Igneous Rocks and Structures

Question 1

igneous rocks that are dominantly composed of dark colored silicates, but can appear green. enriched in olivine, pyroxene, and plagioclase

Answer 1

ultramafic rocks

Question 2

formed from ultramafic magma

Answer 2

peridotite and komatiite

Question 3

igneous rocks dominantly composed of dark colored silicates such as pyroxenes, plagioclase, and amphiboles

Answer 3

mafic/basaltic rocks

Question 4

formed from mafic magma or lava

Answer 4

gabbro or basalt

Question 5

major constituents of ophiolites and mantle

Answer 5

mainly composed of ultramafic rocks

Question 6

major constituents of oceanic crusts

Answer 6

mainly composed of mafic rocks

Question 7

igneous rocks that are gray colored to salt and pepper

Answer 7

intermediate/andesitic rocks

Question 8

major constituents of volcanic arcs

Answer 8

mainly intermediate rocks

Question 9

formed from intermediate magma or lava

Answer 9

diorite and andesite

Question 10

igneous rocks dominantly composed of light colored silicates such as quartz and feldspars

Answer 10

felsic/granitic rocks

Question 11

major constituents of continental crust

Answer 11

felsic rocks

Question 12

formed from felsic magma or lava

Answer 12

granite or rhyolite

Question 13

plutons with surface exposure greater or equal than 100km^2

Answer 13

batholith

Question 14

plutons with surface exposure less or equal to 100km^2

Answer 14

stocks

Question 15

the two types of plutonic structures

Answer 15

concordant and discordant

Question 16

tabular, concordant pluton that is parallel to the country rock

Answer 16

sill

Question 17

dome like concordant pluton with a dome roof and flat floor

Answer 17

laccolith

Question 18

dish shaped concordant pluton that has a “champagne glass” appearance

Answer 18

lopolith

Question 19

tabular intrusions that cut through the country rock

Answer 19

dike

Question 20

cylindrical dikes exposed by erosion and are the conduit of old volcanoes

Answer 20

neck

Question 21

cylindrical pipes that extend up to 20 km

Answer 21

diatremes

Question 22

types of rock classification

Answer 22

modal and normative

Question 23

direct and defines via the relative composition of rocks

Answer 23

modal

Question 24

indirect and based on the chemical composition of rocks

Answer 24

normative

Question 25

two factors for igneous classification

Answer 25

composition and texture

Question 26

coarse grained, ultramafic, ultrabasic, and enriched in pyroxene, olivine, plagioclase

Answer 26

peridotite

Question 27

volcanic, ultramafic, ultrabasic, and enriched in pyroxene, olivine, and plagioclase. Has a spinifex texture

Answer 27

komatiite

Question 28

coarse grained, mafic, basic, and enriched in plagioclase, pyroxene, and olivine

Answer 28

gabbro

Question 29

fine grained, mafic, basic, and enriched in plagioclase, pyroxene, and olivine

Answer 29

basalt

Question 30

coarse grained, salt and pepper, rich in hornblende, pyroxene, and plagioclase. Contains half to 2/3rds SiO2

Answer 30

diorite

Question 31

fine grained, intermediate, rich in hornblende, pyroxene, and plagioclase. contains half to 2/3rds SiO2

Answer 31

andesite

Question 32

coarse grained, felsic, enriched in plagioclase, alkali felspar, and quartz. contains 2/3rds SiO2

Answer 32

granodiorite