Context: Researchers have found the evidence of river activity in central Thar Desert, near Bikaner, as early as 172 thousand years ago.

The presence of a river running through the central Thar Desert would have offered a life-line to Paleolithic populations, and potentially an important corridor for migrations

These findings predate evidence for activity in modern river courses across the Thar Desert as well as dried up course of the Ghaggar-Hakra River.

Map showing the location of Nal Quarry at the threshold of the Asian monsoon, and ~200km away from modern rivers in the Thar Desert.

Map showing the location of Nal Quarry at the threshold of the Asian monsoon, and ~200km away from modern rivers in the Thar Desert

Different phases of river activity

• “The Thar Desert has a rich prehistory, and uncovering a wide range of evidence shows how Stone Age populations not only survived but thrived in these semi-arid landscapes,”
• Studies of satellite imagery have shown a dense network of river channels crossing the Thar Desert.

Luminescence dating

• The researchers used a method called luminescence dating to understand when quartz grains in the river sands were buried.
• The results indicated that the strongest river activity at Nal occurred at approximately 172 and 140 thousand years ago, at a time when the monsoon was much weaker than today in the region.
• River activity continued at the site between 95 to 78 thousand years ago, after which only limited evidence for the presence of a river at the site, with evidence for a brief reactivation of the channel 26 thousand years ago, the study found.
• The river was flowing at its strongest during a phase of weak monsoonal activity in the region, and may have been a life-line to human populations enabling them to inhabit the Thar Desert.
• The timeframe over which this river was active also overlaps with significant changes in human behaviour in the region, which have been linked with the earliest expansions of Homo sapiens from Africa into India.
• “This river flowed at a critical timeframe for understanding human evolution in the Thar Desert, across South Asia and beyond,”

https://www.thehindu.com/sci-tech/science/research-shows-evidence-of-a-river-flowing-through-the-thar-desert-172000-years-ago/article32908090.ece?homepage=true

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