The most important desert in India is in Rajasthan – the Thar Desert of the Great Indian Desert. This desert of Rajasthan is in western India spilling over to the neighbouring states of Haryana, Punjab and Gujarat as well as the neighbouring country of Pakistan.
Rajasthan has the lion’s share of the desert. The Thar is fenced off by the Sutlej River in the north and on the east by the Aravalli Range.
On the south the desert meets salt marshes of the Rann of Kutch, parts of which are included in the Thar.
On the west flows the mighty River Indus. The desert of Rajasthan comprises of 61% of the entire desert region and three fifths of the entire state.
The origin of the desert is mired with controversy – could be either 4,000 or 10,000 years old. Some say very recently the region started to become arid – around 1,500 or 2,000 BC. At that time the flow in the Ghaggar began to trickle and finally terminated in the desert.
Climatic changes contributed to changing the drainage levels. Some paleochannels can still be seen. Most experts agree that the paleochannels of the mythical Sarasvati can be identified with the Ghaggar of today – the Sutlej being its main tributary. Land movements most probably pushed the Sutlej westwards and the Yamuna westwards causing the Ghaggar to shrivel.
There are three types of land forms in the desert regions of Rajasthan – sand covered region of Thar, the plains having hills free from dunes in the centre and the hills.
In the desolate country, sand blown by the wind is piled up to form huge dunes – consisting of three types. There are longitudinal, transverse and barchan types of dunes. The first runs north-south, the second east-west and the barchans are in the centre of the desert with conclave sides wind facing.
The Thar has a tilt westwards and the surface is uneven because of the dunes.
The desert is broken by hillocks and sandy gravel plains. This has allowed for a richly varied flora and fauna. For instance there are 23 lizard species and 25 snake species – some being exclusive residents of this place.
Species that are disappearing fast in other parts of India are thriving well in these arid surroundings like the Great Indian Bustard, the Blackbuck and the Indian Gazelle among many. So too is the Indian Wild Ass merrily multiplying in the Rann. They have come up with superb survival strategies baffling analysis.