Page 457 - (DK) Ocean - The Definitive Visual Guide

G H I THE SEYCHELLES AND MADAGASCAR 455

70˚E
MALDIVES
a u t e Equator 1 The Seychelles
Mabahiss Fracture Zone v e P (14,112ft) THE EASTERN INDIAN OCEAN FLOOR is littered with scars
and Madagascar
a
l
Sealark Fracture Zone
documenting the breakup of Gondwana over the last 150 million
years. The warm waters of the Indian Ocean have also proved to
4,301m
be an ideal environment for diverse marine life.

e C h a g o s – L a c c a d i 2 INDIAN OCEAN D3
g Seychelles
d VOLCANIC Continental islands
i Chagos Archipelago
R Chagos AREA 176 square miles (455 square km)
Bank NUMBER OF ISLANDS 115
n
a The main islands of the Seychelles—
i Diego Chagos Trench
d Garcia the Inner Islands—are made of
3,658m n granite, rising over 3,000 ft (900 m)
(12,002ft) - I 3 above sea level on top of the
d i Seychelles Bank. The other islands to GRANITE BOULDERS IN THE SEYCHELLES
the southwest—the Outer Islands—
Vema Fracture Zone 10˚S seamounts. The Seychelles Bank is the south. This continental fragment broke
M
are coral islands (atolls) on top of
6,102m
off from India around 65 million years
most northerly part of the submarine
(20,021ft)
Saya de Mascarene Plateau, which extends as ago as the current Mid-Indian Ridge
Malha Bank far as the island of Réunion in the started spreading.
Argo Fracture Zone 4 Mozambique Mid-Indian Ridge
INDIAN OCEAN H3
INDIAN OCEAN B5
Channel
LENGTH 2,100 miles (3,400 km)
AREA 386,000 square miles (1 million square km)
RATE OF SPREAD 1 / 4 in (3 cm) per year
1
MAXIMUM DEPTH 370 ft (110 m) AVERAGE HEIGHT ABOVE SEA FLOOR 5,000 ft (1,500 m)
OCEAN Mid-Indian INFLOWS Zambezi, Rio Lúrio rivers The Indian and African plates are
Basin moving apart due to spreading at the
Marie Celeste Fracture Zone Africa. The area is home to the ancient Rifting was triggered 65 million years
569m
(1,869ft) 5 The Mozambique Channel separates Mid-Indian Ridge, which is marked
by a series of transform fracture zones.
Madagascar from the mainland of
ago when the Réunion Hotspot
coelacanth, found on both sides of
Alix the channel and off the Comoros. A erupted a vast amount of basalt
Seamount counterclockwise gyre is found around through the Indian continental plate,
the Comoros, and counterclockwise
eddies dominate the flow in the main forming a plateau called the Deccan
Traps. An older spreading ridge, which
Egeria Fracture Zone Current arises over the Natal Basin, subsided between the Mascarene
first separated India from Africa, lies
part of the channel. The warm Aghulas
fed by the South Equatorial Current.
Basin and the Mascarene Plain.
Rodrigues Ridge
Rodrigues 20˚S 6
INDIAN OCEAN F6 above a deep mantle hotspot. After the
Deccan Traps eruption (see above), the
Mauritius and Réunion Hotspot continued to punch
through the crust as India moved north,
Réunion leaving a trail of volcanic structures
across the ocean floor, including the
TYPE Volcanic islands
Laccadive and Maldive islands and the
AREA 1,800 square miles (4,550 square km) Chagos Bank on the other side of the
NUMBER OF ISLANDS 2 Mid-Indian Ridge. Réunion’s main
Tropic of Capricorn 7
peak, Piton de la Fournaise, is one of
The Mascarene Islands, Mauritius and the most active volcanoes in the world.
Réunion, are the largest and youngest
Mi d- In d i an Ri d ge
2,078m islands associated with the Mascarene
(6,818ft) Plateau, rising 21,300 ft (6,500 m)
Southwest Indian Ridge banks of the plateau to the northeast ATLAS OF THE OCEANS
above the sea floor. Like the older
and the Rodrigues Ridge to the
east, they are volcanic in
SCALE
origin, having formed
8
300
400
0
100
200
500 km
FRINGING REEF
0 100 200 300 400 500 miles A reef fringes the
lagoon on the north
70˚E coast of the volcanic
island of Mauritius.
G H I