METAMORPHIC ROCKS - HMXEarthScience · Rocks Sedimentary Igneous Metamorphic Clastic Crystalline...
Transcript of METAMORPHIC ROCKS - HMXEarthScience · Rocks Sedimentary Igneous Metamorphic Clastic Crystalline...
METAMORPHIC ROCKSBEGIN
WHAT IS A METAMORPHIC ROCK?A metamorphic rock is a rock
that has been changed by heat and/or pressure
without completely melting.
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PRESSURERegional
metamorphism
Regional MetamorphismRegional metamorphism usually occurs deep underground where rocks are put under intense pressure or stress causing the rock to deform
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magma
Contact metamorphism
Contact Metamorphism occurs near magma or lava
Contact Metamorphism
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A parent rock is the original rock that changed into a
metamorphic rock
parent rock
metamorphic rock
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FoliatedMinerals line
up due to metamorphism
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NonfoliatedMinerals don’t
line up
There are two types of Metamorphic Rocks
Base your answ
ers to questions 75 through 78 on the Rock C
lassification flowchart show
n below. Letters A
,B
,and Crepresent specific rocks in this classification schem
e.
Rock C
lassification Flowchart
75R
ock Ais com
posed of very fine-grained quartz and feldspar particles 0.005 centi-m
eter in diameter. State the nam
e of rock A. [1]
76R
ock Bhas a glassy, vesicular texture and is com
posed mainly of potassium
feldsparand quartz. State the nam
e of rock B. [1]
77G
ranite could be placed in the same position in the flow
chart above as gabbro.D
escribe two
differences between granite and gabbro. [1]
78The diagram
below represents tw
o magnified view
s showing the arrangem
ent ofm
inerals before and after metam
orphism of rock C
. State the name of rock C
. [1]
Mineral A
rrangement
Before M
etamorphism
Rock C
Show
ing Banding
After M
etamorphism
Stress
Stress
Stress
Stress
P.S./E. Sci.–A
ug. ’03[19]
[OVE
R]
Rocks
Sedim
entaryIgneous
Metam
orphic
Clastic
Crystalline
Bioclastic
Extrusive
IntrusiveF
oliatedN
onfoliated
Rock A
Rock
saltLim
estoneG
abbroQ
uartziteR
ock BR
ock C
Base your answ
ers to questions 75 through 78 on the Rock C
lassification flowchart show
n below. Letters A
,B
,and Crepresent specific rocks in this classification schem
e.
Rock C
lassification Flowchart
75R
ock Ais com
posed of very fine-grained quartz and feldspar particles 0.005 centi-m
eter in diameter. State the nam
e of rock A. [1]
76R
ock Bhas a glassy, vesicular texture and is com
posed mainly of potassium
feldsparand quartz. State the nam
e of rock B. [1]
77G
ranite could be placed in the same position in the flow
chart above as gabbro.D
escribe two
differences between granite and gabbro. [1]
78The diagram
below represents tw
o magnified view
s showing the arrangem
ent ofm
inerals before and after metam
orphism of rock C
. State the name of rock C
. [1]
Mineral A
rrangement
Before M
etamorphism
Rock C
Show
ing Banding
After M
etamorphism
Stress
Stress
Stress
Stress
P.S./E. Sci.–A
ug. ’03[19]
[OVE
R]
Rocks
Sedim
entaryIgneous
Metam
orphic
Clastic
Crystalline
Bioclastic
Extrusive
IntrusiveF
oliatedN
onfoliated
Rock A
Rock
saltLim
estoneG
abbroQ
uartziteR
ock BR
ock C
Nonfoliatedmineral growth without pressure
pressure
mineral growth with pressure Foliated
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FoliatedNonfoliated
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Physical Setting/Earth Science Reference Tables — 2011 Edition 7
INORGANIC LAND-DERIVED SEDIMENTARY ROCKSCOMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Rounded fragments
Angular fragmentsMostlyquartz,feldspar, andclay minerals;may containfragments ofother rocksand minerals
Pebbles, cobbles,and/or bouldersembedded in sand,silt, and/or clay
Clastic(fragmental)
Very fine grain
Compact; may spliteasily
Conglomerate
Breccia
CHEMICALLY AND/OR ORGANICALLY FORMED SEDIMENTARY ROCKS
Crystalline
Halite
Gypsum
Dolomite
Calcite
Carbon
Crystals fromchemicalprecipitatesand evaporites
Rock salt
Rock gypsum
Dolostone
Limestone
Bituminous coal
. . . . .. . . .
