course outcome 1 Flashcards
introducing the earth and its neighbors
scientific study of Earth: “Science of the Earth”
geology
the study of Earth’s materials, changes of
the surface and interior of the Earth, and the forces that
cause those changes.
Physical geology
Earthquakes, volcanic eruptions, landslides, floods and
tsunamis
most dangerous geologic hazards
eruptions of lava and ash can overwhelm
populated areas and disrupt air traffic
volcanoes
Any portion of the universe that can be isolated from the rest
of the universe to observe and measure changes.
Earth as a System
A self-contained system (in
which the boundary permits
the exchange of energy, but
not matter, with the
surroundings)
CLOSED SYSTEM
Energy and matter flow in
and out of the system
OPEN SYSTEM
what type of system is earth?
closed system
gases that envelop the earth
atmosphere
water on or near the Earth’s
surface, such as the oceans, rivers, lakes and
glaciers
hydrosphere
all living or once-living materials
biosphere
The gas that envelops the
Earth and is one of the
reasons that it can support
life
Relatively shallow
compared to the Earth’s
Geosphere
Composed of 78% Nitrogen,
21% Oxygen and 1% of other
gases such as CO2, Argon,
Helium, Neon, Hydrogen
and etc.
Atmosphere
solid rocky earth
geosphere
The lowest layer where all
weather occurs.
The base is warmer than the
uppermost portion because the
base is heated by the Earth’s
surface that absorbs heat.
Environmental Lapse Rate
The rate of temperature decrease
with an increase in altitude
Normal lapse rate = 6.5°C/km in
average
Tropopause – the outer
boundary of the troposphere
troposphere
Beyond the tropopause.
This is where the airplanes travel.
The site of the ozone layer that
absorbs the sun’s UV rays.
The temperature remains
constant to a height of about 20
km and then begins a gradual
increase that continues until the
stratopause at a height of nearly
50 km above Earth’s surface.
sunlight
stratosphere
Extends upward from the
stratopause
Temperatures decreases with
height until at the mesopause,
more than 80 km above the
surface, the temperature
approaches -90°C.
The coldest temperatures
anywhere in the atmosphere
occur at the mesopause.
One of the least explored regions
of the atmosphere
mesosphere
Above the mesosphere but has
no well-defined upper limit
Temperatures increase due to
the absorption of very short-
wave, high-energy solar radiation
by nitrogen and oxygen atoms
The International Space Station
orbits the Earth within the
middle of the thermosphere,
between 330 and 435 kilometres
(205 and 270 mi).
thermosphere
A dynamic mass of water
that is continually on the
move, evaporating from the
oceans to the atmosphere,
precipitating to the land,
and running back to the
ocean again.
Includes all of water in and
on the Earth.
A unique property of the
Earth is its abundance of
water
hydrosphere
Known as the land hemisphere
61% water
39% land
NORTHERN HEMISPHERE
Known as the water hemisphere
81% water
19% land
SOUTHERN HEMISPHERE
Largest and deepest ocean
Largest single geographic
feature
Extends from the Arctic
Ocean in the North to the
Antarctic Ocean (or Southern
Ocean) to the South
pacific ocean
The third largest ocean in the
world
Largely a Southern
Hemisphere water body
Bounded by Asia to the
North, Africa to the West,
Australia to the east, and
Antarctica to the South
indian ocean
Second largest ocean
Bounded by almost
parallel continental
margins (Europe and
Africa to the East while
the Americas to the
West)
atlantic ocean
7% the size of the Pacific
Ocean
The smallest and
shallowest of the world’s
oceans
Some also call this ocean
the Arctic Mediterranean
Sea
arctic ocean
the
Southern Ocean is defined
by the Antarctic
Convergence.
It is the portions of the
Pacific, Atlantic, and Indian
Oceans that lie about 50
degrees south latitude.
antarctic ocean
The meeting of currents
near Antarctica
antarctic convergence
The sphere that
includes all life on
earth and a key part
of the Carbon Cycle
Ocean life is
concentrated in the
surface water and
most life on land is
concentrated near
the surface as well.
biosphere
The Earth after its formation,
differentiated into the Crust,
Mantle, and Core.
geosphere
The process that created the
Earth’s layered structure
The denser material sinks to
the center (forming the core)
The less dense materials
floated to the top forming
the crust
PLANETARY
DIFFERENTIATION
LITHOSPHERE
ASTHENOSPHERE
MESOSPHERE
OUTER CORE
INNER CORE
This classification
is based on
compositional or
density
differences.
