Physical Features of India Class 9 Flashcards

Tectonic Plate Movements

• Tectonic plate movements cause stresses leading to folding, faulting, and volcanic activities.
• Types of movements include convergent, divergent, and transform boundaries.

Gondwana Land

• The Indian peninsula, oldest part of the subcontinent, was part of Gondwana land.
• Countries included: India, Australia, South Africa, South America, and Antarctica.

Movement of Gondwana Land

• Convectional currents split Earth’s crust; Indo-Australian plate separated from Gondwana.
• Indian plate migrated northward, colliding with the Eurasian plate.

Himalayas Formation

• Collision of Indian and Eurasian plates folded sedimentary rocks from the Tethys Sea into the Himalayas.

Northern Plains Formation

• Himalayas created a depression filled by sediments from rivers, forming alluvium-rich northern plains.

Stable and Unstable Landforms

• The peninsular plateau recognized as most stable landform.
• Himalayan mountains identified as most unstable due to tectonic activity.

Physiographic Divisions of India

• Divided into six main regions: Himalayan mountains, Northern plains, Peninsular plateau, Indian Desert, Coastal Plains, and Islands.

Introduction to the Himalayan Mountains

• Extend 2,400 km from the Indus to the Brahmaputra, with varying widths (400 km in Kashmir to 150 km in Arunachal Pradesh).
• Consist of three ranges: Himadri, Himachal, and Shiwaliks.

Himadri Range

• Continuous range with loftiest peaks (average height of 6 km).
• Composed of granite, perennially snow-bound, contains many glaciers.

Himachal Range

• Located south of Himadri, consists of compressed and altered rocks.
• Altitude range: 3.7 km to 4.5 km; home to valleys such as Kangra and Kullu.

Shiwaliks Range

• Ranges from 0.9 km to 1.1 km in altitude, width 10-50 km.
• Composed of unconsolidated sediments; includes valleys like Dehra Dun.

Tallest Peaks of the Himalayas

• Mount Everest (8,848 m, Nepal) and Kanchenjunga (8,598 m, India) noted as the highest peaks.

Longitudinal Divisions of the Himalayas

• Divided by rivers into Punjab, Kumaon, Nepal, and Assam Himalayas.

Purvachal or Eastern Hills

• Eastward of the Brahmaputra, comprising northeastern hills like Manipur, Mizo, and Naga hills.

Introduction to the Northern Plains

• Formed by sediment deposition from Indus, Ganga, and Brahmaputra rivers; covers 700,000 km².
• Characterized by alluvial soil and extensive river systems.

Riverine Divisions of the Northern Plains

• Three main sections: Punjab plains (Indus region), Ganga plains (Haryana to West Bengal), and Brahmaputra plains (primarily Assam).

Relief Variation Divisions of the Northern Plains

• Bhabar: Pebble deposits along Shiwalik slopes.
• Terai: Wet, marshy area previously forested.
• Bhangar: Largest area with calcareous soil (Kankar).

Introduction to the Peninsular Plateau

• Comprises old crystalline and metamorphic rocks, the oldest landmass, originally part of Gondwana.

Central Highlands

• North of Narmada River, consisting mainly of the Malwa plateau; influenced by nearby ranges like Vindhyan.

Deccan Plateau

• Triangular region south of Narmada, characterized by distinct hill ranges and separation from Chotanagpur plateau.

Ghats of India

• Western Ghats: Parallel to western coast, 0.9 km to 1.6 km elevation, rainfall inducing clouds.
• Eastern Ghats: Discontinuous, lower elevation (0.6 km), dissected by rivers.

Distinct Features of the Deccan Plateau

• Notable for Deccan Trap and black soil of volcanic origin; bordered by Aravali hills.

Indian Desert

• Located east of Aravalis, characterized by sandy plains, arid climate, minimal rainfall, and intermittent streams.

Coastal Plains

• Surround the peninsular plateau, separated by Arabian Sea and Bay of Bengal; notable rivers form deltas.

Islands of India

• Two prominent groups: Lakshadweep (southeast, diverse flora and fauna) and Andaman and Nicobar Islands (strategically significant).

Resources from Physiographic Features

• Mountains offer water and forest resources; northern plains support agriculture; plateaus provide minerals; coastal regions offer fish and ports; diverse physical features foster potential for future development.