Pacific–Antarctic Ridge

It stretches from there in a general southwesterly direction to the Macquarie Triple Junction south of New Zealand.

[6]: 1281  This area of transition in sea floor spreading rate has been mapped by multiple techniques and occurs near the Heirtzler fracture zone.

Until about 33 million years ago, the Proto-Antipodes fracture zone well to the south separated two independent spreading centers, now merged, being the Antarctic–Pacific Ridge and that of the Antarctic–Campbell Plateau.

[7]: 14 Fracture zones are generally areas of low gravity on the seafloor parallel to a spreading center.

[1] The named fracture zones going southwest along the rise, include: Stretching for 4,300 km (2,700 mi) north-west from the Eltanin fault system which intersects the Pacific-Antarctic Ridge to the Osbourn Seamount at Tonga and Kermadec Junction[9] is a long line of seamounts called the Louisville Ridge – the longest such chain in the Pacific[10] – thought to have formed from the Pacific Plate sliding over a long-lived center of upwelling magma called the Louisville hotspot.

The Pacific-Antarctic Ridge is the southern extension of the East Pacific Rise
Bathymetric and magnetostratigraphy mapping with ages of sea floor spreading in millions of years (Ma) before present between Erebus and Udintsev fracture zones on the Pacific-Antarctic Ridge [ 1 ] [ 2 ]
The Louisville Ridge stretches diagonally across this bathymetric map of the southwest Pacific Ocean towards the Pacific-Antarctic Ridge at right bottom