Transcript Metamorphic Rocks

BIG Idea
►Most
rocks are formed from
pre-existing rocks through
external and internal geologic
processes.
METAMORPHISM:
►The
changing of one type of rock to
another by heat, pressure and
chemical processes.
►Rocks
RECRYSTALLIZE - undergo
change WITHOUT true melting
IMPORTANT Metamorphic Facts:
►New
larger, DENSER, harder crystalline
structures form
►Generally
►No
NON-porous (no holes)
fossils (destroyed due to intense
heat and pressure)
TYPES OF METAMORPHISM
1. CONTACT METAMORPHISM –
CHANGE TO A SMALL AREA – heat
from magma alters the rock
in contact
with it.
2. REGIONAL METAMORPHISM –
CHANGE TO A VERY LARGE AREA
(mountain building) –
tectonic
activity.
CLASSIFICATION OF METAMORPHIC
ROCKS
► 1.
FOLIATED – PARALLEL BANDS OF
MINERALS
►What
is slate commonly used for?
► 2.
NON-FOLIATED - ROCKS WITH NO
BANDS OF CRYSTALS.
PARENT MATERIALS:
 Rock
from which metamorphic
rocks form
 Different
rocks form with changes
in heat and pressure
METAMORPHIC PARENTS:
► sandstone
+ heat and pressure =
quartzite
► shale + heat and pressure = schist
► shale + heat and pressure = slate
► granite + heat and pressure = gneiss
(“nice”)
► limestone + heat and pressure = marble