Sand(0.006 to 0.2 cm)
Silt(0.0004 to 0.006 cm)
Clay(less than 0.0004 cm)
Sandstone
Siltstone
Shale
Fine to coarse
COMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Fineto
coarsecrystals
Microscopic tovery coarse
Precipitates of biologicorigin or cemented shellfragments
Compactedplant remains
. . . . .. . . .
Bioclastic
Crystalline orbioclastic
FO
LIAT
ED
Fine
Fineto
medium
Mediumto
coarse
Regional
Low-grademetamorphism of shale
Platy mica crystals visiblefrom metamorphism of clayor feldspars
High-grade metamorphism;mineral types segregatedinto bands
Slate
Schist
Gneiss
COMPOSITIONTEXTUREGRAINSIZE COMMENTS ROCK NAME
TYPE OFMETAMORPHISM
(Heat andpressureincreases)
MIN
ER
AL
ALI
GN
ME
NT
BA
ND
-IN
G
MAP SYMBOL
Foliation surfaces shinyfrom microscopic micacrystals
Phyllite
GA
RN
ET
PY
RO
XE
NE
FELD
SPA
RA
MP
HIB
OLE
MIC
AQ
UA
RTZ
Hornfels
NO
NF
OLI
ATE
D
Metamorphism ofquartz sandstone
Metamorphism oflimestone or dolostone
Pebbles may be distortedor stretched
Metaconglomerate
Quartzite
Marble
Coarse
Fineto
coarse
Quartz
Calcite and/ordolomite
Variousminerals
Contact(heat)
Various rocks changed byheat from nearbymagma/lava
VariousmineralsFine
Anthracite coalRegional Metamorphism ofbituminous coalCarbonFine
Regional
or
contact
Scheme for Metamorphic Rock Identification
Scheme for Sedimentary Rock Identification
Nonfoliated
Foliated
P. 7 of ESRT
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Foliation
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Mineral Alignment
Banding
minerals line up due to pressure
under greater pressure minerals separate into dark and light stripes called bands
Physical Setting/Earth Science Reference Tables — 2011 Edition 7
INORGANIC LAND-DERIVED SEDIMENTARY ROCKSCOMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Rounded fragments
Angular fragmentsMostlyquartz,feldspar, andclay minerals;may containfragments ofother rocksand minerals
Pebbles, cobbles,and/or bouldersembedded in sand,silt, and/or clay
Clastic(fragmental)
Very fine grain
Compact; may spliteasily
Conglomerate
Breccia
CHEMICALLY AND/OR ORGANICALLY FORMED SEDIMENTARY ROCKS
Crystalline
Halite
Gypsum
Dolomite
Calcite
Carbon
Crystals fromchemicalprecipitatesand evaporites
Rock salt
Rock gypsum
Dolostone
Limestone
Bituminous coal
. . . . .. . . .
Sand(0.006 to 0.2 cm)
Silt(0.0004 to 0.006 cm)
Clay(less than 0.0004 cm)
Sandstone
Siltstone
Shale
Fine to coarse
COMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Fineto
coarsecrystals
Microscopic tovery coarse
Precipitates of biologicorigin or cemented shellfragments
Compactedplant remains
. . . . .. . . .
