On the basis of the correlation between seismic tectonostratigraphic units, volcanism, and geochemical distribution patterns of sea-floor sediments on Deception Island (Antarctica), a regional tectonic extension is suggested to explain the sequence of volcanic and hydrothermal events. The syncollapse caldera episode is composed of five tectonostratigraphic units separated by progressively tilted and bent unconformities. Each unit shows a sequence of Quaternary volcanic cones and mound structures that display high contents of Fe, Mn, and Zn. As-rich active fumaroles and hot-spring areas are associated with the postcollapse episode and linked to normal faulting and present volcanism.

We would like to thank the members of the Antarctic Spanish Expedition (Oceanographic Vessel Las Palmas) for their collaboration, especially the expedition chief, Enrique Moreu. Thanks also to IEO (Instituto Espafiol de Oceanografia) and CSIC (Consejo Superior de Investigaciones Cientificas) for financial support of part of the research. This work has been carried out in cooperation with the IGCP project 318 (IUGS/UNESCO), and with the Spanish Working Group on Geology and Metallogeny of Seafloor Hydrothermal Deposits.

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Peer reviewed