Abstract

The Macquarie Ridge Complex is an arcuate system of ridges and troughs which forms the boundary between the Pacific and lndian lithospheric plates, from the southern tip of New Zealand to the triple junction between the Indian, Antarctic and Pacific lithospheric plates at approximately 62°S (figure 1 ). Macquarie lsland occurs at 54.5°S, 159°E in the central region of the Macquarie Ridge Complex. In the letter region the Macquarie Trench occurs to the east of the Ridge, in contrast to the Puysegur Trench in the north, and the Hjort Trench in the south, which occur to the west of the Ridge.