Download Earth`s Tectonic Plates

Geosphere Reference Chart
Earth’s Tectonic Plates
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Geologic Time Scale
(Numbers are in millions of years.)
Supereon
Eon
Era
Period
Quaternary
[2.6 – present]
Cenozoic
[65.5 – present]
Mesozoic
[251.0 – 65.5]
Phanerozoic
[542.0 –
present]
Paleozoic
[542.0 – 251.0]
Tertiary
[65.5 – 2.6]
Cretaceous
[145.5 – 65.5]
Jurassic
[199.6 – 145.5]
Triassic
[251.0 – 199.6]
Permian
[299.0 – 251.0]
Pennsylvanian
[318.1 – 299.0]
Mississippian
[359.2 – 318.1]
Devonian
[416.0 – 359.2]
Silurian
[443.7 – 416.0]
Ordovician
[488.3 – 443.7]
Cambrian
[542.0 – 488.3]
Proterozoic
Precambrian
[~4600 – 542.0]
Archean
Hadean
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Six Basic Crystal Systems
Name and Structure
Features
block- or ball-shaped crystals
include cubes, octahedrons, and
dodecahedrons
three axes of symmetry, with each axis being
at right angles to the others
same length for each axis
examples: diamond, garnet
long, thin, and sometimes needle-like crystals
include four-sided prisms and pyramids
three axes of symmetry, with one axis longer
or shorter than the other two
both similar axes lie in a plane at a 90° angle
long (or short) axis perpendicular to both the
two similar axes
examples: rutile, zircon
crystals shaped like prisms or columns; have
a rounded triangular or hexagonal cross
section
four axes of symmetry, with three being of
equal length and lying in a plane at 120° of
separation
fourth axis shorter or longer, and
perpendicular to the other three
similar to trigonal system (which includes
quartz, ruby, sapphire, and tourmaline)
examples: apatite, aquamarine, emerald
crystals usually short and stubby; have
rectangular or diamond-like cross sections
often show up as pyramids and four-sided
prisms
three axes of symmetry, with all being of
different lengths and perpendicular to one
another
examples: peridot, topaz
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crystals mostly stubby but look tilted
three unequal axes
one axis tilted with respect to the other two
that lie in the same plane at right angles to
one another
example: malachite
crystals usually flat and sharp
no right angles on crystal faces or edges
three axes of symmetry, with all being of
different lengths and none being
perpendicular to the others
examples: turquoise, rhodonite, labradorite
Mohs’ Scale of Hardness
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Mineral Identification Properties and Techniques
Color: the type of light reflected by a mineral; determined by a mineral’s
chemical composition.
Luster: the way light reflects off a mineral.
o metallic
o nonmetallic
 dull or earthy
 glassy
 brilliant or gemlike
 resinous
 greasy or oily
 pearly
 waxy
 silky
Streak: color of the powder of a mineral after it’s been scratched; not
necessarily the same color as the mineral itself.
Specific gravity: ratio of the mass of a substance to the mass of an equal
volume of water.
o density = mass/volume [g/cm3]
o heft = weight, heaviness
Hardness: measure of the durability of a mineral.
o Mohs’ scale of hardness
Fracture: how a mineral breaks.
o uneven
o conchoidal
o splintery
o earthy
o hackly
Cleavage: how a mineral splits along planes determined by its crystal
structure.
o perfect
o good
o distinct
o poor
Tenacity: a mineral’s ability to resist stress.
o brittle
o flexible
o elastic
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o sectile
o malleable
Other mineral properties:
o taste (Never taste an unknown substance!)
o feel
o smell
o magnetism
o radioactivity
o fluorescence
o reaction with acid
Common Nonsilicate Minerals
Group
Native elements
[metal or nonmetal]
Sulfides
2–
[metal + S ]
Halides
–
–
– –
[metal + F , Cl , Br , I ]
Oxides
2–
[metal + O ]
Hydroxides
1–
[metal + (OH) ]
Carbonates
2–
[metal + (CO3) ]
Sulfates
2–
[metal + (SO4) ]
Phosphates
3–
[metal + (PO4) ]
Mineral Name
Chemical Formula
Gold
Silver
Copper
Platinum
Sulfur
Carbon (graphite, diamond)
Pyrite
Cinnabar
Galena
Chalcocite
Chalcopyrite
Halite
Fluorite
Hematite
Magnetite
Rutile
Corundum [ruby (red),
sapphire (blue)]
Bauxite (one form)
Au
Ag
Cu
Pt
S
C
FeS2
HgS
PbS
Cu2S
CuFeS2
NaCl
CaF2
Fe2O3
Fe3O4
TiO2
Al2O3
Calcite
Dolomite
Malachite
Azurite
Barite
Gypsum
Apatite
Turquoise
CaCO3
CaMg(CO3)2
Cu2CO3(OH)2
Cu3(CO3)2(OH)2
BaSO4
CaSO4 · 2H2O
Ca5(PO4)3(F, Cl, OH)
CuAl6(PO4)4(OH)8 · 4–5H2O
Al(OH)3
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Common Silicate Minerals
Structure type
Framework
(Every Si-O tetrahedron
shares the O at each of its
four corners with another
tetrahedron; they fracture
unevenly.)
