Earth Materials, Processes, and Environments
Define pyroclastic
Pyroclastic materials are fragmental substances explosively ejected from a volcano. Example: Ash
Compare and contrast natural resources and reserves.
A resource is a naturally occurring concentration of solid, liquid, or gas in/on Earth's crust that is considered currently or potentially feasible. Minerals, rocks, natural gas and petroleum are examples. A reserve is the only part of the resource base that is known and can be economically recovered.
What is magma?
Any mass of molten rock below Earth's surface.
Compare and contrast minerals that continuously react with the magma during cooling to those that show discontinuous reactions. Give an example of a mineral group for each.
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Compare and contrast the sulfide and oxide mineral groups. Give examples of each and how these minerals commonly used.
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Define crystallization
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Define glassy
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Describe how magmas commonly differ in composition and properties.
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Describe how minerals are differentiated from other Earth materials.
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Describe the different ways in which the silica tetrahedra are linked together.
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How do nonferromagnesian and ferromagnesian silicates chemically and physically differ?
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How is this linking of silica tetrahedra reflected in physical properties?
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List an example of each ionic substitution type.
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List and describe the major areas of magma production (plate tectonic locations). Why does melting and magma formation occur at these locations?
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List and describe the processes that commonly change the composition of magma.
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List the common sources of heat that contribute to melting and earth's high internal temperatures (geothermal gradient). Which two sources are most important?
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What are the two most important controlling factors that determine crystal size when a magma solidifies?
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What is Bowen's Reaction Series?
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What is the silica tetrahedra?
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Why can't most other forms of electromagnetic energy like visible light be used to directly study and measure atomic structure?
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Why does coupled ionic substitution occur in some minerals?
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Why is Bowen's Reaction Series useful?
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Describe the differences between plutonic and volcanic igneous rocks.
1.) Plutonic Rocks/Intrusive Igneous Rocks- Result from the cooling and crystallization of magma below Earth's surface-- From magma intruded into the crust. 2.) Volcanic Rocks/Extrusive Igneous Rocks- Form when lava flows cool or when pyroclastic materials become consolidated.
Define viscosity
A fluid's resistance to flow.
What is a mineral?
A naturally occuring, inorganic, crystalline solid with a narrowly defined chemical composition and characteristic physical properties.
What is a pegmatite? Describe the magmatic conditions that allow the crystals to reach this size.
A pegmatite is an intrusive igneous rock that is composed of interlocking crystals larger than 2.5 cm in size.
Define assimilation
A process whereby magma changes composition as it reacts with country rock.
Define andesite
Andesite is an Intermediate composition rock (53%-65% silica) composed predominately of plagioclase feldspar. It is composed of fine and coarse grained igneous rocks. Andesite is medium to dark gray in appearance. It is a common extrusive igneous rock formed from lava eruped in volcanic chains at convergent plate boundaries.
List three different types of quartz and the impurity that forms each variety.
Amethyst-Purple-Iron Rose Quartz-Pink-Titanium Milky Quartz-White-Water
pluton
An intrusive igneous body that forms when magma cools and crystallizes within the crust, such as a batholith or sill.
batholith
An irregularly shaped, discordant pluton with at least 100 KM² of exposed surface area.
What is an igneous rock?
Any rock formed by cooling and crystallization of magma or lava or the consolidation of pryoclastic materials.
What is an example of a carbonate mineral?
Aragonite, Calcite, Dolomite.
Describe the four different ways in which atoms are bonded together and list the important characteristics of each bond type.
