Geo Rock Exam

d) both b and c

fragmental texture is formed from: a) volcanic lava b) volcanic ash c) volcanic rock debris d) both b and c

hawaii

give an example of a location experiencing hot spot induced volcanism? __________

columbian river

give an example of an LIP in continental US ___________

coal

name an organic sedimentary rock _______

b) groundmass grains

porphyritic rocks are named for the size of: a) phenocrysts b) groundmass grains

c) initial slow cooling and then fast cooling

porphyritic textures indicate: a) slow cooling b) fast cooling c) initial slow cooling and then fast cooling

chamber a

2 magma chambers of similar size are undergoing crystallization. Chamber a is tabular. Chamber b is spherical. Which chamber cools faster?

chamber y

2 magma chambers of similar size are undergoing crystallization. Chamber x is 10 km below earth's surface. Chamber y is 50 km below earth's surface. Which chamber cools faster?

a) granite

A course-grained magmatic igneous rock with 65% SiO2 and containing minerals like quartz, K-feldspar may be called: a) granite b) gabbro c) diorite d) basalt

d) all of them

A dike intrudes into: a) igneous rocks b) sedimentary rocks c) metamorphic rocks d) all of them

c) sample b traveled more distance than sample a

A sandstone sample a has subangular sand grains, while a sandstone sample b has rounded grains. Which of the following statements are true? a) sample b traveled less distance than sample a b) sample b received sediments from two source regions while sample a received from one c) sample b traveled more distance than sample a d) sample b received sediments from one source while sample a received from two

d) is more viscous than mafic magma

Felsic magma: a) crystallizes at highest temperatures b) has ~40% silica c) forms dark-colored igneous rocks d) is more viscous than mafic magma

East african rift valley

Give an example of a place currently undergoing continental rifting __________

c) large igneous provinces

LIP is: a) large intrusive provinces b) long intrusive provinces c) large igneous provinces

d) both a and c

Pyroclastic flow occurs in: a) felsic melts flow b) mafic melt flows c) extrusive settings d) both a and c

d) all of them

Three sedimentary rock layers A, B, C are arranged in layers with A at the bottom and C at the top. An igneous dike I had intruded the rock layers A and B but it did not intrude C. Which of the following statements is true? a) c is younger than b and a b) a and b are older than I c) c is younger than I d) all of them

d) I is older than both b and c

Three sedimentary rock layers A, B, C are arranged in layers with A at the bottom and C at the top. An igneous dike I has intruded the rock layer A but it did not intrude b and c. Which of the following statements about I is true? a) I is older than a b) I is younger than b but not younger than c c) I is older than b but younger than c d) I is older than both b and c

b) mafic fine-grained

What kind of igneous rocks do you expect at mid-ocean ridges ? a) felsic fine-grained b) mafic fine-grained c) intermediate fine-grained d) felsic coarse-grained

c) flux-induced melting

What kind of melting do you expect at subduction zones? a) decompression melting b) heat-transfer melting c) flux-induced melting

a) decompression melting

What kind of melting do you expect just under a mid-ocean ridge? a) decompression melting b) heat-transfer melting c) flux-induced melting

viscosity c) ultramafic > mafic > intermediate > felsic

Which of the following melt compositions are arranged in the order of increasing viscosity? a) ultramafic > mafic > felsic > intermediate b) mafic > ultramafic > intermediate > felsic c) ultramafic > mafic > intermediate > felsic d) felsic > intermediate > mafic > ultramafic

a) molten rock is less dense than the surrounding solid rocks

Why does molten rock move upward through the earth's mantle? a) molten rock is less dense than the surrounding solid rocks b) molten rock is more dense than the surrounding rocks c) molten rock is chemically more homogeneous than the surrounding solid rocks d) molten rock is chemically less homogeneous than the surrounding solid rocks

c) wet magma

a magma that is rich in volatiles is called: a) rich magma b) dry magma c) wet magma d) volatile-rich magma

a) individual crystals can be seen with the naked eye

a phaneritic texture is one in which: a) individual crystals can be seen with the naked eye b) individual crystals cannot be seen with the naked eye c) individual crystals are a mix of coarse and fine grained crystals d) pores are abundant

