(1) What is the major difference (in appearance) between intrusive and extrusive igneous rocks and Why?
(2) What is the difference between basalt and rhyolite (or between gabbro and granite)?
(3) What are andesite and dacite?
(4) Where do basalt magmas most commonly come from?
(5) What is Bowen's reaction series, and how is it important in the origin of different compositions of igneous rocks?
(6) What is the difference between a batholith, a pluton, a dike, and a sill?
(7) What is the difference in style of eruption between basalt and rhyolite... and why?
(8) What are the two main ways in which the mantle is believed to melt?
In addition to these, what additional
mechanism might lead to melting of the crust?
(9) What is the difference between clastic, chemical, and biochemical sedimentary rocks?
(10) What is te difference between conglomerate, sandstone, and mudstone?
(11) What is the difference between conglomerate and breccia?
(12) Explain how the processes of weathering, transportation, and deposition
can affect the
appearance and composition
of sedimentary rocks.
(13) What is lithification, and how does it occur?
(14) What are sedimentary structures (and how are they useful in helping us read the history of rocks)?
(15) What is metamorphism?
(16) What is metamorphic grade?
(17) What are metamorphic textures and deformational fabrics?
(18) Discuss the geologic or tectonic environments in which one might expect to get (1) low-pressure metamorphism (including contact metamorphism), (2) medium pressure metamorphism (regional metamorphism), and (3) high-pressure metamorphism of sedimentary rocks.
(19) What is the rock cycle? Summarize it briefly.
(20) Read over the observations and conclusions on pages 104-106.
x. Take a look at figure 4.2 Determine what the oceanic and continental thermal gradients are (expressed in ûC per km) by measuring their slopes (just consider the straight part of the lines, up to perhaps 75km depth). From the continential thermal gradient you have determined, how hot would you expect it to be at the bottom of a deep (2km) mine shaft if the surface temperature is 0ûC? Describe how you calculate this.
x. Why are there volcanoes in Washington and Oregon today, but none in Kansas?
x. A sandstone composed entirely of well-rounded quartz grains would be called mature. If the original source rock for the sediments was a granite, what processes must have acted on the granite to produce a pure quartz sand?
x. If you lived within 10 km of a volcano that was liable to erupt at any time, which type would you hope it was and why?
x. We know that hard detrital sedimentary rocks must have been originally deposited as loose sediments. What mechanisms can you suggests that would convert a loose sediment into a hard rock?
x. Use figure 4.4 to estimate the types of minerals and their percentages that you would expect to find in (a) granodiorite; (b) basalt (c) rhyolite.
x. a) If a mudstone were subjected to regional metamorphism (high pressure and temperatures), what sort of metamorphic rock might form? b) If the same mudstone was subjected to contact metamorphism (high temperature but low pressures), what sort of metamorphic rock might form? c) What would be the difference in texture between the metamorphic rocks formed in (a) and (b) respectively?
x. Describe the type of sediment that you might find in a mountain stream in terms of clasts, their sizes, and their shapes. If you followed the stream all the way to the ocean, how would the sediment change?
x. What are the major difference among contact metamorphism, regional metamorphism and high-pressure metamorphism? Can you imagine how contact metamorphism might become a type of regional metamorphism? Devise a scenario that could produce eclogite by metamorphosis and return it to the EarthÕs surface.
