Among the following, which one is NOT a young folded mountain?

Question

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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.

Why the other options are wrong — (b) 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) The textbook example of a young fold mountain — formed by the ongoing collision of the Indian and Eurasian plates, still rising today.  (d) A classic young fold mountain of Europe, formed by the collision of the African and Eurasian plates during the Alpine orogeny.

Concept: 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.

State PCS 2021 Q13 — Geography PYQ with Answer

State PCS 2021 Q13 — Geography PYQ with Answer