Among the following, which one is NOT a young folded mountain?
- (a)Sierra Nevada
- (b)Rocky
- (c)Himalaya
- (d)Alps
Correct — A, Sierra Nevada. The Sierra Nevada range in California, USA, is a fault-block (horst) mountain, not a fold mountain — it was formed by vertical uplift of a huge granite batholith along faults, later sculpted by erosion and glaciation, rather than by the compressional folding of rock strata. The Himalaya, Alps and Rockies, by contrast, are all young (Cenozoic/Tertiary) fold mountains thrown up by compressional collision along plate boundaries.
- (b)Rocky — The Rocky Mountains of North America are a young fold mountain range, formed during the Laramide orogeny as part of the same broad mountain-building episode as the Andes and other American Cordillera ranges.
- (c)Himalaya — The textbook example of a young fold mountain — formed by the ongoing collision of the Indian and Eurasian plates, still rising today.
- (d)Alps — A classic young fold mountain of Europe, formed by the collision of the African and Eurasian plates during the Alpine orogeny.
Mountains are classified by how they form. Fold mountains rise where compressional forces at converging plate boundaries buckle and crumple sedimentary rock layers — the Himalaya, Alps, Rockies and Andes are all 'young' (Cenozoic-age) fold mountains from this process. Fault-block (or block) mountains form differently: land is uplifted or dropped along roughly vertical faults, creating an uplifted block (horst) without folding the rock layers — the Sierra Nevada (California), the Vosges and the Black Forest (flanking the Rhine rift valley) are the standard textbook examples.
This question is a classic elimination pattern: three genuine young fold mountains are listed alongside one look-alike (Sierra Nevada) that sounds equally 'mountain-y' but actually belongs to a different formation category — testing whether students know the type, not just the name.
- Fold mountains form by compressional folding of rock strata at converging plate boundaries
- Himalaya, Alps and Rockies are all young (Cenozoic/Tertiary) fold mountains
- Fault-block (horst) mountains form by vertical uplift along faults, without folding — e.g. Sierra Nevada, Vosges, Black Forest
- Sierra Nevada (California) is largely an uplifted granite batholith, tilted along a fault line
- Assuming any tall, famous mountain range must be a fold mountain
- Confusing the Sierra Nevada (California, fault-block) with fold-mountain ranges of similar prominence
Frequently asked as 'which one is NOT a fold/block mountain' elimination questions, or as match-the-mountain-to-its-type table questions.
Consider the following information: Region — Name of the mountain range — Type of mountain 1. Central Asia — Vosges — Fold mountain 2. Europe — Alps — Block mountain 3. North America — Appalachians — Fold mountain 4. South America — Andes — Fold mountain In how many of the above rows is the given information correctly matched?
- (a) Only one
- (b) Only two
- (c) Only three
- (d) All four
Answer(b) Only two — rows 3 and 4 are correct (Appalachians and Andes are genuine fold mountains); the Vosges is actually a fault-block mountain (not fold), and the Alps are a fold mountain (not block).
Tests the identical fold-mountain-vs-fault-block-mountain classification (Alps=fold, Vosges=block) that this Sierra Nevada question is built on.
- practice — not a real PYQ
Which of the following is an example of a fault-block (horst) mountain?
- (a)Himalaya
- (b)Andes
- (c)Vosges
- (d)Rockies
Answer(c) Vosges.
- practice — not a real PYQ
Young fold mountains such as the Himalaya and the Alps were formed mainly due to:
- (a)volcanic eruptions building up layers of lava
- (b)compressional folding of rock strata at converging plate boundaries
- (c)vertical uplift of land blocks along faults
- (d)deposition of river sediments over millions of years
Answer(b) Compressional folding of rock strata at converging plate boundaries.