Geology Exam #1
What is each layer of the earth composed of?
-central core is nickel and iron -mantle is ultramafic and mafic rocks/magma -Crust is granite -ocean is basalt
what are the five different lines of evidence Wegener provided to show that continents moved?
-coastlines (they can fit together like South America and Africa) -glacial activity (striations ran from the sea toward the continents: the opposite way in which modern glaciers move. Wegener plotted the orientation of the striations and realized that the pattern would only make sense if the continents were joined together) -fossil evidence (plants - could only happen if islands were once together) -fossil evidence (animals) -rock assemblages (same rock formations on different continents)
properties of minerals - 7 components
-color -streak -hardness -cleavage/fracture -luster -specific gravity -special properties
mineral - 5 components
-naturally occurring -inorganic -solid -definable chemical composition -crystalline structure -formed by geologic processes
Be familiar with the rock cycle and how the three rock types -- igneous, sedimentary, and metamorphic -- are linked
-rock can be eroded bit by bit, forming a sediment that would form a sedimentary rock -further metamorphism transforms it into a gneiss -high temperatures cause it to melt into a magma, turning it back into an igneous rock
how fast do plates moves?
1 cm a year
What are the three differentiated layers of the Earth
1. Central core 2. Mantle 3. Crust - outer most layer
what are the conditions under which metamorphism occurs?
1. burial under kilometers of rock: weight can put pressure on the rock below -deep in the crust, rocks are subjected to enough heat and pressure to show the deformation and recrystallization characteristic of metamorphism -also result from stresses and heating to which rocks are subject during mountain-building or plate-tectonic movement
What are some of the major hazards related to earthquakes?
Aftershocks (earthquakes that follow) and tsunamis, landslides, fire; Buildings built on bedrock tend to suffer less damage than those built on soil, clay, and ash
what is coal?
An organic sedimentary rock, formed from carbon-rich remains of plants
what is a limestone's chemical formula?
CaCO3
Is carrying capacity a fixed number? Why or why not?
Carrying capacity is not a fixed number because as a human population grows and gets smarter, the carrying capacity increases as well
how does a limestone's formation differ from that of coal?
Coal is formed from dead plants that buried deep inside earth and face temperature and pressure conditions. Limestone organic and sedimentary are formed either by precipitation process as in case of chemical limestone or organic limestone which is formed in shallow warm clear ocean waters from dead organisms.
What is doubling time (size)?
Doubling time is the length of time required for a population to grow
what is the difference between magma and lava?
Magma is molten rock located below the surface - creates plutonic igneous rocks; lava is molten rock erupted above ground - creates volcanic igneous rocks
with regard to their speed, which seismic waves listed below travel fastest? slowest? what are the differences between their modes of travel (body waves vs surface waves) and what limitations are there on the types of material they can pass (solid/liquid?) KNOW THE SEISMOGRAPH RECORDING
P waves: seismic - compressional body waves. These are the fastest waves and can pass through both solid and liquid media. As they pass through the Earth, the material is alternately compressed and expanded. S waves: seismic - shear body waves. These slower-moving waves arrive after P waves and cannot pass through liquids. As S waves travel through the Earth, the material is moved side-to-side. L waves: Surface waves that cause the ground to ripple side-to-side like a snake. Also known as 'Love Waves'. R waves: surface waves that cause the ground to ripple up and down. Also known as 'Raleigh Waves'
what is the difference between an aphanitic and phaneritic texture?
Phaneritic is coarse grained, majority of the crystals are uniformed and can be seen with the naked eye, slow cooling. they are intrusive EX: granite, gabber aphanitic is fine grained, the crystals are tiny and require a microscope; fast cooling. extrusive; EX: rhyolite, andesite, basalt
What is a logistic growth curve and how does it differ from an exponential growth?
The logistic growth model has an upper limit - the carrying capacity. Exponential growth happens when the rate of growth is in proportion to the existing amounts. Though this is true for logistic growth, exponential growth includes competition and resources which are limited.
ionic bonds - definition and example
a bond based on the electrical attraction between oppositely charged ions. ionic bond occurs when a cation (positively charged ion) binds to an anion (negatively charged ion); EX: NaCl (Sodium Chloride)
what is the definition of a metamorphic rock?
a metamorphic rock is one that forms when a pre-existing rock, called protolith, undergoes a solid-state (doesn't melt) in response to being buried and subjected to high temperatures, pressures, and reacts with hydrothermal fluids
What is the difference between a null hypothesis and an alternate hypothesis?
