Ch. 5

a finely crystalline or glassy igneous texture indicates that: a. there was a lot of gas in the magma b. the rock cooled quickly c. the rock broke apart as it flowed d. the rock cooled slowly e. the ash and pumice were hot and became compacted

a vesicular igneous texture indicates that: a. there was a lot of gas in the magma b. the rock cooled c. the rock broke apart as it flowed d. the rock cooled slowly e. the ash and pumice were hot and became compacted

Coarsely crystalline igneous textures indicate that: a. there was a lot of gas in the magma b. the rock cooled c. the rock broke apart as it flowed d. the rock cooled slowly e. the ash and pumice were hot and became compacted

a welded igneous texture indicates that: a. there was a lot of gas in the magma b. the rock cooled quickly c. the rock broke apart as it flowed d. the rock cooled slowly e. the ash and pumice were hot and became compacted

a volcanic breccia texture indicates that: a. there was a lot of gas in the magma b. the rock cooled quickly c. the rock broke apart as it flowed d. the rock cooled slowly e. the ash and pumice were hot and became compacted

An igneous pegmatite indicates that: a. there was water in the magma b. the rock cooled slowly and then quickly c. the rock broke apart as it flowed d. the rock cooled quickly e. the ash and pumice were hot and became compacted

a porphyritic igneous texture indicates that: a. there was water in the magma b. the rock cooled slowly and then quickly c. the rock broke apart as it flowed d. the rock cooled slowly e. the ash and pumice were hot and became compacted

which of the following rock types requires dissolved gas in the magma? a. granite b. pumice c. gabbro d. diorite e. andesite

which of following igneous rocks can be composed of fragments? a. tuff b. scoria c. volcanic breccia d. all of these

which of following rock types does NOT involve dissolved gas in the magma? a. tuff b. pumice c. scoria d. diorite e. vesicular basalt

which of the following can occur within a magma chamber? a. sinking or floating crystals may change the composition of the remaining magma b. wall rocks can melt and become incorporated into the magma c. if two magmas mix, the resulting magma would be between the composition of the two d. all of these

which of the following processes has added heat to Earth's interior during or after its formation? a. collision of asteroids and meteoroids with earth b. formation and sinking of masses of iron and nickel c. radioactive decay d. all of these

the main processes that happens during the alpha type of radioactivity decay is: a. an electron is given off b. an electron is absorbed and turned into a neuron c. an atom splits into two pieces d. an alpha particle combines with small atom to make a larger one

which of the following is the best example of heat transfer by conduction? a. a pan is placed directly on a burner b. water within the pan flows in a circular path c. a burner gives heat through the air without toughing the object

which of the following is the best example of heat transfer by conduction? a. newly created lithosphere loses heat to adjacent rocks b. water flows in a circular path in a pan c. a burner gives heat through the air without touching the object d. seawater is drawn into a mid-ocean ridge

which of the following is an example of heat transfer by convention? a. water within a pan heated and flows in a circular path b. seawater drawn into a mid-ocean ridge, heated, and rises c. the rise of material beneath mid-ocean ridges coupled with subduction d. all of these

How does the addition of water cause melting? a. it heats the rocks b. it decreases the pressure on the rocks c. it increases the temperature while decreasing the pressure d. it changes the location of the liquid-solid boundary

which of the follwoing acts to keep a rock solid (instead of melting)? a. an increases in temp. b. an increase in the vibration with lattice c. an increase in confining pressure d. none of these

When melting forms magma: a. rocks in the source region generally are completely melted b. partial melting produces a magma that is more felsic than the source c. melting of the mantle generally produces felsic magma d. melting of continental crust generally produces mafic magma e. none of these

which of the following is common during crystallization of magma? a. felsic minerals crystallize first b. mafic minerals are light and float in most magma chambers c. felsic crystals are heavy and sink in most magma chambers d. all crystals form at about the same time e. none of these

which of the following processes could result in a felsic magma? a. partial melting of an intermediate-composition source b. partial melting of continental crust c. formation and settling of mafic crystals in an intermediate magma d. all of these

which are important ways that magma can raise through the crust? a. through fractures that can form dikes b. pieces of the wall rocks that break off and provide space c. tectonic forces can help open pathways d. magma is hotter and less dense than its surrounding e. all of these

which of the following factors helps magma rise toward earths surface? a. pressure decreases with increasing depth b. magma is more dense and therefore tougher than the surrounding solid rocks c. gas bubbles generally form at great depth and drive magma upward d. none of these

