SmartStarter
• What are the layers of the earth?
• BONUS: Does your description depend on the
chemical or physical (or both) make up?
Geological Oceanography
• Universe/Solar System/Earth Formation
– Layers
• 2 ways: Physical & Chemical
• Continental Drift
• Seafloor Spreading
– Geologic Features
• Depth data – History
• Unifying Theory: Plate Tectonics
• Formation of the
Solar System:
• Nebular Hypothesis
• Proto-Star
• Proto-Planets
1800 miles
1411 miles
1491 miles
Fe
Chemical: 3 layers
SS – Oceanography
What is the difference between the
crust and the lithosphere?
Lithosphere vs. Crust
– Crust plus upper mantle
• Why is the crust different? – It just cooler! 
– Dynamic changes
– Different rocks…three types
– Pressure/heat make the chemical/physical
characteristics different
If it is cooling, where does the heat
come from?
Why is it molten?
Earth's Heat
Continental Drift
Announcements
• Return tests
– Retake – requirement & responsibility
• Social Contract Raters
• Good things
Continental Drift
Continental Drift
Activity
: USGS
Partners.
Materials:
glue
scissors
crayons/markers
Continental Drift
According to Wegener’s hypothesis, the
continents move slowly across Earth’s surface in a
process called continental drift.
Continental Drift: “Show me the DATA!”
Shapes of the continents, mapmakers noticed how well
the shapes of North and South America fit together
with Europe and Africa.
fossils of species of land-based plants and animals were
discovered on continents separated by large oceans.
Glossopteris
Continental Drift
1912: Alfred Wegener proposed a hypothesis of
continental drift to explain these puzzling
observations.
Wegener called the ancient supercontinent
Pangaea.
The world ocean was called Panthalassa
Continental Drift
The continents move slowly across Earth's surface
over time.
SmartStarter
 What is the name of the ocean that
surrounded Pangaea?
Bonus: What is the name of the person who
proposed the theory of continental drift?
Check your Answers…
SS - Oceanography
• According to the video what was missing from
Wegener’s theory of continental drift?
BONUS: What was it that made the Americans less
accepting of Wegener’s theory than the Europeans?
Continental Drift – The Missing pieces
Wegener was unable to explain how the
continents could plow through the solid rock of
the sea floor or what force could move entire
continents.
As a result, most geologists rejected continental
drift.
Sea-floor Spreading
Several decades after Wegener proposed his hypothesis,
new evidence led geologists to reconsider his ideas.
New evidence helped scientists propose the theory of plate
tectonics.
Sea-floor Spreading: Bathymetric Data
The Mid-Ocean Ridge
When scientists mapped the ocean floor, they found a
chain of underwater mountains which they called the
mid-ocean ridge.
It forms the world’s longest mountain chain.
Sea-floor Spreading
Hess’s Discovery – Nye/Discovery (4 Min.)
Sea-floor Spreading = Formation of Oceanic Crust
Sea-floor spreading is the process by which new
oceanic crust is created at mid-ocean ridges as older
crust moves away.
• The mid-ocean ridge is a huge crack where magma pushes
upward.
• The parts of the ocean floor on both sides of the central
valley are moving apart.
• Magma from the mantle wells up and solidifies to form
new oceanic crust.
Evidence for Sea-floor Spreading: Paleomagnetism
Scientists discovered patterns of parallel magnetic
“stripes” that were identical on the two sides of the
Tool/Technology: Magnetometer
mid-ocean ridge.
• Earth’s magnetic field has reversed itself many times.
• The magnetic field causes rock crystals (magnetite) to line
up in a certain way before the rock solidifies.
• Stripes show that new ocean floor was added to both
sides of the mid-ocean ridge.
Evidence for Sea-floor Spreading:
Paleomagnetism
The pattern of magnetic stripes in the rock
of the ocean floor is the same on both sides
of the mid-ocean ridge.
Normal polarity
Reversed
polarity
Mid-ocean ridge
Magma
Oceanic crust
Mantle
Paleomagnetism Activity
• Directions of magnetism…changes
• Result  magnetic stripping of the sea floor
• movement and age of plates is measurable!
ACTIVITY – Analyze the magnetic stripping of the ocean floor!
SS - Oceanography
• What is the difference between continental
crust and oceanic crust?
