With further subsidence of the rift valley floor, the sediments became more sandy.
The intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems.
During this period of evaporation large evaporite deposits will be made in the rift valley.
The half grabens may have alternating polarities along the rift axis, dividing the rift valley into segments.
Raised coral reefs along the east coast and the frequent occurrences of earthquakes in the rift valley indicate that the fault block is still rising.
There are known kimberlite pipes within the rift valley that are considered to be diamondiferous.
There are some hot springs characteristics of a rift valley to the east.
Again, the floor of the rift valley is quite flat here providing a marked contrast to the escarpment.