Sheet
(Three Os of each Si-O
tetrahedron are shared
with the adjacent units;
they peel easily into thin
layers.)
Chain
(These are linked in single
or double chains, sharing
two or three corners; they
break in splinters.)
Ring
(Ring structure is a basic
building block in which two
Os of each Si-O
tetrahedron are shared
with the neighboring
tetrahedrons.)
Double tetrahedral
(Two Si-O tetrahedrons
are linked by sharing one
O between them.)
Independent tetrahedral
(These are isolated Si-O
tetrahedrons with no direct
linkages between adjacent
tetrahedrons; they break
into irregular grains.)
Group
Mineral Name
Chemical Formula
Orthoclase
Plagioclase
(albite)
Plagioclase
(anorthite)
Quartz
Talc
KAlSi3O8
Muscovite
KAl3Si3O10(OH)2
Biotite
K(Mg, Fe)3(Al, Fe)Si3O10(OH, F)2
Pyroxenes
Augite
(Ca, Na)(Mg, Fe, Al)(Al, Si)2O6
Amphiboles
Hornblende
(Ca, Na, K)2–3(Mg, Fe , Fe , Al)5
(Si, Al)8O22(OH)2
N/A
Beryl
Be3Al2Si6O18
Tourmalines
Various
Na(Mg,Fe)3Al6(BO3)3(Si6O18)(OH,F)4
Epidotes
Various
Ca2Al2FeOSiO4Si2O7(OH)
Forsterite
Mg2SiO4
Fayalite
Fe2SiO4
N/A
Topaz
Al2SiO4(F,OH)2
Garnets
Pyrope
Mg3Al2Si3O12
N/A
Zircon
ZrSiO4
Feldspars
N/A
N/A
NaAlSi3O8
CaAl2Si2O8
SiO2
Mg3Si4O10(OH)2
Micas
2+
Olivines
3+
Common Rocks
Igneous
Metamorphic
Sedimentary
Granite
Rhyolite
Diorite
Andesite
Gabbro
Basalt
Peridotite
Slate
Schist
Gneiss
Marble
Quartzite
Amphibolite
Limestone
Dolomite/Dolostone
Evaporite
Breccia
Conglomerate
Sandstone
Siltstone
Shale
Coal
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Absolute-Age Dating
Here’s an example of how a geologist might determine the age of a rock using
the rubidium-strontium age-dating method. Rubidium-87 (Rb-87) is the parent,
and it decays into strontium-87 (the daughter).
In order to find the age (T) of a rock or mineral containing atoms of these
elements, the following must be known. D is the number of atoms of the daughter
product today, while P is the number of atoms of the parent radioisotope today.
How are these figured out? By using a mass spectrometer and a crushed-up rock
sample!
We also need to know the appropriate decay constant (λ). This is a number that
describes how long it takes a particular radioisotope to decay. It’s related to the
half-life (T1/2) of that substance. Recall that half-life is the amount of time it takes
for half of the atoms of a radioactive material to decay into something else.
These variables can be related using the following equation, T = (1/λ)ln[1 +
(D/P)], where “ln” is the natural logarithm (i.e., log with base e).
From this information a graph such as this one can be constructed:
Notice that as the amount of the parent (Rb-87) decreases, the amount of the
daughter (Sr-87) increases. That makes sense because Rb-87 decays into Sr87. The half-life of Rb-87 is about 48.8 billion years. See how the graphs cross
about half way between 0 and 100 on the x-axis?
So, to determine an age for a rock or mineral, one simply needs to read the
graph. A sample containing an equal amount of Rb-87 and SR-87 would be
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about 48.8 billion years. But that’s much older than Earth itself, so a more
realistic example would be seen to the left of where the curves meet. The graph
provides a “ballpark” number, while the equation gives a more precise number.
Rock Cycle
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Carbon Cycle
The Richter Scale
Richter magnitudes
Less than 2.0
2.0–2.9
3.0–3.9
4.0–4.9
5.0–5.9
6.0–6.9
7.0–7.9
8.0–8.9
9.0–9.9
10.0+
Earthquake effects
Not generally felt
Recorded by instruments but not felt
Felt but rarely causes damage
Shaking indoors, rattling noises, little
damage
Potential major damage to poorly
constructed buildings; little to no
damage to well-constructed buildings
Damage over a region up to 100
miles across
Serious damage over a wide area
Severe damage across several
hundred miles
Extreme destruction across several
thousand miles
Never observed
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Earth’s Interior
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