(crust = tectonic plates)
*If you do not know, look at your notes. If you
don’t have it in your notes, look in your book. If
you don’t have your book, take a guess…writing
nothing is not an option.
The Force Within: Convection Cells
Sea-floor Spreading
During sea-floor spreading, oceanic crust forms at
the mid-ocean ridge. This crust gradually moves
toward a subduction zone, where old crust sinks
beneath a trench.
Mid-ocean ridge
Trench
Oceanic
crust
Oceanic
lithosphere
Magma
Volcano
Continental crust
Asthenosphere
Sediment
Asthenosphere
Continental
lithosphere
3 Types of Boundaries…
7 major plates & 5-8 minor plates
Oceanic vs. Continental Plates
…Basalt vs. Granite
CHARACTERISTICS OF OCEANIC CRUST AND CONTINENTAL CRUST
OCEANIC CRUST
CONTINENTAL CRUST
AVERAGE THICKNESS
7 km
30 to 50 km
DENSITY
3.0 gm/cm3
2.7 gm/cm3
COMPOSITION
basalt underlain by gabbro
granite, other plutonic
rocks, schist, gneiss
EARTH'S MASS
0.099%
0.374%
MANTLE CRUST MASS
0.147%
0.554%
Basalt
• Basalt is predominantly composed of crystals
of grayish plagioclase feldspar, blackish
pyroxene, and greenish olivine minerals and
largely forms from magma extruded along
divergent plate boundaries.
Granite
• Granite is predominantly composed of whitish
to pinkish plagioclase and potassium feldspars
and clear to whitish quartz minerals (along
with minor amounts of biotite, muscovite, and
horneblende minerals
Isostasy explains why ocean basins exist.
• Isostatic adjustment -
SIDE NOTE: Isostatic Rebound – glaciers tie into
the story too!
Isostatic Equilibrium
• Archimedes' principle indicates that the
upward buoyant force that is exerted on a
body immersed in a fluid, whether fully or
partially submerged, is equal to the weight of
the fluid that the body displaces… buoyancy
SmartStarter
The summit of Mount Everest is the highest point
on Earth – 8848 m – 29,029’
Challenger Deep is the lowest point in the ocean at
-10,916 m or 35,994’
1. What do you think the average height (above
sea-level) of continents is?
2. Average depth of the ocean?
• On average the continents are 840 m above sea level
while the average depth of the ocean basins is 3730 m.
• If the earth were a smooth sphere with the land planed
off to fill the ocean basins the earth would be
uniformly covered by water to a depth of 2430 m.
SMARTStarter
• What is the difference between igneous rock
and metamorphic rock?
• Bonus… How hot do you think the inner core
is?
ROCK Cycle
Read / Discuss / Write / Teach
• Groups of 6
• Read pages: 13-6 & 13-7 “The Rock Cycle” (Old – 11-6 & 11-7)
– 1 paragraph each
– Start with facilitator, go to the right.
• Read then previous reader summarizes for the group.
• Take notes / draw the cycle
– ACTIVITY – Connecting the parts
•
•
•
•
•
•
Igneous Rock
Sediments
Sedimentary Rock
Metamorphic Rock
Magma
CENTER (weathering and erosion)
Round 1: Names first…
Round 2: In order…explain how
Igneous Rock
• Cooled magma
– Magma vs. lava…?
• Primary formation is recycling machine
Igneous Rock
Processes:
• Weathering
• Erosion
• Chemical breakdown
– Leaching
• Sediment
– movement
Sedimentary Rock
LAYERS
• Fossils
• Petroleum
• Coal
= fossil fuels
Metamorphic Rock
• Heat and Pressure – chemical change
Rock Cycle describes why and how
“rock” is different from other “rock”
The Rock Cycle
Law of Conservation of Mass
SmartStart
• What processes change rocks from:
– 1. magma/lava to igneous rock
– 2. Igneous to sedimentary
– 3. Sedimentary to metamorphic
– 4. Metamorphic to Igneous
Smart Starter:
Date: 2/9
CLiCK Here for the Video LINK
Thrihnukagigur Crater, Iceland
(3 minutes)
*Write at least 3 things you
find interesting while
watching this short video.
*Then, write 2 questions you
have after watching it.
Date
Announcements:
Science = Awesomeness…as you just saw.
Good Things?