Bioclastic
Crystalline orbioclastic
FO
LIAT
ED
Fine
Fineto
medium
Mediumto
coarse
Regional
Low-grademetamorphism of shale
Platy mica crystals visiblefrom metamorphism of clayor feldspars
High-grade metamorphism;mineral types segregatedinto bands
Slate
Schist
Gneiss
COMPOSITIONTEXTUREGRAINSIZE COMMENTS ROCK NAME
TYPE OFMETAMORPHISM
(Heat andpressureincreases)
MIN
ER
AL
ALI
GN
ME
NT
BA
ND
-IN
G
MAP SYMBOL
Foliation surfaces shinyfrom microscopic micacrystals
Phyllite
GA
RN
ET
PY
RO
XE
NE
FELD
SPA
RA
MP
HIB
OLE
MIC
AQ
UA
RTZ
Hornfels
NO
NF
OLI
ATE
D
Metamorphism ofquartz sandstone
Metamorphism oflimestone or dolostone
Pebbles may be distortedor stretched
Metaconglomerate
Quartzite
Marble
Coarse
Fineto
coarse
Quartz
Calcite and/ordolomite
Variousminerals
Contact(heat)
Various rocks changed byheat from nearbymagma/lava
VariousmineralsFine
Anthracite coalRegional Metamorphism ofbituminous coalCarbonFine
Regional
or
contact
Scheme for Metamorphic Rock Identification
Scheme for Sedimentary Rock Identification
Banding
Mineral AlignmentP. 7 of ESRT
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Intensity of Metamorphism
Low-Grade Metamorphism Little change to rock
High-Grade Metamorphism extreme change to rock
shale
slate
phylliteschist
gneiss
Shale slowly changes into Gneiss
LOW-GRADE
HIGH-GRADENEXT LAST
Physical Setting/Earth Science Reference Tables — 2011 Edition 7
INORGANIC LAND-DERIVED SEDIMENTARY ROCKSCOMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Rounded fragments
Angular fragmentsMostlyquartz,feldspar, andclay minerals;may containfragments ofother rocksand minerals
Pebbles, cobbles,and/or bouldersembedded in sand,silt, and/or clay
Clastic(fragmental)
Very fine grain
Compact; may spliteasily
Conglomerate
Breccia
CHEMICALLY AND/OR ORGANICALLY FORMED SEDIMENTARY ROCKS
Crystalline
Halite
Gypsum
Dolomite
Calcite
Carbon
Crystals fromchemicalprecipitatesand evaporites
Rock salt
Rock gypsum
Dolostone
Limestone
Bituminous coal
. . . . .. . . .
Sand(0.006 to 0.2 cm)
Silt(0.0004 to 0.006 cm)
Clay(less than 0.0004 cm)
Sandstone
Siltstone
Shale
Fine to coarse
COMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Fineto
coarsecrystals
Microscopic tovery coarse
Precipitates of biologicorigin or cemented shellfragments
Compactedplant remains
. . . . .. . . .
Bioclastic
Crystalline orbioclastic
FO
LIAT
ED
Fine
Fineto
medium
Mediumto
coarse
Regional
Low-grademetamorphism of shale
Platy mica crystals visiblefrom metamorphism of clayor feldspars
High-grade metamorphism;mineral types segregatedinto bands
Slate
Schist
Gneiss
COMPOSITIONTEXTUREGRAINSIZE COMMENTS ROCK NAME
TYPE OFMETAMORPHISM
(Heat andpressureincreases)
MIN
ER
AL
ALI
GN
ME
NT
BA
ND
-IN
G
MAP SYMBOL
Foliation surfaces shinyfrom microscopic micacrystals
Phyllite
GA
RN
ET
PY
RO
XE
NE
FELD
SPA
RA
MP
HIB
OLE
MIC
AQ
UA
RTZ
Hornfels
NO
NF
OLI
ATE
D
Metamorphism ofquartz sandstone
Metamorphism oflimestone or dolostone
Pebbles may be distortedor stretched
Metaconglomerate
Quartzite
Marble
Coarse
Fineto
coarse
Quartz
Calcite and/ordolomite
Variousminerals
Contact(heat)
Various rocks changed byheat from nearbymagma/lava
VariousmineralsFine
Anthracite coalRegional Metamorphism ofbituminous coalCarbonFine
Regional
or
contact
Scheme for Metamorphic Rock Identification
Scheme for Sedimentary Rock Identification
Physical Setting/Earth Science Reference Tables — 2011 Edition 7
INORGANIC LAND-DERIVED SEDIMENTARY ROCKSCOMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Rounded fragments
Angular fragmentsMostlyquartz,feldspar, andclay minerals;may containfragments ofother rocksand minerals
Pebbles, cobbles,and/or bouldersembedded in sand,silt, and/or clay
Clastic(fragmental)
Very fine grain
Compact; may spliteasily
Conglomerate
Breccia
CHEMICALLY AND/OR ORGANICALLY FORMED SEDIMENTARY ROCKS
Crystalline
Halite
Gypsum
Dolomite
Calcite
Carbon
Crystals fromchemicalprecipitatesand evaporites
Rock salt
Rock gypsum
Dolostone
Limestone
Bituminous coal
. . . . .. . . .
