Distribution of oceanic crust from Chalmers & Oakey (2007). Dark brown segments are Palaeocene oceanic crust, light brown segments are Eocene oceanic crust. The configuration at 33 ma (left-hand panel) is also valid for today. At 54 ma (right-hand panel) the greatest gap occurs in Palaeocene oceanic crust with the poles of rotation from Oakey (2005).