Sao Tome and Principe

Geography

This island state of São Tomé and Príncipe consists of two major and a few very small islands in the Gulf of Guinea, some 275 km west of Gabon and southwest of Equatorial Guinea and Cameroon. The agricultural sector accounts for 23% of the GDP and employs some 27% of the working population. The largest export crop is cocoa, followed by coconut products and cinnamon. The mineral industry of São Tomé and Príncipe is limited to the production of local building materials, small clay and stone open pit operations. Petroleum exploration in offshore areas has been intensified over the last few years.

Geology

All islands of this archipelago are made up of volcanic rocks. They occur as extensions of the ‘Cameroon line’. 

The volcano of São Tomé is a complex strato-volcano type with a total height of about 5,000 m, rising from the abyssal plain of the ocean floor to an elevation of 2,024 m above sea level. The volcano is principally made up of basaltic lavas resting on Cretaceous sandstones. Palagonitic tuffs and pillow lavas, representing submarine eruptions, are overlain by younger subaerial lavas. The oldest dated volcanic rocks are 15.7 million years old.

The island of Príncipe is also of volcanic origin, with basaltic, phonolitic and tephritic compositions. The island rests on the ocean floor at a depth of approximately 3,000 m, and reaches 948 m above sea level (source).