c) individual crystals are a mix of coarse and fine grained crystals

a porphyritic texture is one in which: a) individual crystals can be seen with the naked eye b) individual crystals cannot be seen with the naked eye c) individual crystals are a mix of coarse and fine grained crystals d) pores are abundant

b) mudrocks

a small stream in an arid region which is experiencing severe droughts for a few years continuously is expected to best preserve the following sedimentary structures? a) ripple marks b) mudcracks c) cross beddings d) dunes

d) pores are abundant

a vesicular texture is one in which: a) individual crystals can be seen with the naked eye b) individual crystals cannot be seen with the naked eye c) individual crystals are a mix of coarse and fine grained crystals d) pores are abundant

aphanitic d) all of these

all aphanitic textures are: a) fine grained b) derived from lava c) cooled faster d) all of these

a) phaneritic texture

all intrusive igneous rocks have: a) phaneritic textures b) porphyritic texture c) glassy texture d) vesicular texture

phaneritic d) all of these

all phaneritic textures are: a) coarse grained b) derived from magma c) cooled slowly d) all of these

b) individual crystals cannot be seen with the naked eye

an aphanitic texture is one in which: a) individual crystals can be seen with the naked eye b) individual crystals cannot be seen with the naked eye c) individual crystals are a mix of coarse and fine grained crystals d) pores are abundant

b) ultramafic rock

an igneous rock containing <45% SiO2 is called : a) mafic rock b) ultramafic rock c) felsic rock d) intermediate rock

pyroclastic

another name for fragmental texture is ______ texture

c) weathering-erosion-deposition-burial-compaction-cementation

arrange in correct order the set of processes leading to a clastic rock formation. a) erosion-weathering-deposition-cementation-compaction-burial b) weathering-erosion-deposition-compaction-burial-cementation c) weathering-erosion-deposition-burial-compaction-cementation d) erosion-weathering-deposition-burial-compaction-cementation

a) shows that minerals in a cooling magma crystallize in a predictable order

bowen's reaction series: a) shows that minerals in a cooling magma crystallize in a predictable order b) shows that as magma crystallizes, the remaining melt is depleted in silica c) explains why some igneous rocks are phaneritic and others are aphanitic

phenocrysts

coarse grained crystals in porphyritic textures are called ______

c) mafic to ultramafic

composition of earth's mantle is: a) felsic b) intermediate c) mafic to ultramafic

a) high-angle and low-angle igneous intrusions

dikes and sills are: a) high-angle and low-angle igneous intrusions b) high-angle and low-angle felsic intrusions c) low-angle and high-angle igneous intrusions d) low-angle and high-angle felsic intrusions

d) aphanitic or glassy or fragmental texture

extrusive igneous rock textures can be: a) fragmental or glassy texture b) glassy or aphanitic texture c) phaneritic or aphanitic texture d) aphanitic or glassy or fragmental texture

lighter

felsic igneous rocks tend to have ____ color shades

c) LIPs

flood basalts are characteristics of: a) subduction zones b) mid-ocean ridges c) LIPs d) all of them

lava

hot rock melt on earth's surface is called ________

magma

hot rock melts inside the earth is called ________

d) all of them

in a flux-induced melting which of the following can act as flux? a) water vapor b) carbon dioxide c) sulphur dioxide d) all of them

c) hotspots

intraplate volcanism is seen at: a) subduction zones b) mid-ocean ridges c) hotspots d) all of these

mid-ocean ridges, continental rifts, hot spots

list 3 tectonic and or mantle processes that trigger decompression melting.

