Rounded features and low elevation
Explanation
Mountains are generally classified based on their mode of formation and age. Fold mountains are formed due to the collision of tectonic plates. They are further categorized into Young Fold Mountains (e.g., Himalayas, Alps) and Old Fold Mountains (e.g., Urals, Appalachians, Aravallis) based on the geological period of their origin.
Detailed Analysis:
- High conical peaks and rugged relief is incorrect: High conical peaks and rugged relief are characteristic features of Young Fold Mountains. These mountains are geologically recent and have not yet been significantly subjected to denudation (erosion). Examples include the Himalayas and the Andes.
- Rounded features and low elevation is correct: The Ural Mountains in Russia are Old Fold Mountains formed during the Hercynian orogeny (Late Paleozoic era). Due to millions of years of exposure to denudational forces (wind, water, ice), their original sharp peaks have been eroded, resulting in rounded features and relatively low elevation.
- Block mountain structure with horsts is incorrect: Block mountains are formed when faults or cracks in the earth's crust force some blocks of rock up and others down. Examples include the Black Forest and the Vosges in Europe. The Urals are formed by folding, not faulting.
- Volcanic origin with lava deposits is incorrect: Volcanic mountains are formed from the accumulation of lava and volcanic debris (e.g., Mount Kilimanjaro, Mount Fuji). The Urals are tectonic in origin, resulting from the collision of ancient continents.
Key Takeaway:
Old Fold Mountains (like the Urals, Appalachians, and Aravallis) are characterized by low elevation and rounded peaks due to prolonged erosion, whereas Young Fold Mountains feature high elevations and sharp, conical peaks.