xx) Andesite magma may be produced from a basaltic magma by: (a) fractional crystallization (b) partial melting (c) addition of gases (d) increased pressure (e) increased temperature
xx) The exact sequence of mineral crystallization from a given magma depends upon: (a) magma composition (b) pressure (c) Bowen's Reaction Series (d) rate of crystallization (e) all of these
xx) A wide range of igneous rock compositions is generated by: (a) partial melting (b) fractional crystallization (c) different sites of magma origin (d) contamination (e) all of these
xx) The mantle geotherm and mantle solidus come closest at the: (a) base of the continental crust (b) base of the mantle (c) all of these (d) base of the oceanic crust (e) base of the lithosphere
xx) The single most characteristic feature of sedimentary rocks is: (a) layering (b) fossils (c) quartz grains (d) red color (e) oil xx) The fossil fuel produced by compression of accumulated land plants is: (a) coal (b) oil (c) natural gas (d) uranium (e) all of these
xx) Which of these minerals survives erosion and transport nearly unaltered? (a) plagioclase (b) olivine (c) pyroxene (d) amphibole (e) quartz
xx) The most common cementing agents in sedimentary rocks are: (a) anhydrite, calcite (b) pyrite, gypsum (c) silica, calcite (d) calcite, pyrite (e) silica, gypsum
xx) Which of the sedimentary processes is diagenetic? (a) decrease in volume (b) expulsion of water (c) formation of new minerals (d) cementation (e) composition
xx) Which rock represents the highest grade of metamorphism? (a) migmatite (b) schist (c) phyllite (d) gneiss (e) slate
xx) Which of the following is not an example of foliation in a rock: (a) schistosity (b) slaty cleavage (c) alignment of mica flakes (d) gneissic banding (e) sedimentary layering
xx) Mylonite is a cataclastic metamorphic rock produced by: (a) meteorite impact (b) batholithic heat (c) hydrothermal processes (d) fault movement (e) all of these xx) Metallic ore deposits at oceanic ridge crests are a result of _________ metamorphism: (a) high-pressure (b) hydrothermal (c) regional (d) contact (e) cataclastic
xx) Which feature would you not expect to observe in a volcanic rock: (a) glassy texture (b) porphyritic texture (c) porphyroblasts (d) phenocrysts (e) bubbles
xx) Which feature would you expect to see in a foliated metamorphic rock: (a) bedding (b) aligned platy minerals (c) intergrown calcite crystals (d) fossils (e) all of these
xx) Which of these physical features would most likely be present in a plutonic rock: (a) aligned platy minerals (b) trace fossils (c) glassy texture (d) phaneritic texture (e) bubbles
xx) Internal heat of the Earth fuels these types of processes: (a) erosion and weathering (b) weathering, and formation of magma (c) sediment deposition, and plate tectonics (d) hydrologic and hydrothermal (e) plate tectonics, and magma formation
1) A fine-grained igneous rock of intermediate composition is A) obsidian. B) granite. C) andesite. D) basalt. E) gabbro. -Answer: __
2) A phaneritic igneous rock of felsic composition is A) granite. B) rhyolite. C) diorite. D) andesite. E) gabbro. -Answer: __
Match the igneous rock textural terms with their definitions below.
3) A rock will all crystals visible to the naked eye A) phaneritic B) porphyritic C) glassy D) aphanitic E) phenocrystic -Answer: __
4) A rock with some visible and some microscopic crystals A) phaneritic B) porphyritic C) glassy D) aphanitic E) phenocrystic -Answer: __
5) A rock with all crystals microscopic A) phaneritic B) porphyritic C) glassy D) aphanitic E) phenocrystic -Answer: __
6) A rock with no crystals A) phaneritic B) porphyritic C) glassy D) aphanitic E) phenocrystic -Answer: __ 7) Visible crystals in a mixed-texture rock A) phaneritic B) porphyritic C) glassy D) aphanitic E) phenocrystic -Answer: __
8) A petrographer would not use this mineral attribute to identify a mineral in thin section. A) cleavage B) color C) relief D) hardness E) birefringence -Answer: __
9) Andesite magma may be produced from a basaltic magma by A) fractional crystallization. B) partial melting. C) addition of gases. D) increased pressure. E) increased temperature. -Answer: __
10) The exact sequence of mineral crystallization from a given magma depends upon A) magma composition. B) pressure. C) Bowen's Reaction Series. D) rate of crystallization. E) all of the above -Answer: __
11) A wide range of igneous rock compositions is generated by A) partial melting. B) fractional crystallization. C) different sites of magma origin. D) contamination. E) all of the above -Answer: __ Fit the types of igneous intrusions in A through E to their descriptions in the following questions.
12) A large mosaic of plutons welded together A) pluton B) sill C) dike D) batholith E) volcanic neck -Answer: __
13) Sheet-like intrusive which cuts across the grain of older rocks A) pluton B) sill C) dike D) batholith E) volcanic neck -Answer: __
14) Cylindrical mass of shallow plutonic rock A) pluton B) sill C) dike D) batholith E) volcanic neck -Answer: __
15) Thin intrusive parallel to layers of near-surface rocks A) pluton B) sill C) dike D) batholith E) volcanic neck -Answer: __
16) Irregularly shaped intrusive mass a few kilometers across A) pluton B) sill C) dike D) batholith E) volcanic neck -Answer: __ Match each of the volcanic features listed in A through D with its description.