rift valleys, mid-ocean ridges, subduction zones, hot spots

list the 4 tectonic settings where igneous activity occurs: ________________________

very dark

mafic igneous rocks tend to have _____ color shades

a) limestone

the dominant rock type in coral reef is: a) limestone b) sandstone c) shale d) conglomerate

d) labrador, canada was a shallow marine underwater region close to the equator

the early cambrian (~500 Ma) rocks in labrador, canada contain ancient coral reefs preserved in rocks. What can you infer about the paleo-geographic position of the labrador region 500 million years ago? a) labrador canada was at the same geographic location in the arctic as it is today b) labrador canada was a depp marine region close to the equator c) labrador canada was in between tropic of cancer and arctic circle d) labrador canada was a shallow marine underwater region close to the equator

d) all of them

the grand canyon carved out by the colorado river exposes? a) sedimentary rocks b) igneous rocks c) metamorphic rocks d) all of them

b) volatile passages in an igneous rock

vesicles in vesicular textures are remnants of: a) melt passages in an igneous rocks b) volatile passages in an igneous rock c) passages through which crystals settle out from an igneous rock

c) number of sources involved

what does sorting of a clastic sedimentary rock indicate? a) distance of transport b) degree of rounding c) number of sources involved d) all of them

great barrier reef

what is the giant reed system along the coast of NE australia known as?

c) overburden pressure

what is the primary factor that keeps the mantle rocks from melting at very high temperatures of ~3000C? a) chemical composition of the rocks b) crystal structure of the minerals in rocks d) overburden pressure

c) decompression melting

what kind of melting do you expect in a continental rift tectonic setting? a) flux-induced melting b) heat-transfer melting c) decompression melting

d) breccia

what would you call a rock that has pebble-size angular clasts? a) sandstone b) shale c) conglomerate d) breccia

b) shale

what would you call a very-fine clastic grained sedimentary rock with clay minerals? a) sandstone b) shale c) conglomerate d) rock salt

c) beach

where would you expect a chemical sedimentary rock like rock salt to be deposited? a) deep marine basin b) shallow marine basin c) beach d) swamp

b) shallow marine basin

where would you expect coal to be deposited? a) deep marine basin b) shallow marine basin c) coral reefs d) swamps

c) breccia-conglomerate-sandstone-shale

which of the following arrangements represent a correct sequence of deposition away from the source (i.e. closest to farthest) ? a) shale-breccia-conglomerate-sandstone b) conglomerate-breccia-sandstone-shale c) breccia-conglomerate-sandstone-shale d) shale-sandstone-conglomerate-breccia

d) all of them

which of the following is a chemical sedimentary rock? a) fossiliferous limestone b) oolitic limestone c) micritic limestone d) all of them

a) calcite

which of the following is a dominant mineral in limestone? a) calcite b) quartz c) olivine d) plagioclase feldspar

b) quartz

which of the following is a dominant mineral in sandstone? a) calcite b) quartz c) olivine d) plagioclase feldspar

volcanic explosivity c) ultramafic > mafic > intermediate > felsic

which of the following melt compositions are arranged in the order of increasing volcanic explosivity? a) mafic > ultramafic > intermediate > felsic b) ultramafic > mafic > felsic > intermediate c) ultramafic > mafic > intermediate > felsic d) felsic > intermediate > mafic > ultramafic

a) basalt melts

which of the following melt compositions do you expect to travel long distances? a) basalt melts b) granite melts c) rhyolite melts d) andesite melts

d) all of them

which of the following minerals crystallize via the discontinuous reaction series? a) olivine b) pyroxene c) amphibole d) all of them

b) ca-rich plagioclase and na-rich plagioclase

which of the following pairs of minerals are part of the continuous reaction series? a)pyroxene and amphibole b)ca-rich plagioclase and na-rich plagioclase c)pyroxene and olivine d)olivine and ca-plagioclase

d) obsidian

which of the following rocks displays a stunningly black glassy texture? a) basalt b) andesite c) scoria d) obsidian

c) coquina

which of the following rocks is made up entirely of shells or marine organisms? a) micritic limestone b) oolitic limestone c) coquina d) fossiliferous limestone

b) tuff

which of the following rocks is not derived from an igneous rock melt? a) granite b) tuff c) basalt d) obsidian e) porphyritic andesite

d) all of them

which of the following rocks would you expect to react with acid? a) micrite b) fossiliferous limestone c) chalk d) all of them

d) all of them

which of the following statements are true about sedimentary formations? a) they are arranged in layers b) they are mappable c) they may contain sedimentary structures d) all of them

d) all of them

which of the following words may be used to describe portions of rock with porphyritic texture? a) aphanitic b) phenocrysts c) groundmass d) all of them