Transcript Metamorphic Rocks - smsk

Metamorphic Rocks
Section 4-3
Metamorphic Rocks
 Rocks that have
changed due to heat
and pressure
 Banding effect –
causes the minerals to
become squashed in
lined or banded
(foliated) forming a
gneiss.
2 ways gneiss is formed
 Flattening due to
pressure from above
 Stretching due to
pulling along fault
lines
Flattened rock with foliation versus stretched rock with
lineation. Illustration by Anne Crowder.
Foliation
Notice banding of minerals
Notice bending of bands due to
folding pressure

Causes of heat and pressure
 Heat –


1. Radioactive decay
2. Contact with magma
pools
 Pressure


1. Overlying rock
2. Plate boundaries
Formation of Metamorphic
rocks
Classification of
Metamorphic Rocks
Foliated Rocks –
minerals are flattened
and line up in parallel
bands
Ex. Gneiss – forms from
granite
Slate – forms from shale
- minerals so tightly
packed water cannot
pass through
Careful on this pronunciation.
There’s an “s” before the “t”.
 Schist – layering of
minerals
 Ex. Mica schist
Metamorphic rocks that are not
banded. (nonfoliated)
 Nonfoliated rocks –
no banding occurs

- mineral
grains change, grow
and rearrange
 Ex sandstone (mostly
quartz) – forms
quartzite.
 Marble – formed from
limestone
Marble
 Calcite – give it a shiny
appearance
 Hornblende and
serpentine – give it its
greenish tint
 Hematite – give it is
reddish tint
 Used in statues
Textbook page 102
answer in notebook
 Self check – 2,3,4
 Applying skills