RAS question
The Hadoti Plateau in southeastern Rajasthan is primarily composed of which type of rocks?
Correct answer: (C) Deccan Trap basalt / lava flows.
The Hadoti Plateau of south-eastern Rajasthan is primarily composed of Deccan Trap basaltic lava flows.
Explanation
The Hadoti Plateau, covering Kota, Bundi, Baran and Jhalawar, belongs to the south-eastern plateau tract of Rajasthan. Its key geological clue is its link with the Deccan Trap: Connect Civils (RajRAS) divides the Hadoti Plateau into the Deccan Highlands and the Vindhyan Region, and notes that the Deccan Highlands have mostly black soil with visible deposits of Deccan Trap lava. Hadoti is the northern extension of Deccan Trap basaltic lava flows. The associated black cotton soil, or regur, follows from this basaltic volcanic base, so Deccan Trap basalt/lava flows is the best answer.
Why the other options are wrong
- (A) Granite and gneiss occur in parts of Rajasthan, but Hadoti's plateau tract points instead to Deccan Trap lava and black soil.
- (B) Sandstone alone cannot explain the basaltic Deccan Trap character and black cotton soil identified for Hadoti.
- (D) Limestone and dolomite may occur in parts of Rajasthan, but the Hadoti Plateau is described here as primarily volcanic and basaltic, not mainly carbonate rock.
Concept
This tests the physical divisions of Rajasthan, especially the link between plateau geology and soil type. RAS repeats this because regions such as Hadoti are best remembered through their rock base, relief and associated soils together.