Download Earth Structure

Marine Science Unit 3
Earth Structure
iceagenow.com
Objectives
•
•
•
•
•
•
•
•
•
•
•
How do scientists classify the Earth’s internal layers?
What is isostatic equilibrium?
Explain the theory of continental drift.
What are mid-ocean ridges, rift valleys, and trenches?
What is the theory of sea floor spreading?
What is the theory of plate tectonics
Explain the difference between convergent, divergent, and
transform boundaries
What tools do scientists use to study ocean sediments?
What are the different types of ocean sediments?
Explain how sedimentation differs on the continental shelf versus
the deep ocean basin.
Explain marine deposition and erosion in passive vs. active coasts
Layers of the Earth
•
•
•
•
_________________
_________________
_________________
_________________
myschoolhouse.com
The Core
• Made up of __________ (90%) and nickel with
some silicon, sulfur, and other heavy elements
• Temperature of ____________oC (9032oF)
• The total core (inner and outer together) have
an estimated radius of 3470km
• 31.5% of the Earth’s mass and 16% of the
Earth’s volume
Inner Core
• Theorized to be ______
due to intense
________________
• New evidence suggests
that the inner core may
get as hot as 6,600oC at
its center – hotter than
the surface of the sun
news.sciencemag.org
Outer Core
• Less pressure than inner
core it is theorized to be
a dense ______________
• Can have thermal plumes
colorado.edu
Mantle
• Contains ________ and
____________ with some
iron and magnesium
• Estimated to be about
2,900km thick
• Made up of the upper and
lower mantle
• 68% of the Earth’s mass
and 83% of the Earth’s
volume
volcano.oregonstate.edu
Mantle
• Upper Mantle
– Made up of _______ layers
– 1. Asthenosphere
(asthenes=____): The top hot
layer that is partially melted
slowly flowing below the
lithosphere extending to a
depth of 350-650km
– 2. Lithosphere (lithos=______):
Earth’s cool rigid outer layer
that is 100-200km thick
• Lower Mantle
– Extends to the _________
– More ________ and
_________ more slowly
• Made up of the rigid solid upper
portion of the mantel and the
crust
ksl.com
Crust
• Thin _______ outermost
layer of the Earth
• Relatively _______
temperature
• 0.4% of Earth’s mass and 1%
of Earth’s volume
• Composed of oxygen, silicon,
magnesium, and irosn
• ______________ Crust
– Thin and made up of mostly
basalt (heavy dark colored
rock)
• ______________ Crust
– Thicker and made up of mostly
granite (light-colored rock)
How does the crust float on the mantle?
• _____________Equilibrium: Balance
between the weight of the crust and
the buoyancy provided by the
mantle
– As material adds to the oceanic
crust or leaves the continental crust
the balance becomes disrupted
– Isostatic Rebound: The additional
weight causes the crust to move
down while the removal of material
will cause the crust to move
upwards
– To restore ___________ landmasses
rise or sink along a weak area called
a fault
– One theory of what causes
earthquakes is when landmasses on
either side of an involved fault to
not move together
cliffsnotes.com
Buoyancy
• Archimedes’ Principle of Buoyancy: An object
immersed in a fluid (gas or liquid) is buoyed
up by a force _________ to the weight of the
fluid displaced – an object that weighs
_________ than the fluid it displaces will float
– If the weight of the crust changes, the landmass
must ______ or ___________ to compensate
Theory of Continental Drift
• 1912 Alfred Wegener
proposes that the
continents were once a
_________ landmass that
drifted apart (and are still
doing so)
• Pangaea (pan=all;
gaea=ocean) “super
continent”
• Pathalassa (thalassa=the
sea) single large
________________
geo.tcu.edu
Tectonic Jigsaw Activities 1 & 2
Compare the Pangaea you made in
Activity 2 to the “real” Pangaea
Evidence for Continental Drift
• 1600’s - People notice the shape • Distribution of animal
_____________
of continents fit together like a
– Led scientists to conclude that 200
jigsaw ________________
mill yrs ago Pangaea split into to
• Distribution of ______________
continents
– Coal forms from remains of plants
and animals in swampy climates…
coal is present in antatica where
there are currently no swamps
• Distribution of plant __________
– 1855 Edward Suess found fossils of
Glossopteris fern in South America,
Africa, Australia, India, and Anartica
– The seeds of this plant are too
fragile to travel by sea and are too
heavy to travel by wind… so, how
did they get to so many different
places?
en.wikipedia.org
• Lower - Gondwanaland
• Upper-Laurasia
Invention of Sonar
• Detects objects under water by
transmitting a __________ and
receiving an __________
• SONAR is an acronym that stands
for SOund _________ and Ranging
• Invented around the same time
that Wegener proposed the theory
of continental drift and partly in
response to the wreck of the
_______________
• Scientists almost immediately
began using sonar technology to
_________ the ocean floor
– German Meteor expedition mapped
the contours and depths of the South
Atlantic in 1925
oscilatii2011.wikispaces.com