Transcript Interior of the Earth

Geology is the study of the Earth, the materials of which it is
made, the structure of those materials, and the processes
acting upon them.
 Explored shallowly through mines and wells –
deepest mines on Earth are only about 2.5 miles deep
 Temperature and pressure increase with depth
 Earthquake (Seismic) Waves
 scientists are able to tell the density and
composition of materials in the Earth by
how these waves travel through the Earth
 caused by earthquakes or manmade
explosions
 Magnetic Fields on Earth
 created by massive circulation of the hot,
liquid mantle beneath Earth’s surface
 Differences in density resulted in materials within
Earth forming layers
 Crust – least dense
 Mantle
 Outer Core
 Inner Core – most dense
 the brittle, rocky outer layer of Earth
 very thin compared to other layers,
like the shell of an egg
 composed of magnesium and iron
 earthquake waves speed up through
this layer because it is the least dense
 Two types:
 Oceanic Crust – crust under the oceans
 Continental Crust – crust on land (3x thicker than
oceanic)
 thickest middle layer in the solid part of the Earth
 contains more iron and magnesium than the crust,
making it more dense
 first 50 miles believed to be very hard rigid rock
 next 150 miles is super-heated solid rock that is weak
from heat energy and can “flow”
 next several hundred miles is
very solid, sturdy rock again
 Uppermost Mantle (Lithosphere)
 similar rocks to that of the crust
 Asthenosphere
 heated rocks begin to melt and flow slowly underneath the lithosphere
 Upper Mantle
 higher temperatures and pressure cause rocks to stop melting and
become solid again
 Lower Mantle
 most dense part of the mantle
Lower Mantle – down to 1800 miles
 dense and metallic center of the Earth
 composed mainly of iron and a small amount of
nickel
Outer Core
Inner Core
 higher temperatures
 high pressure
outweigh the high
pressure and makes the
outer core a liquid,
molten lava
 discovered by analyzing
earthquake wave data
outweighs the high
temperatures and makes
the inner core a ball of
dense, solid iron with a
bit of nickel
 spins faster than the rest
of Earth
 Kola Superdeep Borehole in Russia
 Drilling began on May 24, 1970
 In 1989, reached 40,230 feet (7.5 miles)
 Hole is only about 9 inches wide
 Still holds record in 2012 for the deepest hole ever
drilled. (longest hole is drilled on an angle)
 Due to higher than expected temperatures at this
depth and location, drilling deeper was stopped in 1994
 Rocks taken from this depth date 2.7 billion years old
 Atmosphere
0.0009 (avg ~ decreasing with distance)
 layer of gases/air surrounding earth
 Continental Crust
2.7 to 3.0
 thin, rocky layer of the earth that forms the continents
 Oceanic Crust
3.0 to 3.3
 thin, rocky layer of the earth under the oceans
 Mantle
3.3 to 5.7 (increasing with depth)
 part liquid rock, part solid rock layer of earth
 Outer Core (liquid)
9.9 to 12.2
 hot, dense, liquid, metal layer of earth
 Inner Core (solid)
12.6 to 13.0
 hot, dense, solid, metal layer of earth