Southwest Indian Ridge

Map
Approximate surface projection on southern oceans of Southwest Indian Ridge (white) and fracture zones (shades of orange). Click to expand map to obtain interactive details.
Separating the African (or Nubian–Somali plates) and Antarctic plates, the Southwest Indian Ridge (SWIR) stretches 7,700 km (4,800 mi) from the Atlantic Ocean to the Indian Ocean. With an average spreading rate of 14–15 millimetres per year (0.55–0.59 in/year), the SWIR is one of the slowest-spreading mid-ocean ridges on Earth. Characterised by numerous large transform offsets, most of the SWIR is highly segmented and oblique relative to the spreading direction.[1]

The Southwest Indian Ridge (SWIR) is a mid-ocean ridge located along the floors of the south-west Indian Ocean and south-east Atlantic Ocean. A divergent tectonic plate boundary separating the Somali plate to the north from the Antarctic plate to the south, the SWIR is characterised by ultra-slow spreading rates (only exceeding those of the Gakkel Ridge in the Arctic) combined with a fast lengthening of its axis between the two flanking triple junctions, Rodrigues (20°30′S 70°00′E / 20.500°S 70.000°E / -20.500; 70.000) in the Indian Ocean and Bouvet (54°17′S 1°5′W / 54.283°S 1.083°W / -54.283; -1.083) in the Atlantic Ocean.[2]

  1. ^ Standish et al. 2008, Regional setting, p. 3:5
  2. ^ Patriat et al. 1997, Abstract