Transcript MB Chapter 02

History
• Darwin and the hms Beagle 1831-1836
• Studied barnacles
HMS Challenger led by Sir Charles
Wyville Thomson (1830-1882)
Findings
• 4,717 new species;
• The first systematic plot of currents and temperatures in the
ocean;
• A map of bottom deposits much of which has remained current
to the present;
• An outline of the main contours of the ocean basins; and
• The discovery of the mid-Atlantic Ridge; 1,800 feet, findings
such as:
Charles Wyville Thomas
• Spearheaded the challenger expedition
Alexander Agassiz
• 1877
• Studied the collaboration of marine
animals.
• Founded Woods Hole Oceanographic
Institute.
Habitat
•Where an
organism lives
Ocean Basin
•Depressions filled
with sea water that
we call oceans
Pacific
•Largest and
deepest
Atlantic & Indian
•About half the size
as the Pacific &
almost as deep
Figure 2.1
Arctic
•Smallest and
shallowest
Density
•Mass per unit
volume
•D = m/V
Earth's Structure
• Inner core: 0-1200 km
• Outer core: 1200-2500
km
• Mantle: 2500-6300 km
• Crust: Outer most 100
Oceanic Crust
•Crust directly under
oceans
•thin & dense
•made of mostly basalt
Continental Crust
• Crust containing the
continents
• thick & less dense
• Made of mostly granite
Plate Tectonics
• The Earth’s crust is
made up of many plate
that are in constant
motion
Pangaea
• Original supercontinent
containing all of the
present day continents
Plate Boundary
• Crack between plates
• Where two plate meet
• Fault line
• Rift
Plate Boundaries and Geologic
Processes
• The lithosphere is fragmented into
fourteen major tectonic plates
• Plates are moving across the Earth's
surface in different directions and at
different velocities.
• Many geologic processes, such as
plutonism, volcanism, and earthquakes
result from the interaction of plates
along their boundaries
Types of Boundaries
• Mid-ocean Ridges
• Subduction Boundary
• Shear Boundary
• Mountain Range
Mid-Ocean Ridge
• Divergent boundaries
• Spreading center
• Continuous chain of volcanic
submarine mountains that encircle
the globe
• Like seams on a baseball
Convergent boundaries
• formed between two plates that
are moving toward one another
• 2 forms
• Subduction
• Collisional
Subduction
• When an oceanic plate
slides under another plate
• Both volcanic and
earthquake activity occur
• Forms very deep trenches
Figure 2.7
Collisional Boundary
• Mountain Range
• Forms when two
continental plates collide
Shear (transform)
Boundary
• When two plates slide
parallel to each other
• Only earthquake activity
• San Andreas Fault
Hot Spot
• Forms when there is
enough heat upwelling to
form a volcano, but not
enough to form a mid-ocean
ridge
Active Margin
• A continental margin that is
geologically active
• A continental margin near a
plate boundary
• USA’s west coast
Continental Margin
• Where the continent
meets the sea
Passive Margin
• A continental margin with no
geological activity
• A continental margin not
near a plate boundary
• USA’s east coast
Sediment
• Loose material like sand or
mud that settles to the
bottom of any body of water
• Sediment thickness
increases as you move from
m-o-r
Sediment is the word geologists
use for loose pieces of minerals
and rock.
Types of Sediment
• Lithogenous: from a nonliving source
• Biogenous: from a living
source
Calcareous Ooze
• Carbon based sediment
• Sediment containing
calcium carbonate
• CaCO3
Siliceous Ooze
• Silicon based sediment
• Sediment containing
silicon dioxide or silicates
-4
• SiO2 or SiO4
Ocean bottom sediment
map
Ocean bottom sediment map. Lithogenous
areas are mauve, biogenous areas are
purple and brown (purple = siliceous ooze,
brown = calcareous ooze), and
hydrogenous areas are blue.
Seamounts
•Oceanic volcanoes
that do not penetrate
the surface of the
ocean
Guyots
• Flat-topped seamounts
• Seamounts that are no
longer active
Guyots
Hydrothermal Vent
• Oceanic hot spot where
hot gases escape
through the ocean floor
Black Smoker
• Another name for
hydrothermal vents
• As hydrogen sulfide gas
precipitates in cold water,
you get a black precipitate
Passive Margins
Parts
• Continental shelf
• Shelf break
• Continental slope
• Continental rise
• The Abyss
Continental Shelf
• Nearly flat, slightly
sloping, not too deep
area just off the shoreline
Atlantic Continental Shelf
Shelf Break
• Where the continental
shelf abruptly breaks off
into a steep slope
Continental Slope
• The steeply sloping part
of the margin that goes
from the shelf break to
the ocean floor
Continental Rise
• Where sediment builds
up between the slope
and the abyss
The Abyss
•The Ocean Floor
•The Abyssal plain
Pelagic
• In the water column or at
any depth in the sea
Pelagic Zones
• Epipelagic
• Mesopelagic
• Bathopelagic
• Abyssopelagic
• Hadopelagic
Epipelagic Zone
• Surface water where
light can penetrate &
photosynthesis can
take place
• Photic zone
Mesopelagic
Zone
Middle zone, just
below the epipelagic
where no light
penetrates, but is
shadowy
Twilight zone
Bathopelagic Zone
• Deep ocean water where no
light penetrates and it is
pitch black
• Complete darkness
Abyssopelagic Zone
• The water near the sea
floor
• Bottom water
Hadopelagic Zone
• Sea water in the deep
trenches
• Trench water
The Deep Sea
• Because the bathopelagic,
abyssopelagic, &
hadopelagic zones are so
similar, they are lumped
together as the deep sea