The correct option is 2 only
Explanation
The Great Indian Desert, also known as the Thar Desert, is a distinct physiographic region in the northwest of India, characterized by arid conditions and specific geological features.
- Statement 1 is Incorrect: The Great Indian Desert lies to the northwest of the Aravali hills. It covers a significant portion of Western Rajasthan and extends into Pakistan. It is a land of undulating topography dotted with longitudinal dunes and barchans.
- Statement 2 is Correct: Geological evidence suggests that this region was under the sea during the Mesozoic era. This is substantiated by the discovery of marine fossils in the region. For instance, the fossil beds at the Aakal Wood Fossil Park near Jaisalmer and marine deposits around Brahmsar indicate past marine transgression.
- Statement 3 is Incorrect: The underlying rock structure of the desert is not distinct from the Peninsular Plateau; rather, it is an extension of the Peninsular Plateau. Although the surface features have been modified by weathering and wind action (aeolian processes), the bedrock beneath the sands consists of the same gneiss and granite structures found in the Peninsular block.
Key Takeaway: The Indian Desert is geologically an extension of the Peninsular Plateau that was submerged under the sea during the Mesozoic era, located northwest of the Aravali range.