Abstract. A continuous wavelet technique has been recently introduced to analyzepotential fields data. First, we summarize the theory, which primarily consists of interpreting potential fields via the properties of the upward continued derivative field. Using complex wavelets to analyze magnetic data gives an inverse scheme to find the depth and homogeneity degree of local homogeneous sources and the inclination of their magnetization vector. This is analytically applied on several local and extended synthetic magnetic sources. The application to other potential fields is also discussed. Then, profiles crossing dikes and faults are extracted from the recent high-resolution aeromagnetic survey of French Guiana and analyzed using complex one dimensional wavelets. Maps of estimated depth to sources and their magnetization inclination and homogeneity degree are proposed for a region between Cayenne and Kourou.

The island of Réunion has been studied using data from airborne and shipborne magnetic surveys. The subaerial history of Réunion spans the last 2.1 million years. The Brunhes‐Matuyama geomagnetic reversal enables differentiation of volcanic rocks older and younger than 0.78 Ma. The lower submarine flanks are poorly magnetized and are interpreted as landslide deposits. The core of the island is composed of highly magnetized rocks. Piton des Neiges volcano is composed mostly of rocks older than 0.78 Ma. Only its western flank and central area include thick piles of younger rocks. Piton de la Fournaise is a highly and normally magnetized edifice, but its northern and eastern flanks are underlain at shallow depth by reversely magnetized formations. The latter are regarded as remnants of Les Alizés volcano, associated with the Grand‐Brûlé hypovolcanic complex. At the Matuyama‐Brunhes transition the island was composed of at least two main volcanoes (Piton des Neiges and Les Alizés) and perhaps also of a third old volcano (Takamaka) at the center‐north of the island. Piton de la Fournaise grows on the flank of Les Alizés and is a relatively young focus of volcanism. These volcanoes have had successive phases of construction and destruction. The analysis of magnetic anomalies over Réunion was decisive in defining a new coherent model for the evolution of the island.

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