For those wondering about the timing of Indus Valley civilization and the reasons for its decline.

(Our text books and articles and historians still attribute the arrival of "Aryans" who conquered the Harappans!)

Just to share what i learnt and hoping it may get u interested

The tweets will be addressing with scientific evidence

1. When did the actual IVC start (earliest date as per evidence)
2. How did it flourish
3. Why did it decline

I have added the references alongside.
If i have made any mistakes, pls correct

The beginnings

Using oxygen isotope studies and optically stimulated luminescence (OSL) dating of pottery from various cultural levels of Bhirrana - Harappan site, Haryana the earliest level has provided mean 14C age of 8597 to 8171 years before present.

#india #indus #harappa

It means that IVC already existed by 8,500 years before present!!!
This makes the civilization the oldest and much before Egyptian (7000BC to 3000BC) and Mesopotamian (6500BC to 3100).
Results are taken from Sarkar et al., 2016 https://www.nature.com/articles/srep26555#Fig1

Isotope studies and archaeological data suggest that the pre-Harappans started inhabiting this area along the mighty Ghaggar-Hakra rivers (wch is the legendary river Saraswati) fed by intensified monsoon from 9 to 7 ka BP.

(1ka = 1000 years).

Bhirrana study site

The Indus Civilization urban settlements grew along the Ghaggar–Hakra palaeochannel which was the archaic remains of the recently abandoned valley Himalayan Sutlej River. (results from Singh et al., 2017).

https://www.nature.com/articles/s41467-017-01643-9#Sec10

The decline
How the river system shaped IVC

For those interested in the morphodynamics of the river ecosystem and its influence on the flourishing and decline of IVC – this paper by Chatterjee et al., 2019 provides additional insight. https://www.nature.com/articles/s41598-019-53489-4#Fig3

Based on the sedimentological evidence and radiocarbon dating the study professes that
1.Ghaggar river was perennial during 80-20 ka and 9-4.5 ka (1ka = 1000 years).

2. The revival of the perennial river in ~9 ka and continued dominance until ~4.5 ka

can be attributed to intensification of Indian Summer Monsoon and melting of glaciers. (Early Harappan)

3.A break in the supply of Sutlej-Ghaggar system in ~4.5 ka made the Ghaggar a ephemeral (transient) stream for next 1000 years. (Mature Harappan age)

These had a major affect on IVC with the rejuvenated perennial phase of the Ghaggar (9-4.5 ka) coincides with that of the flourishing of the Pre-Harappan and Early Harappan cultures along its banks.

There is evidence of human migration towards the upper and lower parts of river during the end of the Mature Harappan phase (4.6-3.9 ka), due to disorganised river supply. This would have led to the decline of IVC.

These evidences prove that the decline of Harappan civilization was brought abt by the geological changes and not the advent of the so called "Aryans".

The so called "Aryans" are the actual Steppe pastoralists who arrived from Kazakhstan and settled in regions of Kashmir

They were nomads and not advanced as IVC. There are no conclusive evidences that they migrated to IVC settlements. On the contrary - in the post Urban Harappan era, after the drought - IVC settlers moved north and mixed with the settlers forming a new lineage called ANI.

Finally
The IVC formed on account of the fertile region and water supply resulting in one of kind advanced settlement.
The flourishing was partially due to the river becoming ephemeral - resulting in a fertile catchment basin - Ghaggar Hakra paleochannel.

And the decline was due to the continued drought of about 900 years resulting in the migration upwards and downwards and not some Aryan invasion as proposed by some.
Hope this article helps.

If i have left out any details - you are welcome to add/correct.
Pls read the actual scientific papers rather than some half-baked version published in trashy magazines.

My only intent is to make more ppl interested in Archaeology, genomics and Indian history.