Thousands of years ago, the lava flows of numerous volcanic eruptions in the Ngorongoro area formed Crater Highlands southeast of the Serengeti. Over a period of time, the volcanic ash settled on the plains to the west, filling in the terrain to form vast expanses of flat land. The ancient granite [G 26 / kopjes] that dot the plains are all that remain of the former landscape.
The volcanic ash formed hard layers below the surface soil. As a result, the plains do not support trees but rather shallow root grasses. The gray powdery volcanic soil is rich in minerals such as calcium, iodine and potassium, enriching [G 38 / perennial] short grasses that cover the 3,500 miles of plains.