LAYERING BY
PHYSICAL
PROPERTIES
CRUST
MANTLE
CORE
Classification based on
whether the layer is
solid or liquid and could
be on how weak or
strong it is
LAYERING BY
CHEMICAL
PROPERTIES
The thinnest layer
ranging from 5 to 80 km
thick and occupies <1%
of the Earth’s volume.
Two Distinct Types:
Oceanic
Continental
crust
Mostly composed of
granitic rocks
Thicker with an average
thickness of 35 km
Less dense (2.7 g/cm3)
Older (some are 4 billion
years old
continental
Mostly composed of
basaltic rocks
The denser and thinner
crust (3.0 g/cm3)
Roughly 7 km thick
Younger (180 million years
old or less)
oceanic
The thickest layer
occupying 83% of the
Earth’s volume.
MANTLE
The boundary between the
Crust and Mantle.
Named after seismologist
Andrija Mohorovičić
MOHOROVIČIĆ
DISCONTINUITY
The composition is thought to be
mostly iron and nickel with some
oxygen, sulfur, and silicon.
Comprises 16% of the Earth’s volume
The densest portion of the Earth
with an average density of 11 g/cm³
to nearly 14 the times the density of
water
CORE
The boundary between the mantle
and core
Named after seismologist Beno
Gutenberg.
GUTENBERG
DISCONTINUITY
Passes through solid and
liquid
P WAVE/ PRIMARY WAVE
Does not pass through
liquid
S WAVE / SHEAR WAVE
The uppermost mantle + the
crust
Relatively rigid and is known
to break due to stress and the
site of most earthquakes
Broken up into large
fragments called lithospheric
plates
Lithosphere
“Weak” sphere
Lies below the lithosphere from ~100
km until a depth of 660 km
The lithosphere “floats” on top of
this layer.
Convection is also thought to occur
here.
Asthenosphere
The lower portion of the mantle from
660 km to 2900 km depth
Because of an increase in pressure
(caused by the weight of the rock
above), the mantle gradually
strengthens with depth.
The rocks within the lower mantle are
very hot and capable of very gradual
flow.
Mesosphere
It is identified to be a liquid layer
extending from 2900 km to 5150
km depth.
It is known to be liquid as S waves
do not travel through it.
It also circulates via convection, which
generates the Earth’s magnetic field
outer core
The boundary between the inner and
outer core,
discovered by seismologist
Inge Lehmann.
Lehmann discontinuity
The solid inner core from 5150 km
to the center of the Earth.
Despite its higher temperature, the
iron in the inner core is solid due to
the immense pressures that exist
in the center of the planet.
inner core
Most natural systems have mechanisms to enhance
change or to resist change
Feedback Mechanisms between Earth’s
System
Enhances or drives
changes
Positive Feedback
Resists change
Stabilizes or maintains
the system
Negative Feedback
a hypothesis that
suggested all present continents once
existed as a single supercontinent
continental drift
A German meteorologist and geophysicist
who wrote The Origin of Continents and
Oceans which outlined Wegener’s
hypothesis called continental drift.
He proposed that beginning about 200
million years ago, the supercontinent
called Pangaea began breaking into
smaller continents, which then drifted to
their positions.
Alfred Lothar Wegener (1915)
Remarkable similarity between the
coastlines on opposite sides of the
Atlantic Ocean.
In the early 1960s, Sir Edward
Bullard and two associates
constructed a map that pieced
together the edges of the
continental shelves of South
America and Africa at a depth of
about 900 meters.
Some of these overlaps are related to
stretching and thinning of the
continental margins as they drifted
apart (due to the Mid-Atlantic
Ridge).
Evidence 1: The Continental
Jigsaw Puzzle
Wegener learned that most paleontologists
agreed that some type of land connection
was needed to explain the existence of
similar Mesozoic age life forms on widely
separated landmasses.
Mesosaurus – a freshwater reptile
incapable of swimming the 5000
kilometers of open ocean that now
separate the continents.
a.
Glossopteris – a fossil “seed fern”
identified by its tongue-shaped leaves
and seeds, found in Australia, Africa,
South America, Antarctica, and India
(it grew only on subpolar climate).
b.
Lystrosaurus – a land-dwelling reptilec.
He concluded that when these landmasses
were joined, they were located much closer
to the South Pole.
Evidence 2: Fossil Evidence
Wegener found evidence of
2.2-billion-year-old igneous
rocks in Brazil that closely
resembled similarly aged
rocks in Africa.
Similar evidence can be found
in mountain belts that
terminate at one coastline,
only to reappear on
landmasses across the ocean
(e.g. Appalachian Mountains
and Caledonian Mountains)
Evidence 3: Rock Types and
Geologic Structures
Because Alfred Wegener
was a student of world
climates, he suspected
that paleoclimate data
might also support the idea
of mobile continents.
