EOSC 110 QUESTIONS AND ANSWERS
Define Biosphere - Answer -all of the living or once-living material on earth
Define Hydrosphere - Answer -the water on or surrounding the surface of the globe,
including the water of the oceans, glaciers, and the water in the atmosphere
Define Lithosphere - Answer -lithosphere includes the Earth's crust and the uppermost
part of the mantle
Define Atmosphere - Answer -gases that envelope the earth
Deep Time and an Example - Answer -Refers to the entirety of geologic history, an
unimaginable length of time that goes far beyond our human scale
Example: India used to be south of Asia, moved up slowly & created the himilayas,
caused permanent change in Africa as it moved away from a luscious tropical forest to a
dry landscape.
Define Uniformitarianism and provide an example - Answer -"The present is the key to
the past"--> The theory that all geologic phenomena may be explained as the result of
existing forces having operated uniformly from the origin of the earth to the present
time.
e.g. Pangea splitting apart (plate tectonics still occuring today) OR weathering and
erosion by wind, rain and gravity can wear whole mountain ranges away like to
Caledonian mountain range 490 million years ago
The earth's layered structure - Answer -The earth is divided into different layers that are
distinct in terms of their behavior and composition
The core of the earth: - Answer -composition: predominantly iron and nickel
-inner core is solid
-outer core is liquid
The mantle of the earth: - Answer -Less dense, Abundant iron & magnesium Silicates,
rock type = peridotite, it is solid
Uppermost mantle - Answer -Rigid
Asthenosphere - Answer -Plastic part of the mantle (below uppermost rigid mantle)
e.g. silly putty example
Lower mantle (mesosphere): - Answer -rigid
The crust of the earth: - Answer -Least dense, abundant silicates, overall richer in
potassium and sodium
,The Two Types of crust and their Mnemonics - Answer -1) continental crust (FELSIC):
"Granite-like" in composition. It is richer in feldspar and silicate minerals. This makes up
the continents and is generally thicker.
2) Oceanic crust (MAFIC): "Basaltic in composition. Richer in "ferro-magnesian"
minerals. Ocean crust is generally thinner than continental crust.
The lithosphere - Answer -The uppermost mantle and
overlying crust are less dense than the underlying layers. Together, they form the rigid
lithosphere. The
lithosphere moves over the plastic asthenosphere. Lithosphere ranges in
thickness from ~50km to ~200 km.
Earth classified by chemical composition (layers) - Answer -Crust (granite and basaltic
rock), mantle (silicate minerals), core (iron and nickel and sulphur).
The asthenosphere is the physical properties definition because it is plastic and is
referred to the mantle under chemical composition because it is made of silicate
minerals
Earth classified by physical properties (layers) - Answer -Lithosphere (rigid),
asthenosphere(plastic), mesophere (rigid), outer core (liquid), inner core (rigid)
Anatomy of a plate - Answer -Lithosphere= Crust + Upper Mantle
-Plates are fractured blocks of lithosphere "floating"on ductile asthenosphere
-plates' are composed of
lithosphere
-strong, cool composition
-Due to these properties plates are brittle -"fractured"
Plates of the earth - Answer -lithosphere is broken into 12 large and several small
plates
-plates move on top of the weak asthenosphere
NOTE: Oceanic Crust + Continental Crust can sit on the same lithospheric plate.
