L 10 - Geology Flashcards
what changes of the preexisting rocks during the metamorphic process?
textural
mineralogical
and both
when do metamorphic changes happen?
while the rocks remain under the solid state
exception - migmatite
what is the transformation of a limestone to marble of?
metamorphism - involves rock recrystallization
limestone - sedimentary
marble - metamorphic
why is the study of metamorphic rocks important?
they provide a WINDOW into the different levels into the earths crust
economic significance
understand how crust behaves
what are the four major types of metamorphism?
He only listed three….
regional meta
contact meta
burial meta
how does depth/pressure and temp relate to the grade of meta rocks?
LTLP low grade
HTHP high grade
MTMP med. grade
HPLT rocks that are not known in nature
what two new textures are developed during meta?
re crystallization (limestone to marble) foliation (parallel alignment of minerals in the rock which results in layered appearance of the rock)
what are the two major classes of textures in meta rocks
foliated and non foliated (granoblastic)
what is rock cleavage?
the tendency of a rock to break along parallel or sub-parallel surfaces
what are the kinds of cleavage and foliation?
slaty cleavage (black slate, green slate) phyllitic (cleav or foli) (come from meta changes of very fine sedimentary rocks) schisotose foli (schist) Gneissic foli
rock response to force and stress
force - push or pull that result in a change in the motion
Stress - amount of force per unit area
kinds of stress
confining stress
differential stress - compression, tension and shear
two major categories of crustal structures
folds - result of ductile deformation
fault - result of brittle deformation
three types of folds
anticline
syncline
monocline
parts of a anticline
hinge limb axial plane upright inclined plunging overturned recumbent
