The Great Indian Desert is a part of the greater Thar Desert, which spans through India into Pakistan. This vast desert encompasses the western states of Gujarat, Rajasthan, Haryana, Punjab, and Delhi.
It is because of these characteristic features that this is also known as Marusthali. The Luni river flowing in the southern part of the desert is of some significance. Low precipitation and high evaporation makes it a water deficit region.
Most of the arid plain was under the sea from Permo-Carboniferous period and later it was uplifted during the Pleistocene age. This can be corroborated by the evidence available at wood fossils park at Aakal and marine deposits around Brahmsar, near Jaisalmer (The approximate age of the wood fossils is estimated to be 180 million years).
The presence of dry beds of rivers (eg Saraswati) indicates that the region was once fertile. Geologically, the desert area is a part of peninsular plateau region but on the surface it looks like an aggradational plain.
The desert proper is called the Marusthali (dead land) as this region has an arid climate with low vegetation cover. In general, the Eastern part of the Marushthali is rocky, while its western part is covered by shifting sand dunes.
Bagar: Bagar refers to the semi-desert area which is west of Aravallis. Bagar has a thin layer of sand. It is drained by Luni in the south whereas the northern section has a number of salt lakes.
The Rajasthan Bagar region has a number of short seasonal streams which originate from the Aravallis. These streams support agriculture in some fertile patches called Rohi.
Even the most important river ‘Luni’ is a seasonal stream. The Luni originates in the Pushkar valley of the Aravalli Range, near Ajmer and flows towards the southwest into the Rann of Kutch.
