Life of the Bellingshausen plate

The onset of independent Bellingshausen plate movement in the South Pacific is estimated at just after chron C33o. This event closely follows a change in the offset sense on the transform arm of the Late Cretaceous Pacific‐Phoenix‐Antarctic triple junction and accompanies the creation and/or lengthening, by different mechanisms, of long‐offsets on the Pacific‐Antarctic ridge at the Udintsev, Tharp, Heezen and V transforms, as the triple junction stepped away from the ridge. At around chron C27, the Bellingshausen plate ceased to move independently and the Pacific‐Antarctic ridge inherited the set of long offset transforms. Shortly afterwards, the gravity fabric on the flanks of much of the ridge displays evidence for a spreading rate decrease possibly related to transpression on the long‐offset transforms. We speculate on a link between these events and regional tectonic changes around chron C27.