Step

Name

Location

Length (km)

Remark

1

Pacific-Antarctic Ridge

54˚30' - 65˚28S/

160˚15' - 180˚E

Southern Extension of East Pacific Rise (EPR)

(Pacific Plate/Antarctic Plate)

2

Mid-Atlantic Rise

15˚W

Atlantic Ocean

3

Southwest Indian Ridge

53˚S/20 - 24˚E

250 km

Indian Ocean

(African Plate/Antarctic Plate)

4

Southeast Indian Ridge

25 - 62˚S/

70 - 170˚E

Indian Ocean seafloor

(Indo-Australian Plate/Antarctic Plate)

5

S. Tasman Rise

(Tasmania Ridge)

45 - 51˚S/

147 - 150˚E

(800 - 3000 m depth)

Southern Ocean, Australia seafloor

6

Campbell Plateau

50˚40'S/171˚E

(500 - 1000 m depth)

New Zealand

(Large submarine plateau)

7

Chatham Rise

39˚50'S - 50˚04'S/ 171˚29' - 178˚03'

1000 km

(544 - 3735 m depth)

New Zealand

(Productive fishing ground)

8

Marie Byrd Seamount

114 - 131˚W/

68 - 71˚S

800 km

Amundsen Sea

9

Orca Seamount

62˚S/58˚W

3 km wide

(500 m height)

Bransfield Strait

10

South Sandwitch Islands

(11 volcanic islands)

56˚18' - 59˚27'S/ 26˚23' - 28˚08'W

310 km²

(1370 m highest)

South Atlantic Ocean/Scotia Sea