Transcript Mid-Ocean Ridges - University of Utah

Mid-Ocean Ridges
JdFR
MAR
EPR
CIR
SWIR
PAR
Thuan Chau, Yao Yao
SEIR
Mid-Ocean Ridge
• Underwater mountain system formed by plate
tectonics.
• Oceanic spreading center
– Valley of rifts running along its spine
– Responsible for seafloor spreading
• Magma, which comes out at the linear weakness
part in the oceanic crust, becomes the new seafloor
when it cools down.
• Longest mountain range in the world 80,000km long
(65,000km continuous).
Classes of Ridges
• Fast-spreading ridges, like
the East Pacific Rise, the
spreading rate is 100 to 200
millimeters per year.
• Slow-spreading ridges, like
the Mid Atlantic Ridge, the
spreading rate is 20 to 40
millimeters per year.
• Ultraslow-spreading ridges,
like the Southwest Indian
Ridge, the spreading rate is
less than 20 millimeters per
year.
Central Indian Ridge:
Western regions of the Indian Ocean.
Lava flow: 0.51-0.68 km3/year
Average spreading rate: 1.13 cm/year
Southwest Indian Ridge:
Southwest Indian ocean
Separated the African and Antarctic plates
Average spreading rate: 13-18 mm/year
Mid-Atlantic Ridge:
Atlantic Ocean
Separated Africa and South America
Average spreading rate: 2.5 cm/year
Juan de Fuca Ridge:
• (500km long, 8km wide)
• Subduction zone, divergent zone,
transform zone.
• 1.8 to 3 cm/yr.
• frequency of seismic events.
East Pacific Rise:
• Volcanic chain – 1,800 to 2,700 m above
seafloor
• 16 cm/ yr (Chile)
• 6cm/yr (Gulf of California)
Pacific Antarctic Ridge:
• Divergent tectonic plate boundary
located in the South Pacific Ocean.
• Rate of spreading is 54-76mm/yr.
Southeast Indian Ridge:
• Intermediate spreading ridge
• ~60 to 80 mm/yr