The mysterious extinction of the Harappans
An archaeological site off the western coast of India indicates that the harappans, the indus valley civilization could date back as far as 9,000 years ago, making it one of the oldest in the world.
Nearly five thousand years ago, the Indus Valley Civilization was at its peak. Extending over an area of over one million square kilometers in the territories that today belong to Pakistan, north-western India and eastern Afghanistan, it was one of the first and most important urban cultures of antiquity.
The excavations that began in the 1920s brought to light thousands of finds of trade routes, buildings, artefacts and a writing system yet to be deciphered. Then, between 3900 and 3000 years ago it began to decline, for reasons that are far from clear.
It is thought that the progressive decrease in rainfall stopped the overflowing of the rivers. In the long run, the little water made it impossible to cultivate the land and pushed the population to move elsewhere.
This is the scenario reconstructed by a research group coordinated by Liviu Giosan of the Woods Hole Oceanographic Institution, in the USA, in a study published in Pnas.
“We felt it was finally time to contribute to the debate on the mysterious end of this people”
says Giosan.
His team worked in Pakistan from 2003 to 2008 compiling archaeological and geological data. First, the researchers developed digital maps of the territory using satellite photos and topographic data collected by the Shuttle Radar Topography Mission, the joint NASA-NGA (National Geospatial-Intelligence Agency) mission which made it possible to map the surface of the globe in three dimensions terrestrial with a level of detail never achieved before.
Then they moved on to the collection and analysis of soil samples to trace the origin of the sediments and to understand how they were modified over time by the action of rivers and wind. By combining this information with archaeological data, they ultimately reconstructed the scenario that saw the rise, and decline, of civilization.
The fate of the population of Harappa, named after the first settlement discovered in 1857, was entrusted to the monsoons. Early on, heavy rains fed the Indus and other rivers from the Himalayas, causing floods that left the surrounding plains very fertile.
Then the monsoons began to diminish, the rivers stopped overflowing and the population was free to build their settlements along the waterways, where the fertility of the soil made agriculture flourish. Ultimately, however, the lack of rainfall dealt the final blow to agricultural practices and forced the population to move eastward to the Gangetic plain, where the rains continued.
But this radically changed the culture: large cities gave way to small agricultural communities, marking the end of the urban civilization of the Indus Valley.
In addition to this mystery, US researchers believe they have also solved that of the mythical Sarasvati, one of the seven rivers which, according to the ancient Indian Veda texts, crossed the region west of the Ganges and was fed by the perennial glaciers of the Himalayas.
Today it is thought that the Sarasvati corresponds to the Ghaggar, an intermittent river that flows only in the monsoon season and then dissipates in the desert along the Hakra valley. If this were true, geological data would not confirm Sarasvati's Himalayan origin.
Instead, it seems that the river has always been fed by monsoons and that desertification eventually reduced it to a seasonal watercourse.
An ancient civilization… submerged!
An archaeological site off the western coast of India indicates that Indian civilization could date back as far as 9,000 years ago, making it one of the oldest in the world.
This discovery is the result of approximately eight months of sonar imaging of the seabed, where structures resembling those built by the ancient Harappan civilization were observed.
Although some Paleolithic sites dating back to around 20 thousand years ago have been identified in the Indian state of Gujarata, this is the first discovery of such ancient structures beneath the surface of the sea. The area of discovery, the Gulf of Cambay, has been the subject of great interest from archaeologists, due to its proximity to another underwater site, Dwarka, in the nearby Gulf of Kutch.
However, studies of the new site were made difficult by the presence of strong tidal currents, with speeds of up to three meters per second. Precisely due to the impossibility of carrying out real dives, archaeologists from the Indian National Institute of Ocean Technology resorted to sonar images.
The images not only show the symmetrical structures attributed to man, but also the bed of an ancient river, on whose banks civilization flourished. The dating of the site was done by recovering a fragment of wood from one of the structures, which was found to date back to the year 7600 BC.