a null hypothesis is a general statement, whereas an alternative hypothesis is a second hypothesis
what is a rock?
a rock is a naturally occurring solid that is made up of one or more minerals or mineral materials
what is a porphyry?
a rock that begins as a plutonic igneous rock but is erupted out of the volcano before completely cooling, and finishes its cooling quickly as a volcanic rock; begins intrusive and finishes extrusive
What is the difference between a hypothesis and a theory?
a theory has undergone many tests to be proven correct, whereas a hypothesis is a proposed explanation made on the basis of limited evidence as a starting point for further investigation
what are the geographic features of the ocean floor
abyssal plain: underwater plain on deep ocean floor; found at 3,000 meters and covers 50% earth's surface mid-ocean ridge: underwater mountain range formed by plate tectonics deep-ocean trench: steep depressions in the deepest parts of the ocean (where old oceanic crust from one tectonic plate are pushed beneath another plate)
who was alfred wegener and what was continental drift?
alfred lothar wegener was a german polar researcher, geophysicist, and meteorologist. continental drift is the gradual movement of the continents across the earth's surface through geological time
where are earthquakes more likely to occur: in the lithosphere or the asthenosphere?
asthenosphere because it is weak and easily deformed
covalent bonds - definition and example
atoms that share a pair of electrons; EX: H20
why is the age of the seafloor no older than 200 million years old, whereas continental crust has been discovered that is over 4 billion years in age?
because the sea floor continues to spread out causing continents to shift and new seafloor to be formed
How are earthquakes and their associated ground movements recorded? how is the epicenter of an earthquake determined?
by seismometers. the P wave arrives before S waves; the difference of these arrival times is the distance to the earthquakes epicenter. The longer the route to be traveled between the two points, the farther the seismograph is from the epicenter.
what did Wegener name his supercontinent? about how long ago did it break up? what were the major continents that comprised it and how does that compare with the current continental arrangement of the present day?
called Pangaea, broke 175 million years ago; Africa, Europe, Asia, North America, South America, Australia (oceania), Antartica
What is carrying capacity?
carrying capacity is the number of people, other living organisms, or crops that a region can support without environmental degradation
ions: cations and anions: what's the difference
cations are positively charged ions anions are negatively charged ions
what are the two general categories of sedimentary rock?
clastic and chemical sedimentary rock
within each category of sedimentary rocks, how are the rocks organized / classified?
clastic: formed by breakup of other rocks; named; tend to have pore space between grains; EX: breccia, conglomerate, sandstone chemical: crystals formed by precipitation or growth from solution. EX: limestone
what is the difference between fracture and cleavage?
cleavage is the pattern that minerals break into. when a mineral has no cleavage, they break into irregular surfaces called fractures
how do these terms apply to sedimentary rock formation: compaction, cementation, lithification?
compaction: compress sediment grains together cementation: dissolved minerals crystallize and glue sediment grains together lithification: the process in which sediments are transformed into sedimentary rocks
what is the difference between regional and contact metamorphism?
contact metamorphism is a type of metamorphism where rock minerals and textures are changed, mainly by heat, due to contact with magma. regional metamorphism is when rock minerals and textures are changed by heat and pressure over a wide area or region
what are carbonate rocks? provide an example
contain 1 atom of carbon bound to 3 atoms of oxygen (CO3). EX: calcite, CaCO3 - calcium carbonate that forms limestone.
what are common examples of ferromagnesian minerals?
contains iron and magnesium; EX: olivine
what are convection cells and how do they play a role in plate tectonics? what is the difference between slab-pull and ridge-push?
convection cell is when hot mantle material rises up at spreading centers (MORs), then spreads outward, pulling along the overlying lithosphere with it. once the mantle material cools, it sinks at subduction zones, pulling the lithosphere with it. the mantle material then rises and creates circular convection cell. -warm fluids rise, cold fluids sink -slab-pull mode: the weight of the dense, down-going slab of lithosphere in the subduction zone pulls the rest of the trailing plate along with it, opening up the spreading ridges so magma can ooze upward -ridge push: lithosphere slide off the topographic highs formed at spreading ridges and rift zones by rising warm asthenospheric mantle -believe that combination of these two are responsible for plate motion
what is a dip-slip fault? what is a hanging wall? what is a foot wall?
dip-slip fault: SEE GOOGLE DOC; displacement is vertical/up/down in direction of dip. -the part that lies above the fault surface is the hanging wall the triangular block below the fault surface is the foot wall
what is divergent plate boundary, what does it form, and what happens at this boundary? where is such a boundary found?
