| Popis: |
The mineralogy, major element composition, REE patterns and Sc, Co, Hf, Cr, Sr, and Cu contents of nine pillow lavas from the pre-Cenozoic basement complex of Maio reveal the presence of oceanic tholeiites on the Cape Verde archipelago. These uplifted tholeiites constitute the oldest rocks exposed on the islands and are related to an Early Cretaceous (or still somewhat older?) oceanic ridge crest. It is suggested that the formation of east-west trending fracture zones in the Atlantic Ocean induced the alkalic character of the Cape Verde magmatism from the middle of the Cretaceous up to historical times. |
