| Abstract: | Filtered SEASAT data have been interpreted in an area covering the Cook-Austral archipelagoes (South Central Pacific) in order to detect or confirm the existence of structural directions. SEABEAM data recorded by N/O “Jean Charcot” were also interpreted. Additionally to the Austral fracture zone and Cook-Austral archipelagoes trends, the SEASAT data reveal the existence of two directions, the azimuths of which are N150° and N95° respectively. The first, which intersects the Austral archipelago close to the island of Maria corresponds to a long linear topographic bump. It is interpreted as evidence for the existence of an ancient hot spot with a trace copolar to the Emperor chain. This result explains the very important thermal rejuvenation found previously in that area by several authors. It also explains the very disturbed ages and morphologies of volcanic structures recorded in the Austral archipelago. The second direction, located south of the Cook archipelago is underlined by geoid signatures of fracture zone type. These postulated linear features are probably of similar origin to the ones detected previously farther east. They are interpreted as a possible consequence of some recent intraplate deformation. |
