Table 4: Geothermal gradients of some formations in Nigeria.
| S/No. | Sedimentary Basin | Geothermal Gradient | Sediments Types and Thickness |
|---|---|---|---|
| 1. | Niger Delta | 1.3 - 4.7 ℃/100 m | Cretaceous to recent sediments of Akata shale, Agbada sandstone and Benin Formation |
| 2. | Anambra | 3.2 - 5.5 ℃/100 m | A cretaceous basin with sediment thickness of about 9 km including the Asu River Group, Eze-aku, Agwu, Nkporo and Mamu formations |
| 3. | Chad | 3.0 - 4.4 ℃/100 m; 5.9 ℃/100 m | Cretaceous to Quaternary sediments of about 4 to 7 km thick. The basin is made up of marine to continental sediments consisting of Bima Sandstone, Fika Shale, Kerri Kerri, Chad and Gongila Formations |
| 4. | Sokoto | 7.5 ℃/100 m | |
| 5. | Benue Trough | 1.5 - 2.7 ℃/100 m | The NE - SW trending synclinorium which contains about 5 km thick Cretaceous to recent marine and continental sediments |