IGNEOUS ROCKS BEGIN WHAT IS AN IGNEOUS ROCK? An igneous rock is a rock that has formed from the cooling and solidification of magma or lava. NEXT MAGMA Melted rock that is beneath the surface of the Earth. LAVA Melted rock that is at or near the surface of the Earth. NEXT Lava Magma NEXT NEXT NEXT TYPES OF IGNEOUS ROCKS Igneous rocks are classified according to where they cooled and solidified. NEXT INTRUSIVE Rocks that form from magma cooling and solidifying while still inside the Earth EXTRUSIVE Rocks that form from lava cooling and solidifying while at or near the Earth’s surface NEXT Page 6 of the ESRT Scheme for Igneous Rock Identification NEXT Rock Cycle in Earth’s Crust Relationship of Transported r Dep Particle Size to Water Velocity d/o osi an an tion 100.0 ion n d Bu ct atio ria Boulders pa nt l m e o em 25.6 C C 10.0 Cobbles SEDIMENTS 6.4 E (cm) SEDIMENTARY n r o o i 1.0 Pebbles ROCK s s o H ( i We Up o r e a lift n th ) E a e M rin 0.2 t g & & e E a ro M s l ion g 0.1 n t i ) n e n d i t f r t Pre g r s / d/o sur i a n e l o a at e Sand m e p r H ph h amor ism t P t e U o M a ( r r e 0.01 p e h s W 0.006 i s n s ) o u ft i m li s r p ro e (U IGNEOUS & E Silt g DIAMETER PARTICLE erin ROCK 0.001 ath We g eltin 0.0004 METAMORPHIC M n o Clay ROCK ti a 0.0001 c 1 100 1000 10 i 0.01 0.05 0.1 0.5 500 f 5 50 di M oli el S ting MAGMA STREAM VELOCITY (cm/s) This generalized graph shows the water velocity needed to maintain, but not start, movement. Variations occur due to differences in particle density and shape. CRYSTAL TEXTURE Scheme for Igneous Rock Identification SIZE Non- Obsidian Basaltic glass (usually appears black) Glassy vesicular non- Pumice Scoria crystalline Vesicular (gas Vesicular rhyolite Vesicular Vesicular basalt pockets) EXTRUSIVE andesite (Volcanic) Fine EXTRUSIVE Basalt Rhyolite Andesite 1 mm less than Diabase Peri- Non- Diorite to Coarse IGNEOUS ROCKS Granite Gabbro dotite vesicular 1 mm Dunite 10 mm INTRUSIVE Very ENVIRONMENT OF FORMATION ENVIRONMENT (Plutonic) Pegmatite or INTRUSIVE coarse larger 10 mm LIGHTER COLOR DARKER LOWER DENSITY HIGHER FELSIC COMPOSITION MAFIC (rich in Si, Al) (rich in Fe, Mg) 100% 100% Potassium CHARACTERISTICS feldspar (pink to white) 75% 75% Quartz (clear to white) Plagioclase feldspar (white to gray) 50% 50% Pyroxene (green) Biotite (black) (relative by volume) 25% Olivine 25% MINERAL COMPOSITION MINERAL (green) Amphibole (black) 0% 0% NEXT 6 Physical Setting/Earth Science Reference Tables — 2010 Edition INTRUSIVE IGNEOUS ROCKS Because these rocks form inside the Earth, where it is very hot, it takes a long time for the magma to cool and solidify. This time allows mineral crystals to grow large. So all intrusive igneous rocks have inter-grown crystals that are larger than 1mm. NEXT INTRUSIVE IGNEOUS ROCKS PEGMATITE GRANITE *Notice the large mineral crystals NEXT Rock Cycle in Earth’s Crust Relationship of Transported r Dep Particle Size to Water Velocity d/o osi an an tion 100.0 ion n d Bu ct atio ria Boulders pa nt l m e o em 25.6 C C 10.0 Cobbles SEDIMENTS 6.4 E (cm) SEDIMENTARY n r o o i 1.0 Pebbles ROCK s s o H ( i We Up o r e a lift n th ) E a e M rin 0.2 t g & & e E a ro M s l ion g 0.1 n t i ) n e n d i t f r t Pre g r s / d/o sur i a n e l o a at e Sand m e p r H ph h amor ism t P t e U o M a ( r r e 0.01 p e h s W 0.006 i s n s ) o u ft i m li s r p ro e (U IGNEOUS & E Silt g DIAMETER PARTICLE erin ROCK 0.001 ath We g eltin 0.0004 METAMORPHIC M n o Clay ROCK ti a 0.0001 c 1 100 1000 10 i 0.01 0.05 0.1 0.5 500 f 5 50 di M oli el S ting MAGMA STREAM VELOCITY (cm/s) This generalized graph shows the water velocity needed to maintain, but not start, movement. Variations occur due to differences in particle density and shape. CRYSTAL TEXTURE Scheme for Igneous Rock Identification SIZE Non- Obsidian Basaltic glass (usually appears black) Glassy vesicular non- Pumice Scoria crystalline Vesicular (gas INTRUSIVEVesicular rhyolite Vesicular IGNEOUSVesicular basalt ROCKSpockets) andesite (Volcanic) Fine EXTRUSIVE Basalt Rhyolite Andesite 1 mm less than Diabase Peri- Non- Diorite to Coarse IGNEOUS ROCKS Granite Gabbro dotite vesicular 1 mm Dunite 10 mm Very ENVIRONMENT OF FORMATION ENVIRONMENT (Plutonic) Pegmatite or INTRUSIVE coarse larger 10 mm LIGHTER COLOR DARKER LOWEREnvironment of Formation (where DENSITY HIGHER the rock formed) FELSIC COMPOSITION MAFIC (rich in Si, Al) (rich in Fe, Mg) 100% 100% Potassium CHARACTERISTICS feldspar (pink to white) 75% 75% Quartz (clear to white) Plagioclase feldspar (white to gray) 50% 50% Pyroxene (green) Biotite NEXT (black) (relative by volume) 25% Olivine 25% MINERAL COMPOSITION MINERAL (green) Amphibole (black) 0% 0% 6 Physical Setting/Earth Science Reference Tables — 2010 Edition Rock Cycle in Earth’s Crust Relationship of Transported r Dep Particle Size to Water Velocity d/o osi an an tion 100.0 ion n d Bu ct atio ria Boulders pa nt l m e o em 25.6 C C 10.0 Cobbles SEDIMENTS 6.4 E (cm) SEDIMENTARY n r o o i 1.0 Pebbles ROCK s s o H ( i We Up o r e a lift n th ) E a e M rin 0.2 t g & & e E a ro M s l ion g 0.1 n t i ) n e n d i t f r t Pre g r s / d/o sur i a n e l o a at e Sand m e p r H ph h amor ism t P t e U o M a ( r r e 0.01 p e h s W 0.006 i s n s ) o u ft i m li s r p ro e (U IGNEOUS & E Silt g DIAMETER PARTICLE erin ROCK 0.001 ath We g eltin 0.0004 METAMORPHIC M n o Clay ROCK ti a 0.0001 c 1 100 1000 10 i 0.01 0.05 0.1 0.5 500 f 5 50 di M oli el S ting MAGMA STREAM VELOCITY (cm/s) This generalized graph shows the water velocity needed to maintain, but not start, movement. Variations occur due to differences in particle density and shape. CRYSTAL TEXTURE Scheme for Igneous Rock Identification SIZE Non- Obsidian Basaltic glass (usually appears black) Glassy vesicular non- Pumice Scoria crystalline Vesicular (gas INTRUSIVEVesicular rhyolite Vesicular IGNEOUSVesicular basalt ROCKSpockets) andesite (Volcanic) Fine EXTRUSIVE Basalt Rhyolite Andesite 1 mm less than Diabase Peri- Non- Diorite to Coarse IGNEOUS ROCKS Granite Gabbro dotite vesicular 1 mm Dunite 10 mm Very ENVIRONMENT OF FORMATION ENVIRONMENT (Plutonic) Pegmatite or INTRUSIVE coarse larger 10 mm LIGHTER COLOR DARKER LOWEREnvironment of Formation (where DENSITY HIGHER the rock formed) FELSIC COMPOSITION MAFIC (rich in Si, Al) (rich in