Download ocean ridge - deb-or-ah

• A mid-ocean ridge is an underwater mountain
range, typically having a valley known as a rift
running along it’s spine, formed by plate
tectonics.
Mid-ocean ridges have different shapes
depending on how fast they are spreading, how
active they are magmatically and volcanically, and
how much tectonic stretching and faulting is
taking place. Scientists believe that the most
likely reason for the different shapes is due to the
strength of the ocean crust at these different
sites, and how cold and brittle the upper part of
the tectonic plate is.
• The mid-ocean ridges of the world are
connected and form a single global midoceanic ridge system that is part of every
ocean, making the mid-oceanic ridge system
the longest mountain range in the world, with
a total length of about 60,000 km
• A composite map showing the ocean floor
clearly reveals the mid-ocean ridge system,
which appears here as dark "seams"
extending through the oceans.
There are two types of mid-ocean ridges: fastspreading and slow-spreading. Fast-spreading
ridges like the northern and southern East.
• Slow-spreading ridges like the Mid-Atlantic
Ridge have large, wide, rift valleys, sometimes
as wide as 6 to 12 miles and very rugged
terrain at the crest. The Mid-Atlantic Ridge
moves at an average of 1 inch per year.
• Fast-spreading ridges are "hotter," meaning
that more magma is present beneath the
ridge axis, and that more volcanic eruptions
occur.
FUN FACT:
• We didn’t send divers down to explore the
Mid-Ocean Ridge until 1973 — four years
after Neil Armstrong walked on the moon —
when a French-American crew of seven
entered the 9,000-foot-deep Great Rift in the
French submersible Archimede.