Petrology

Question 1

It is the most abundant mineral in the earth’s crust compromising 39% of earth’s crust

a. clay
b. plagioclase feldspar
c. pyroxene
d. quartz

Answer 1

b. plagioclase feldspar

Question 2

It is one of the most abundant mineral in the earth’s crust compromising 12% of earth’s crust

a. nonsilicates
b. mica
c. amphibole
d. alkali feldspar

Answer 2

d. alkali feldspar

Question 3

SiO2 content of ultramafic mineral

a. >66 wt. %
b. 52 - 66 wt. %
c. <45 wt. %
d. 45 - 52 wt. %

Answer 3

c. <45 wt. %

Question 4

SiO2 content of mafic mineral

a. >66 wt. %
b. 52 - 66 wt. %
c. <45 wt. %
d. 45 - 52 wt. %

Answer 4

d. 45 - 52 wt. %

Question 5

SiO2 content of intermediate mineral

a. >66 wt. %
b. 52 - 66 wt. %
c. <45 wt. %
d. 45 - 52 wt. %

Answer 5

b. 52 - 66 wt. %

Question 6

SiO2 content of felsic mineral

a. >66 wt. %
b. 52 - 66 wt. %
c. <45 wt. %
d. 45 - 52 wt. %

Answer 6

a. >66 wt. %

Question 7

Igneous rocks with this texture usually occur from the rapid crystallization of lava.

a. aphanitic
b. pegmatitic
c. glassy

Answer 7

a. aphanitic

Question 8

This texture forms when lava from a volcanic eruption cools very rapidly such that no crystallization occurs.

a. aphanitic
b. pegmatitic
c. glassy

Answer 8

c. glassy

Question 9

This type of texture id formed when magma cools and some minerals increase in size extensively.

a. aphanitic
b. pegmatitic
c. glassy

Answer 9

b. pegmatitic

Question 10

form when violent volcanic eruptions throw the lava into the atmosphere creating fragmental and glassy materials.

a. porphyritic
b. phaneritic
c. pyroclastic

Answer 10

c. pyroclastic

Question 11

This texture is seen in plutonic igneous rocks, which underwent slow crystallization underneath the surface of the earth.

a. porphyritic
b. phaneritic
c. pyroclastic

Answer 11

b. phaneritic

Question 12

This texture is caused by the rapid change of conditions as the magma continues to cool down. The minerals that had been created earlier, by the slow cooling magma, will posses’ large crystals.

a. porphyritic
b. phaneritic
c. pyroclastic

Answer 12

a. porphyritic

Question 13

Rocks composed mostly of pyroxene, calcium-rich plagioclase, and minor amounts of olivine.

a. ultramafic
b. mafic
c. intermediate
d. felsic

Answer 13

b. mafic

Question 14

Their low silica and gas contents make them very fluid; i.e., they have a low viscosity, or resistance to flow

a. ultramafic
b. mafic
c. intermediate
d. felsic

Answer 14

a. ultramafic

Question 15

Rocks composed mostly of biotite, muscovite, sodium-rich plagioclase feldspars, potassium feldspars, and quartz

a. ultramafic
b. mafic
c. intermediate
d. felsic

Answer 15

d. felsic

Question 16

Rocks composed mostly of hornblende and plagioclase feldspars

a. ultramafic
b. mafic
c. intermediate
d. felsic

Answer 16

c. intermediate

Question 17

Formed at spreading ridges on the ocean floor when two oceanic plates are separating

a. cinders
b. lava
c. pumice
d. tephra
e. pillow basalt

Answer 17

e. pillow basalt

Question 18

Molten rock that flows out of a volcano during eruption

a. cinders
b. lava
c. pumice
d. tephra
e. pillow basalt

Answer 18

b. lava

Question 19

Igneous rocks that have been airborne for a period of time before settling to the earth

a. cinders
b. lava
c. pumice
d. tephra
e. pillow basalt

Answer 19

d. tephra

Question 20

A volcanic glass that is associated with violent volcanic eruptions.

a. cinders
b. lava
c. pumice
d. tephra
e. pillow basalt

Answer 20

c. pumice

Question 21

Similar to pumice but usually made of iron-rich minerals found in basalt lava.

a. cinders
b. lava
c. pumice
d. tephra
e. pillow basalt

Answer 21

a. cinders

Question 22

P increases due to the weight of the overburden and T also increases due to the geothermal gradient.

a. faultzone and impact metamorphism
b. burial metamorphism
c. regional metamorphism
d. ocean floor metamorphism

Answer 22

b. burial metamorphism

Question 23

Interaction of heated seawater with newly-created oceanic crust at mid-ocean ridges.

