Geology Lab Midterm
Which mineral(s) might you be examining if you place some hydrochloric (HCl) acid on a sample and it fizzes?
Calcite and Dolomite
How are elastic rebound and elastic deformation different?
Elastic deformation causes objects to bend, whereas rebound causes objects to return to their original shape.
Which of the following rock types is most abundant on Earth's land surface?
Sedimentary rocks
Igneous rocks are mainly composed of _______ minerals.
Silicate
Why is decompression melting common at mid-ocean ridges but not at subduction zones?
Tectonic plates are moving apart at mid-ocean ridges, resulting in a lowering of pressure beneath the ridge. Tectonic plates are moving together at subduction zones, resulting in an increase of pressure under new mountains.
______ is the shape, size, and arrangement of grains that make up a rock.
Texture
Why is water a necessary component of the melting process in subduction zones?
The addition of water lowers the melting temperature of rock.
What will happen to a straight fence that undergoes elastic strain during an earthquake?
The fence will bend in the direction of stress.
Why are volcanoes NOT found at transform boundaries?
Transform boundaries do not cause changes to the pressure, temperature, or composition of the mantle.
Where does the water involved in melting at subduction zones come from?
Water contained within minerals in the subducting plate is released during metamorphism.
What is a plume?
a zone of upwelling material originating at the outer core-mantle boundary
Which of the following terms best characterizes upwelling in the asthenosphere?
concentrated
Which two processes commonly generate magma?
decompression melting and wet melting (the addition of volatiles)
In general, where do earthquakes AND volcanic eruptions occur?
divergent plate boundaries convergent plate boundaries
Which of the following could cause rock to melt?
increase in pressure decrease in pressure
In general, where do volcanoes form in subduction zones?
on the overriding plate, away from the convergent boundary
What is peridotite?
the rock making up the mantle
