🌎 Earth’s Layers & Plate Tectonics

Earth's Four Layers

• ● Inner Core — solid iron-nickel, ~5,200°C. Despite extreme heat, it stays solid due to immense pressure.
• 🔴 Outer Core — liquid iron-nickel, ~4,500–5,000°C. Its movement generates Earth's magnetic field.
• ☀ Mantle — semi-solid silicate rock, ~1,000–3,700°C. Slow convection currents drive plate movement.
• 🌿 Crust — thin, solid rock. Oceanic crust (~7 km thick); continental crust (~35 km thick).

Plate Tectonics

Earth's crust is broken into about 15 major tectonic plates that float on the mantle. They move 2–15 cm per year. At plate boundaries:

• 🔺 Convergent — plates collide. Creates mountains (Himalayas) or subduction zones with volcanoes.
• 🔹 Divergent — plates pull apart. Creates mid-ocean ridges and rift valleys (Iceland, East African Rift).
• ➔ Transform — plates slide past each other. Creates fault lines and earthquakes (San Andreas Fault).