a. faultzone and impact metamorphism
b. burial metamorphism
c. regional metamorphism
d. ocean floor metamorphism

Answer 23

d. ocean floor metamorphism

Question 24

Rock in the deep portions of faults undergoes dynamic metamorphism and creates a fine grained metamorphic rock called a mylonite.

a. faultzone and impact metamorphism
b. burial metamorphism
c. orogenic metamorphism
d. ocean floor metamorphism

Answer 24

a. faultzone and impact metamorphism

Question 25

occurs during the development of island arcs, continental arcs, and continental collision zones. It is a dynamo-thermal type of metamorphism. a. faultzone and impact metamorphism b. burial metamorphism c. orogenic metamorphism d. ocean floor metamorphism

Answer 25

c. orogenic metamorphism

Question 26

rocks undergo metamorphic reactions due to heating (little or no pressure change). when a hot igneous intrusion (magma) comes into contact with cold country rock, it creates a metamorphic aureole a. hydrothermal metamorphism b. contact metamorphism c. regional metamorphism

Answer 26

b. contact metamorphism

Question 27

Characterized by involvement of hot aqueous fluid which passes through the metamorphosing rock that leads to changes in its chemical composition a. hydrothermal metamorphism b. contact metamorphism c. regional metamorphism

Answer 27

a. hydrothermal metamorphism

Question 28

Complex composition, many different kinds of minerals. Has many new minerals produced with a change in T/P a. texture b. foliated c. equant mineral d. non-foliated

Answer 28

b. foliated

Question 29

Simple composition with no new minerals form with a change in T/P a. texture b. foliated c. equant mineral d. non-foliated

Answer 29

d. non-foliated

Question 30

Started out originally with clay minerals and as a result of metamorphism, alumna-rich minerals form. a. calcareous b. mafic c. pelitic d. quartzo-feldspathic

Answer 30

c. pelitic

Question 31

Minerals like biotite, hornblende and plagioclase form during metamorphism and commonly produce amphibolites. a. calcareous b. mafic c. pelitic d. quartzo-feldspathic

Answer 31

b. mafic

Question 32

Usually derived from limestones or dolostones, and thus contain an abundance of Calcite a. calcareous b. mafic c. pelitic d. quartzo-feldspathic

Answer 32

a. calcareous

Question 33

Protoliths are usually granites, rhyolites, or arkose sandstone and metamorphism results in gneisses a. calcareous b. mafic c. pelitic d. quartzo-feldspathic

Answer 33

d. quartzo-feldspathic

Question 34

Preferred orientation of these sheet silicates causes the rock to easily break along the planes parallel to the sheet silicates a. schist b. phyllite c. slate d. pophyroblasts

Answer 34

c. slate

Question 35

The rock developed a near planar foliation caused by the preferred orientation of sheet silicates a. schist b. phyllite c. slate d. pophyroblasts

Answer 35

a. schist

Question 36

The clay minerals have recrystallized into tiny micas which reflect a glossy luster. a. schist b. phyllite c. slate d. pophyroblasts

Answer 36

b. phyllite

Question 37

When non-mica minerals (quartz, feldspars, kyanite, garnet, staurolite, and sillimanite) occur with a grain size greater than the rest of the rock, they are called _________. a. schist b. phyllite c. slate d. pophyroblasts

Answer 37

d. pophyroblasts

Question 38

These dark colored minerals tend to become segregated in distinct bands through the rock, giving the rock a __________. a. migmatites b. granulite c. gneissic banding d. gneiss

Answer 38

c. gneissic banding

Question 39

If the temperature reaches the solidus temperature, the rock may begin to melt and start to co-mingle with the solids. a. migmatites b. granulite c. gneissic banding d. gneiss

Answer 39

a. migmatites

Question 40

At the highest grades of metamorphism, all of the hydrous minerals and sheet silicates become unstable and thus there are few minerals present that would show a preferred orientation resulting a ___________. a. migmatites b. granulite c. gneissic banding d. gneiss

Answer 40

b. granulite

Question 41

As metamorphic grade increases, the sheet silicates become unstable and dark colored minerals like hornblende and pyroxene start to grow. a. migmatites b. granulite c. gneissic banding d. gneiss

Answer 41

d. gneiss

Question 42

limestone or dolostone made up only if calcite or dolomite will metamorphose to a _______. a. amphibolite b. hornfels c. quartzite d. marble

Answer 42

d. marble

Question 43

Very fine- grained rocks that usually form as a result from magma intruding into fine grained igneous rocks or shales a. amphibolite b. hornfels c. quartzite d. marble

Answer 43

b. hornfels

Question 44

Dark-colored rocks with amphibole as their major mineral. a. amphibolite b. hornfels c. quartzite d. marble

Answer 44

a. amphibolite