Geology of Nigeria

The country is actually not very rich in caves, and there is not much karst in the country. There are numerous caves in sandstone and granite though, which is quite unique. In our list there is not a single dripstone cave though, erosional caves generally have no speleothems.

The country is located on a craton, crystalline and metamorphic rocks from the Precambrian, the Archean and Proterozoic Eons. As a result more than half of the country is insoluble crystalline basement and the only caves are erosional and tectonic, they are small and rare. Those rocks contain deposits of gold, lead, zinc, tantalite, columbite, and tin. There were three orogenies over time and two periods where the surface went down forming basins which caused the transgression of the sea and thus the sedimentation of sedimentary rocks. The first was during the Cambrian following the Pan-African orogeny, the second during the Cretaceous. This transgression and sedimentation ended in the Cenozoic about 50 Ma ago. The result are massive coal, oil and gas deposits in the thick sedimentary basins in the southeast. Also, these areas have limestone and gypsum deposits which allow karstification. There were also granite intrusions and some sedimentary rocks experienced lead and zinc mineralization.

All in all the country has no karst and caves to speak of. On the other hand it has some erosional caves in sandstone which are quite big for this kind of rock. Also, some crystalline hills have erosion which formed huge boulders and thus numerous talus caves. Like other countries, the shelters, overhangs and small caves were popular stops on hunting trip by our prehistoric ancestors and so there are some quite famous archaeological excavations.