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43 Cards in this Set
- Front
- Back
What is "Circle of Illumination"?
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Divides darkness/daylight on a globe
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Subsolar Point?
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Point at which the Sun's rays hit directly at 90 degrees
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Declination?
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Latitude of subsolar point
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Approximate radius of the earth?
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6400 Km
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Seasons?
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cyclical changes in temperature that occur throughout the year. Caused by changes in the amount of solar energy receive.
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Aphelion
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Farthest position from the Sun (July 4th)
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Perihelion
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Closest position to the Sun (Jan 3rd)
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Remote sensing
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info acquired at a distance without physical contact with subject (e.g. radar)
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What is the thickness of the crust?
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8-40 km
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What is the thickness of the mantle?
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2900 km
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What is the thickness of the core?
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3500 km
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Mineral?
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Naturally occurring, inorganic crystalline solid with a definite chemical composition and characteristic physical properties
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Three most abundant elements in the Earth's crust?
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Oxygen, Silicon, Aluminum
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Chemical formula for quartz?
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SiO2
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What are the three ways that minerals are formed?
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Liquids (magma, lava) goes to a cooling state to a rock
Evaporation of a briny liquid Precipitation from a fluid |
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Igneous rocks?
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rock that solidified and crystallized from a molten state (e.g., granite, basalt, obsidian, pumice)
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What's the difference between extrusive and intrusive rocks?
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Extrusive rocks cools above the surface and have smaller crystals
Intrusive rocks cool beneath the earth's surface and have larger crystals |
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Weathering?
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surface processes that physically disrupt and chemically change rocks
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Sediment?
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Igneous rock that has undergone weathering, transport and deposition. Fine grained mineral matter transported by air, water or ice.
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Sedimentary rock?
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formed through erosion, transportation, deposition, compaction, cementation and hardening of sediment.
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What are the three types of sedimentary rock and how do they form?
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Clastic—derived from weathered and fragmented rock
Chemical—dissolved minerals. Transported in solution and precipitated. Organic—remains of dead organisms |
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Metamorphic Rocks?
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rocks changed by heat and/or pressure
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What is the primary difference between metamorphic rocks and igneous rocks?
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Igneous rocks are cooled and solidified magma
Metamorphic rocks are heated and pressurized sedimentary rocks. |
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What are the two types of geologic dating?
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Relative= sequential age
based on positions of rocks relative to each other e.g., rock layer B is older than A and younger than C Numerical = number age based on radiometric age e.g., rock layer B is 50 million years old |
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Geologic contacts
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boundary between different rocks
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Deformation
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processes that fault and fold rocks
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Unconformity
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erosional contact
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Isotopes
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protons do not equal neutrons
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Half-life
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time required for half of the original parent atoms to decay to their daughter
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Decay Constant
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rate at which isotopes decay (yr ^-1)
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What assumptions are necessary for radioactive dating?
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Decay occurred at a constant rate over time
isotope system (in rock) has remained a closed system since the rock formed (I.e.--no gains or losses of isotopes) |
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What is the formula used to calculate the age of a rock?
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T = 1/k ln(D/P + 1)
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What rocks are suitable/unsuitable for isotopic dating?
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Suitable—igneous rocks, (but why?)
Unsuitable—sedimentary rocks! They contain pieces of older material, thus dating the age of source materials not when deposition occurred |
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How old are the oldest rocks?
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3.96 billion years old
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Plate Tectonics
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Process for continental drift
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What parts of the earth’s layers make up a tectonic (lthospheric) plate?
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Crust, mantle, asthenosphere and mesosphere
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What are the three major types of plate boundaries and what type of plate movement does each accommodate (i.e. plates colliding, pulling apart, etc).
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Spreading (plates pulling apart)
Convergent zones (plates colliding) Transform (plates sliding...san andreas fault) |
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How is oceanic crust made at spreading boundaries. Where is the most famous spreading zone in the world? In what two regions do spreading centers interrupt continental crust?
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Mid-Atlantic Ridge, Rift Valleys
Magma rises up from mantle, spreads and cools (occurs at spreading boundaries. |
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What generally forms above the subducting plate?
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Volcanic Arc
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What is the most famous transform boundary in North America?
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San Andreas Fault
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What are three modern pieces of evidence that support the theory of plate tectonics? Explain each in detail. Don’t forget sediment thickness.
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Paleomagnetism
same pattern on both sides of ridge alternating bands of normal and reversed polarity Radiometric dating the higher the distance from the ridge, the higher the age Sediment thickens away from mid-ocean ridge |
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Orogeny
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mountain-building episode. Can involve deformation, uplift, plate tectonics, intrusion of magma, or combo
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Limestone
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Sedimentary rock composed of calcite, commonly forms from the remains of marine organisms
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