divergent boundaries, called spreading centers, two lithospheric plates move apart. Mafic magma rises up from the mantle to fill in the space, often erupting out through volcanoes that form in divergent boundaries; earthquakes can also be formed. as the magma cools, it forms new crust (the new crust can be either oceanic or continental, depending on where the spreading center has formed)
What does an exponential growth curve look like?
exponential growth curve has Time on the x-axis and population on the y-axis
Inn reference to population growth, what is exponential growth?
exponential growth is when the population growth rate is constant, the number of individuals added per unit of time increases over time
what are feldspars?
feldspars are composed of silicon and aluminum, etc.; they are the most abundant silicate minerals in earth's crust
what is the difference between the focus and the epicenter of an earthquake?
focus: point on a fault at which the first movement or break occurs during an earthquake, also called hypocenter epicenter: the point on earth's surface directly above the focus; this is where news accounts tell where an earthquake occurred
what is the difference between a foliated and non-foliated metamorphic rock?
foliated metamorphic rocks have a layered or banded appearance that is produced by exposure to heat and directed pressure. non-foliated metamorphic rocks do not have a layered or banded appearance
what is foliation and how does it occur?
foliation refers to a parallel layering in a metamorphic rock and occurs when rocks have been subjected to some sort of stress
how do sedimentary rocks form?
form from sediment or from the breakdown of pre-existing igneous or metamorphic rocks
what is the difference between geographic north and magnetic north? what specific layer within the earth generates the Earth's magnetic field? what is magnetic declination?
geographic north are determined by earth's spin, whereas magnetic north is determined by the direction the compass points -the outer core generates the magnetic field due to the currents of molten iron -magnetic declination is the angle between the magnetic north and true north. true north is location in contrast to the north pole
what is the difference between a basalt and a granite?
granite is an example of a plutonic igneous rock: it contains viewable crystals of silicate minerals like quartz/feldspar/ferromagnesian minerals like mica and amphibole. basalt is a rock that makes up the ocean floor - volcanic igneous rock
what is the difference between a granite and a rhyolite?
granite is intrusive. Rhyolite is an extrusive igneous rock and has much finer crystals, plus it also cooled much more rapidly than granite giving it a glassy appearance.
If the entirety of Earth's history were laid out in a 24-hour day, when does our species, Homo sapiens, arrive?
homo sapiens arrived 10 seconds ago
what are the three general categories of rocks?
igneous, sedimentary, metamorphic
what is a peridotite and where are they found?
intrusive phaneritic, coarse-grained, dark-colored, ultramafic igneous rocks so has low viscosity and high magma temperature. more representative of Earth's mantle than of the crust
What are the four most common elements in the Earth?
iron oxygen silicon magnesium
was wagerer's idea of continental drift accepted by the geologic community? why or why not?
it was not accepted because most people could fathom the idea of land masses shifting over time
what are phenocrysts?
larger crystal in a porphyritic rock
what do phenocrysts imply about how the rock cooled?
larger grains generally indicate longer cooling rates, the phenocrysts indicate that the magma experienced an initial phase of slow cooling deep underground
What are carbonate rocks typically found / formed?
limestone forms by precipitating out of seawater and is the major component of coral reefs
what is limestone?
limestone is a rock composed of the mineral calcium carbonate (CaCO3)
what is the lithosphere? is it the same thing as continental crust? what is between oceanic and continental lithosphere?
lithosphere is the outer solid layer of Earth, it is the uppermost mantle of the continental crust. it means "rock" it is 100-150 km thick; this layer is rigid and does not flow - it is brittle and its materials bend or break. thickness varies: -thinnest underneath the ocean where it extends 50 km; under the continents extends 250 km and it is thicker on average than oceanic lithosphere
what is a transform plate boundary, what type of plate motion is involved, and what type of geological features result from them? where can examples of these be found?
locations where two plates slide past one another. most plate boundaries consist of short segments that slightly offset from one another from a break in the lithosphere known as a transform fault. As the plates scrape past each other, earthquakes occur along the transform faults. This may also occur in a subduction zone and spreading ridge/ mid-ocean ridge -Example is San Andreas fault in California - pacific rise disappears under the edge of the continent in the gulf of California - earthquake activity
what is the mineral that makes rocks magnetic?
