Figure F3. Regional cross section through time across Site 1170, southwest across the Tasmanian block, two blocks of the South Tasman Rise, and the abyssal plain, based on seismic profile SO36-58 and other geological information. The Eocene was marked by development of ridges by fast north-south strike-slip motion between Australia and Antarctica, and the Oligocene by departure of Antarctica by strike-slip motion, emplacement of oceanic crust, collapse of the western block, and development of the saddle between the South Tasman Rise and Tasmania. TWT = two-way traveltime. Ant. = Antarctica.