Geology 1403 Exam 2 questions and answers 2025.

Geology 1403 Exam 2
questions and answers
2025
How do igneous rocks form - answer Melting and
Recrystallization of magma


What are plutons - answer -large bodies of rock
formed at or near plate boundaries
-intrusive igneous bodies formed by the cooling
and crystallization of magma within the earth's
crust


Importance of igneous rocks - answer -one of 3
rock families
-large percentage of continental crust
-nearly all of oceanic crust
-provides information about conditions when rocks
formed
-economic resource


What are the ecomic reasons for igneous rocks -
answer - building materials
-copper

,-gold
-silver
-platinum


Location of magma - answer -intrusive
-plutonic
-below earth's surface


Location of lava - answer -extrusive
-volcanic
-at the earth's surface


Properties of magma - answer -composition
Felsic & Mafic
-temperature
Felsic & Mafic
-Viscosity
Felsic & Mafic


Describe Felsic - answer -silica rich
-hot
-less dense
-more viscosity or sticky

, -convergent boundaries
-continental crust (not subduction)


Describe Mafic - answer -silica poor
-hotter
-more dense
-less viscosity or more fluid
-divergent boundaries or mid-ocean ridges
-oceanic crust (subduction zone)


Nature of magma - answer -liquid portion or melt
-solids
-volatiles or gases


Describe UltraMafic - answer -even less silica
-never reach the surface
-too dense
-mantle
-rock name peridotite


what is geothermal gradient - answer observed
phenomena that the deeper you go in the earth the
hotter it gets