Igneous Rocks

Question 1

Answer 1

• Name- Porphritic Rhyolite
• Enviroment or formation- Both
• Mineral compostion- (Felsic)- Rocks are usually Pink, white, or light in color (some may be red, dark red or dark purple) They are usually high in Si, AI, Na and are the last to crystallize out if the melt.
• Texture- (Porphritic) Coarse crystals “floating” in a finer grained groundmass. these larger crystals are floating in a molten liquid. this material is then cooled more rapidly, where the finer grained groundmass forms.
• Larger crystals are called Phenocrysts

Question 2

Answer 2

• Name- Scocia
• Enviorment Formation- Extrusive
• Mineral compostion- (Mafic)- Mafic rocks are usually Black in color (olvine in our mineral lab exception) They are usually high in Fe,Mg and, Ca and are the first to crystallize out of the molten material
• Texture-(Vesicular)- Many holes due to expanding gas bubbles. usually in extrusive rocks.

Question 3

Answer 3

• Name-(Granite)
• Enviorment of formation- Intrusive
• Mineral compostion-(Felsic)- Felsic Rocks are usually pink, white, or light gray in color. (some red,darkred, or dark purple) usually high in Si, Al, Na
• Texure- (Phaneritic)- Coarse crystals (1-10) slow cooling below ground.
• mineral in - Kspar, quartz

Question 4

Answer 4

• Name-Obssidan
• Enviorment of formation- Extrusive
• Mineral compostion- Felsic becuase made out of glass which is Quartz. - Is colored.
• Texture-(glassy)- no crystals (glass) very rapid in cooling in air or water, above ground.

Question 5

Answer 5

• Name- Diorite
• Enviorment of formation- Intrusive
• Mineral compostion-(Intermediate)- These rocks are ususally medium gray in color, or in coarsley crystalline rocks have equal amounts of dark and light minerals. They are intermediate in compostion between mafic and felsic.
• Texture-(Phaneritic)- coarse grained crystals (1-10mm) slow cooling below ground.

Question 6

Answer 6

• Name- granite pegmatite
• Enviorment of formation- (Intrusive)
• Mineral Compostion- (Felsic)- rocks are usually pink, white, or light gray in color ( some Red, dark red, or dark purple) they are usally high in Si, Al, Na and are last to crystallize out of the melt.
• Texture-(Pegmatitic)- very coarse crystals (bigger than 10mm (1cm)). very slow cooling, often in the presence of fluids. slow cooling occurs below ground in plutonic or intrusive rocks.

Question 7

Answer 7

• Name- Basalt
• Enviroment of formation- Extrusive
• Mineral compostion-(Mafic)- mafic rocks are usually Black in color. they are usually high in Fe, Mg, and Ca and are the first to crystallize out of the molten material.
• Texture-(Aphanitic)- fine crystals (less then 1mm, usually too small to see) rapid cooling above ground, volcanic or extrusive rocks.

Question 8

Answer 8

• Name- Andesite
• Enviorment of formation- Both
• Mineral compostion-(Intermediate)- there rocks are usually medium gray in color, or in coarsely crystalline rocks have equal amounts of dark and light minerals. They are intermediate in compostion between mafic and felsic rocks.
• Texture-(Porphyritic)- Coarse crystals ‘floating’ in a finer groundmass. large crystals form first by slow underground cooling. these larger crystals are floating in a molten liquid . this material is then cooled more rapidly, where the finer grained ground mass froms. the larger crystals are called (Phenocrysts)

Question 9

Answer 9

• Name- Pumice
• Enviorment of formation- Extrusive
• Mineral compostion-(Felsic) - rocks are usually pink,white, or light gray in color some may be red dark red or dark purple) usually high in Si, Al and Na.
• Texture-(Vescular)- many holes due to expanding gas bubbles. usually In Extrusive rocks.

Question 10

Answer 10

• Name-GAbbro
• Enviorment of formation- Intrusive
• Mineral compostion-(Mafic)- usually black in color. they are high in Fe, Mg, and Ca and are the first to crystallize out of the molten material.
• Texture- (Phaneritic)- Coarse crystals (1-10) slow cooling below ground.

Question 11

Answer 11

• Name- Granite
• Enviorment of formation- Intrusive
• Mineral comp-(Felsic)- are usually pink , white or light gray in color (some may be red, dark red, or dark purple) they are usually high in Si, AI, Na. are the last tot crystallize out of melt.
• Texure-(Phaneritic)- coarse crystals (1-10) slow cooling below ground.

Question 12

Answer 12

• Name-Breccia
• Enviorment- Extrusive
• Mineral Comp-(Felsic)- rocks are usually pink, white or light gray in color (some red, dark red, Dark purple) They are usually high in (Si, Al, Na)
• Texture-(Pyroclastic)- broken rock fragments usually due to explosive volcanism. often confused with porphyritic textures. contain rock fragments rather than invidual grains.

Question 13

Answer 13

• Name- Basalt
• Enviorment of formaTION-Extrusive
• Mineral compostin-(mafic)- usually black in color. usually high in Fe, Mg and Ca are the first to crystallize out of the molten material.
• Texture-(Aphanitic)- fine crystals (less than 1mm, usually to small to see) rapid cooling above ground. volcanic or extrusive rocks.

Question 14

Answer 14

• Name-Porhritic Granite
• Enviorment of formation- Intrusive
• Mineral compostion-(Felsic) rocks usually pink, white or light gray in color. usually high in Si, Al and Na
• Texture-(Phaneritic)- coarse crystals (1-10 mm) slow cooling below ground.

Question 15

Answer 15

• Name-Rhyolite
• Enviorment formation-Extrusive
• Mineral compostion-(felsic) rocks are usually pink,white,or light gray in color
• High in Si, Al, Na
• Texture-(Aphanitic)-fine crystals (less than 1 mm to small to see) rapid cooling above ground, volcanic or extrusive rocks.

Question 16

Intrusive

Answer 16

• -Liquid (magma) that solidifies at depth is termed intrusive or plutonic

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Question 17

Extrusive

Answer 17

• Liquid (lava) (out of grown) that solidifies on the surface is termed extrusive or volcanic.