Which one of the following is a part of Deccan Plateau?

Correct — B, Karbi Anglong Hills. The Karbi Anglong plateau of Assam is a detached fragment of the same ancient peninsular block that forms the Deccan. NCERT's physical geography puts it plainly: 'the Karbi Anglong and the Meghalaya Plateau in the northeast and Rajasthan in the west are also extensions of this block', and the north-eastern piece stands apart only because a fault opened between the Rajmahal hills and the Meghalaya plateau and was later filled by river deposition. The other three hills belong to entirely different structures.

• (a)Aravalli Hills — The Aravalis are one of the oldest fold mountains on earth, but they bound the Central Highlands on the west; NCERT runs the northern boundary of the peninsular block along their western flank rather than counting them into the Deccan.
• (c)Shivalik Hills — The Shivaliks are the outermost and youngest range of the Himalaya, built of river-borne sediment shed by the rising mountains. They are Himalayan, not peninsular.
• (d)Vindhyan Hills — The Vindhyas belong to the Central Highlands north of the Narmada; the Deccan's own northern boundary is drawn along the Satpura, the Maikal range and the Mahadeo hills, which lie south of them.

The Peninsular Plateau is divided into three — the Deccan Plateau, the Central Highlands, and the Northeastern Plateau. The Deccan is bordered by the Western Ghats, the Eastern Ghats, and the Satpura, Maikal and Mahadeo hills to the north. The north-eastern piece, comprising the Meghalaya and Karbi Anglong plateaus, is geologically the same block, separated by the Malda fault.

The item tests whether a candidate can tell structure from location. Karbi Anglong sits in Assam, surrounded by the north-eastern hills, so it looks Himalayan on a map — and its rocks say otherwise. The two hill systems that actually stand between the Ganga plain and the Deccan, the Aravalis and the Vindhyas, are the ones a candidate is likeliest to pick.

• NCERT places the Karbi Anglong and Meghalaya plateaus, and Rajasthan, as extensions of the peninsular block.
• The Malda fault in West Bengal separates the north-eastern plateau from the Chotanagpur plateau.
• The Meghalaya plateau divides into the Garo, Khasi and Jaintia hills; Karbi Anglong is an extension of the same.
• The Shivaliks are the youngest, outermost Himalayan range; the Aravalis are relict fold mountains bounding the Central Highlands.

• Judging structure from position on the map; Karbi Anglong is peninsular rock in a Himalayan neighbourhood.
• Assuming the Vindhyas are the Deccan's northern boundary — NCERT gives that role to the Satpura, Maikal and Mahadeo hills.

As which feature belongs to which physiographic division, or as the boundary of the Deccan Plateau.

• practice — not a real PYQ

  The Meghalaya and Karbi Anglong plateaus stand detached from the main peninsular block because of

  • (a)the Malda fault
  • (b)the Great Boundary Fault
  • (c)the Narmada rift
  • (d)the Purna alluvium

  Answer(a) the Malda fault — the depression it opened was later filled by river deposition, separating the north-eastern plateau from Chotanagpur.

• practice — not a real PYQ

  The northern boundary of the Deccan Plateau is formed by

  • (a)the Aravalli range
  • (b)the Vindhyan range
  • (c)the Satpura, Maikal and Mahadeo hills
  • (d)the Shivalik range

  Answer(c) the Satpura, Maikal and Mahadeo hills — the Vindhyas lie further north, in the Central Highlands.