Describe 5 processes in the water cycle.
Evaporation (liquid → gas), melting (solid → liquid), condensation (gas → liquid), precipitation (rainfall, snow, hail), and runoff (water moving over the surface of the earth from condensation or melting)
What is uniformitarianism?
Geologic processes that happened in the past are happening today. Proposed by James Hutton.
What are the Moho, lithosphere, and asthenosphere?
Moho is the junction of the crust and mantle (line between 3 and 4 in the diagram above). Lithosphere is the crust and upper part of upper mantle (1/2 + 3). Asthenosphere is the lower part of the upper mantle (4).
How do the physical properties of the lithosphere differ from those of the asthenosphere?
The lithosphere is slightly elastic and rigid. It will crack and break. The asthenosphere is like plastic. It is very hot, not very rigid and can permanently change shape.
How is the inner core different from the outer core?
Inner core is solid, outer is liquid. Inner core is hotter. Inner core is made of iron and nickel, outer core is iron and sulfur.
How did geologists study the earth's interior?
Volcanic eruptions, seismic waves or shockwaves from explosions, meteorites, gravitational studies, drilling
What ate 3 types of rocks? How do they form?
Metamorphic: other rocks under conditions of high temperature and pressure, usually from being buried
Igneous: lava (surface of earth)/ magma (inside the earth) cooling
Sedimentary: particles from erosion being cemented together
What features distinguish intrusive from extrusive igneous rocks?
Intrusive: crystals - gradual cooling of magma inside the earth
Extrusive: air bubbles - rapid cooling of lava on the surface of the earth
What are the three types of sedimentary rocks?
Chemical: form from precipitation reactions
Clastic: form from particles of other rock cemented together
Organic: form from particles once associated with plants/animals
What three processes may affect rock in the rock cycle?
Subduction: melting of rock eventually leading to igneous rock
Burying: buried rocks deep in the crust lead to metamorphic
Erosion: erosion produces sediments. Sediments deposited in areas where they get cemented together become sedimentary rocks
Any rock may be subjected to any of these 3 processes!
What theory did Alfred Wegener propose? What observations led him to propose this?
Wegener proposed continental drift because of the "jigsaw puzzle" look of the earth and because of the rock/fossil distribution
Why was his theories rejected?
It was rejected, because he was not a geologist (he was a meteorologist) and because he could not explain how the continents could be moving
What later evidence showed he was correct?
Echo sound mapping showed the ocean floor had mountains and valleys. Heat emissions showed magma oozes from inside the earth (sea floor spreading). Rock magnetism of the sea floor showed magnetic poles reversals
What does convection in the mantle cause?
All plate tectonic activity: earthquake, volcanoes, mountains, hot spots
What causes convection currents in the mantle?
Differential heating/temperature difference inside the earth
What are convergent, divergent and transform plate boundaries?
Convergent come together, divergent move apart, transform slide next to each other
What is a ridge and a trench? What occurs at these locations?
Ridge: structure forming from divergent ocean plates (sea floor spreading)
Trench: subduction zone, One plate (usually oceanic) is pushed under another (continental or oceanic)
What plates are responsible for the San Andreas fault? What type of boundary is it?
North American and Pacific. Transform boundary.
Describe 3 types of earthquake scales.
Richter: rates on earthquakes based on times and size of waves
Moment Magnitude: measures amount of energy released
Mercalli: rates earthquakes based on observations and damage
Describe 3 types of earthquake waves.
P wave: longitudinal waves that cause medium (ground) to move parallel to wave direction
S wave: transverse wave that causes medium to move perpendicular to wave direction
Surface wave: created when seismic waves reach the surface. May have more of a rolling motion.
What two bits of information are needed to determine the magnitude of an earthquake?
SP interval and s wave amplitude
Describe 5 parts of a volcano.
Magma chamber: pocket of magma
Pipe: narrow vertical channel
Vent: opening in ground
Crater: bowl shaped pit on top of central vent
Caldera: huge depression formed if crater collapses
What is a hot spot?
Region where hot rock extends from deep within the mantle. Usually away from a plate boundary/middle of a plate