Between the Late Cretaceous and the Early Oligocene (90–30 Ma) little changed in the region, except for the subduction of the Phoenix Plate along the Shackleton Fracture Zone. The Late Paleocene and Early Eocene (60–50 Ma) saw the formation of South Scotia Sea and South Scotia Ridge — the first sign of separation of the southern Andes and the Antarctic Peninsula — which resulted in seafloor spreading in the West Scotia Sea and hence the initial opening of a deep Drake Passage. The ongoing lengthening of the North Scotia Ridge beyond the Burdwood Bank caused South Georgia to move further east. The banks of the North Scotia Ridge contain volcanic rocks similar to those found in Tierra del Fuego, including on Isla de los Estados on the easternmost tip.