Today… Computer Lab
Be respectful of other users by keeping your voices down.
In pairs, complete the Where on Earth!? handout plus the Boundary Type Table
*You may work on your own if you would rather…
Use the links provided --- follow this path to get there:
Mr. Hill’s Page  Assignments (all classes)  “Mapping Dynamic Plates”
Bring your books. If you finish early you can start your homework.
Smart Starter:
Date: 2/16/16
Can you think of a volcanic island
arc?
Bonus: How did it form?
Hawaii is a Hot Spot Island Chain
Tuesday 9/22/15
Announcements:
Good Things?
INTRODUCTION
Science answers questions:
How do the features form?
16
LAVA – 6 minutes
Smart Starter:
Date 2/12
The mid-ocean mountains, such as the ridges and rises,
A. …are similar in origin to the Alps, the Rockies, and the
Appalachians.
B. …are composed of folded and faulted marine sedimentary rocks.
C. …are constructed of volcanic basalt.
D. …are similar in size and features to most coastal mountain ranges.
Explain why you chose your answer.
Unrelated FYI: Guyots are seamounts that have built above sea level.
Erosion by waves destroyed the top of the seamount resulting in a
flattened shape. Due to the movement of the ocean floor away from
oceanic ridges, the sea floor gradually sinks and the flattened guyots are
submerged to become undersea flat-topped peaks.
Announcements:
Date
Today… The Endless Voyage: Over the Edge
Answer Questions – take some notes on how features form
Turn in before you leave.
After video:
1-Finish questions – turn them in
2-Check Grades – Get missing assignments in! Deadline is test day 10/9
3- Get returned papers out of the return folder!
4-Do homework assignment =
Read the second section of chapter 14 in your text; Sediments of the Sea
pages 14-10 --> 14-15.
DUE Friday.
As evidence of your study....You will turn in:
•
Section Reading Notes – ( ½ page outline of reading)
•
Qs 1, 2, 3, 4 - pg. 14-10 – Should take several sentences.
•
Qs 1, 2, 3, 4 - pg. 14-15 (numbers and just the letter is fine)
HW – Why Study Marine Sediments?
14-2614-29 Qs 1-3 (X 2)
• Read 14-26 through 14-29
• Take notes with bullet points under each study
question (1-3) on page 14-26.
• Quiz your understanding of what you read by
doing the multiple choice questions 1-3 on
page 14-29
Read and Notes Demonstration
• Read Aloud – pg. 14-2
– EDIT THIS MORE>…
READ-DISCUSS-WRITE-SHARE
Sediments: Tools, Techniques, Types
• GROUPS OF 2-3
– Define the term
– Study from the text
– 5 major points to share
• Types (14-10)
BY ORIGIN
1.
2.
3.
4.
Lithogenous
Biogenous
Hydrogenous
Cosmogenous
BY SIZE
5. Wentworth Scale (7 class.)
• Three Roles in GROUPS
– Facilitator
– Timer
– Spokesman
• Tools (14-3)
6. Clamshell sampler
7. Piston Corer
8. Seismic Refraction
• Techniques (14-6)
9. Stratigraphy
10. Paleo-oceanography
Formative Assessment:
Q’s 1-2 pg. 14-8
Q’s 1-2 pg. 14-15
The Red Sea between
Africa and the Arabian
peninsula in Asia marks
a region where two
pieces of the
lithosphere are slowly
moving apart. Over the
next 100 million years,
the Red Sea could
become an ocean.
Africa
Red Sea
Continental Drift
What are plate tectonics and continental drift?
The theory of plate tectonics explains the
formation and movement of Earth’s plates.
Wegener hypothesized that the continents were
once joined in a single supercontinent, which then
broke into pieces that moved apart.
Continental Drift
Plate tectonics is the theory that pieces of Earth’s
lithosphere, called plates, move about slowly on
top of the asthenosphere.
According to Wegener’s hypothesis, the
continents move slowly across Earth’s surface in a
process called continental drift.
Continental Drift
When the early explorers began to discover the
shapes of the continents, mapmakers noticed how
well the shapes of North and South America fit
together with Europe and Africa.
Later on, geologists discovered fossils of species of
land-based plants and animals on continents
separated by large oceans.
Continental Drift
Fossils of Glossopteris and other plants and
animals on widely separated land masses led
Alfred Wegener to hypothesize that the
continents had once been joined.