Fe, Mg) 100% Names of common 100% Potassium CHARACTERISTICS feldsparintrusive igneous rocks (pink to white) 75% 75% Quartz (clear to white) Plagioclase feldspar (white to gray) 50% 50% Pyroxene (green) Biotite NEXT (black) (relative by volume) 25% Olivine 25% MINERAL COMPOSITION MINERAL (green) Amphibole (black) 0% 0% 6 Physical Setting/Earth Science Reference Tables — 2010 Edition Rock Cycle in Earth’s Crust Relationship of Transported r Dep Particle Size to Water Velocity d/o osi an an tion 100.0 ion n d Bu ct atio ria Boulders pa nt l m e o em 25.6 C C 10.0 Cobbles SEDIMENTS 6.4 E (cm) SEDIMENTARY n r o o i 1.0 Pebbles ROCK s s o H ( i We Up o r e a lift n th ) E a e M rin 0.2 t g & & e E a ro M s l ion g 0.1 n t i ) n e n d i t f r t Pre g r s / d/o sur i a n e l o a at e Sand m e p r H ph h amor ism t P t e U o M a ( r r e 0.01 p e h s W 0.006 i s n s ) o u ft i m li s r p ro e (U IGNEOUS & E Silt g DIAMETER PARTICLE erin ROCK 0.001 ath We g eltin 0.0004 METAMORPHIC M n o Clay ROCK ti a 0.0001 c 1 100 1000 10 i 0.01 0.05 0.1 0.5 500 f 5 50 di M oli el S ting MAGMA STREAM VELOCITY (cm/s) This generalized graph shows the water velocity needed to maintain, but not start, movement. Variations occur due to differences in particle density and shape. CRYSTAL TEXTURE Scheme for Igneous Rock Identification SIZE Non- Obsidian Basaltic glass (usually appears black) Glassy vesicular non- Pumice Scoria crystalline Vesicular (gas INTRUSIVEVesicular rhyolite Vesicular IGNEOUSVesicular basalt ROCKSpockets) andesite (Volcanic) Fine EXTRUSIVE Basalt Rhyolite Andesite 1 mm less than Diabase Peri- Non- Diorite to Coarse IGNEOUS ROCKS Granite Gabbro dotite vesicular 1 mm Dunite 10 mm Very ENVIRONMENT OF FORMATION ENVIRONMENT (Plutonic) Pegmatite or INTRUSIVE coarse larger 10 mm LIGHTER COLOR DARKER LOWEREnvironment of Formation (where DENSITY Range of crystal sizesHIGHER the rock formed) FELSIC COMPOSITION MAFIC (rich in Si, Al) (rich in Fe, Mg) 100% Names of common 100% Potassium CHARACTERISTICS feldsparintrusive igneous rocks (pink to white) 75% 75% Quartz (clear to white) Plagioclase feldspar (white to gray) 50% 50% Pyroxene (green) Biotite NEXT (black) (relative by volume) 25% Olivine 25% MINERAL COMPOSITION MINERAL (green) Amphibole (black) 0% 0% 6 Physical Setting/Earth Science Reference Tables — 2010 Edition Rock Cycle in Earth’s Crust Relationship of Transported r Dep Particle Size to Water Velocity d/o osi an an tion 100.0 ion n d Bu ct atio ria Boulders pa nt l m e o em 25.6 C C 10.0 Cobbles SEDIMENTS 6.4 E (cm) SEDIMENTARY n r o o i 1.0 Pebbles ROCK s s o H ( i We Up o r e a lift n th ) E a e M rin 0.2 t g & & e E a ro M s l ion g 0.1 n t i ) n e n d i t f r t Pre g r s / d/o sur i a n e l o a at e Sand m e p r H ph h amor ism t P t e U o M a ( r r e 0.01 p e h s W 0.006 i s n s ) o u ft i m li s r p ro e (U IGNEOUS & E Silt g DIAMETER PARTICLE erin ROCK 0.001 ath We g eltin 0.0004 METAMORPHIC M n o Clay ROCK ti a 0.0001 c 1 100 1000 10 i 0.01 0.05 0.1 0.5 500 f 5 50 di M oli el S ting MAGMA STREAM VELOCITY (cm/s) This generalized graph shows the water velocity needed to maintain, but not start, movement.