KOLKATA: Two major floods caused by monsoon pattern anomalies, which inundated large parts of the subcontinent approximately 800 and 700 years ago, might have wiped out powerful dynasties across what is now known as India.
Startling evidence of this has been unearthed by a group of geology experts from IIT Kharagpur.
The group’s findings, published in Elsevier, a reputable Dutch journal specialising in scientific, technical and medical content, has stunned historians and archaeologists.
The findings are based on years of study of oxygen isotopes on ancient stalagmites of Meghalaya’s Wah Shikar caves. Oxygen isotopes are pointers to the traces that are left behind by precipitation or rainfall over a time-period, called time slide by scientists.
The stalagmites are thousands of years old but the group studied the history of precipitation for a little over 900 years — between 1100AD and 2012AD — considering the fact that three major climatic events took place in the subcontinent during this phase.
The three major climatic changes that took place during this time are: Medieval Climate Anomaly that took place between 1100AD-1300AD; the Little Ice Age that is roughly between 1300AD-1750AD; and the current warm period between 1750AD to the present. The two major floods that have been indicated by the geologists occurred roughly around 1210AD and 1320AD respectively, going by the intensity of precipitation marks on the stalagmites.
“It rained heavily for months, inundating large parts of what we know as India today. The floods were so high and severe that they not only wiped out dynasties, killing common people and forcing them to leave their homes and turn into nomads in search of high ground but also ruined the agrarian economy of the era,” said Anil Gupta, the group’s lead scientist.
Among the dynasties that were finished around this time were Sena in Bengal, Solanki in the west, and Paramar, Yadav and Pandyan in the south. “We are working in close connect with historians and archaeologists so that we can corroborate our period details with theirs,” Gupta told TOI.
The stalagmites were drilled at an interval of every half millimetre, following a process of dating where every half millimetre stands for two years of real time experience of the rock. The drilled portions have rainfall traces etched on them and these were then made to pass through the uranium-thorium time series dating to arrive at the right conclusion about the time of the precipitation.
“The two floods were never recorded in history and hence the uniqueness of the finding,” Gupta said. “There is little documented history during the 13th and 14th centuries that have come down to us. Most of the time, wars were considered to be the reasons for downfall, but the discovery of the two mega floods will now add better value to earlier explanations. One can allude to the flood theory that perhaps ended the Indus Valley civilisation.”
The group has also indicated that the floods might have occurred in China as well, and might have been the cause of the downfall of the Ming dynasty there. The Elsevier article points out that from 1750AD onwards, the subcontinent has experienced severe precipitation and monsoon vagaries have seen the worst extremes during this time. “The stalagmites have indicated 12 floods and 12 droughts during this phase. This phase of history, however, is relatively better documented, thanks to the arrival of the British and we are easily able to corroborate our findings with what has come down to us in history,” Gupta said.
Scholars who deal with ancient Indian history feel that these findings will be of immense use in pinpointing antiquities of known events. “Gradually, the divide between humanities and technology is slimming. We have very little documentation as far as the pre-British era goes. Naturally, it is difficult to arrive at scientific conclusions about a lot of events in Indian history. Antiquities that historians have tried to establish have often been challenged, too, for want of proof. Happily, IIT Kharagpur has been consistently helping with this. Its findings have recently helped push back the beginning of the Indus civilisation by at least 2,000 years. The flood theory will similarly help put certain endings and migrations in perspective,” said historian Ramkrishna Chatterjee, the publications secretary of Asiatic Society.
Historian Arun Bandyopadhyay, too, sounded excited. He felt that such geological study of Indian history was necessary for a long time. In the past, similar climatological study of famines were done in the European context. “It is heartening to know that geologists of IIT Kharagpur are applying similar scientific methods to uncover major geological events that will add new perspective to Indian history,” Bandyopadhyay said.