Answer:
Uplift raised the level of a piece of crust.
Mountains eroded.
Basaltic lava flowed from cracks in the crust.
Explanation:
A plateau can form in several different ways. It can form because of volcanic activity, the collision of plates, uplift of crust, and erosion.
Uplift that has raised a piece of crust can easily form this plateau. If the crust that is moving up is relatively flat at the top, then it will stick out in the surrounding area like a mountain will, but it will have a relatively flat top, thus making a plateau.
Erosion is very often a factor that creates plateaus. If there is a very large piece of crust that is much more solid than its surroundings, it will erode at a much slower rate. This will result in the crust around it to erode while it remains close to its initial form, thus sticking out as a higher relief form.
In the areas where there is or has been volcanic activity, it is common that plateaus as the one on the image are found. When the lava flows it fills in the valleys, cracks, holes, and when it solidifies it creates solid masses of igneous rocks. These rocks erode very slowly, so while all of the surroundings erode faster and lower down, it remains largely the same in the form of a plateau.
