1. Rocks near mid-ocean ridge were younger than rock near trenches.
2. Matching bands of magnetic rocks were found on either side the mid-ocean ridge; record changes in earth's magnetic field over a period of time.
3. Earthquake data showed oceanic crust is sinking on to the mantle at the trenches.
1. Rocks near mid-ocean ridge were younger than rock near trenches.
2. Matching bands of magnetic rocks were found on either side the mid-ocean ridge; record changes in earth's magnetic field over a period of time.
3. Earthquake data showed oceanic crust is sinking on to the mantle at the trenches.
