Transcript Unit 2: Study Guide

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A mineral is a naturally occurring usually
inorganic solid that has a definite crystalline
structure and chemical composition.
Minerals are formed:
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As magma and lava cool
By metamorphism
From solutions
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Elements are pure substances that cannot be
broken down into simpler substances by
ordinary chemical means
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A substance made up of atoms or ions of two
or more different elements joined by chemical
bonds.
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Silicate minerals contain silicon and oxygen,
normally in the form of silicate tetrahedrons.
Nonsilicate minerals do not.
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Color- color of the mineral
Streak- color of the powdered form of the mineral.
(Remember: that if a scientist draws on a white tile
with the mineral, this is how the streak is found.)
Luster- way a surface reflects light
Cleavage and Fracture- The way the mineral
breaks/splits
Density- measure of how much matter in a given
amount of space.
Hardness- mineral’s resistance to being scratched.
Special Properties- any property specific to the mineral
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Igneous rock forms when magma or lava cools
and hardens
Sedimentary rock forms from compressed or
cemented layers of sediment.
Metamorphic rock forms from other rocks as a
result of intense heat, pressure, or chemical
processes.
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Weathering is the natural process by which
atmospheric and environmental agents, such as
wind, rain, and temperature changes,
disintegrate and decompose rocks.
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Erosion is the process by which wind, water,
ice, or gravity moves soil and sediment from
one location to another.
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Deposition is the process in which material is
laid down.
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The rock cycle is the series of processes in
which rock forms, changes from one type to
another, is destroyed, and forms again by
geologic processes.
Look in your book on page 78 for a diagram of
the rock cycle.
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Uplift is the rising of regions of Earth’s crust to
higher elevations.
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Subsidence is the sinking of regions of the
Earth’s crust to lower elevations.
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A rift zone is an area of deep cracks that forms
between two tectonic plates that are pulling
away from each other.
Crust
Mantle
Core
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Convection is the movement of matter due to
differences in density that are caused by
temperature variations; can result in a transfer
of energy as heat.
Convection takes place in the Earth’s mantle.
Convection helps rocks move slowing in the
mantle. (Cooler rocks sink and warmer rocks
rise)
Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
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Scientists think that about 245 million years ago
the continents were joined in a single large
landmass that they call Pangaea.
It’s important to understand that at one time
scientists think that all the continents were
connected and during millions of years the
continents moved into their current locations.
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Sea-floor spreading is the process by which
new oceanic lithosphere sea floor forms when
magma rises to Earth’s surface at mid-ocean
ridges and solidifies, as older existing sea floor
moves away from the ridge.
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Older rock- far from ridge
Newer rock- formed near ridge
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This theory explains how large pieces of the
lithosphere, called plates, move and change
shape.
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A tectonic plate is a block of lithosphere that
consists of the crust and the rigid, outermost
part of the mantle.
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Convergent- Two plates collide.
Divergent- Two plates move away from each
other
Transform- Two plates move past each other
horizontally
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Mantle Convection
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Ridge Push
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Slab Pull
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Anticlines- oldest layers of rock are in the
middle of the fold. The youngest rocks are
towards the outside.
Anticlines are shaped like a:
n
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In syncline folds the youngest rocks are in the
middle and the older rocks are on the outside
edges.
Synclines are shaped like a:
u
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Strike-Slip Faults
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Normal Faults
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Formed when rocks are under shear stress and at
transform boundaries
Formed when rocks undergo tension and at
divergent boundaries
Reverse Faults
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Formed when rocks undergo compression and at
convergent boundaries
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Be able to label a diagram of each fault, with
where the hanging wall, footwall and fault
plane are! (Look on page 109)
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Folded Mountains- Form when rock layers are
squeezed together and pushed upward.
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Usually at convergent boundaries
Volcanic Mountains- Form when melted rock
erupts onto Earth’s surface
Fault-Block Mountains- Form when tension
makes the lithosphere break into many normal
faults. Along the faults, pieces of the
lithosphere drop down compared with other
pieces. The pieces left standing form fault-block
mountains.
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Earthquakes are ground movements that occur
when blocks of rock in Earth move suddenly
and release energy.
Label #6 page 116 in your book.
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Know that the Focus is the point underneath the
Earth
The Fault Line is the line between both of the plates
The Epicenter is on the Earth’s surface.
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Label #5 on page 126 in your book.
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Know this!
Know magma is underneath the Earth & lava is
when it has reached the Earth’s surface
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Shield Volcanoes- Broad base, gently sloping
sides, and form from mild eruptions.
Cinder Cones- Steep volcano formed from
violent eruptions
Composite Volcanoes- Alternates between mild
and violent eruptions.
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Divergent boundaries
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Convergent boundaries
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Hot Spots