e.g. south american plate
Plate tectonics - Answer -the study of plate movement and interaction
-the majority of geological activity is at the plate boundaries
Plate tectonics: the development of a theory - Answer -Wegener, 1912 "the jigsaw fit"--
the coast of Africa and the coast of South America fit together like two pieces of a
puzzle
-fossil, climate, and rock types and styles of deformation match across different
continents -like the picture on a jigsaw puzzle
,-Mountains like the Appalachians, Mountains of N-England and Scotland, Norway and
others are all
composed of rocks of similar age / structure
-Remove North Atlantic and you "reform" the Caledonian Mountain 490 and 390MA
-Fossil distribution: Ancient geographic distribution of Fossils are also good
indicators of connection of landmasses
-Evidence of glaciation: The Dwyka tillite in South Africa. It is of Permian age-- there are
glacial striations
-Glacial patterns (permo-carboniferous glaciation) only makes sense when you
reconfigure the continents
Summarize what evidence there is for continents once being joined - Answer -fossil
distributions, continental edges, rock distributions, glaciation
Pangaea: - Answer -existed about 225 million years ago
-rifts apart 175 million years ago
-this was not well-respected by the scientific community in 1915
Why was Wegener's hypothesis of pangea rejected? - Answer -The MECHANISM :
-continents plow through denser oceanic crust didn't make sense
-Interaction between ocean and continent lead to crumpling mountain ranges (ocean
and continental crust can be on same plate or different plates)
-Propelled by: centrifugal force & gravity of sun and moon .... FAR TOO WEAK TO
CAUSE THIS!
Vinidcating moving continents: Harry Hess - Answer -During WWII -development of
sonar to find U boats (submarines): Captain Harry Hess
-Allows for Mapping of the sea floor revealed topographic features of the oceanic crust
previously unobservable
-Hess proposed that seafloor was spreading, generated at
the Spreading Centers
represented by the oceanic ridges.
-Continents didn't plough through ocean crust, they ride around on plates as the plates
moved relative to each
other.
Sea Floor Spreading and Plate Tectonics (What Hess Discovered) - Answer -Last
lecture -Hess' new view of the ocean floor:
-Ridges (long volcanic mountain chains)
-Sunken volcanoes
-Volcanic Mountain Chains or ridges
-Deep trenches along margins of some continents
Hess's Mechanism to explain the drifting continents: - Answer --Magma "oozes" up at
ridges forming new ocean crust
-Pushes older ocean floor to either side
, -Eventually ocean crust descends into the Earth at the ocean trenches
•This Mechanism is called Sea Floor Spreading
•Continents carried as new ocean crust spreads
Wegner's thoery: continental drift is now called: - Answer -Plate tectonics
-With this mechanism can interpret the geological activity / features on Earth--> from
this idea is where the development of modern plate tectonics theory began
Types of Margins: Passive - Answer -Transitions between oceanic and continental
crust where there is no
interaction between plates are referred to as Passive Margins.
Passive Margins are typically marked by thick accumulations of sediment. Ocean-
continental crust meet eachother but they are on the same plate.
Types of Margins: Active Margins - Answer -We refer to the regions where lithospheric
plates are interacting with each other as Active Margins
Active Boundaries: Divergent 1) Rift Valley - Answer -Plates are spreading apart
-Rift valley: continental crust. Continent undergoes extension, the crust is thinned and a
rift valley forms. There is a release of pressure --> Magma and volcanoes. e.g. African
Rift Valley
-this same phenomenon happened between S.A. and Africa 100 million years ago
Active Boundaries: Divergent 2) Continued rifting - Answer -Continent tears in two.
Continent edges are faulted and uplifted. Basalt eruptions from oceanic crust.
Active Boundaries: Divergent 3) Mature Ocean basin with mid-ocean ridge - Answer -
continental sediments blanket the subsiding margins to form continental shelves. The
ocean widens and a mid-oceanic reidge develops as in the Atlantic Ocean.
Active Boundaries: Convergent 1) oceanic and continental - Answer --convergence
between oceanic and continental lithosphere
-SUBDUCTION of oceanic plate because of its density
-mountains / trench / volcanoes / earthquakes--> MOST GEOLOGIC ACTIVITY HERE
Seismology and the geometry of subduction zones - Answer -Seismic profiles through
convergent margins reveal bands of earthquakes-reveal the geometry of subduction
zones
Active Boundaries: Convergent 2) Oceanic vs oceanic - Answer --SUBDUCTION, one
will subduct below the other. The older one will subduct because it is colder and more
dense than the new plate
-Volcanic island arcs / trench / earthquakes
Active Boundaries: Convergent 3) continental vs. continental - Answer -Mountains /
earthquakes
Define Biosphere - Answer -all of the living or once-living material on earth
Define Hydrosphere - Answer -the water on or surrounding the surface of the globe,
including the water of the oceans, glaciers, and the water in the atmosphere
Define Lithosphere - Answer -lithosphere includes the Earth's crust and the uppermost
part of the mantle
Define Atmosphere - Answer -gases that envelope the earth
Deep Time and an Example - Answer -Refers to the entirety of geologic history, an
unimaginable length of time that goes far beyond our human scale
Example: India used to be south of Asia, moved up slowly & created the himilayas,
caused permanent change in Africa as it moved away from a luscious tropical forest to a
dry landscape.