Sand(0.006 to 0.2 cm)
Silt(0.0004 to 0.006 cm)
Clay(less than 0.0004 cm)
Sandstone
Siltstone
Shale
Fine to coarse
COMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Fineto
coarsecrystals
Microscopic tovery coarse
Precipitates of biologicorigin or cemented shellfragments
Compactedplant remains
. . . . .. . . .
Bioclastic
Crystalline orbioclastic
FO
LIAT
ED
Fine
Fineto
medium
Mediumto
coarse
Regional
Low-grademetamorphism of shale
Platy mica crystals visiblefrom metamorphism of clayor feldspars
High-grade metamorphism;mineral types segregatedinto bands
Slate
Schist
Gneiss
COMPOSITIONTEXTUREGRAINSIZE COMMENTS ROCK NAME
TYPE OFMETAMORPHISM
(Heat andpressureincreases)
MIN
ER
AL
ALI
GN
ME
NT
BA
ND
-IN
G
MAP SYMBOL
Foliation surfaces shinyfrom microscopic micacrystals
Phyllite
GA
RN
ET
PY
RO
XE
NE
FELD
SPA
RA
MP
HIB
OLE
MIC
AQ
UA
RTZ
Hornfels
NO
NF
OLI
ATE
D
Metamorphism ofquartz sandstone
Metamorphism oflimestone or dolostone
Pebbles may be distortedor stretched
Metaconglomerate
Quartzite
Marble
Coarse
Fineto
coarse
Quartz
Calcite and/ordolomite
Variousminerals
Contact(heat)
Various rocks changed byheat from nearbymagma/lava
VariousmineralsFine
Anthracite coalRegional Metamorphism ofbituminous coalCarbonFine
Regional
or
contact
Scheme for Metamorphic Rock Identification
Scheme for Sedimentary Rock Identification
Shale becomes Slate becomes Phyllite becomes Schist becomes GneissAs heat and pressure increases:
P. 7 of ESRT
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Physical Setting/Earth Science Reference Tables — 2011 Edition 7
INORGANIC LAND-DERIVED SEDIMENTARY ROCKSCOMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Rounded fragments
Angular fragmentsMostlyquartz,feldspar, andclay minerals;may containfragments ofother rocksand minerals
Pebbles, cobbles,and/or bouldersembedded in sand,silt, and/or clay
Clastic(fragmental)
Very fine grain
Compact; may spliteasily
Conglomerate
Breccia
CHEMICALLY AND/OR ORGANICALLY FORMED SEDIMENTARY ROCKS
Crystalline
Halite
Gypsum
Dolomite
Calcite
Carbon
Crystals fromchemicalprecipitatesand evaporites
Rock salt
Rock gypsum
Dolostone
Limestone
Bituminous coal
. . . . .. . . .
Sand(0.006 to 0.2 cm)
Silt(0.0004 to 0.006 cm)
Clay(less than 0.0004 cm)
Sandstone
Siltstone
Shale
Fine to coarse
COMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Fineto
coarsecrystals
Microscopic tovery coarse
Precipitates of biologicorigin or cemented shellfragments
Compactedplant remains
. . . . .. . . .
