The opening of the Tasman Sea at ~ 80–90 Ma (Gaina et al., 1998) likely caused lithospheric thinning and may have given rise to the Southern Highlands in eastern New South Wales and Victoria, which have a maximum elevation of over 2 km, although the exact timing and formation mechanism are debated (Lambeck and Stephenson, 1986, Lister et al., 1991 and van der Beek et al., 1999).