Chapter 23, Section 1 - The Water Planet
Global Ocean – The
body of salt water that covers nearly three-fourths of the Earth’s surface.
Sea – A large, commonly saline body of water
that is smaller than an ocean and that may be partially or completely
surrounded by land.
The Global Ocean…
…contains 97% of Earth’s surface water.
…is divided into five major oceans:
the study of the ocean, including the properties and movements of ocean water,
the characteristics of the ocean floor, and the organisms that live in the
SONAR – SOund
Ranging. A system that uses acoustic signals and
returned echoes to determine the location of objects or to communicate.
- A transmitter sends out a continuous
series of sound waves.
- The waves bounce off the ocean floor and
return to a receiver.
- Depth is calculated based on the time it
takes the waves to return.
Info from sonar is used to make maps of
the ocean floor.
Sound waves travel at about 1500 m/s
through sea water.
Bathyspheres remain attached to the
research ship for communications & life support.
Bathyscaphs are self-propelled,
Robotic submarines can take photos,
collect mineral samples, and remain at depth for long periods of time.
Chapter 23, Section 2 - Features of the Ocean Floor
Continental Margin –
Shallow parts of the ocean, made of continental crust and a thick wedge of
zone of shallow water where ocean covers the edge of the continent.
gently away from the shoreline.
glacial periods, water level drops and the shelf may be exposed.
steep slope at the edge of the continental shelf.
base of the slope marks the boundary between continental and oceanic crust.
wedge of sediments at the base of the continental slope.
V-shaped valleys that cut through the continental shelf & slope.
at the mouths of major rivers or by turbidity currents from underwater
Deep-Ocean Basin –
Deep part of the ocean, beyond the continental margin, made of oceanic crust
and a thin layer of sediment.
large, flat, almost level area of the deep-ocean basin.
than 4km deep.
half of the deep-ocean basin.
area on Earth.
with fine sediment…
from continents by ocean currents and wind.
die and settle to the bottom.
of oceanic crust
crust = thicker sediment)
from continental margin
= less brought there)
where bordered by trenches)
chain of underwater mountains with a narrow depression in the center.
zone of sea-floor spreading.
rises, cools, and forms new crust, pushing away the old crust.
that run parallel to the rift form abyssal hills.
that form from faults that run perpendicular to the ridge are fracture
long, narrow, steep depression that forms on the ocean floor as a result of
parallel to a chain of volcanic islands or the coast of a continent.
be as deep as 11km below sea level.
Submerged volcanic mountain, taller than 1km.
Formed by hot spots in the mantle.
Guyot – A seamount that has sunk and eroded. /GEE-oh/
Chapter 23, Section 3 - Ocean-Floor Sediments
…carried in by rivers.
…blown in by wind.
…eroded from shore by waves.
…formed from dead organisms that
settle to the bottom.
Core Sample – A cylindrical piece of
sediment, rock, soil, snow or ice that is collected by drilling.
Heavier sediments tend to be closer to
land; lighter sediments can be transported farther.
particles carried from land by rivers.
landslides move large amounts of sediment down the continental slope.
turbidity currents that spread sediments over continental rise and abyssal
dust particles blown out to sea by wind.
picked up by glaciers are transported out to sea when icebergs are calved.
from meteorites falls into the ocean, contributing to sediment layers on the
formed from the remains of living things.
common compounds in biogenic sediments are…
(SiO2) - from diatoms and radiolarians
carbonate (CaCO3) - from foraminifera
deposits that form when dissolved substances crystalize on the ocean floor.
of minerals found scattered on the ocean floor.
of iron, copper, nickel or manganese.
Classification of Deep Ocean-Floor
fine silt- and clay-sized particles of rock.
clay (very common)
clay particles, mixed with silt, sand and biogenic material.
be red, grey, blue, green, yellow-brown.
40% of ocean floor covered in ooze.
of ooze is biogenic materials; the rest is fine mud.
found below 5km, because CaCO3
dissolves at that depth.
at any depth.
is found near Antarctica because of the abundance of diatoms and radiolarians