Atomic Bond Types: Ionic Bonding: Formed by the electrical attraction of oppsitely charged atoms. An ion is a charged atom that gains (anion-) or looses (cation-) electrons. Opposite charges hold them together. Properties: Low to moderate hardness, average density, high solubility, low electrical conductivity, fairly brittle behavior. Covalent Bonding: Formed by the sharing of electrons between 2 adjacent atoms. Overlapping electron shells allow for sharing of electrons and result in very strong bonds. Properties: High hardness (very strong bond), average density, insoluble, low electrical conductivity (insulators), and brittle behavior. Metallic Bonding: Formed by the sharing of electrons between a group of atoms. Electrons can move freely between these atoms. Properties: Moderate hardness, high density (due to close packing of atoms), high electrical conductivity, malleable (bendable, not brittle) van der Waals Bonding: Formed by the weak electrical attraction of uncharged groups of atoms. This results in wweak bonding between layers of atoms.
What are isotopes?
Atoms of elements with the same atomic number, (therefore the same element) but with different atomic mass (different number of neutrons).
Describe the texture, cooling history and composition of basalt.
BASALT: Texture: Cooling History: Composition:
Why are silicates so abundant?
Because Silica and Oxygen are the main components in Earth's crust.
Why do atomic structures appear solid even though the component atoms are mostly empty space?
Because of the bond of the electrons to the nucleus, because of the strong magnetic force between the positive protons and the negative electrons.
Define carat
Carat - a fifth of a gram
Define diorite
Diorite is an Intermediate composition rock (53%-65% silica) composed predominately of plagioclase feldspar. It is composed of fine and coarse grained igneous rocks. Diorite has a salt and pepper appearance because of its white to light gray plagioclase and dark ferromagnesian silicates.
How can polymorphs be used as evidence of different bond types?
Diamond and graphite are both composed of Carbon, but different bond types create different characteristics.
Why is it believed that all rocks were originally derived from igneous rocks?
Earth formed at a temperature where it was mostly molten material.
Describe why atoms are composed mostly of open space.
Electrons are so small and the distance between electrons, the nucleus, and the shells end up making up most of the atom.
What is ionic substitution?
Exchange of charged atoms. Variations in composition resulting from a systematic substitution of ions - There are several minerals which display solid solution (solids which act like solutions during crystallization and melting). The olivine group, forsterite (Mg2SiO4) - fayalite (Fe2SiO4) is a good example. Both Mg+2 and Fe+2 have the same charge (+2) and about the same ionic size so that either can fit into the olivine crystalline structure.
How are igneous rocks classified and what information can be obtained from this classification?
Felsic, Intermediate, Mafic ,Ultramafic.
Define electron shell
Fixed positions or energy levels at which the electrons are located.
Describe the texture, cooling history and composition of gabbro.
GABBRO: Texture: Cooling History: Composition:
Describe the texture, cooling history and composition of granite.
GRANITE: Texture: Cooling History: Composition:
Define element
Group of atoms with the same atomic number (number of protons) and therefore displaying the same behavior.
How is the fixed atomic arrangement reflected in the characteristics and properties of the mineral (specifically in hardness, cleavage and crystal form)?
Hardness: reflects the strength of the bond between atoms within the crystal structure. Cleavage: In some minerals, there exist planar surfaces within the structure wherein the bonds are weaker than in other directions. If a mineral is struck at one of these weak regions, it will break along smooth surfaces
Give an example of an inert or noble gas.
Helium, neon, argon.
Define phaneritic
Igneous rock texture where minerals are easily visible without magnification. Results from slow cooling of magma and generally indicates an intrusive origin.
Define aphanitic
Igneous rock texture where minerals are not easily viable without magnification. Results from rapid cooling of magma and generally indicates an extrusive origin.
Give an example of a mineral that is held together by each atomic bond type.
Ionic Bonding: Halite (salt) = NaCl Covalent Bonding: Carbon in Diamond Metallic Bonding: Copper, Gold, Silver, etc. van der Waals Bonding: Graphite
Describe how impurities can change certain properties.
It most commonly changes color.
Define karat
Karat - a measure of the proportion of gold mixed in a gold/alloy mixture
How did the study of ice and mineral crystals (crystallography) provide evidence for the existence of the atom?
