Earth Systems Flashcards
Crust
the outer most layer of the earth; the thinnest/least dense layer; made of rock
Inner Core
innermost layer of earth; densest layer; solid iron/nickel
Continental Crust
thicker but less dense than the oceanic crust; located in crust layer of the earth
Mantle
the layer of the Earth between the crust and the core; the convective layer of Earth; thickest layer; molten rock
Magnetic Field
caused by the rotation of Earth as the outer core circulates around the inner core
Atmosphere
a relatively thin layer of gas surrounding the entire planet
Outer Core
layer of earth between mantle and inner core molten metal; liquid iron and nickel; denser than the crust and mantle but not as dense as the inner core
Dynamo Effect
the creation of a magnetic field as the liquid outer core circulates around the solid inner core
Oceanic Crust
not as thick as continental crust (about 5 miles thick); located in crust layer of the earth
Tectonic Plate
the broken up pieces of the lithosphere
Sea-Floor Spreading
process of new oceanic crust forming as magma rises toward the surface and solidifies
Mid-Ocean Ridge
a place where sea-floor spreading takes place
Continental Drift
hypothesis that the continents once formed a single land mass, broke up, and drifted to their present locations
Pangea
the landmass that existed when all continents were joined
Mid-Atlantic Ridge
longest unbroken mountain chain in the world, running through the middle of the Atlantic Ocean
Subduction
occurs when 2 tectonic plates collide, and one plate moves under the other & sinks into the mantle
Subduction Zone
regions where subduction occurs
Theory of Plate Tectonics
theory explaining how tectonic plates move and change shape
Boundaries
places where tectonic plates meet
Convergent Boundary
boundary formed by collision of 2 plates (collide, crash, collision)
Divergent Boundary
boundary between 2 plates moving away from each other (separate, divide)
Transform Boundary
boundary between 2 plates that are scraping past each other (scrape)
Ring of Fire
ring of volcanoes around the Pacific Plate
Alfred Wegner
German scientists who developed the theory of continental drift
Lithosphere
consists of all of the crust as well as the upper, rigid part of the mantle
stress
a force that acts on a rock to change its shape or volume
compression
stress that squeezes rock until it folds or breaks
tension
stress that pulls rock until it becomes thinner in the middle or breaks
shearing
stress that pushes rock in opposite directions until it breaks
deformation
the change in the shape of rock in response to stress
folding
bending of rock layers due to stress
anticline
fold in rock that bends upward into an arch
syncline
fold in rock that bends downward to form a valley
fault
a break in the Earth’s crust
normal fault
caused by tensional stress and results in a downward movement of the hanging wall
reverse fault
caused by compressional stress and results in an upward movement of the hanging wall
strike-slip fault
caused by shearing stress and results in rocks on both sides of the fault sliding past each other
hanging wall
The block of rock that forms the upper half of a fault.
foot wall
The block of rock that forms the lower half of a fault
fold mountains
mountains that form where two plates collide and force layers of rock into folds; formed due to compression
fault-block mountains
mountains that form where two plates divide and force layers of rock to fault; formed due to tension
volcano
an opening in Earth that emits gases, ash, and magma
magma
molten rock inside the Earth’s crust
lava
molten rock that flows from a volcano (outside the earth’s crust)
hotspot
volcanically active places on Earth’s surface that are far from tectonic plate boundaries (Hawaii)
viscosity
resistance to flow
composite volcano
The most common type of volcano that has very explosive eruptions of pyroclastic material followed by calm lava follows.
cindercone volcano
Volcano that tends to be smaller and can form quickly. They have a dome on top and form from moderately explosive eruptions of pyroclastic material.
shield volcano
Volcanoes that have gently sloping sides and can be enormous. They are formed from non-explosive eruptions with gentle lava flows.
active
Volcanoes that are currently erupting or show signs of erupting in the near future.
dormant
Volcanoes that are currently not erupting, but the record of past eruptions suggests that they may erupt again.
extinct
Volcanoes that have not erupted in recorded history and probably never will erupt again.
earthquake
a sudden movement of the Earth’s crust caused by the release of stress accumulated along geologic faults or by volcanic activity.
tectonic plates boundaries
most earthquakes take place along these
focus
the point inside the Earth, along a fault, at which an earthquake begins
epicenter
the point on the earth’s surface directly above an earthquake’s starting point, or focus
seismologist
scientists who study earthquakes
seismology
the scientific study of earthquakes
seismograph
an instrument located at or near the surface of the Earth that records seismic waves
seismic wave
the waves produced by an earthquake
primary wave
the first wave to be detected during an earthquake; are longitudinal
secondary wave
the second wave to be detected during an earthquake; are transverse
surface wave
a type of seismic wave that forms when P waves and S waves reach Earth’s surface; most destructive
