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UPSC Prelims 1990 · Indian Geography · Minerals and Energy
Important oil fields of the Brahmaputra Valley include
- (a) Digboi and Kilboi
- (b) Lunej and Ankleshwar
- (c) Badarpur and Masimpur
- (d) Naharkatia and Moran
Show the answer and explanation
Answer: (d) Naharkatia and Moran
Naharkatia and Moran are Brahmaputra valley oil fields.
The idea
A valley label is a regional location clue for an oil field, rather than a claim that oil comes from river water. Assam contains distinct sedimentary settings around the Brahmaputra and Barak regions. Fixing that regional divide prevents mixing nearby north-eastern field names.
Why the others are wrong
(a) Digboi is in Assam, but “Kilboi” is not a real field.
(b) Lunej and Ankleshwar are in Gujarat.
(c) Badarpur and Masimpur are in the Surma valley (Barak), not the Brahmaputra valley.
The trap
(a) pairs a real field with a fake one.
Elimination technique
Lunej and Ankleshwar are Gujarat anchors, removing (b). Badarpur and Masimpur belong to the Barak/Surma setting, removing (c); the remaining list still needs its named fields checked.
Also know
Digboi and Rudrasagar are other Assam oil anchors. Ankleshwar belongs to Gujarat’s Cambay basin. Mumbai High and the Krishna–Godavari fields are offshore examples; the same hydrocarbon can occur in quite different surface landscapes.
🔒 Assam oil: Digboi (oldest, 1901), Naharkatia, Moran, Rudrasagar.
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