He learned that evidence
for a glacial period that
dated to the late Paleozoic
had been discovered in
southern Africa, South
America, Australia, and
India.
Evidence 4: Ancient Climates
The “Rejection” of Wegener’s Theory
inability to provide an acceptable
mechanism for the movement of continents.
The Grand Unifying Theory of Geology
Describes lithosphere as being broken into plates that
are in motion.
Explains origin and distribution of volcanoes, fault
zones, and mountain belts.
Included new understanding of the sea-floor and
explanation of driving force.
Gained significant support in the late 1960s.
Theory of Plate Tectonics
The uppermost mantle and the
overlying crust behave as a
strong, rigid layer, known as the
lithosphere, which is broken
into segments commonly
referred to as plates.
The lithosphere overlies a weak
region in the mantle known as
the asthenosphere, where the
temperatures and pressures are
such that rocks there are very
near melting temperatures,
and hence, respond to stress by
flowing (plastic or ductile
deformation).
Plate Tectonic Mechanism of Movement
Due to the small amounts of
melting present, it flows like the
flow of honey, being very slow
DUCTILE BEHAVIOR
Because plates are in constant motion relative to each
other, most major interactions among them occur
along their boundaries.
In fact, plate boundaries were first established by
plotting the locations of earthquakes and volcanoes.
Plates are bounded by three distinct types of
boundaries:
Divergent boundaries (constructive margin)a.
Convergent boundaries (destructive margin)b.
Transform fault boundaries (conservative margin)c.
PLATE BOUNDARIES
spreading centers) are the boundaries
between two plates that are diverging
or moving away from each other.
Mid-oceanic ridge
Continental rift zone
The global ridge system (Mid-Atlantic
Ridge, East Pacific Rise, and Mid-
Indian Ridge) is the longest
topographic feature on Earth’s surface.
None of the ocean floor that has been
dated thus far exceeds 180 million
years.
DIVERGENT BOUNDARIES
boundaries between
two plates that are converging or moving towards
each other. Three are three types:
An ocean floor plate collides with a less dense continental
plate
(OCEANIC-CONTINENTAL = VOLCANIC ARC)
An ocean floor plate collides with another ocean floor plate
(OCEANIC-OCEANIC = ISLAND ARC)
A continental plate collides with another continental plate
(CONTINENTAL-CONTINENTAL = MOUNTAIN RANGE)
CONVERGENT BOUNDARIES
boundaries
between two plates that are sliding horizontally past
one another.
Fault zones and earthquakes mark boundaries.
TRANSFORM FAULT BOUNDARIES
Left-lateral strike-slip
sinistral fault
Right-lateral strike-slip
dextral fault
Rift valleys. Mid-ocean ridges (in oceanic crust)
Continental rift zones (in continental crust
divergent
Mountain ranges
(CONVERGENT; continental-
continental
Volcanic arcs
CONVERGENT; oceanic-continental
Island arcs
CONVERGENT; oceanic-oceanic
Faults
TRANSFORM FAULT
is a star that has no solid
surface, but rather is a huge ball of
very hot gas
75% H, 25% H e
Overwhelming majority of mass in
the solar system is in the Sun
Hydrogen is fusing into helium in
the core of the Sun, releasing
energy in the form of sunlight
Gravity associated with Sun’s huge
mass holds planets, asteroids, and
comets in their orbits
Source: Naval Research
laboratory/NASA
sun
rocky or metallic
objects, ~ 1000 km or less in
diameter
asteroids
between the orbits of Mars and
Jupiter
asteroid belt
icy bodies, ~1000 km
or less in diameter
Found in the Kuiper Belt and the
Oort Cloud.
Comets
our galaxy contains approximately 100 billion
stars
Light Year = Distance light travels in one year
(10,000,000,000,000 km).
Milky Way is roughly 100,000 light years across.
The Universe - includes myriads of galaxies and is
estimated to be 13.75 billion years old starting with the Big
Bang
The Milky Way
All the planets orbit the Sun in the same direction
Counterclockwise when viewed from above Earth’s north pole
Orbits of all planets lie within 7 degrees of the plane of Earth’s orbit around the
Sun
Solar system is distinctly disk-shaped
Planetary Orbits
the solar
system originated from a
rotating, flattened disk of gas and
dust known as the solar nebula
Observed compositional trend
from metal and rock in the inner
solar system, to gases and ices in
the outer solar system, supports
hypothesis.
Sun, Moon, Earth, and meteorites
all appear to have same age
(about 4.6 billion years)
suggesting they formed in a
single event.
Nebular hypothesis
formed from dust clumped together which further
clumped into planets
Gravity drives process.
Differentiation.