magnetite makes rocks magnetic
What is the difference between magnitude, amplitude, and intensity, in reference to earthquakes? What is the difference between an earthquake of magnitude 4 vs one of, say, magnitude 3 with regard to ground movement? ...with regard to energy released? (pp. 68-71)
magnitude: quantitative objective scale; each increase represents 10-fold increase in ground motion and 30 in energy amplitude: amount of back-and-forth or up-and-down motion of the ground intensity: qualitative subjective scale; based on effects on humans and surface area -energy released rises faster with increased magnitude. An earthquake of magnitude 4 releases 30x more energy than one of 3, 900x as one of 2.
what are native elements? provide an example
minerals that consist of single chemical element; EX: gold, silver, platinum. Diamond and graphite are examples of native carbon
what are silicates?
minerals that contain silicon and oxygen; the two most common elements in earth's crust are oxygen and silicon
what is the difference between the following fault types - normal fault, reverse fault, thrust fault, strike-slip fault (right/left/lateral), oblique fault KNOW WHAT THEY LOOK LIKE
normal fault: a dip-slip fault in which the block above the fault has moved down relative to the block below; continental rifting or mid-ocean rift reverse fault: dip-slip fault in which the block above has moved up relative to the block below; happens when tectonic plates collide -thrust fault: reverse fault where the fault angle slope is 30 degrees or less; also called low-angle reverse fault -strike-slip fault: plates slide past one another along the fault horizontally; no up/down motion or deformation; two types: right/lateral is the block across the fault slipped to your right ; left/lateral: if block slips to the left -oblique: a combination of #1 occurs on diagonal plane
in what kind of tectonic setting do the faults occur?
normal faults: shallow earthquakes reverse faults: deep earthquakes thrust faults: deep earthquakes strike-slip faults: shallow earthquakes
atomic mass number
number of protons and neutrons in an atom's nucleus
What is the difference in composition between the outer core and inner core?
outer core is liquid while the inner core is solid
What are the four most common elements in Earth's crust?
oxygen silicon aluminum iron
what is the concept behind paleomagnetism? what is a magnetic reversal? what is the curie temperature?
paleomagnetism is the study of the record of the earth's magnetic field in rocks. certain minerals in rocks lock-in a record of the direction and intensity of the magnetic field when they form. -Magnetic reversal is when North/south pole switch. -curie temperature is the temp in which certain materials lose their permanent magnetic properties, to be replaced by induced magnetism
what is the difference between physical and chemical weathering?
physical weathering is caused by natural elements while chemical weathering is not
what is a fault? what is an earthquake?
planar breaks in rock along which there is displacement of one side relative to the other. an earthquake is a release of built-up stress in the lithosphere
what is the difference between a plutonic and volcanic igneous rock with regard to (1) their origin, (2) the size of their mineral grains, (3) the rate at which they cooled from a liquid?
plutonic igneous rocks form underground in belly of volcano (magma chamber) or are intruded underground between other rocks. they are intrusive because they form underground and take thousands of years to cool down; cooling process is slow and crystals form large enough to be seen by naked eye/ coarse-grained. Volcanic igneous rocks are created at/above earth's surface; extruded from volcano in form of lava. extrusive and cool quickly, fine-grained and cannot be see by naked eye
nucleus: protons, neutrons, and electrons - their charges
protons - positive charge neutrons - no charge electrons - negative charge
How is the magnitude of an earthquake determined and what is the difference between the Richter scale and the Mercalli intensity scale?
ritcher magnitude scale is logarithmic and the Mercalli intensity scale looks at the earthquakes effects on people/surface area
what is the difference between a conglomerate, breccia, sandstone, and shale?
sandstone: rock composed of sand-sized sediment particles shale: finer-grained sediments, individual grains cannot be seen with the naked eye conglomerate: coarse-grained rock breccia: coarse-grained sedimentary rocks with angular grains.
what is the seafloor spreading hypothesis? who proposed the idea? how does the discovery of magnetic ocean floor tie in with support for plate tectonics?
seafloor spreading hypothesis proposed that new seafloor (new oceanic crust) was created at the mid-ocean ridges which then pushed the older crust away from the mid-ocean ridge on either side. it was proposed by Harry Hess and refined by F.J. Vine -magnetic ocean floor proves plate tectonics
which is the pathway by which shale, for example, metamorphoses into a metamorphic rock such as a slate?
shale has developed foliation under stress. the resulting slate rock breaks along the foliation and forms into shale
what is the general chemical formula of a silicate mineral?