Kepler proposed that atoms and atomic structure existed by studying ice crystals. He saw that there was a repeating underlying structure (hexagonal) in every ice crystal.
Name and describe the different properties used in the identification of minerals. Why are these same properties important in determining how society uses these materials?
Luster and color, crystal form, cleavage and fracture, hardness, specific gravity (density), feel, streak, chemical reaction.
Define mafic
Magma with 45%-52% silica.
Define felsic
Magma with 65% or higher silica.
Define ultramafic
Magma with less than 45% silica.
Why must a mineral have a well-defined chemical composition?
Minerals have to have fixed structure to have stability and properties.
Define silicates
Minerals that contain silica (oxygen and silicone)
Describe and give an example of polymorphs.
Minerals which have the identical chemical composition, but different internal structure. Example: Carbon polymorphs, diamond and graphite, which are both composed of pure carbon but have substantial differences in their atomic packing and bonding.
Name some of the geologic materials and processes that will be studied in this class.
Minerals, rocks, resources, volcanic mountain building, ground water, etc.
Describe why reserve estimates commonly change.
Most resources are nonrenewable, so they can't be replenished by a natural process as fast as they are used. This allows for trade with other regions that haven't yet depleted a resource we could use.
Why do isotopes display similar behavior even though they have different atomic weights?
Neutrons have no charge, so they don't affect the behavior of the atom. The protons and electrons remain constant, and the electromagnetic activity between the protons and electrons in one atom and the electrons of different atoms determines its behavior.
Do all minerals melt at the same temperature?
No.
Why are noble gases non-reactive?
Noble gasses have 8 electrons in their outermost shell, so they do not react with other electrons.
Describe the texture, cooling history and composition of obsidian.
OBSIDIAN: Texture: Cooling History: Composition:
What are valence electrons?
Outermost electrons that react to stabilize the atom through sharing, losing, and gaining electrons. (Doesn't include stable electrons, with 8 on the outermost shell)
What is the current world population (just give an approximate)?
Over 7 Billion.
Describe the texture, cooling history and composition of pumice.
PUMICE: Texture: Cooling History: Composition:
Why are pegmatites commonly mined?
Pegmatites are important because they often contain rare earth minerals and gemstones, such as aquamarine, tourmaline, topaz, fluorite, apatite and corundum, often along with tin and tungsten minerals, among others.
Define peridotite
Peridotite is an ultramafic rock (<45%), which are composed of ferromagnesian silicates. Peridotite contains olivine, pyroxene, and plagioclase feldspar. Usually green in color, and is likely that peridotite makes up Earth's crust. These originate by concentration of the early-formed ferromagnesian mineals that seperated from mafic magmas.
Compare and contrast the charge, mass, size and location of these subatomic particles.
Protons- Very dense, positively-charged, sub-atomic particles located in the nucleus. Important because they determine charge and elemental behavior. Neutrons- Very dense, neutral (uncharged) sub-atomic particles located in the nucleus. Electrons- Nearly mass-less, negatively-charged, sub-atomic particles that orbit the nucleus (on electron shells) at fixed distances of energy levels. Opposite charge from protons hold them in orbit at fixed distances (opposites attract and like charges repel which is why electrons stay so far away from each other in orbit. Neutrons and electrons are around the same size, while electrons are much smaller.
Describe the following components of the atom: proton, neutron and electron
Protons- Very dense, positively-charged, sub-atomic particles located in the nucleus. Important because they determine charge and elemental behavior. The number of protons equals the atomic number of the element. (The subscript above the element Neutrons- Very dense, neutral (uncharged) sub-atomic particles located in the nucleus. *The number of neutrons and plus protons equals the atomic mass. Electrons- Nearly mass-less, negatively-charged, sub-atomic particles that orbit the nucleus (on electron shells) at fixed distances of energy levels. Opposite charge from protons hold them in orbit at fixed distances (opposites attract and like charges repel which is why electrons stay so far away from each other in orbit.
