Perth Abyssal Plain - Option 2, suggested placement oblique to the Dirk Hartog Ridge, ID: 2-7-2-2

Time of cessation: Probably close to 102 Ma from age constraints of dated samples from the Dirk Hartog Ridge (Watson et al., 2016)


On review of the updated vertical gravity gradient map (Sandwell et al., 2014), we observe several linear features at an oblique angle to the Dirk Hartog Ridge, on the Perth Abyssal Plain. These features have a negative gravity signal and are slightly deeper than surrounding seafloor, with a generally symmetric form in profile. Although there is limited information available regarding these features it is possible they represent a former axis of spreading.


MacLeod, S.J., Williams, S.E., Matthews, K. J., Müller, R.D. and Qin, Xiadong, 2017, Geosphere (in press).

Watson, S.J., Whittaker, J.M., Halpin, J.A., Williams, S.E., Milan, L.A., Daczko, N.R., Wyman, D.A., 2016, Tectonic drivers and the influence of the Kerguelen plume on seafloor spreading during formation of the Early Indian Ocean, Gondwana Research, v. 35, p. 97-114, doi: 10.1016/

Maps showing the location of extinct ridge segments

Depth profiles across the axes of extinct ridge segments

Gravity profiles across the axes of extinct ridge segments