silicate minerals are made from oxygen and silicon
What is liquefaction and what hazard does it play when designing buildings to withstand earthquakes? (pp. 76-77)
soil/clay/ash liquefy when impacted by earthquake vibrations, they can cause beds of wet sand or silt to lose their cohesion (the soil particles separate from one another) and become a slurry, like quicksand, unable to support whatever it on top of it (e.g., a building). The soil undergoes liquefaction a result of the intense shaking, and the buildings tip over.
what is strain? what is the difference between elastic, plastic, and brittle deformation?
strain is when the rock is deformed due to stress -elastic strain is when they can change their shape without breaking -plastic deformation is when the object can be deformed through strain but doesn't return to its original shape -brittle deformation break without taking on any change in shape
what is stress? what are the three main types?
stress is defined as a force acting on an object per unit area (the amount of force acting on a specific area of an object) -compressive stress: when a rock is squeezed -tensile stress: when a rock is stretched or pulled apart, tension is produced. happens at mid-ocean ridges -shear stress: one part of a rock moves sideways past another across a plane, similar to how a deck of cards slides past another when shuffled. happens at transform faults
what are sheet silicates?
tetrahedra link to form two-dimensional sheets. each tetrahedron shares 3 oxygen atoms with its neighbors. other ions fit between the sheets. EX: minerals like micas and clays
what is the asthenosphere? how does it differ from the lithosphere?
the asthenosphere is right under the lithosphere, it translates to "without strength." it is 300 km of the mantle and lacks strength and rigidity, resulting in combination of high temperatures and moderate pressures that allow the rock to flow under stress. grains of rocks within the asthenosphere have partially melted
what is the most common silicate and what is its formula?
the best known silicate mineral is quartz, SiO2
atomic number
the number of protons in an element
atom
the smallest particle into which an element can be divided and still retain chemical characteristics of the element
what is a lithospheric plate? what is a plate boundary? what are three kinds of plate boundaries? what is the difference between the three different kinds of plate boundaries?
there are 20 plates that make up the lithosphere; a plate boundary is the contact point between the two plates -divergent boundary: two plates moved apart from one another (mid-ocean ridge, continental rift) type of tensile/extensional stress -convergent boundary: plates moving toward one another (subduction zone, continent collision) type of compressive stress -transform boundary: two plates slide past one another. shear stress
what are hot spots? how do they form? how do they provide evidence for plate tectonics? where can examples be found, both within the continental US and within the oceans?
they are columns of warm mantle material (primes) at the base of earth's mantle that rise up through cooler, denser mantle. they reveal temperature for temperature differences within the crust and mantle. -They monitor direction of plate movements. If a plume rises up, it could lead to melting and create a volcano; they leave behind a chain of extinct volcanoes that show up in a line. This demonstrates that a tectonic plate travels over top of a stationary hot spot. EX: north pacific Ocean V-shaped Hawaiian volcanic islands and submerged volcanoes , Yellowstone National park in Wyoming, and Iceland
what are ferromagnesian minerals?
they are found in the earth's crust and normally are darker in color
isotopes (definition and example)
two or more forms of the same element that contain equal number of protons but different number of neutrons in their nuclei - they differ in relative atomic mass but not in chemical properties. EX: carbon 12, 13, and 14
what is a mid-ocean ridge?
underwater mountain range formed by plate tectonics. this uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.
How does a limestone form - two methods
when marine invertebrates extract dissolved ions from seawater and incorporate those ions to form their shells. when these organisms die, their shells remain and consolidate and lithify to form a sedimentary rock called limestone; another way is directly from solution without fossil precursor via the precipitation of calcite
what is a convergent plate boundary, how many different types are there and how are they distinguished? where can examples of each be found? what landforms do they produce?
when two plates collide with one another -ocean-ocean: plate of oceanic lithosphere collides with another plate of oceanic lithosphere; creates new crust -ocean-continent: a plate of oceanic lithosphere collides with a plate of continental lithosphere; when oceanic plate slides under the continental, it forms into magma and creates volcanoes/earthquakes -continent-continent: a plate of continental lithosphere collides w another plate of continental lithosphere and push up to create mountain ranges
what is a subduction zone? what happens to the sinking plate? how is it determined which plate sinks?
when two plates collide, the denser plate bends and slides under the overriding plate, forming a subduction zone. as the down-going slab is subjected to higher pressures deeper in the mantle, the rocks may be metamorphosed into denser ones and promote more subduction as gravity pulls on the denser lithosphere
What happens to the growth of a population as it reaches its carrying capacity?
when you exceed carrying capacity, the consequences are a collapse - a crash or die-off in which there is a decline in population density