Define Uniformitarianism and provide an example - Answer -"The present is the key to
the past"--> The theory that all geologic phenomena may be explained as the result of
existing forces having operated uniformly from the origin of the earth to the present
time.
e.g. Pangea splitting apart (plate tectonics still occuring today) OR weathering and
erosion by wind, rain and gravity can wear whole mountain ranges away like to
Caledonian mountain range 490 million years ago
The earth's layered structure - Answer -The earth is divided into different layers that are
distinct in terms of their behavior and composition
The core of the earth: - Answer -composition: predominantly iron and nickel
-inner core is solid
-outer core is liquid
The mantle of the earth: - Answer -Less dense, Abundant iron & magnesium Silicates,
rock type = peridotite, it is solid
Uppermost mantle - Answer -Rigid
Asthenosphere - Answer -Plastic part of the mantle (below uppermost rigid mantle)
e.g. silly putty example
Lower mantle (mesosphere): - Answer -rigid
The crust of the earth: - Answer -Least dense, abundant silicates, overall richer in
potassium and sodium
,The Two Types of crust and their Mnemonics - Answer -1) continental crust (FELSIC):
"Granite-like" in composition. It is richer in feldspar and silicate minerals. This makes up
the continents and is generally thicker.
2) Oceanic crust (MAFIC): "Basaltic in composition. Richer in "ferro-magnesian"
minerals. Ocean crust is generally thinner than continental crust.
The lithosphere - Answer -The uppermost mantle and
overlying crust are less dense than the underlying layers. Together, they form the rigid
lithosphere. The
lithosphere moves over the plastic asthenosphere. Lithosphere ranges in
thickness from ~50km to ~200 km.
Earth classified by chemical composition (layers) - Answer -Crust (granite and basaltic
rock), mantle (silicate minerals), core (iron and nickel and sulphur).
The asthenosphere is the physical properties definition because it is plastic and is
referred to the mantle under chemical composition because it is made of silicate
minerals
Earth classified by physical properties (layers) - Answer -Lithosphere (rigid),
asthenosphere(plastic), mesophere (rigid), outer core (liquid), inner core (rigid)
Anatomy of a plate - Answer -Lithosphere= Crust + Upper Mantle
-Plates are fractured blocks of lithosphere "floating"on ductile asthenosphere
-plates' are composed of
lithosphere
-strong, cool composition
-Due to these properties plates are brittle -"fractured"
Plates of the earth - Answer -lithosphere is broken into 12 large and several small
plates
-plates move on top of the weak asthenosphere
NOTE: Oceanic Crust + Continental Crust can sit on the same lithospheric plate.
