The correct option is (c) 1 and 3 only.
Explanation
The Himalayas consist of three parallel ranges in their longitudinal extent: the Great Himalayas (Himadri), the Lesser Himalayas (Himachal), and the Outer Himalayas (Shiwaliks). These ranges differ significantly in their geological structure and composition.- Statement 1 is Correct: The Himadri (Great or Inner Himalayas) is the northernmost and most continuous range. The core of this part of the Himalayas is composed of granite. It is perennially snowbound, and numerous glaciers descend from this range.
- Statement 2 is Incorrect: The Himachal (Lesser Himalayas) lies to the south of the Himadri and forms the most rugged mountain system. It is mainly composed of highly compressed and altered rocks, rather than loose sand and silt. The altitude varies between 3,700 and 4,500 metres.
- Statement 3 is Correct: The Shiwaliks (Outer Himalayas) are the southernmost range. They are composed of unconsolidated sediments brought down by rivers from the main Himalayan ranges located farther north. These valleys are typically covered with thick gravel and alluvium.
Key Takeaway: The geological composition of the Himalayas transitions from the crystalline granite core of the Himadri to the compressed metamorphic rocks of the Himachal, and finally to the unconsolidated river sediments of the Shiwaliks.