Briefly explain how it is possible for a single magma to yield rocks of felsic, intermediate, and mafic
composition. What will be an ideal response?
There are three ways for a magma to yield rocks of vastly different composition. With crystal settling,
the first crystals to form, the ferromagnesian minerals, settle to the bottom of the magma chamber,
where they can cool to form a mafic rock. The remaining liquid is more intermediate and, if the
process continues, more felsic than the original magma. At any point, these liquids can cool to become
an intermediate or felsic rock. Assimilation adds the country rock to a magma. If a magma is mafic, it
can melt more felsic rock and change its composition from mafic to intermediate to felsic. Magma
mixing can combine magmas of different composition. If a mafic magma and a felsic magma mix,
they will create a magma of intermediate composition. These three magmas can lead to three different
rock types.
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On the windward side of the mountain, is the relative humidity of the parcel increasing or decreasing as it rises from sea level to 2000 meters? Why?
Assume that a parcel of air is forced to rise up and over a 4000-meter-high mountain (as shown). The initial temperature of the parcel at sea level is 30°C, and the lifting condensation level (LCL) of the parcel is 2000 meters. The DAR is 10°C/1000 m and the SAR is 6°C/1000 m. Assume that condensation begins at 100% relative humidity and that no evaporation takes place as the parcel descends.
What will be an ideal response?
The ____ cycle describes the synthesis of plate tectonics, where over great spans of geologic time oceanic floors are
constantly forming and destroying, mountains are eroding, sediments are subducting, continents are rebuilding, and the world ocean moves from basin to basin. a. Watson b. continental c. tectonic d. Wilson e. convergent
The Mississippi River delta is what kind of delta?
a. contributary b. arcuate c. cuspate d. bird's-foot
Why doesn't the moon have an atmosphere?
What will be an ideal response?