RAS question
The Narmada River flows through which rift valley?
Correct answer: (B) Narmada-Son Rift Valley.
The Narmada River flows through the Narmada-Son Rift Valley, also described as the Narmada-Son Tectonic Lineament.
Explanation
The Narmada is associated with the Narmada-Son lineament, a rift valley between the Vindhya and Satpura ranges. The official NDR/DGH source describes the east-west trending Narmada-Son Tectonic Lineament as an important line of discontinuity across the Indian shield and as a mid-continental rift system. This supports option B because the question asks for the rift valley through which the Narmada flows, not for a neighbouring river valley or an eastern-margin graben. A key exam clue is that the Narmada is one of the few major Indian rivers that flows westward, which is closely linked in standard geography teaching with its structurally controlled rift-valley course.
Why the other options are wrong
- (A) The Tapti-Purna Valley belongs to the separate Tapi system, while the Narmada is tied to the Narmada-Son lineament.
- (C) The NDR/DGH source discusses Godavari grabens in the eastern-margin rift context, but the Narmada's supported rift feature is the Narmada-Son Tectonic Lineament.
- (D) The Damodar Valley is associated with the Jharkhand-West Bengal region, whereas the Narmada flows along the Narmada-Son lineament between the Vindhya and Satpura ranges.
Concept
This tests the geomorphology of peninsular India, especially structurally controlled drainage and rift valleys. It recurs in RAS because west-flowing rivers, lineaments and plateau relief are frequent map-based geography themes.