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7/29/2019 Rock Cycles Minerals
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Rock Cycles, Rocks, Minerals,
& Resources
Education 370
Joseph Lombardi
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The Rock Cycle
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The Rock Cycle
Crystallization- Molten magma cools, and
solidifies within the Earth to produce igneous
rocks. Crystallization may occur either beneath the
surface or, following a volcanic eruption, at the
surface.
If the igneous rocks are exposed at the surface,
they will undergo a process termed weathering.
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The Rock Cycle Continued
Weathering is defined as the disintegration and
decomposition of igneous rock at or near the
surface of the Earth. The materials, or sediment that result are moved
down-slope by gravity before being picked up and
transported by any of a number of erosional
agents- running water, glaciers, wind, or waves.
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The Rock Cycle Continued
Eventually these particles and dissolved
substances are deposited in the ocean, river
floodplains, desert basins, swamps, and dunes. Next, the sediments undergo lithification, a term
meaning conversion into rock.
Sediment is usually lithified into sedimentary rock
when compacted by the weight of overlying layers
or when cemented as percolating groundwater fills
the pores with mineral matter.
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The Rock Cycle Continued
If the resulting sedimentary rock is buried deep within the
Earth and involved in the dynamics of mountain building,
or intruded by a mass of magma, it will be subjected to
great pressures and/or intense heat.
The sedimentary rock will react to the changing
environment and turn into metamorphic rock.
When metamorphic rock is subjected to additional pressure
changes or to still higher temperatures, it will melt,
creating magma, which will eventually crystallize into
igneous rock.
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Summary: The Rock Cycle
Processes driven by heat from the Earths interiorare responsible for creating igneous andmetamorphic rocks.
Weathering and erosion, external processespowered by energy from the sun, produce thesediment from which sedimentary rocks form.
Although rocks may seem to be unchangingmasses, the rock cycle shows that they are not.The changes, however, take time-great amounts oftime.
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The Rock Cycle: Alternative
Pathways Igneous rocks, rather than being exposed to
weathering and erosion at the Earths surface may
remain deeply buried. Eventually these masses may be subjected to the
strong compressional forces and high temperatures
associated with mountain building.
When this occurs, the igneous rocks are
transformed directly into metamorphic rocks.
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The Rock Cycle: Alternative
Pathways Continued Metamorphic and sedimentary rocks, as
well as sediment, do not always remain
buried. Rather, overlying layers may be stripped
away, exposing the once buried rock.
When this happens the material is attackedby weathering processes and turned intonew raw materials for sedimentary rocks.
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The Rock Cycle
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Earth Materials & Processes
The materials that make up the Earth are
mainly rocks (including soil, sand, silt, and
dust).
Rocks in turn are composed of minerals,
and minerals are composed of atoms.
Processes range from those that occurrapidly to those that occur slowly.
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Earth Materials & Processes
Continued Examples of slow processes include:
formation of rocks, chemical breakdown of
rock to form soil (weathering), chemicalcementation of sand grains together to form
rocks (diagenesis), re-crystallization of rock
to form a different rock (metamorphism),construction of mountain ranges
(tectonism), erosion of mountain ranges.
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Earth Materials & Processes
Continued Examples of faster processes include: beach
erosion during a storm, construction of a
volcanic cone, landslides (avalanches), duststorms, mud flows.
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Types Of Rocks
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Types Of Rocks Continued
Igneous Sedimentary, &
Metamorphic Rocks
Igneous rock is formed by the crystallization of
molten magma. Sedimentary rock is formed from the weathered
products of free-existing rocks that have beentransported, deposited, and lithified.
Metamorphic rock is formed by the alteration ofpre-existing rock deep within the Earth (but still insolid state) by heat, pressure, and/or chemicallyactive fluids.
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Characteristics of Minerals
Minerals are defined as naturally occurring,
inorganic crystalline solids that possess a
definite chemical structure.
Minerals are the building blocks of rocks.
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Properties of Minerals
Crystal form: The external appearance of a
mineral as determined by its internal
arrangement of atoms. Luster: Luster is the appearance or quality
of light reflected from the surface of a
mineral. Color.
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Properties of Minerals
Continued Streak: The color of a mineral in its
powdered form.
Hardness: The resistance a mineral offers toscratching.
Cleavage: The tendency of a mineral to
break along planes of weak bonding.
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Mohs Scale of Mineral
Hardness
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Mineral Groups
Minerals can be classified into groups
depending upon their chemical composition.
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Relative Abundance Of The
Most Common Elements In
The Earths Crust Oxygen (O) 46.6%, Silicon (Si) 27.7%,
Aluminum (Al) 8.1%, Iron (Fe) 5.0%, Calcium
(Ca) 3.6%, Sodium (Na) 2.8%, Potassium (K)2.6%, Magnesium (Mg) 2.1%, All others 1.7%.