Bioclastic
Crystalline orbioclastic
FO
LIAT
ED
Fine
Fineto
medium
Mediumto
coarse
Regional
Low-grademetamorphism of shale
Platy mica crystals visiblefrom metamorphism of clayor feldspars
High-grade metamorphism;mineral types segregatedinto bands
Slate
Schist
Gneiss
COMPOSITIONTEXTUREGRAINSIZE COMMENTS ROCK NAME
TYPE OFMETAMORPHISM
(Heat andpressureincreases)
MIN
ER
AL
ALI
GN
ME
NT
BA
ND
-IN
G
MAP SYMBOL
Foliation surfaces shinyfrom microscopic micacrystals
Phyllite
GA
RN
ET
PY
RO
XE
NE
FELD
SPA
RA
MP
HIB
OLE
MIC
AQ
UA
RTZ
Hornfels
NO
NF
OLI
ATE
D
Metamorphism ofquartz sandstone
Metamorphism oflimestone or dolostone
Pebbles may be distortedor stretched
Metaconglomerate
Quartzite
Marble
Coarse
Fineto
coarse
Quartz
Calcite and/ordolomite
Variousminerals
Contact(heat)
Various rocks changed byheat from nearbymagma/lava
VariousmineralsFine
Anthracite coalRegional Metamorphism ofbituminous coalCarbonFine
Regional
or
contact
Scheme for Metamorphic Rock Identification
Scheme for Sedimentary Rock Identification
Sedimentary Rock
Base your answers to questions 55 and 56 on the graph below, which shows a generalized sequence of rocktypes that form from original clay deposits at certain depths and temperature conditions within Earth’s interior.
55 When clay materials are buried to a depth of 14 kilometers, which type of meta-morphic rock is normally formed? [1]
56 Explain why gneiss would not form at a depth of 27 kilometers and at a temperatureof 800°C. [1]
0 200 400 600 800 1000
Temperature (oC)
Clay deposits
ShaleSedimentary
zone
Slate
Phyllite
Schist
Gneiss
0
5
10
15
20
25
30
Dep
th (
km)
At these temperaturesrock melts
Inferred Metamorphism of Shale
Metamorphiczone
Key
Surface of Earth
Boundary betweensedimentary zone andmetamorphic zone
P.S./E. Sci.–Jan. ’03 [21] [OVER]
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Physical Setting/Earth Science Reference Tables — 2011 Edition 7
INORGANIC LAND-DERIVED SEDIMENTARY ROCKSCOMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Rounded fragments
Angular fragmentsMostlyquartz,feldspar, andclay minerals;may containfragments ofother rocksand minerals
Pebbles, cobbles,and/or bouldersembedded in sand,silt, and/or clay
Clastic(fragmental)
Very fine grain
Compact; may spliteasily
Conglomerate
Breccia
CHEMICALLY AND/OR ORGANICALLY FORMED SEDIMENTARY ROCKS
Crystalline
Halite
Gypsum
Dolomite
Calcite
Carbon
Crystals fromchemicalprecipitatesand evaporites
Rock salt
Rock gypsum
Dolostone
Limestone
Bituminous coal
. . . . .. . . .
Sand(0.006 to 0.2 cm)
Silt(0.0004 to 0.006 cm)
Clay(less than 0.0004 cm)
Sandstone
Siltstone
Shale
Fine to coarse
COMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Fineto
coarsecrystals
Microscopic tovery coarse
Precipitates of biologicorigin or cemented shellfragments
Compactedplant remains
. . . . .. . . .