Planetesimals
Originated by clumping of rings of debris around planets or by gravitational
capture.
Formation of Moons
Planetesimals bombarded planets leaving craters.
The Moon may have been formed by this process.
Tilted rotational axes may have been created by large planetesimal collisions.
Earth, Mars, Venus, Uranus.
Final Stages of Planet Formation
Formed either by gravitational capture of gases or
from volcanic eruptions and cometary impacts
Outer planets captures their atmospheres from the
solar nebula and are rich in hydrogen and helium
Inner planets probably formed from a combination of
processes such as volcanic eruptions, vaporization of
comets and/or planetesimals
Formation of Atmospheres
Apollo program lunar samples failed to confirm previous
hypotheses of Moon’s origin
New hypothesis – the Moon formed from debris ejected
following a large impact of the Earth with a Mars sized
planetesimal.
Supported by age of lunar rocks and absences of any
enormous impact feature on Earth.
origin and history of the moon
Earth’s only natural satellite,
possesses no air, water or life,
about ¼ the diameter of Earth
general features of the moon
extensive
lighter colored areas covered
with craters and composed of
anorthite rocks
Lunar Highlands
large smooth
dark areas composed of
basaltic rocks
Lunar Maria
Smallest and innermost planet
Heavily cratered, but with smooth plains and
scarps
Temperature range of -280 to 800 degrees F
No atmosphere
Large iron core beneath its thin silicate crust
and mantle
Strong magnetic field
Spins very slowly on its axis or once every 58.6
Earth days which is two thirds its orbital period
around the Sun.
mercury
most similar to Earth in size
96% carbon dioxide, 3.5% nitrogen trace H2O
Extremely dense – about 90 times greater than Earth
Surface temperature is approximately 900 degrees F
C O2 is creating strong greenhouse effect.
Radar maps show some peaks, folded mountains and fractured plains
but is dominated by volcanic landforms
Deep interior likely similar to Earth with an iron core and silicate mantle
No global magnetic field
venus
The Red Planet
About 1% as thick as Earth’s and contains 95% C O2, 3% nitrogen
and traces of oxygen and water
Very cold with clouds of frozen C O2 and water ice but no rainfall
Numerous dry channels on surface suggest flowing water in the
past
Polar Ice Caps with frozen C O2 and buried water ice
Numerous volcanic structures, fractures and canyons on surface
Crust, mantle and core but no longer tectonically active
No folded mountains
Phobos and Deimos – likely to be captured asteroids
mars
Why Are the Terrestrial Planets So
Different?
Role of mass and radius
Role of distance from the sun
Role of biological processes
largest planet in the solar system
Composed of hydrogen and helium gases, with a small
ice/rock core
Atmospheric clouds are composed of methane,
ammonia and water ices
High pressure deep in the interior, results in hydrogen
compressed first into liquid, then into a liquid metal
Galileo first viewed it’s four largest Moons:
Ganymede – largest of all moons in the solar
system.
Io – nearest to Jupiter, volcanically active.
Europa – covered with a crust of water ice.
Callisto – Jupiter’s second largest moon.
jupiter
largest of all mons in the solar system
ganymede
nearest to jupiter, volcanically active
Io
Covered with a crust of water ice
Europa
Jupiter’s second largest moon
Callisto
second-largest planet in solar
system, composed of hydrogen and
helium gases, with small ice/rock core
Wide thin ring system of chunks of ice
and rock possibly formed from tiny
moon collisions
First observed by Galileo
Several large moons and ~50 smaller
ones
Largest moon, Titan
Nitrogen atmosphere with methane lakes
and stream channels on the surface.
saturn
largest moon of saturn
titan
4 times the diameter of Earth
Hydrogen and methane rich
atmosphere gives it a blue appearance
Iron and silica core
Rotational axis and moons’ orbits
tipped on side
Narrow thin ring system
uranus
outermost planet
3.9 times the diameter of the Earth
Hydrogen and methane rich
atmosphere gives it a blue appearance
Great Dark Spot – surface storm
Narrow thin ring system
Triton – largest moon, retrograde orbit
neptune
recently demoted to dwarf planet status by the
International Astronomical Union
Composed of water ice and rock
Moons include Charon, Hydra and Nix
Located in the kuiper belt
pluto
Fragments large enough to reach the ground (Stony, iron, and stony-iron.
meteorites
Small, rocky bodies that orbit the Sun; most lie in the asteroid belt between orbits of Mars and Jupiter
Fragments of planetisimals
asteroids
small, icy bodies that orbit the sun
comets
Periodically occur when Earth sweeps up one of these remnants from formation of the solar system
20-meter diameter meteoroid would have the energy of one thermonuclear bomb.
giant impacts
