Thermochronologic constraints on the tectonic evolution of the western Antarctic Peninsula in late Mesozoic and Cenozoic times

West of the Antarctic Peninsula, oceanic lithosphere of the Phoenix plate has been subducted below the
Antarctic plate. Subduction has ceased successively from south to north over the last 65 Myr. An influence of this
evolution on the segmentation of the crust in the Antarctic plate is disputed. Opposing scenarios consider effects of
ridge crest – trench interactions with the subduction zone or differences in slip along a basal detachment in the
overriding plate. Fission track (FT) analyses on apatites and zircons may detect thermochronologic patterns to test these
hypotheses. While existing data concentrate on accretionary processes in Palmer Land, new data extend information to
the northern part of the Antarctic Peninsula. Zircons from different geological units over wide areas of the Antarctic
Peninsula yield fission track ages between 90 and 80 Ma, indicating a uniform regional cooling episode. Apatite FT
ages obtained so far show considerable regional variability