17) Hawaiian-type volcano A) cinder cone B) shield volcano C) composite volcano D) pyroclastic flow -Answer: __
18) Small, steep sided volcano formed mostly of pyroclastic debris A) cinder cone B) shield volcano C) composite volcano D) pyroclastic flow -Answer: __
19) Collapsing tower of hot ash and gas A) cinder cone B) shield volcano C) composite volcano D) pyroclastic flow -Answer: __
20) Volcano type at convergence (subduction) zones A) cinder cone B) shield volcano C) composite volcano D) pyroclastic flow -Answer: __
21) A dike and a sill are related in that they A) are both tabular. B) are both igneous bodies. C) both can be basaltic in composition. D) may be intruded at shallow levels in Earth's crust. E) all of the above -Answer: __
22) The mantle geotherm and mantle solidus are closest at the A) base of the continental crust. B) base of the mantle. C) all of these D) base of the oceanic crust. E) base of the lithosphere. -Answer: __
23) Bowen's reaction series explains A) the sequence of crystallization of minerals from a granitic magma. B) the sequence of formation of minerals in a sedimentary cement. C) the continuous reaction from anorthite to hornblende. D) d.d. the sequence of crystallization of minerals from a basaltic magma. E) the discontinuous reaction from anorthite to albite. -Answer: __
24) Felsic rocks are generally A) dark colored. B) light colored. C) rich in olivine and pyroxene. D) not found in continental crust. E) rich in iron. -Answer: __
25) The single most characteristic feature of sedimentary rocks is A) layering. B) fossils. C) quartz grains. D) red color. E) oil. -Answer: __
26) The fossil fuel produced by compression of accumulated land plants is A) coal. B) oil. C) natural gas D) uranium E) all of these -Answer: __
27) Which of these minerals survives erosion and transport nearly unaltered? A) plagioclase B) olivine C) pyroxene D) amphibole E) quartz -Answer: __
28) Given the following values, calculate the temperature in the Earth at a depth of 15 km below the surface. (geothermal gradient = 25eC/km, surface temperature = 20eC/km) A) 1000eC B) 395eC C) 375eC D) 355eC E) 300eC -Answer: __
29) Shield volcanoes are A) broad with gentle slopes. B) narrow with steep slopes. C) composed mostly of ash. D) almost always felsic. E) generally found above subduction zones. -Answer: __
30) A mature sedimentary rock is characterized by A) rounded grains. B) durable minerals. C) small grain size. D) well sorted texture. E) all of the above -Answer: __
31) Which of these clastic rocks exhibits the least maturity? A) conglomerate B) sandstone C) breccia D) shale E) all of the above -Answer: __
32) The sedimentary rock type which is altered organic remains is A) salt. B) chalk. C) bioclastic limestone. D) coal. E) shale. -Answer: __
33) A rock formed from gravel is called A) conglomerate. B) peat. C) dolomite. D) stone. E) gravel. -Answer: __
34) By definition, a sediment is A) always deposited in marine water. B) unconsolidated. C) lithified. D) never organic. E) always deposited in streams and rivers. -Answer: __ Match the sedimentary structures in A through E with their descriptions in the following question(s).
35) Indicates alternating wet and dry conditions A) cross-bedding B) graded beds C) mudcracks D) trace fossils -Answer: __
36) Deposited from a current A) cross-bedding B) graded beds C) mudcracks D) trace fossils -Answer: __
37) Burrows, tracks and trails organisms A) cross-bedding B) graded beds C) mudcracks D) trace fossils -Answer: __
38) Submarine mudflow feature A) cross-bedding B) graded beds C) mudcracks D) trace fossils -Answer: __
39) The most common cementing agents in sedimentary rocks are A) anhydrite, calcite. B) pyrite, gypsum. C) silica, calcite. D) calcite, pyrite. E) silica, gypsum. -Answer: __
40) Which of the following sedimentary processes is diagenetic? A) decrease in volume B) expulsion of water C) formation of new minerals D) cementation E) composition -Answer: __
41) The normal sequence of events in the production of sedimentary rocks is A) erosion, weathering, transportation, deposition, compaction, cementation. B) weathering, erosion, transportation, deposition, compaction, cementation. C) stoping, slumping, abrasion, contraction, compaction, subsidence. D) weathering, erosion, transportation, compaction, deposition, cementation. E) weathering, erosion, connection, conduction, transportation, landing, disembarkation. -Answer: __
Match the type of change in A through D to each of the metamorphic transitions below.
