Indian Subcontinent and Plate Tectonics

India in the Plate Tectonic Framework

Geological Journey

• ~150 million years ago – Part of Gondwanaland with Africa, Antarctica, Australia, and South America.

• ~120 million years ago – Broke away and drifted north across the Tethys Ocean at exceptional speed (~15–20 cm/year).

• ~50 million years ago – Collided with the Eurasian Plate, closing the Tethys Ocean.

• Present – Still converging with Eurasia (~5 cm/year), causing active mountain building and earthquakes.

Tectonic Plate of India

• Indian Plate – Once part of Gondwanaland; now includes the Indian subcontinent and surrounding oceanic crust.

• Collision with Eurasia – Caused the Himalayan Orogeny and uplift of the Tibetan Plateau.

• Ongoing Movement – Himalayas rise ~5 mm/year; frequent seismic events occur.

Current Tectonic Setting

• North – Convergent boundary with Eurasian Plate → Himalayan uplift, seismicity (e.g., Nepal 2015 earthquake).

• West – Interaction with Arabian Plate along Owen Fracture Zone and Makran Subduction Zone.

• East – Convergent boundary with Burma and Sunda Plates → Andaman volcanic arc, earthquakes.

• South – Indian Ocean spreading ridges (divergent boundaries).

Tectonic Zones in and Around India

1. Himalayan Belt – Active continental collision, high seismic risk.

2. Indo-Burmese Arc – Oceanic–continental convergence and thrust faulting.

3. Narmada–Son Lineament – Ancient rift zone with occasional intraplate earthquakes.

4. Stable Peninsular Shield – Geologically stable but not immune to quakes (e.g., Latur 1993).

5. Andaman–Nicobar Arc – Oceanic–oceanic subduction zone with active volcanoes (e.g., Barren Island).

Key Geological Terms

• Orogeny – Mountain-building process.

• Subduction zone – One plate sinks beneath another.

• Suture zone – Boundary where two plates have collided (e.g., Indus–Tsangpo Suture).

• Seismicity – Frequency/intensity of earthquakes.

• Fold-and-thrust belt – Layers of rock folded and faulted by compression.

• Craton – Stable continental crust (e.g., Indian Shield).

• Hotspot volcanism – Volcanic activity from mantle plumes (e.g., Deccan Traps).

Geological & Geopolitical Implications

• Natural Hazards – Earthquakes, landslides, glacier lake outburst floods (GLOFs), tsunamis.

• Resource Distribution – River systems and mineral deposits influenced by tectonics.

• Strategic Geography – Mountain barriers influencing defence, trade, and culture.

Time Period	Event	Impact
~150 Ma	India part of Gondwanaland	Connected to Antarctica, Africa, Australia
~120 Ma	Broke away from Gondwanaland	Northward drift across Tethys
~50 Ma	Collision with Eurasia	Formation of Himalayas, Tibetan Plateau
Present	Active convergence	Earthquakes, mountain building, volcanism