Evolución Geomorfológica de la Isla de Gran Canaria: Isostasia, vulcanismo y disección fluvial (Islas Canarias, España) Geomorphologic development of the Gran Canaria Island: Isostasy, Volcanism and fluvial dissection (Canary Islands Spain)

The analysis of the volume of material wasted by fluvial erosion in Gran Canaria allows to evaluate the subsequent isostatic response (uplift) by means of the application of simple equations of Geophysical relief. The total removed volume (223.95 km 3 ) in Gran Canaria only represents about 0.5% of the bulk volcanic edifice, but about 26% of its emerged sector (859.77 km 3 ). Even this small amount of erosional unloading can explain the 83% (+71.1 m) of the maximum uplift (+143 m) recorded by pliocene (ca. 4 Ma) pillow-lava horizons in the NE slope of the island. The study of the evolutionary relationships between erosion and volcanism within the context of the differential dissection and uplift (SW-NE) are interpreted here as linked to the isostatic flexure generated by the neighbour and massive Tenerife Island since 3.5-3.8 Ma ago. Complex feedback between fluvial unloading, differential uplift, orographic effect, lithospheric flexure, and volcanic underplating, seems to control the geomorphological development of hot-spot volcanic islands during their rejuvenation stage.