Science

Paleo-rivers predated Harappans by 35,000 years

Using an ultra sensitive optical spectrometer, a researcher measures the intensity of stimulated light signal which is related to the age of burial of the samples.  

A recent study on direct dating of sediments extracted from paleochannels close to Harappan sites in the region of Sutlej-Yamuna interfluve by a team of scientists from the Physical Research Laboratory, Ahmedabad (PRL) and CNRS, France, indicate that these rivers changed their course nearly 35,000 years before the Harappans came to settle there.

Scientific evidence

Along with a 2017 paper in Nature Communications by A. Singh from IIT Kanpur and others, this study now provides scientific evidence that contradicts the suggestions on Harappans flourishing on the banks of the mythical Vedic rivers, Sarasvati and Drishadvati. These studies provide evidence that these rivers changed their course much before the time of Harappan settlements about 5,000 years ago. The study was published recently in Quaternary Geochronology.

The discovery of several hundred Harappan sites in the Sutlej–Yamuna interfluves led archaeologists to infer that like other ancient civilisations, Harappans too flourished on the banks of mighty rivers. Presence of ephemeral rivers Ghaggar-Hakra and Chautang in this area led people to suggest that these were vestiges of the once mighty glacial rivers on whose banks the Harappan civilisation was established. This gained popularity when a paleo-channel (ancient remains of rivers) was discovered in this region.

The naming of a paleo-channel and associating it with archaeological sites irked the curiosity of Prof. A.K. Singhvi from PRL. “To me this appeared unrealistic and far-fetched. A ballpark analysis of Harappan site per unit time indicated that the numbers of settlements to be supported [by a large river] were too few and the need to invoke a mighty river was somewhat misplaced,” he says.

For over three decades many papers were written but this premise was not tested scientifically using modern dating techniques till now.

Settlement patterns

This study analysed the distribution of Harappan sites along the two main rivers in the region – the Indus, which is perennial, and the Ghaggar-Hakra, which is ephemeral; examined the mineralogy of river sediments to establish their source and dated the entire sediment succession of the region using dating technique to establish the event chronology of the evolution of the region.

The authors conclude thus: “Settlement patterns and other analysis suggest that factors other than perennial rivers dictated their [Harappan’s] settlement” and that, “Major change in the river dynamics occurred between 24,000-45,000 years ago (most likely around 40,000-45,000 years ago), and since 25,000 years the landscape has not changed significantly.”

Prof Singhvi, who led the study, states that ipso-facto this study implies that so called paleo-river features are far too old to be associated with Vedic times.

“Care should be taken in making a linear association of river hydrology with abundance of archeological sites,” he says.

He points out that this inference is also buttressed by the evidences of water harvesting techniques of Harappans, the cropping patterns suggesting their dependence on seasonal monsoon rather than constant supply of water.


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Printable version | Sep 18, 2021 9:43:05 PM | https://www.thehindu.com/sci-tech/science/paleo-rivers-predated-harappans-by-35000-years/article24666100.ece

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