12/5 EARTH SCIENCE UNIT 3 EXAM Flashcards
Continental Drift Theory
The continents we know today drifted from one big supercontinent called pangea
What is the evidence of Continental Drift?
1) the continents look like pieces of a puzzle
2)Fossils of animals were found on 5 separate continents along with plant fossils
3)There are glacial deposits of the same age on different continents
4) coal deposits were found in cold climates meaning there had to be plants which means Pangea had an equally warmer climate
5) Similar rock structures have been found on different continents
6)Magnetic polarity evidence, Magnetite crystals of different ages on different continents point to all different directions which means the continents have moved.
what is the elastic rebound theory?
the theory that explains how energy is stored in rocks
focus
the point within Earth where faulting starts, where rocks actually break deep in Earth also known as the hypocenter
epicenter
the point directly above the focus on Earth’s surface
fault
a rock fracture zone with displacement on one side
seismograph
An instrument that records and measures details of earthquakes, seismographs record the energy waves by earthquake events
where does an earthquake occur
the epicenter
seismogram
a record that is produced by a seismograph
what is the pacific ring of fire
where most (80%) of earthquakes occur because there is a lot of plate movement there
what are the 4 societal and economic impacts caused by earthquakes
building collapses, fire, tsunami, & ground failure
what are earthquakes measured by
intensity and magnitude
what are surface waves
waves generated by an earthquake and travels along the surface of the earth, known as R and L waves
what are body waves
waves generated by earthquakes and travels within the interior of the earth, known as P and S waves
what can s waves not travel through
liquids
mercalli sacale
measures the kind of damage the earthquake has done
richter scale
measures the total amount of energy released by the Earthquake
fracking
when people break rocks for extracting oil, natural gas, water, etc, the rocks move which can cause tectonic plates to shift causing a small earthquake
tsunami
formed by an earthquake below or near the ocean floor can cause a tsunami
theory of plate tectonics
the uppermost mantle along with the crust are a strong layer which more over the material of the asthenosphere
divergent plate boundary
the place where two plates move apart
convergent plate boundary
where two plates move together
transform plate boundary
where two plates grind past each other without the destruction of the lithosphere
margin
the edge of a continent
active margin
there is a plate boundary, continent to sea with plate boundary
passive margin
there is no plate boundary, continent to sea with no plate boundary
what are some passive margin features?
coast (edge of continent), continental shelf (wide shallow extension of continent), continental slope (steepest gradient drop toward the ocean floor, continental rise (collection of sediment found between the continental slope and the abyssal plain)
abyssal plain
deep ocean floor, flattest places on Earth
how do ocean trenches form?
created at subduction boundaries by the bending down of the subducting plate and warping off of the crust
what is the cause of plate tectonics?
the movement of the Earth’s lithospheric plates, caused by continental drift, seafloor spreading, and mountain formation.
mantle convection
masses of hotter than normal mantle material which ascend toward the surface, the unequal distribution of heat causes thermal convection in the mantle; this leads to plate movement
Harry hes
a geologist who conducted sonar seafloor mapping during ww2, discovered seafloor spreading
seafloor spreading
Harry Hes’s discovery, the new crust is generated as magma flows up into the mid-ocean ridges, this pushes the crust apart at the ridge
sonar
a device that bounces sound waves off underwater objects and then record the echoes of these sound waves
what is the mid Atlantic ridge
the longest chains of moutains in the world
what is the evidence for the theory of seafloor spreading?
The discovery of alternating bands of magnetic polarity in rocks on either side of mid-ocean ridges (the diverging of the seafloor) , rock core samples; rocks from the ocean floor show that older rocks are further from the ridge which proves that seafloor spreading is real. and more obviously
Iceland is important to seafloor spreading because ?
Iceland is important to seafloor spreading because it sits directly on top of the Mid-Atlantic Ridge, a major tectonic boundary where new oceanic crust is formed.
