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New evidence about the structure and growth of ocean island volcanoes from aeromagnetic data: The case of Tenerife, Canary Islands

Abstract:

We present 3-D magnetic models of Tenerife based on a high-resolution aeromagnetic survey carried out in 2006. Two different inverse modeling techniques have been applied: (1) a linear method aimed at imaging lateral magnetization contacts and (2) a nonlinear method aimed at obtaining a 3-D description of deep intrusive bodies, in which a constant magnetization value characterizes the main sources. Magnetic models show that deep intrusive structures are located beneath the northern part of the island and aligned along the E-W direction. This arrangement of intrusive bodies does not support the hypothesis of a three-armed rift system that has been present since the early formation of the island. The shallow portion of the intrusive structures shows a round geometry that agrees with the previously proposed location of some of the landslide headwalls, suggesting that collapse scars have acted as preferential sites for magma upwelling. Our magnetic model probably provides the first geophysical evidence of the location of the headwall of the Icod landslide beneath the Teide-Pico Viejo complex, thus supporting the vertical collapse hypothesis for the origin of the Caadas caldera. The largest intrusive complex is located to the northwest of Teide and Pico Viejo, revealing the presence of a very high dike density in this area. This complex probably resulted from the intrusion of magma over the span of millions of years, beginning with the early phases of basaltic shield volcanism in central Tenerife and lasting until the building of Teide and Pico Viejo stratovolcanoes. Copyright 2011 by the American Geophysical Union.