Eastern Australia hosts a wide range of volcanic edifices, ranging from localised outcrops to lava fields and central volcanoes (Figure 1). In general, the older volcanics are in the north with distinct tracks of decreasing age to the south (see Figure 1 and, e.g., Davies et al., 2015). Similar age profiles are seen for two lines of seamounts through the Tasman Sea (e.g., Seton et al., 2019). This pattern of age progression reflects the rapid