Continental Drift
In 1912, Alfred Wegener proposed a hypothesis of
continental drift to explain these puzzling
observations.
Wegener called the ancient supercontinent
Pangaea.
Panthalassa.
Continental Drift
Continental drift explains why the continents
seem to fit together. It also explains why the
fossils from a single region appear across the
globe.
Wegener was unable to explain how the
continents could plow through the solid rock of
the sea floor or what force could move entire
continents.
As a result, most geologists rejected continental
drift.
Continental Drift
The continents move slowly across Earth's surface
over time.
Sea-floor Spreading
What are the roles of sea-floor spreading and
subduction in plate tectonics?
Sea-floor spreading creates new oceanic crust at
mid-ocean ridges. Subduction destroys old oceanic
crust at subduction zones.
Where is the newest oceanic lithosphere? Oldest?
Sea-floor Spreading
Sea-floor spreading is the process by which new
oceanic crust is created at mid-ocean ridges as
older crust moves away.
As sea-floor spreading occurs, old oceanic plates
sink into the mantle in the process of subduction.
Sea-floor Spreading
Several decades after Wegener proposed his
hypothesis, new evidence led geologists to
reconsider his ideas.
New evidence helped scientists propose the
theory of plate tectonics.
Sea-floor Spreading
The Mid-Ocean Ridge
When scientists mapped the ocean floor, they found a
chain of underwater mountains which they called the
mid-ocean ridge.
It forms the world’s longest mountain chain.
Sea-floor Spreading
This false-color
satellite image
shows a segment
of the mid-ocean
ridge in the
Atlantic Ocean.
The ridge system
winds through
all of Earth’s
oceans.
Sea-floor Spreading
Formation of Oceanic Crust
Sea-floor spreading is the process by which new
oceanic crust is created at mid-ocean ridges as older
crust moves away.
• The mid-ocean ridge is a huge crack where magma pushes
upward.
• The parts of the ocean floor on both sides of the central
valley are moving apart.
• Magma from the mantle wells up and solidifies to form
new oceanic crust.
Sea-floor Spreading
During sea-floor spreading, oceanic crust forms at
the mid-ocean ridge. This crust gradually moves
toward a subduction zone, where old crust sinks
beneath a trench.
Mid-ocean ridge
Trench
Oceanic
crust
Oceanic
lithosphere
Magma
Volcano
Continental crust
Asthenosphere
Sediment
Asthenosphere
Continental
lithosphere
Sea-floor Spreading
Subduction of Oceanic Plates
As sea-floor spreading occurs, old oceanic plates sink
into the mantle in the process of subduction.
Subduction zones are near the edges of oceanic plates.
As a plate sinks through a subduction zone, it bends,
forming a depression in the ocean floor called a
trench.
Sea-floor Spreading
Subduction occurs because, as an oceanic plate
moves away from the mid-ocean ridge, it
gradually cools and becomes more dense.
During subduction, the force of gravity slowly
pulls the dense edges of oceanic plates into the
mantle, destroying old ocean floor.
Sea-floor spreading and subduction together act
like a giant conveyor belt.
Sea-floor Spreading
Evidence for Sea-floor Spreading
Scientists discovered patterns of parallel magnetic
“stripes” that were identical on the two sides of the
mid-ocean ridge.
• Earth’s magnetic field has reversed itself many times.
• The magnetic field causes rock crystals to line up in a
certain way before the rock solidifies.
• Stripes show that new ocean floor was added to both
sides of the mid-ocean ridge.
Sea-floor Spreading
The pattern of magnetic stripes in the rock of the
ocean floor is the same on both sides of the midocean ridge.
Normal polarity
Reversed
polarity
Mid-ocean ridge
Magma
Oceanic crust
Mantle
Sea-floor Spreading
Geologists used radioactive dating to determine
the ages of rock samples from the ocean floor.
They found that rocks nearer the mid-ocean ridge
were younger, and rocks farther from the ridge
were older.
The Theory of Plate Tectonics
Why do tectonic plates move?
Plate motions are the visible part of the process of
mantle convection.
The Theory of Plate Tectonics
Convection currents form in the mantle as hot
rock rises, cools and spreads out, and then sinks
back into the mantle at subduction zones.
These sinking slabs of dense lithosphere and heat
from within Earth drive the circulation of
convection currents in the mantle.