e.g. south american plate
Plate tectonics - Answer -the study of plate movement and interaction
-the majority of geological activity is at the plate boundaries
Plate tectonics: the development of a theory - Answer -Wegener, 1912 "the jigsaw fit"--
the coast of Africa and the coast of South America fit together like two pieces of a
puzzle
-fossil, climate, and rock types and styles of deformation match across different
continents -like the picture on a jigsaw puzzle
,-Mountains like the Appalachians, Mountains of N-England and Scotland, Norway and
others are all
composed of rocks of similar age / structure
-Remove North Atlantic and you "reform" the Caledonian Mountain 490 and 390MA
-Fossil distribution: Ancient geographic distribution of Fossils are also good
indicators of connection of landmasses
-Evidence of glaciation: The Dwyka tillite in South Africa. It is of Permian age-- there are
glacial striations
-Glacial patterns (permo-carboniferous glaciation) only makes sense when you
reconfigure the continents
Summarize what evidence there is for continents once being joined - Answer -fossil
distributions, continental edges, rock distributions, glaciation
Pangaea: - Answer -existed about 225 million years ago
-rifts apart 175 million years ago
-this was not well-respected by the scientific community in 1915
Why was Wegener's hypothesis of pangea rejected? - Answer -The MECHANISM :
-continents plow through denser oceanic crust didn't make sense
-Interaction between ocean and continent lead to crumpling mountain ranges (ocean
and continental crust can be on same plate or different plates)
-Propelled by: centrifugal force & gravity of sun and moon .... FAR TOO WEAK TO
CAUSE THIS!
Vinidcating moving continents: Harry Hess - Answer -During WWII -development of
sonar to find U boats (submarines): Captain Harry Hess
-Allows for Mapping of the sea floor revealed topographic features of the oceanic crust
previously unobservable
-Hess proposed that seafloor was spreading, generated at
the Spreading Centers
represented by the oceanic ridges.
-Continents didn't plough through ocean crust, they ride around on plates as the plates
moved relative to each
other.
Sea Floor Spreading and Plate Tectonics (What Hess Discovered) - Answer -Last
lecture -Hess' new view of the ocean floor:
-Ridges (long volcanic mountain chains)
-Sunken volcanoes
-Volcanic Mountain Chains or ridges
-Deep trenches along margins of some continents
Hess's Mechanism to explain the drifting continents: - Answer --Magma "oozes" up at
ridges forming new ocean crust
-Pushes older ocean floor to either side
, -Eventually ocean crust descends into the Earth at the ocean trenches
•This Mechanism is called Sea Floor Spreading
•Continents carried as new ocean crust spreads
Wegner's thoery: continental drift is now called: - Answer -Plate tectonics
-With this mechanism can interpret the geological activity / features on Earth--> from
this idea is where the development of modern plate tectonics theory began
Types of Margins: Passive - Answer -Transitions between oceanic and continental
crust where there is no
interaction between plates are referred to as Passive Margins.
Passive Margins are typically marked by thick accumulations of sediment. Ocean-
continental crust meet eachother but they are on the same plate.
Types of Margins: Active Margins - Answer -We refer to the regions where lithospheric
plates are interacting with each other as Active Margins
Active Boundaries: Divergent 1) Rift Valley - Answer -Plates are spreading apart
-Rift valley: continental crust. Continent undergoes extension, the crust is thinned and a
rift valley forms. There is a release of pressure --> Magma and volcanoes. e.g. African
Rift Valley
-this same phenomenon happened between S.A. and Africa 100 million years ago
Active Boundaries: Divergent 2) Continued rifting - Answer -Continent tears in two.
Continent edges are faulted and uplifted. Basalt eruptions from oceanic crust.
Active Boundaries: Divergent 3) Mature Ocean basin with mid-ocean ridge - Answer -
continental sediments blanket the subsiding margins to form continental shelves. The
ocean widens and a mid-oceanic reidge develops as in the Atlantic Ocean.
Active Boundaries: Convergent 1) oceanic and continental - Answer --convergence
between oceanic and continental lithosphere
-SUBDUCTION of oceanic plate because of its density
-mountains / trench / volcanoes / earthquakes--> MOST GEOLOGIC ACTIVITY HERE
Seismology and the geometry of subduction zones - Answer -Seismic profiles through
convergent margins reveal bands of earthquakes-reveal the geometry of subduction
zones
Active Boundaries: Convergent 2) Oceanic vs oceanic - Answer --SUBDUCTION, one
will subduct below the other. The older one will subduct because it is colder and more
dense than the new plate
-Volcanic island arcs / trench / earthquakes
Active Boundaries: Convergent 3) continental vs. continental - Answer -Mountains /
earthquakes
