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GEO101 Exam I
Terms in this set (41)
About how old is the universe?
13.7 Ga (billion years)
About how old is the solar system?
4.56 Ga (billion years)
What is the Big Bang Theory? What evidence is used to support the big bang? When was it?
-states that all matter and energy in the Universe was once packed into a single point
-because we live in an expanding universe, that means that at one point everything was all together; there are no stars older than 13.8 billion years;
-happened 13.8 billion years ago
How do we form elements?
-they are formed in stars
-Fusion- Stellar Nucleosynthesis (stars)- take elements and squeeze them together
Stars can make elements up to Iron (Fe) then they have to be made in a supernova (end of suns life and dead stars)
What determines if a planet is a planet?
-it must orbit a star
-be roughly spherical in shape
-and clear it's neighborhood of other objects
Why isn't Pluto a planet?
it breaks rule number 3 (has another object that passes through it's orbit
What are the different types of planets?
-Terrestrial: Mercury, Venus, Earth, Mars
-have a shell of rock around metallic iron alloy core
-Jovian (gas/ice planet): Jupiter, Saturn, Uranus, Neptune
-the front line where gasses begin to freeze
-mostly gas or ice
How was our moon formed?
through the understanding of the giant impact theory, scientists believe that a smaller planet collided with earth the made a disk the began to orbit Earth
Where did the early atmosphere come from?
from gas from volcanoes as the Earth began to cool
What are the main interacting spheres of the earth?
atmosphere, hydrosphere, geosphere, biosphere, (cryosphere?)
What are the energy forces that drives the interactions between the spheres of the earth?
-where the surface of the geosphere is in contact with water, air, or life is where majority of these interactions take place
-humans (biosphere) built a dam out of rock
-water (hydrosphere) seeps into the rocks cliffs (geosphere) or evaporates (atmosphere)
-Humans (biosphere) harness energy from the water (hydrosphere) by having it spin turbines (geosphere) to produce electricity
What are the major gases in the atmosphere today?
78% Nitrogen, 21% Oxygen
Know the main parts of the Earth (inner and outer core, mantle, crust) and their main compositions.
-crust- outer shell
-made mostly out of silicon, oxygen, plus some aluminum
-mantle- 3,000 kilometers thick, largest part of earth by volume, mostly one rock type (silicate rocks rich in magnesium and iron)
-soft solid rock near the surface flows very slowly (like a plastic)
-small percentage is liquid
-core- innermost section
-outer core- liquid iron alloy due to high temperature (generates the magnetic field)
-inner core- solid iron- nickel alloy die to high pressure despite even higher temperature
-generates earths magnetic field
What is the difference between crust and lithosphere?
the crust is just the outer shell while the lithosphere contains the outer shell plus the mantle
-the lithosphere behaves rigidly and has varied thickness
What is the asthenosphere?
portion of mantle that can flow (rock behaves plastic but not liquid)
What are the main differences between continental and oceanic crust (composition, age, thickness)
-continental crust- relatively thick, felsic, relatively low density
-oceanic crust- relatively thing, mafic, relatively high density
-continental crust is older because it does not subduct and get reused like oceanic crust does
What evidence supports plate tectonics?
-location of North pole has changed over time
-Wegener developed the theory of plate tectonics (continental drift) that states that the plates are always moving
-the fit of the continents
-the distribution of fossils
-matching geologic rock units
-the magnetic axis is not parallel to the axis of rotation- the field is generated by flow in the outer core
What is paleomagnetism?
-it is the study of the record of the Earth's magnetic field in rocks, sediment, or archaeological material
Evidence for seafloor spreading?
-Wegener's hypothesis of continental drift
-there are eruptions of molten material
-magnetic stripes in the rock of the ocean floor
-the ages of the rock themselves
What are the main types of plate boundaries?
-divergent: two plates that are slowly moving away from each other
-convergent: plates that move toward each other
-transform: plates move alongside each other
(more notes in notebook)
What are the rock types/compositional differences associated with continental and oceanic crust and how does this effect their interaction at plate boundaries?
-the continental crust contains more granite
-oceanic crust contains more basalt
-oceanic crust is more dense than continental crust which causes oceanic crust to subduct under the continental crust and melt back/recycle into the Earth
Divergent margins: Where is the main place a divergent boundary exists?
they are typically found in mid-ocean ridges (Atlantic)
-produces basalt and gabbro
-earthquakes and small volcanic eruptions (can't typically feel)
-produces new (young) oceanic crust
Convergent margins: Which type of convergent boundaries are associated with volcanoes?
-the more dense plates sink under the less dense plates
-earthquakes (typically bad because people live near these)
-large volcanic eruptions (oceanic-oceanic)
Why is there little to no volcanism at continent-continent convergence?
-continental lithosphere is low in density and very thick so continental lithosphere cannot subduct
-when two plates of continental crust collide, the material pushes upward (mountains)
Where in the world today do we have massive continent-continent convergence?
Transform margins: Where is the largest transform fault/boundary in the world located?
San Andres fault in California
-they tend to have violent and shallow earthquakes
What's a hotspot? Where does one occur today?
-comes from the outer core
-a location at the base of the lithosphere, at the top of the mantle plume, where temperatures can cause melting
-very consistent movement of heat flow from deep down towards the surface (blow torch)
What natural hazards (earthquakes, volcanoes) are associated with each type of boundary?
-divergent: earthquakes, small volcanic eruptions that you can't normally feel
-convergent: earthquakes and large volcanic eruptions
-transform: no volcanoes but has violent earthquakes
Be able to describe the different parts of an atom and how different elements are different from each other.
-protons (positive charge) and neutrons (neutral charge) are located in the center of the atom
-electrons (negative charge) are in orbit of the nucleus
What is an ion? Types of bonding?
-a charged atom/molecule
-the charge of the electron is equal to the charge of the proton
-covalent bond: nonmetal-nonmetal (share electrons)
-metallic bond: metal-metal
-Ionic bond: metal-nonmetal (trade electrons) (stronger bond)
What's a polymorph?
minerals with the same composition but different structure
-ex) diamond and graphite are both made up of carbon but a diamond has very strong bonds and a hard material (dependent on how the atoms are arranged) while graphite has a very weak bond and is a soft material
What defines a mineral?
atoms have to be ordered
What are the different ways minerals form?
-igneous material crystalize/cool from molten rock
-metamorphic minerals are recrystallized from other minerals without melting
-sedimentary minerals precipitate from water
How do trace elements affect a mineral?***
your body needs larger amounts of macro minerals
What are the different diagnostic characteristics used to identify minerals? (color, hardness, cleavage,magnetism)
-color (least useful)
-hardness (mohs hardness scale)
-cleavage (which way will the mineral naturally break)
-density and specific gravity (a ration of weight/volume)
-magnetism and streak (doesn't always work)
Felsic or mafic for the following silicate minerals: Quartz, orthoclase and plagioclase, muscovite, olivine, pyroxene, amphibole (hornblende), biotite.
What the difference between magma and lava?
magma is molten rock that is below the ground while lava is molten rock once it has reached the surface
What is intrusive?
-forms on the inside of the Earth (under the earth's surface)
-takes a very long time to cool forming large crystals
-loses heat slowly
What is extrusive?
-when magma cools quickly above earth's surface
-forms small crystals (Basalt and rhyolite)
-cools rapidly/ chills fast (so it's hard to grow big crystals)
How do dikes differ from sills?
dikes cut across preexisting layering (do not fit nicely) while sills are injected parallels to rock layering (inject parallel to layers under the earth's surface, they're very symmetrical)
What causes melting of rock to make magma/lava?
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