vTHE INTERNAL STRUCTURE OF THE EARTH Flashcards
describes the outermost shell of a terrestrial planet
part of a single geologic unit called the lithosphere
THE CRUST
mostly made up of igneous rocks, like granite and basalt
Our planet’s thin, 40-kilometer (25-mile) deep crust—just 1% of Earth’s mass—contains all known life in
the universe.
THE CRUST
Today, tectonic activity is responsible for the formation (and destruction) of crustal materials.
THE CRUST
Billions of years ago, the
planetary blob that would
become the Earth started out
as a hot, viscous ball of rock.
earth’s core
The molten material
that surrounded the
core was the early
mantle
The heaviest material,
that sank
to the center of the new
planet and became its core.
iron and nickel
Over millions of years, the
mantle cooled. Water
trapped inside minerals
erupted with lava, a
process called
“outgassing.”
Materials that initially stayed in
their liquid phase during this
process, called _______ ultimately became
Earth’s brittle crust.
“incompatible
elements,”
TWO TYPES OF CRUST
Continental Crust
Oceanic Crust
The transition zone between these two
types of crust
Conrad discontinuity
Conrad discontinuity
named after the seismologist
Victor
Conrad
are the most abundant
rocks and minerals in both oceanic
and continental crust
Silicates
(mostly compounds made of silicon
and oxygen)
Silicates
mostly composed of different types of granites. Geologists often refer to the rocks of the
continental crust as “sial”
CONTINENTAL CRUST
made up of silicate and aluminium
- the most abundant elements
Sial
created by plate tectonics
CONTINENTAL CRUST
where tectonic plates crash into each other, continental crust is thrust up in the process of orogeny, or mountain-building.
convergent plate boundaries,
the thickest parts of continental crust are at the
world’s tallest mountain ranges.
the crust extends unevenly below the Earth as well as soaring into the atmosphere
CONTINENTAL CRUST
the oldest and most stable part of the continental
lithosphere
usually found deep in the interior of most
continents
Cratons
2 Types of Cratons
Shields
Platforms
cratons in which the ancient basement
rock crops out into the atmosphere
SHIELDS
are cratons in which the basement rock is
buried beneath overlying sediment
PLATFORMS
is almost always much older than the
oceanic crust. Because continental crust is rarely destroyed and
recycled in the process of subduction, some sections of
continental crust are nearly as old as the Earth itself.
continental crust
Extending 5-10 kilometres beneath the ocean floor
Mainly composed of basalts
The rocks are often refer as “sima”
OCEANIC CRUST
made up of silicate and magnesium
- the most abundant minerals in the crust
Sima
Denser than the continental crust
Constantly formed at mid-ocean ridges, where
tectonic plates are tearing apart from each other
Destroyed at subduction zones
OCEANIC CRUST
the ___ and _____ of oceanic crust increases with
distance from mid-ocean ridges.
age and density
important geologic process in which a tectonic
plate made of dense lithospheric materials melts
or falls below a plate made of less-dense lithosphere
at a convergent plate boundary
Subduction
Mostly solid bulk of Earth’s interior
Lies between Earth’s dense, superheated
core and its thin outer layer, crust
Makes the 84% of the Earth’s total
volume
THE MANTLE
2 types of TEMPERATURE in the mantle
Near boundary between crust
Near boundary with the core
- Varies from 1000 degrees Celsius
Near boundary between crust
- 3,700 degrees Celsius
Near boundary with the core
4 TYPES OF ROCKS
Olivine
Garnet
Pyroxene
Magnesium oxide
Mostly silicates (a wide variety of
compounds that share a silicon and oxygen
TYPES OF ROCKS in the mantle
5 ELEMENTS FOUND IN THE MANTLE
Iron
Aluminum
Calcium
Sodium
Potassium
Extends from the crust to a depth of about
410 kilometres
Mostly solid, but its more malleable
regions
Contributes to tectonic activity
THE UPPER MANTLE
TWO PARTS OF THE MANTLE
Lithosphere
Asthenosphere
The division between the crust and
the mantle
THE
MOHOROVICIC
DISCONTINUITY
THE
MOHOROVICIC
DISCONTINUITY Simply called as
Moho
THE
MOHOROVICIC
DISCONTINUITY Named after Croatian seismologist
Andrija Mohorovicic
Who first detected in 1909 by
examining the seismic waves
moving through the Earth
Andrija Mohorovicic
Is the solid, outer part of Earth
Includes both crust and the brittle upper portion of the mantle
Both the coolest and the most rigid of Earth’s layers
LITHOSPHERE
Tectonic Activity is found in
LITHOSPHERE
Describes the interaction of the huge slabs
(flat, thick piece of material such as earth or
stone) lithosphere called tectonic plates
Tectonic Activity
Denser, weaker layer beneath the
lithosphere mantle
Temperature and pressure are so high
that rocks soften and partly melt,
becoming semi-molten
ASTHENOSPHERE
More ductile than either the
lithosphere or lower mantle
More viscous than the lithosphere
ASTHENOSPHERE
The very slow motion of lithospheric
plates
“floating”
is
the cause of plate tectonics, continental
drift, earthquakes, the formation
plates “floating”
One of the most obscure places in the world separates two continents and two tectonic plates, namely the North American and Eurasian plates.
THE SILFRA RIFT
THE SILFRA RIFT divides two tectonic plates namely
North
American and Eurasian plates.
hotter and denser than the
upper mantle
much less ductile than the
upper mantle
intense pressure keeps the
lower mantle solid
THE
LOWER
MANTLE
responsible
for transferring heat from
the inner and outer core to
the upper layers of the
planet
THE
LOWER
MANTLE
