Star Student Builder logoStar Student Builder

← 🌍 Earth science · usually met in Std 7-12

Plate tectonics

The Earth's surface is broken into plates that move a few centimetres a year. Everything dramatic in geology happens where they meet.

Pulling apart new crust forms mid-ocean ridges Colliding mountains, volcanoes, deep trenches Sliding past friction builds, then releases — earthquakes The plates move about as fast as your fingernails grow. India broke away, sailed north, and ran into Asia — and is still pushing, which is why the Himalaya are still rising.
Drawn for Star Student.
Rock layers folded by the movement of the crust
Jonathan Wilkins · CC BY-SA 2.0 ↗ · where it came from ↗

The rigid outer shell is divided into plates that ride on the slowly flowing mantle beneath. Where they pull apart, new crust forms — mid-ocean ridges. Where they collide, one may slide beneath the other, producing volcanoes and deep trenches, or neither gives way and the crust crumples upward into mountains. Where they slide past each other, the friction builds until it releases as an earthquake.

The Himalaya are the clearest example anywhere. The Indian plate broke from the ancient southern landmass, travelled north, and ran into Asia around fifty million years ago. It is still pushing, which is why the Himalaya are still rising and why the region is seismically active. Wegener proposed continental drift in 1912 and was dismissed because he had no mechanism; sea-floor spreading supplied it half a century later.

Worth knowing

  • Plates move at roughly the speed your fingernails grow.
  • The Deccan Traps in western India are the remains of colossal volcanic eruptions around the time the dinosaurs died out.
  • The fit of South America against Africa is the clue that started the whole argument.

Want to see it moving? Search YouTube for “Plate tectonics” ↗ — we send you to the search rather than to one video, because a link to one video eventually rots.

See also

🌍 Inside the Earth🌍 Earthquakes🌍 Rocks and minerals

🧭 Do not take our word for it

This entry was written for Star Student in our own words — it is a summary, not a source. Here is where the people who actually hold these facts keep them. Go and check.

Your own textbook ↗Balbharati publishes the textbooks free to read online. Your chapter is the thing to check first — an encyclopedia is a summary, and the syllabus is the syllabus. Geological Survey of India ↗Rocks, earthquakes, the Himalaya and seismic zoning. India Meteorological Department ↗The monsoon, rainfall and cyclone warnings, from the department that issues them.

Last gone through: 1 October 2026 · How these entries are written

← All 86 entries 🧘 Ask the Guru about this

Ask GuruAcharya Samayeshwar