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Mineral Groups Continued The largest group of rock forming minerals is the
silicate group.
All silicate minerals contain silicon and oxygen.
Some examples of silicate minerals are olivine,augite hornblende, garnet, biotite, albite, andquartz.
Silicates are the most common minerals because
most of the Earths crust is made of silicon andoxygen.
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Mineral Groups Continued
Non-silicate minerals are those that do not
contain silicon and oxygen.
There are five groups of non-silicates:oxides, sulfides, halides, carbonates and
sulfates.
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Mineral Groups Continued
Oxides Oxides are minerals that form when an
element combines with oxygen.
Some examples of oxides are corundum,hematite, and magnetite.
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Mineral Groups Continued
Sulfides Sulfides are minerals that form from
compounds that contain sulfur.
Some examples of sulfides are galena andpyrite.
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Mineral Groups Continued
Halides Halides are minerals that form when certainelements combine with the Halogen Group
from the periodic table.
The halogen group includes chlorine,
bromine, fluorine, and iodine.
Some examples of halides are halite and
fluorite.
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Mineral Groups Continued
Carbonates Carbonates are minerals that contain a
carbon atom surrounded by three oxygen
atoms (carbonate ion). Some minerals that contain this ion are
azurite, aragonite, and malachite.
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Mineral Groups Continued
Sulfates Sulfates are minerals that contain a sulfur
atom surrounded by four oxygen atoms
(sulfate ion). Some minerals that contain this ion are
gypsum, celestite, and barite.
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Mineral Resources
Mineral resources are the Earths storehouse of
useful minerals that can be recovered for use.
Resources include already identified deposits fromwhich minerals can be extracted profitably, called
reserves, as well as well known deposits that are
not yet recoverable under present economic
conditions or technology.
Deposits inferred to exist, but not yet discovered,
are also considered as mineral resources.
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Mineral Resources Continued
There three principal categories for mineral uses
are: rock forming, economic, gems and
ornamentals. Rock forming refers to the primary function or use
of some minerals.
Many minerals have commercial or economic use.
Some minerals are considered ore minerals (e.g.
hematiteiron ore), while others are common
commercial products (e.g. calcitecement).
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Mineral Resources Continued
Common gemstones used in jewelry are
actually minerals. Examples are diamonds,
garnet, and amethyst. Large mineral specimens can also be used
for decorative or ornamental purposes.
Examples are pyrite (fools gold), or geodeslined with quartz or amethyst crystals.
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Mineral Resources Continued
Recall that more than 98% of the Earths
crust is composed of only eight elements.
Except for oxygen and silicon, all otherelements make up a relatively small fraction
of common crustal rocks. Indeed, the
natural concentrations of many elements areexceedingly small.
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Mineral Resources Continued
A deposit containing only the average
crustal percentage of a valuable element
like gold is worthless if the cost ofextracting it greatly exceeds the value of the
material recovered.
To be considered of value, an element mustbe concentrated above the level of its
average crustal abundance.
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Mineral Resources Continued
Examples of minerals and their economic
use: Hematite (oxides) ore of iron, Galena
(sulfides) ore of lead, Gypsum (sulfates)plaster, Gold (native elements) trade and
jewelry, Fluorite (halides) used in steel
making, and Calcite (carbonates) Portlandcement and lime.
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Works Cited
1.) The Mineral Gallery
http://minerals.galleries.com/default.html
2.) Minerals
http://www.tulane.edu/~sanelson/geol111/m
inerals.html
3.) Rock Cycle Images
http://rst.gsfc.nasa.gov/Sect2/Sect2_1a.html
http://minerals.galleries.com/default.htmlhttp://www.tulane.edu/~sanelson/geol111/minerals.htmlhttp://www.tulane.edu/~sanelson/geol111/minerals.htmlhttp://rst.gsfc.nasa.gov/Sect2/Sect2_1a.htmlhttp://rst.gsfc.nasa.gov/Sect2/Sect2_1a.htmlhttp://www.tulane.edu/~sanelson/geol111/minerals.htmlhttp://www.tulane.edu/~sanelson/geol111/minerals.htmlhttp://minerals.galleries.com/default.html7/29/2019 Rock Cycles Minerals
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Works Cited Continued
4.) Tarbuck, Edward J., Lutgens, Frederick
K. Earth Science 8th Ed. 1997 New Jersey:
Prentice Hall Inc. 5.) Image- silicon-oxygen tetrahedron
http://www.msdwc.k12.in.us/msdclass/WE
NJ
http://www.msdwc.k12.in.us/msdclass/WENJhttp://www.msdwc.k12.in.us/msdclass/WENJhttp://www.msdwc.k12.in.us/msdclass/WENJhttp://www.msdwc.k12.in.us/msdclass/WENJRecommended