Geological Map of Ascension Island
Scoria cones - red; Mafic ash - grey; Trachyte and rhyolite flows and domes - green; Silicic pyroclastic deposits - yellow; Volcanic breccia - brown; Superficial deposits (alluvium, beach sand, etc.) - cream.
High Zr/Nb mafic flows - pink; Intermediate Zr/Nb mafic flows - blue (darker shades represents younger flows); Low Zr/Nb mafic flows - purple; Dark Slope Crater mafic flows - salmon.
Compositions of some mafic flows are indicated: B - basalt; H - hawaiite; M - mugearite; Be - benmoreite.
Map is somewhat simplified and modified after Nielson and Sibbett (1996).
Ascension geology pagePage maintained by Barry Weaver