having the most complete records of the Cretaceous-Palaeogene (K-Pg) boundary transition in India. There is also a high level of iridium metal from the boundary marking the catastrophic event when a giant meteorite hit the earth.
Most of the large vertebrates such as dinosaurs, plesiosaurs, mosasaurs and pterosaurs on earth, most plankton and many tropical invertebrates suddenly became extinct at the end of the Cretaceous period. At about the same time, the Earth was hit by a giant meteorite causing very high values of the iridium metal in the contemporary rock record.
There is also evidence of foraminiferal bloom (with records of macroinvertebrates and coralline algae) in the Palaeogene sediments of Meghalaya. The GSI officials also pointed out that the richly fossiliferous Shella formation in Meghalaya is a treasure house of microfossils.
Speaking to a section of the press at Therriaghat, Superintending Geologist, Palaeotology Division, GSI, NER, Shillong, Debahuti Mukherjee while pointing to the geological significance of the place important to Meghalaya said the display board has been put up to preserve the site and for posterity to be aware of such geological developments.
Pointing to an ordinary rock she said, “Here what we can see is a unit of iridium anomaly which is because of a meteorite impact and probably that was the major cause due to which this mass extinction had occurred and in the Um-Sohryngkew section we have this iridium layer.”
She said Therriaghat has evidence of being an ancient sea which turned into rocks and the ancient sea with its marine life and rock character and everything has got preserved in this.
The installation of the geo-scientific information at Therriaghat will also serve the purpose of tourism.
Superintending Geologist and PRO of GSI, NER, Bashab Nandan Mahanta, said, “This is one step towards the declaration of the site as geological monument in future.”
He said the site will be preserved in collaboration with the state government and the Sohbar sirdarship, for study and geo-tourism purposes.
Jarngal also unveiled the information display board at Mawmluh cave.
The stalagmite in the Mawmluh cave has been tagged a Global Stratotype Section and Point (GSSP) which is the first formally ratified marker of a geological time period in India.
The Meghalayan Age period which began 4200 years ago experienced an abrupt mega-drought and cooling around the globe.
A significant weakening of the monsoon is recorded by a mega-drought event which had a strong effect on the amount of precipitation and therefore on human civilisations worldwide.