Untitled Flashcards Set

• What happened when the asteroid entered the atmosphere over Chelyabinsk? 

It exploded into 100s of fragments that fell to Earth 

• Two meteorites occupy the same volume. Meteorite A is made of Iron (Fe) & has a 

mass of 312 grams (g). Meteorite B is made of igneous rock & has a mass of 176 g. 

Density = Mass/Volume, the higher the mass, the higher the density (given equal volumes) 

• Two meteorites have the same mass. Meteorite C has a volume of 13 cm3. Meteorite D has a volume of 21cm3. 

Density = Mass/Volume given an equal mass, the smaller the volume the higher the density 

• How do we determine the probability of an impact? 

It depends on all the above variables (It depends on the size of the meteorite or asteroid, it depends on the orbit of the meteorite or asteroid, and it depends on Earth’s orbit) 

Treating Earth as a solid sphere (disregarding oceans and continents) then all surfaces have the same probability of being impacted. 

• Which element is NOT a major constituent in meteorites & asteroids? 

Uranium (U), Silicon & oxygen are the primary building blocks of the outer shell of all rocky planets. Iron is the primary building block of their cores. There are other elements that make up meteorites & asteroids not listed here. 

• Which source of meteorites & asteroids in our solar system consists primarily of Iron 

(Fe), Magnesium (Mg), Silicon (Si) and oxygen (O)? 

Mantle material from rocky planets. 

• Matching - What is the difference between a meteor, meteorite, meteoroid, asteroid, and bolide? 

Meteor: Streak of light seen when a meteoroid heats up in the atmosphere. 

Meteorite: Meteor fragment that reaches the ground. 

Meteoroid: Rocky or metallic fragment of an asteroid, comet, or planet. 

Asteroid: Rocky body smaller than a planet that orbits the Sun. 

Bolide: The light emitted by a large meteoroid or an asteroid as it explodes in the atmosphere. 

• What statement about the probability of an asteroid impact on Earth is CORRECT 

The probability of an asteroid impact on Earth is the same everywhere. 

• What places on Earth are at GREATEST RISK to humans of an impact? 

Continents are at greater risk from an impact. All locations on Earth’s surface have the same probability of being impacted, but continents are at greater RISK because of potential damage & loss of life. 

• What do you think causes tectonic activity? 

Tectonic activity is the release of Earth’s energy – namely in the form of magmatism and earthquakes. 

• Based on the properties of continental and oceanic crust, which will subduct (be pushed under) at a continent-ocean convergent boundary? 

Oceanic Crust because oceanic crust is thinner and more dense. 

• The Earth’s tectonic plates are in constant motion at a rate equal to that at which your fingernail grows. All of Earth’s plates move at the same speed. 

False 

• The rheology of the lower mantle is: 

A. Rigid solid = lithosphere; inner core 

B. Weak plastic solid = asthenosphere 

C. Liquid = outer core 

D. Lower mantle = strong plastic solid 

• Earth’s lithospheric plates slowly move as a result of: 

Convection in the asthenosphere (mantle) 

• Choose the item below that is NOT a plate boundary type. 

Resurgent, as a result of plate motion, plates interact at their boundaries in different ways. 

• Ocean-ocean divergent boundaries is where new oceanic crust is created, what type of rock is created here? 

Basalt 

• What process at convergent boundaries creates volcanoes and an ocean trench? 

Subduction of oceanic plates, oceanic plates descend, get compressed, and release water which causes the overlying asthenosphere to melt. The descending plate creates a trench, the melted asthenosphere (magma) rises to create volcanoes. 

• Which one of the following locations is not a convergent boundary? 

West coast of Africa is a passive margin. 

• What tectonic process does NOT exist at continent-continent convergent boundaries, which is why there are no (to very few) volcanoes at these boundaries? 

Subduction, without subduction and the release of water from the downgoing slab there is no creatoin of melt in the asthenosphere which means there are no volcanoes at Earth’s surface.