The Theory of Plate Tectonics
Heat flows from
Earth’s hot interior
toward the cooler
surface mainly
through large
convection currents
in the mantle.
Plates are the
uppermost part of a
global convection
system.
Lithosphere
Convection currents
Outer
core
Inner
core
Mantle
The Theory of Plate Tectonics
The heat that drives convection in the mantle
comes from two sources.
• Earth was very hot when it first formed, and some of
the heat moving upward in convection currents is
due to the gradual cooling of its interior.
• A second source of heat is the result of the decay of
radioactive isotopes that are distributed throughout
the mantle and crust.
Plate Boundaries
What are the types of plate boundaries and what
are their characteristics?
There are three types of plate boundaries:
divergent boundaries, convergent boundaries, and
transform boundaries.
Plate Boundaries
There are about a dozen major tectonic plates.
Most major plates contain both continental and
oceanic crust. The edges of plates meet at plate
boundaries.
As the plates move apart, collide, or slide past
each other, they cause changes in Earth’s surface.
Plate Boundaries
The lithosphere is broken into about a dozen large plates,
which move slowly over Earth’s surface.
Plate Boundaries
The plates move very slowly, about 0.1 to 10
centimeters per year.
• Plates move away from each other along a divergent
boundary. The mid-ocean ridge forms a divergent
boundary. Divergent boundaries can also be found
on land, for instance, in Africa.
• When plates move apart, magma rises to fill the gap
and form new rock at the edge of each plate.
Plate Boundaries
• Plates come together, or collide, at a convergent
boundary. The most common convergent
boundary is one where an oceanic plate is
subducted beneath a trench.
• At a transform boundary, plates slide past each
other, moving in opposite directions. Rock is
neither created nor destroyed at a transform
boundary.
Plate Boundaries
Plates meet at three types of boundaries:
divergent boundaries, convergent boundaries, and
transform boundaries.
Divergent Boundary
Convergent Boundary
Lithosphere
Asthenosphere
Transform Boundary
Lithosphere
Mountain Building
Where do most mountains form?
Geologists found that most mountains form along
plate boundaries.
Mountain Building
Some mountains form when two plates with
continental crust at their edges collide along a
convergent boundary.
• Neither plate is subducted during such collisions.
• The crust buckles, folds, and thickens, pushing up tall
mountains.
Mountain Building
Mountains can also form along diverging plate
boundaries.
• The mid-ocean ridge system forms one long chain of
mountains on the ocean floor.
• In places, the mountains of the mid-ocean ridge rise
above sea level. One example is the island of Iceland
in the North Atlantic Ocean.
Mountain Building
The Andes, which
extend along the
western side of the
South American
plate, have risen as a
result of a collision
between that plate
and the Nazca Plate
Assessment Questions
1. According to Wegener’s hypothesis of continental drift,
what is Pangaea?
a.
b.
c.
d.
Africa and South America before they drifted apart
a tectonic plate located in the Pacific Ocean
the process by which continents move
an ancient supercontinent formed 260 million years ago
Assessment Questions
1. According to Wegener’s hypothesis of continental drift,
what is Pangaea?
a.
b.
c.
d.
Africa and South America before they drifted apart
a tectonic plate located in the Pacific Ocean
the process by which continents move
an ancient supercontinent formed 260 million years ago
ANS:
D
SS – OC
1. What type of plate boundary causes mountain chains,
such as the Himalayas, to form?
a.
b.
c.
d.
divergent
convection
convergent
transform
2. What causes Earth’s plates to move?
a.
b.
c.
d.
gravitational force between continents
magnetic forces in the lithosphere
global winds pushing continents
convection currents in Earth’s mantle
Assessment Questions
2. What type of plate boundary causes mountain chains,
such as the Himalayas, to form?
a.
b.
c.
d.
divergent
convection
convergent
transform
ANS:
C
Assessment Questions
3. What causes Earth’s plates to move?
a.
b.
c.
d.
gravitational force between continents
magnetic forces in the lithosphere
global winds pushing continents
convection currents in Earth’s mantle
Assessment Questions
3. What causes Earth’s plates to move?
a.
b.
c.
d.
gravitational force between continents
magnetic forces in the lithosphere
global winds pushing continents
convection currents in Earth’s mantle
ANS:
D