- Created by: WGSB Geography
- Created on: 13-03-17 12:52
A constructive plate margin (also known as a divergent margin) is one where plates move apart from each other. Where the plates move apart in the ocean they form mid-ocean ridges and where they move apart on the land (continental crust) they produce rift valleys. The space between the diverging plates is filled with basaltic lava that rises up from the mantel into the new space.
The movement of the plates moving apart causes huge ridges of mountains and volcanoes along the sea-bed to form. The form of the ridge appears to be influenced by the rate at which the plates separate which are as follows:
- slow rate (10-15mm / year) : found at parts of the mid-atlantic ridge which produces a wide ridge axis (up to 50km) and a…