Which one of the following valleys of Madhya Pradesh is not a rift valley?

Question

UnlockIAS · Accepted Answer

Correct — D, Chambal Valley. The Chambal is not a rift valley: it rises in the Vindhyan scarp and cuts across the Malwa plateau, carving its famous badland ravines before joining the Yamuna. The Narmada, Tapti (Tapi) and Son valleys, by contrast, all lie along the great Son-Narmada-Tapti (SONATA) rift/fault zone of central India, so they are true rift valleys.

Why the other options are wrong — (a) It is a rift valley — the Son flows along the eastern arm of the Narmada-Son rift (the SONATA lineament), so it is not the answer.  (b) The classic Indian rift valley — the Narmada runs westward through a trough down-faulted between the Vindhya and Satpura ranges.  (c) Also a rift valley — the Tapti (Tapi) occupies a parallel rift trough just south of the Satpuras and, like the Narmada, flows west to the Arabian Sea.

Concept: A rift valley is a long trough formed where a block of land subsides (down-faults) between two roughly parallel faults. In central India the Narmada, Son and Tapti occupy such rifts along the SONATA (Son-Narmada-Tapti) tectonic zone, which is why the Narmada and Tapti flow west into the Arabian Sea against the peninsula's general eastward slope. The Chambal has no such rift structure — it is an ordinary river of the Malwa plateau, famous for its ravines.

State PCS 2018 Q55 — Madhya Pradesh GK PYQ with Answer

State PCS 2018 Q55 — Madhya Pradesh GK PYQ with Answer