Volcanic and morphological evolution of La Gomera (Canary Islands), based on new K–Ar ages and magnetic stratigraphy: implications for oceanic island evolution
The spatial and chronological evolution of Canary Islands volcanism is due to eastward progression of the slow-moving African plate over a mantle plume. La Gomera is located between the western shield stage islands (<2 Ma) and the central rejuvenated stage islands (>12 Ma). With 23 K–Ar ages and palaeomagnetic data, we can constrain the timing of the main subaerial volcanic phases of La Gomera: the shield volcano (c. 9.4–8.0 Ma), the postshield peripheral lava flows (c. 7.4–5.0 Ma), the postshield horizontal lava flows (c. 5.4–4.3 Ma), and late intra-canyon lava flows (c. 1.9 Ma). The horizontal lava flows fill a 10 km wide depression formed by a giant landslide (Garajonay). The entire structure of La Gomera is in relief inversion. Declining volcanic construction rates from the shield to the postshield stages are correlated with increasing erosion rates, whereas the period of volcanic quiescence (hiatus) has low erosion rates. The succession and duration of the hotspot volcanic stages in the Canary Islands are compared with those in the Hawaiian Islands, thus underlining differences between slow-moving and fast-moving plate settings.