Name: _______________________
Period:_____
Marine Science Unit 1 Section 1:
Formation of the Oceans
A) How did the oceans form?
1) Volcanic cycling theory –
2)
Comet theory –
3) Which is more likely?
The 4 oceans:
1.
(largest and deepest)
2.
3.
4.
(smallest and shallowest)
B) The Origins of the Oceans & Seas
1) 200 million years ago:
a) Pangaea–
b) Panthalassa-
c) Sinus Borealis –
2) 180 million years ago:
a) Pangaea split into two smaller contents:
(I) Laurasia- North America, Europe, and Asia
(II) Gondwana – South America, Africa, Antarctica, India, and Australia
b) What was the rift zone that split Pangaea called?
c) What would the rift zone that split Pangaea create?
3) 150 million years ago:
a) A new rift forms in Gondwana splitting Africa from Antarctica.
b) What would the rift zone that split Gondwana create?
4) Today:
a) What ocean is getting larger?
b) What ocean is getting smaller?
c) What sea is going to become an ocean?
C) Alfred Wegner & Plate Tectonics
1) Alfred Wegener –first scientist to proposed the idea of continental drift/Plate tectonics
a) Continental Drift / Plate tectonics –
b) Wegner had 2 pieces of evidence to support his theory:
(I)
(II)
c) What was the problem with Wegner’s theory?
D) Henry Hess & the Mid Atlantic Ridge
1) During World War II, Henry Hess, mapped the Atlantic sea floor , and accidentally discovered the Mid
Atlantic Ridge
a) Mid Atlantic Ridge – a spreading center in the middle of the Atlantic ocean that is marked by the
largest and longest mountain chain on earth
(I) The discovery of the Mid Atlantic ridge, and other ocean ridges provided a mechanism to explain
Continental Drift / Plate tectonics
E) What happens when plates meet?
1) The earths crust is mostly made out of two main types of rock, oceanic basalt, and continental granite
a) Basalt –
b) Granite –
(I) Because basalt is more dense than granite, when plates made of these rocks meet, the ocean
plate (basalt) sinks under the continental plate (granite) and melts
(II) Subduction –
(i) Subduction causes trenches to form on the ocean floor
(III) Trench –
(i) Ocean trenches form the deepest parts of the ocean
(ii) The Marianas Trench is the world’s deepest trench at 36,201 feet (6.8 miles) deep
F) The Importance of subduction & Ocean Trenches
1) Different land and ocean futures result from subduction
2) Subduction always creates a trench, however different land features form depending on the
composition of tectonic plants that meet
When oceanic basalt meets continental granite:
1. More dense basalt subducts under the less
dense granite creating a ______________
2. This hot melted basalt rises under the
continental plate and creates
_______________________________
When oceanic basalt meets oceanic basalt :
1. One basalt plate still subducts under the
other creating a _______________
2. This hot melted basalt rises under the
opposite plate and creates
________________________________
Marine Science Unit 1 Section 2:
Features of the Oceans
A) Two main regions of the ocean
1) The ocean floor is divided into two main regions or provinces, the relatively shallow continental margin
and the deep ocean basin
a) The Continental Margin –
b) The Deep Ocean Basin–
(I) Features on the deep ocean basin:
(i) The Abyssal Plain –
(ii) Ridges or Rift Valleys -
Marine Science Unit 1 Section 3:
The movement of ocean water
A) Currents, Upwelling & Downwelling
1) Ocean water moves in two main directions in the ocean, horizontally across the surface of the water,
and vertically from the depths of water into the shallows
2) Current –the wind driven horizontal movement of water across the oceans surface
a) What creates currents?
b) What do currents do for the ocean?
3) Upwelling and Downwelling – the density driven upward and downward movement of water within
the ocean
a) What creates Upwelling and downwelling?
b) What does Upwelling and downwelling do for the ocean?
4) Great Ocean Conveyer (Thermohaline circulation) – a global circulation of water throughout all the
oceans created by upwelling and downwelling
a) It takes the great ocean conveyer 4000 years to circulates one water through all 4 of the worlds
oceans
B) Anatomy of a wave
Wave Crest –
Wave Trough
Wave Height –
Wave Length –
C) How to make a wave
a) What natural force creates waves?
b) What three characteristics does wind have to have to create large waves?
(I) Wind speed – How fast wind is blowing (High or low)
(II) Wind fetch – The area of open water over witch wind blows (Large or small)
(III) Wind duration – How long wind has blown in the same direction (Long or short)
D) Why do waves break?
1) Surf zone – the border between the ocean and shore where waves break
2) There are 3 steps to how a wave breaks: 1)______________2)_________________3)____________
a) As the wave enters the surf zone it starts to ________ as the bottom of the wave begins to
rub against the bottom of the ocean and slows down while the top keeps moving at the same
speed
b) As the wave bottom begins to slow its starts to ________ its sides together and the wave
height becomes larger
c) Eventually the wave height becomes too high to be supported by the base and the wave
___________
E) Wave types
1) What type of wave breaks depends on the characteristics of the shore bottom
2) There are two basic types of waves, plunging breakers and spilling breakers
Plunging breakers – waves the have a curling
crest that curls over a air pocket or “pipe line”
What creates plunging Breakers?
WAVE SIZE HAS NOTHING TO DO WITH WAVE TYPE
Spilling breakers – waves that have a turbulent
mixture of air and water at the crest
What creates spilling breakers?
WAVE SIZE HAS NOTHING TO DO WITH WAVE TYPE
F) Rogue Waves
a) Rogue wave –randomly occurring waves that are much higher than surrounding surf resulting
b) What creates Rouge Waves?
G) Tsunamis
1) Tsunami – a wave with a large wave length that does not break once it reaches the surf zone
a) Three causes of a tsunami:
(I)
(II)
(III)
H) Tides
1) Tides – the rise and fall of water level on earth resulting from the gravitational pull of the moon and
sun on the earth’s water
a) Though the moon and suns gravity both pull on earths water the moon pulls more than the sun
because it is closer
2) High and low tide:
a) As the moon rotates around the earth 2 tidal bulges are created, one under the moon and one on
the opposite side of the earth
3) How do to determine high tide and low tide?
a) High tide and low tide is determined only be the moons location around the earth.
(I) High tide will always be directly under and opposite the moon
(II) Low tide will always be on the sides of the earth that the moon is not
Draw in the tidal budges and label both high and low tides
M
Earth
M
Earth
I) Types of Tides
1) Spring tides –A large difference between high and low tide on __________ or ___________ moons
a) During a full moon or new moons, the gravity of the sun and moon work together to pull earths
water creating a larger tidal bulges
2) Neap tides – A small difference between high and low tide on __________ or ___________ moons
a) During a quarter
moons, the gravity of
the sun and moon
work against each
other, pulling earths
water in opposite
directions and
creating smaller tidal
bulges