REFLECTION SEISMIC INVESTIGATIONS IN THE VOLCANICLASTIC APRON OF GRAN-CANARIA AND IMPLICATIONS FOR ITS VOLCANIC EVOLUTION

High-resolution reflection seismic data obtained around Gran Canaria a llow a detailed and consistent correlation of seismic reflectors of th e northern and southern Canary Basins with the lithology drilled by DS DP Leg 47A SSE of Gran Canaria, as well as with major phases of volcan ic activity on Gran Canaria as mapped onshore. Two prominent reflector s were chosen as marker horizons and correlated with the drilled litho logy. The results indicate that reflector R7 above the Miocene volcani clastic debris flows V1-V3 reflects the shield-building phase of Gran Canaria. Reflector R3 is interpreted as corresponding with the Pliocen e Rogue Nublo formation. The top of the massive island flank of Gran C anaria, defined by seismically chaotic facies, extends 44 to 72 km off the coast of Gran Canaria. West of Gran Canaria the flank of Tenerife onlaps the steeper and older flank of Gran Canaria, which, in turn, i s onlapping the older flank of Fuerteventura to the east in a similar way. Erosional channels, which can also be traced up to 50 km from the area between Gran Canaria and Fuerteventura into the deeper northern basin, have been identified in the bathymetry. The data presented prov ide new detailed information for modelling the submarine and subaerial evolution of the central Canary Islands of Gran Canaria and Tenerife, i.e. the timing of their shield-building phases and later stages of m ajor volcanic activity, as reflected by the position of prominent seis mic reflectors in the seismic stratigraphy.