Asymmetric seafloor spreading and short ridge jumps in the Australian-Antarctic discordance

The crenulated geometry of the Southeast Indian Ridge within the Australian-Antarctic Discordance is formed by numerous spreading ridge segments that are offset, alternately to the north and south, by transform faults. Suggested causes for these offsets, which largely developed since similar to 20 Ma, include asymmetric seafloor spreading, ridge jumps, and propagating rifts that have transferred seafloor from one flank of the spreading ridge to the other. Each of these processes has operated at different times in different locations of the discordance; here we document an instance where a small ( similar to 20 km), young (