42) Growth of garnets in basalt protolith A) texture B) fabric C) mineralogy D) chemistry -Answer: __
43) Development of schistosity A) texture B) fabric C) mineralogy D) chemistry -Answer: __
44) Growth of porphyroblasts A) texture B) fabric C) mineralogy D) chemistry -Answer: __
45) Conversion of amphibole to pyroxene A) texture B) fabric C) mineralogy D) chemistry -Answer: __
46) Which rock represents the highest grade of metamorphism? A) migmatite B) schist C) phyllite D) gneiss E) slate -Answer: __
47) The rate at which temperature increases with depth is known as the A) metasomatic gradient. B) geothermal gradient. C) metamorphic gradient. D) depth gradient. -Answer: __
Select the metamorphic rock that fits each description given in the following questions.
48) The metamorphic equivalent of sandstone A) marble B) quartzite C) slate D) schist E) gneiss -Answer: __
49) The low grade metamorphic equivalent of shale A) marble B) quartzite C) slate D) schist E) gneiss -Answer: __
50) The rock made of calcite crystals A) marble B) quartzite C) slate D) schist E) gneiss -Answer: __
51) Granite could become this rock under strong directed stress A) marble B) quartzite C) slate D) schist E) gneiss -Answer: __
52) Consists mostly of megascopic aligned platy minerals A) marble B) quartzite C) slate D) schist E) gneiss -Answer: __
53) Which of the following is not an example of foliation in a rock? A) schistosity B) slaty cleavage C) alignment of mica flakes D) gneissic banding E) sedimentary layering -Answer: __
54) A fine grained metamorphic rock that splits easily along parallel planes is a A) slate. B) gneiss. C) schist. D) marble. E) hornblende. -Answer: __
55) Metamorphism is caused by changes in A) magma composition. B) pressure and temperature. C) earthquake magnitude. D) water vapor. E) bed load. -Answer: __
56) The type of metamorphic rock produced by contact (thermal) metamorphism is A) hornfels. B) granite. C) schist. D) shale. E) breccia. -Answer: __
57) High-pressure low-temperature (blueschist) metamorphic rocks originate at A) convergent plate boundaries. B) passive plate margins. C) divergent plate boundaries. D) transform plate boundaries. E) all of the above -Answer: __
58) Which of the following lists represents the most probable sequence of rocks produced by the metamorphism of a shale? A) shale > slate > schist > micaceous gneiss B) shale > sleet > swish > gneiss C) sandstone > shale > siltstone > gneiss D) shale > gneiss > slate > basalt E) shale > slate > schist > amphibolite -Answer: __
59) When a metamorphic rock is exposed to the surface by uplift and erosion it is subjected to new and different conditions of lower temperature and lower pressure than when the rock formed. When this happens, A) all of its minerals undergo rapid chemical reactions to reflect the new conditions. B) some of its minerals may not change while others do, reflecting a metastable condition. C) the rock begins to melt. D) volcanic eruptions occur because of escaping gases. E) no changes are likely to occur. -Answer: __
Match each geologic setting below with the most likely type of rock change produced (A through E).
60) Change affecting a subducting plate. A) crystallization B) diagenesis C) regional metamorphism D) high-pressure metamorphism E) contact metamorphism -Answer: __
61) Colliding plates and mountain building. A) crystallization B) diagenesis C) regional metamorphism D) high-pressure metamorphism E) contact metamorphism -Answer: __
62) Processes within a cooling pluton. A) crystallization B) diagenesis C) regional metamorphism D) high-pressure metamorphism E) contact metamorphism -Answer: __
63) Process in country rock near a cooling pluton. A) crystallization B) diagenesis C) regional metamorphism D) high-pressure metamorphism E) contact metamorphism -Answer: __
64) Low temperature, low pressure changes to sediment after burial. A) crystallization B) diagenesis C) regional metamorphism D) high-pressure metamorphism E) contact metamorphism -Answer: __
65) Which feature would you not expect to observe in a volcanic rock? A) glassy texture B) porphyritic texture C) porphyroblasts D) phenocrysts E) bubbles -Answer: __
66) Which feature might you see in a slate? A) barely visible bedding B) aligned platy minerals C) cleavage D) distorted fossils E) all of the above -Answer: __
67) Which of these physical features would most likely be present in a plutonic rock? A) aligned platy minerals B) trace fossils C) glassy texture D) phaneritic texture E) bubbles -Answer: __
68) Internal heat of the Earth fuels these types of processes A) erosion and weathering. B) weathering, and formation of magma. C) sediment deposition and plate tectonics. D) hydrologic and hydrothermal. E) plate tectonics and magma formation. -Answer: __