Give examples of quartz and corundum gemstones.
Quartz: Amethyst, Citrine, Tiger's Eye Corundum: Ruby and Sapphire
Describe the texture, cooling history and composition of rhyolite.
RHYOLITE: Texture: Cooling History: Composition:
Explain why it is important to increase public awareness concerning geosciences issues, especially relative to population growth.
Regarding population growth- women should be educated and know their rights. Rapid population growth is highly due to the fact that women don't know what is available to them concerning family planning methods. If population growth keeps rising at such a speed, we will eventually deplete all of our resources and trash the planet. That is preventable if we take action, which brings me to geosciences as a whole; we are directly responsible for what happens to us and our planet in the future, and now. We need to be education so we can take action.
Describe the texture, cooling history and composition of scoria.
SCORIA: Texture: Cooling History: Composition:
List and give examples of each mineral group.
Silicates- Ferromagnesian: Olivine Nonferromagnesian: Quartz Carbonates- Calcite Sulfides- Galena Oxides- Hematite Halides- Halite Others- Kaolinite
What are the two most abundant elements in magma?
Silicon and Oxygen
Define the atom.
Smallest subdivision of matter that retains it's elemental properties. Roughly 1/1,000,000,000 of a centimeter in size.
Define Law of Constancy of Interfacial Angles
Steno determined that the angles of intersection of equivalent crystal faces on different specimens of quartz are identical. The arrangement of the internal building blocks of a mineral crystal determines its external form.
Describe three major physical causes of melting.
Temperature, pressure, and composition are the 3 major causes of melting.
Define vesicular.
Texture of an igneous rock characterized by gas bubbles solidified in the rock. Example: Pumice (light colored) and Scoria (dark colored).
Describe how the electron shell structure and outer electrons control reactivity?
The atomic number determines the number of electrons in an element. The innermost shell may only have 2 electrons, while each shell after that will have 8, until you reach the outer most shell, which will have the remaining number of electrons. These electron will react with other atoms that have electrons in their outermost shell that may be picked up or given away easily, respectively. If an atom picks up an electron, it gives it a negative charge. If an atom looses an electron, it has a positive charge. If it picks up/looses an electron leaving it with the same number of protons and electrons, it has a neutral charge.
How is atomic mass determined?
The number of neutrons plus protons equals the atomic mass.
What is the atomic number?
The number of protons equals the atomic number of the element. (The superscript above the element).
What happens to rock material at the atomic level when it melts?
The particles get excited, causing friction. This movement produces heat which causes the solid to melt.
Define crystal settling
The physical separation and concentration of minerals in the lower part of a magma chamber or pluton by crystallization and gravitational settling.
Why are isotopes important in certain geologic studies?
The presence of isotopes determines whether or not a rock will undergo radioactive decay, which is how scientists determine the age of a rock.
How is this open space (atoms are composed mostly of) defined by the subatomic particles?
The size of the particles is so minuscule and the distance between them is so great.
Why do atoms with the same atomic number display similar properties?
They have the same number of electrons in their outermost shell.
What is the major focus of this class?
To educate ourselves in matters of earth materials, processes, and environment.
How can plutonic and volcanic igneous rocks be distinguished in hand sample?
Volcanic igneous rocks are fine grained from quick cooling, whereas Plutonic igneous rocks are coarse grained from slow cooling.
Why are impurities commonly found in most minerals?
With such a high density of atoms, it's very difficult for nonstructural items to not get stuck inside the minerals.
Describe how modern X‑ray techniques are used to directly study atomic structures.
X-rays have a much smaller wavelength on the scale of the size of an atom vs. regular light waves, which allows them to be used to study atomic structure.
How is the value of a gem determined?
based on quality and size
What are the common characteristics of gemstones?
high hardness, unusual color, brilliant luster, and rare occurrence.
Define solid solution
solids which act like solutions during crystallization and melting.
Describe how and why minerals are grouped according to their anion or anion complex.
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