In which type of geological formation are gorges most commonly developed?

Question

In which type of geological formation are gorges most commonly developed?

1. A. Soft sediment
2. B. Hard rocks (Correct answer)
3. C. Glacial till
4. D. Volcanic ash

Correct Answer

Option B — Hard rocks

Detailed Solution & Explanation

The correct answer is Hard rocks.

Key Points

• A gorge is a deep, narrow valley with near-vertical sides, formed where a river cuts downward far faster than the valley widens.
• That profile requires hard, resistant rock: the steep walls stand because they resist weathering and mass movement while the river deepens the channel.
• In soft sediment the sides would collapse and widen into an open V-shaped valley, so a gorge could not persist.

Additional Information

• Gorges are typical of the youthful stage of a river, where gradient and velocity are high and vertical erosion dominates over lateral erosion.
• A canyon is essentially a gorge on a larger scale in horizontally bedded rock — the Grand Canyon of the Colorado being the classic example.
• Indian examples: the Bhedaghat marble rocks gorge on the Narmada at Jabalpur, and the deep gorges cut by the Indus, Satluj and Brahmaputra where they cross the Himalaya.
• Related fluvial landforms: V-shaped valleys, waterfalls, rapids and potholes upstream; meanders, ox-bow lakes, floodplains and deltas downstream.

प्रश्न (हिन्दी में)

किस प्रकार की भूवैज्ञानिक संरचना में गॉर्ज सबसे अधिक विकसित होते हैं?

1. A. नरम तलछट
2. B. कठोर चट्टानें
3. C. हिम दर्राज़
4. D. ज्वालामुखी राख