which of the following causes magma to be less viscous? a. a lower temperature b. fewer silicate chains in the magma c. a more felsic composition d. a higher percentage of crystals? e. none of these

which of the following minerals would likely crystallize early from magma? a. mafic minerals b. quartz c. muscovite d. potassium

which of the following is NOT a way that magma can lose heat to begin solidifying ? a. conduction to surrounding solid rocks b. loss of thermal energy c. water that is heated and circulated near the magma d. an increase in the rate of radioactive decay

which of the following igneous rocks would be formed by the fastest cooling? a. very coarse granite pegamite b. coarse granite c. medium-grained granite d. fine-grained granite e. volcanic glass

which of the following igneous rocks would be formed by the slowest cooling? a. coarse granite b. medium-grained granite c. fine-grained granite d. volcanic glass e. there is not enough info to tell

which of the following igneous rocks has a texture consistent with a magma that cooled and solidified slowly at first, followed by more rapid cooling? a. small felsic crystals enclosed in large mafic ones b. small mafic crystals enclosed in large felsic ones c. large crystals like those in pegamite d. large, early formed crystals surrounded by smaller, late formed crystals

which of the following igneous rocks is NOT characteristics of mid ocean ridges? a. finely crystalline rocks that formed in dikes b. gabbro that solidified in a magma chamber c. pillow basalt d. andesite and grandiorite

the main cause of melting along subduction zones is the: a. rise and decompression melting of mantle lithosphere b. rise and decompression melting of mantle lithosphere c. melting of the subducting plate d. release of water from the subducting plate

what generally happens when subduction-derived magma encounters thick continental crust? a. most magma reaches the surface with minor modification b. the magma solidifies in sheeted dikes with a composition of basalt c. the magma interacts with the crust, forming felsic or intermediate compsoitions d. the oceanic crust melts

which of the following settings is most likely to have eruptions? a. island arcs b. subduction beneath a thin continental plate c. subduction beneath a thick continental plate d. mid ocean ridge e. none of these

the main way water gets into a subduction zone is by: a. heating of the overlying continental crust b. a decrease in pressure that causes melting c. rain associated with eruptions in the island arcs d. seawater introduced into oceanic crust at the mid ocean ridge prior to subduction e. all of these

which of the following occurs during a continental collision, after any subduction has ended? a. the decreasing continental plate gets hotter and decreases in pressure b. decreasing pressure causes downgoing crust to melt c. volcanoes are widespread above continental collisions d. all of these e. none of these

Hot spots in oceanic settings typically produce: a. flood basalts in the middle of a continent b. huge caldera explosions c. island arcs d. lines or clusters of volcanic islands

a hot spot is interpreted to have formed from: a. extreme heating of the seas near the equator b. abundant magma produced within a subduction zone c. abundant magma formed within a typical mid-ocean ridge d. a rising plume of hot mantle material

a mantle plume rises because: a. it is mostly molten b. it is solid but less dense than material around it c. it is molten and more dense than material around it d. it is propelled upward by gas out the magma

hot spots in continental setting typically produce? a. high continental plateaus, such as Tibet b. lines or clusters of islands c. basaltic lava flows or explosive calderas d. new oceanic crust

what is typically occurring when magmatism occurs far away from plate boundaries? a. new oceanic crust is created at mid-ocean ridges b. large volcanoes are built above subduction zones c. some type of thermal disturbance is occuring in the mantle d. all of these

a volcanic neck can form by: a. erosion of the volcano, leaving behind the solidified conduit inside the volcano b. erosion of the overlying rock layers exposing the conduit below the volcano c. both of these

which of the following were involved in bringing the deep batholithic rocks to the surface? a. uplift of the rocks over tens of millions of years b. a hot spot that formed a broad continental plateau c. a continent-continent collision with Australia d. the recent restarting of subduction beneath the area

most igneous rocks in the Sierra-Nevada batholith formed form: a. a hot spot beneath continental crust b. continental rifting c. ocean-continent convergence d. transform faulting

which of the following was NOT in forming magmas of the main batholith? a. subduction beneath western North America b. water that caused partial melting of hot mantle c. partial melting of continental crust d. solidification of magma below the surface e. recent normal faulting along the east side of the batholith

which of the following characteristics of the Sierra Nevada? a. peaks and cliffs of gray granite b. a large area of granite rock c. metamorphism of rocks within and adjacent to a batholith d. all of these