Bioclastic
Crystalline orbioclastic
FO
LIAT
ED
Fine
Fineto
medium
Mediumto
coarse
Regional
Low-grademetamorphism of shale
Platy mica crystals visiblefrom metamorphism of clayor feldspars
High-grade metamorphism;mineral types segregatedinto bands
Slate
Schist
Gneiss
COMPOSITIONTEXTUREGRAINSIZE COMMENTS ROCK NAME
TYPE OFMETAMORPHISM
(Heat andpressureincreases)
MIN
ER
AL
ALI
GN
ME
NT
BA
ND
-IN
G
MAP SYMBOL
Foliation surfaces shinyfrom microscopic micacrystals
Phyllite
GA
RN
ET
PY
RO
XE
NE
FELD
SPA
RA
MP
HIB
OLE
MIC
AQ
UA
RTZ
Hornfels
NO
NF
OLI
ATE
D
Metamorphism ofquartz sandstone
Metamorphism oflimestone or dolostone
Pebbles may be distortedor stretched
Metaconglomerate
Quartzite
Marble
Coarse
Fineto
coarse
Quartz
Calcite and/ordolomite
Variousminerals
Contact(heat)
Various rocks changed byheat from nearbymagma/lava
VariousmineralsFine
Anthracite coalRegional Metamorphism ofbituminous coalCarbonFine
Regional
or
contact
Scheme for Metamorphic Rock Identification
Scheme for Sedimentary Rock Identification
The minerals in Foliated Metamorphic rocks can be determined by looking at the bar graph in the composition section
P. 7 of ESRT
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Physical Setting/Earth Science Reference Tables — 2011 Edition 7
INORGANIC LAND-DERIVED SEDIMENTARY ROCKSCOMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Rounded fragments
Angular fragmentsMostlyquartz,feldspar, andclay minerals;may containfragments ofother rocksand minerals
Pebbles, cobbles,and/or bouldersembedded in sand,silt, and/or clay
Clastic(fragmental)
Very fine grain
Compact; may spliteasily
Conglomerate
Breccia
CHEMICALLY AND/OR ORGANICALLY FORMED SEDIMENTARY ROCKS
Crystalline
Halite
Gypsum
Dolomite
Calcite
Carbon
Crystals fromchemicalprecipitatesand evaporites
Rock salt
Rock gypsum
Dolostone
Limestone
Bituminous coal
. . . . .. . . .
Sand(0.006 to 0.2 cm)
Silt(0.0004 to 0.006 cm)
Clay(less than 0.0004 cm)
Sandstone
Siltstone
Shale
Fine to coarse
COMPOSITIONTEXTURE GRAIN SIZE COMMENTS ROCK NAME MAP SYMBOL
Fineto
coarsecrystals
Microscopic tovery coarse
Precipitates of biologicorigin or cemented shellfragments
Compactedplant remains
. . . . .. . . .
Bioclastic
Crystalline orbioclastic
FO
LIAT
ED
Fine
Fineto
medium
Mediumto
coarse
Regional
Low-grademetamorphism of shale
Platy mica crystals visiblefrom metamorphism of clayor feldspars
High-grade metamorphism;mineral types segregatedinto bands
Slate
Schist
Gneiss
COMPOSITIONTEXTUREGRAINSIZE COMMENTS ROCK NAME
TYPE OFMETAMORPHISM
(Heat andpressureincreases)
MIN
ER
AL
ALI
GN
ME
NT
BA
ND
-IN
G
MAP SYMBOL
Foliation surfaces shinyfrom microscopic micacrystals
Phyllite
GA
RN
ET
PY
RO
XE
NE
FELD
SPA
RA
MP
HIB
OLE
MIC
AQ
UA
RTZ
Hornfels
NO
NF
OLI
ATE
D
Metamorphism ofquartz sandstone
Metamorphism oflimestone or dolostone
Pebbles may be distortedor stretched
Metaconglomerate
Quartzite
Marble
Coarse
Fineto
coarse
Quartz
Calcite and/ordolomite
Variousminerals
Contact(heat)
Various rocks changed byheat from nearbymagma/lava
VariousmineralsFine
Anthracite coalRegional Metamorphism ofbituminous coalCarbonFine
Regional
or
contact
Scheme for Metamorphic Rock Identification
Scheme for Sedimentary Rock Identification
Nonfoliated rocks sometimes indicate the parent rock
P. 7 of ESRT
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