Transcript Continental Margins

Ocean Bathymetry
Topography of the ocean floor
Bathymetry
Bathymetry is the study of the
"beds" or "floors" of water bodies,
including the ocean, rivers,
streams, and lakes.
Main Regions
Continental Margins – drowned edges
of the continents
Deep-ocean Basins – the ocean floor
that lies deeper than 2000 m
Mid-ocean Ridges – a continuous
underwater mountain range that winds
its way through all the oceans
Continental Margins
From the land:
Continental shelf – almost flat, gradual
slope seaward at the edges of the
continents; covered with sediments
from the land
Continental slope – steeper slope
seaward; contains submarine canyons
Continental rise – shallower slope
composed of sediments that have fallen
from slope.
Active vs. Passive Continental Margins
Active Continental Margins
found on the leading edge of the continent
where it is crashing into an oceanic plate.
They are common sites of tectonic activity
(earthquakes, volcanoes, etc.
Example: West Coast of North America
Passive Continental Margins
remaining coastlines that have minimal
tectonic activity and no collision of plates.
Example: East Coast of North America
Continental Margin
Deep-Ocean Basins
Lie beyond the continental margins and
contain:
Abyssal plains – very flat areas at depths of
3-5 km
Seamounts – underwater volcanoes, some >
1000 m high
Goyut – a seamount with a flat top.
Deep-sea trenches – steep-sided, long,
narrow depressions. Deepest regions on
earth; found near continental margins
Deep-Ocean Basins
Mid-Ocean Ridges
Underwater mountain ranges that are
the longest on earth
Occupy 1/3 of the ocean floor
Not all are “mid-ocean”
Contain rift valleys at the summits as
well as many fracture zones, where
rocks have cracked and slid past one
another
Mid-Ocean Ridges
Mid-Ocean Ridge Locations
Which coast has the wider shelf?
Mysteries of the Deep
http://oneocean.cbc.ca/series/episodes/3-mysteries-of-the-deep
Video Description:
Starting in the deepest part of the ocean, Mysteries of the
Deep takes us to a secret and magical world beneath the
surface where for the first time in human history, technology is
allowing us to explore the darkness and crushing pressure of
the deep seas to reveal a strange world full of mystery and
surprise.
Scientists, now modern day explorers, are in a race to answer
these questions before human appetites and reckless
exploitation forever destroy the deep seas’ undiscovered
wonders. In Mysteries of the Deep , we join twenty scientists
from four countries on an expedition to the Mariana Arc on the
Pacific Ring of Fire. They want to map the deepest and the most
dramatic topography on earth.