Q&A Hero

Q: When rocks experience high temperatures and differential stresses deep in the Earth, their grains tend to ________. A) break in small fragments like a piece of fine crystal B) fracture along planes of weakness C) flatten and elongate D) form new minerals

Q: Confining pressure is where ________. A) forces are applied equally in all directions B) forces are applied from the top and the bottom equally C) pressure is applied in a cubic region D) pressure is parallel to the bedding planes

Q: The quartz in granite begins to melt at 650oC, so if we find a migmatite where quartz has melted in a granitic rock and we know the temperature in the region increased with depth by about 25oC per kilometer, we could estimate the depth that the rock had been at to be about ________. A) 12.5 km B) 18.0 km C) 23.5 km D) 26.0 km

Q: In an area where the temperature increase with depth averages 20oC per kilometer, the temperature at a depth of 5 kilometers would be ________. A) 100oC B) 200oC C) 50oC D) 20oC

Q: The major role of thermal energy (heat) in metamorphism is ________. A) reducing the strength of rocks so that stress can be an effective agent of change B) increasing the processes of dissolution and flow of different minerals C) driving chemical reactions that lead to recrystallization D) providing energy for the physical changes that occur during metamorphism

Q: The most important agent(s) of metamorphism, according to your text, is (are) ________. A) chemically active fluids B) heat C) differential stress D) confining pressure

Q: Mountain building causes metamorphism because ________. A) mountains are heavy and they compress the rocks under them. B) mountains are heavy and they push shallow, cool rocks to depths where they get heated C) mountains form by the gradual buildup of material that comes from other areas and this can produce an uneven pressure on rocks D) all of the above

Q: The low grade metamorphism of shale produces ________. A) marble B) schist C) gneiss D) slate

Q: Metamorphism occurs when a rock ________. A) experiences conditions that include high temperatures B) experiences conditions that include high pressures C) experiences conditions that are significantly different from those that formed the rock D) experiences conditions that are similar to those that formed the rock

Q: For a geologist, the most important characteristic of a sedimentary rock is its ________. A) texture B) composition C) layering D) lithology

Q: The common source of pressure during compaction of sediments is ________. A) the weight of the sediments deposited above the compacting sediments B) the pressure of the sediments pushing the compacting sediments out of the way during deposition C) the weight of the compacting sediments causing internal pressure D) the weight of water above the sediments after they are deposited

Q: Coal beds originate in ________. A) shallow lakes in a dry, desert region B) channels of fast-moving streams C) deep, marine basins below wave action D) freshwater coastal swamps and bogs

Q: Which of the following best describes bedded gypsum and rock salt? A) detrital sedimentary rocks B) varieties of dolostone C) varieties of coal and peat D) evaporates; chemical, sedimentary rocks

Q: The most abundant chemical sedimentary rock is ________. A) limestone B) dolomite C) chert D) rock salt

Q: Compaction would probably be most significant as a lithification process for ________. A) shale B) sandstone C) conglomerate D) breccia

Q: Detrital sediments would predominate in all of the following environments except ________. A) swamp B) salt flat C) river floodplain D) delta

Q: Which rock type is associated with a high-energy environment (such as a very turbulent stream)? A) conglomerate B) shale C) chert D) none of these

Q: Sedimentary rocks comprise approximately ________ percent of Earth's outermost 10 miles. A) 5 B) 15 C) 30 D) 50

Q: An important condition for the formation of coal is ________. A) abundant plant and animal life in a region B) decomposition of organic matter with abundant oxygen C) incomplete decomposition of organic matter due to a lack of oxygen D) acid rich waters that reduce the organic matter to pure carbon

Q: Death Valley is a site where ________ sedimentary rocks are common. A) detrital B) evaporite C) biochemical D) clastic

Q: Travertine, a form of limestone commonly found in caves, forms ________. A) when water in a cave is heated B) when water in a cave is cooled C) when carbon dioxide in the water escapes into the air D) when carbon dioxide from the air contacts the moisture in the cave

Q: Chemical weathering would be most effective ________. A) in a warm, dry climate B) in a cold, dry climate C) in a warm, humid climate D) equally in any kind of climate

Q: Which one of the following is not related to chemical weathering? A) decomposition B) frost wedging C) hydrolysis D) oxidation

Q: Chalk forms from ________. A) the hard parts of microscopic organisms that accumulate on the sea floor B) magnesium rich fluids that chemically alter limestone bearing reefs C) direct precipitation from seawater D) evaporation of magnesium rich waters

Q: Limestone is formed primarily through ________. A) direct precipitation from seawater B) chemical interactions between ocean bottom sediments and ions in sea water C) biochemical sediments secreted by marine organisms D) evaporation of calcite rich seawater

Q: Chemical sedimentary rocks form from materials ________. A) carried in solution B) too fine to see without a microscope C) that form weak bonds with oxygen D) all of the above

Q: Silts and clays are commonly deposited in lakes, lagoons, swamps and marine environments because ________. A) those settings are more acidic B) those settings are more basic C) those settings have relatively still water D) those settings have highly varied activities and multiple inlets for water

Q: The most common sedimentary rock is ________. A) sandstone B) shale C) conglomerate D) breccia

Q: When sand lithifies, the resulting rock is commonly called ________. A) sandstone B) shale C) conglomerate D) breccia

Q: Breccia, a rock with angular particles, is likely to have traveled ________. A) in a mountain stream B) only a short distance C) a long distance D) in a glacier

Q: Detrital sedimentary rocks are typically classified on the basis of their ________. A) lithology B) texture C) provenance D) particle size

Q: Which of the following is not a product of the chemical weathering of potassium feldspar? A) silica B) potassium ions C) iron oxide D) clay

Q: Which of the following pairs are likely products of weathering granite? A) sandstone and calcite B) feldspar and mica C) clay and quartz D) olivine and pyroxene

Q: Which of the following is an economically important sedimentary rock? A) marble B) coal C) pumice D) calcite

Q: Most sediment is formed by ________. A) settling out of a fluid B) the downhill movement of material during mass wasting C) the rapid distribution of material in a mountain stream D) rocks that erode from the bottoms of glaciers

Q: The first step in turning a rock into a sediment is ________. A) gravity and erosional agents (wind, water, etc.) remove material from the parent rock B) rock is broken into small pieces during the transportation phase C) weathering alters the rock D) compaction

Q: Igneous rock is formed ________. A) by the weathering of preexisting rocks B) by changes in mineral composition C) at great depth within Earth D) by crystallization of magma

Q: The texture of an igneous rock ________. A) is controlled by the composition of magma B) determines the color of the rock C) is caused by leaching D) records the rock's cooling history

Q: Select from the list below the coarse-grained rock which is composed mainly of quartz and potassium feldspar. A) basalt B) andesite C) granite D) diorite

Q: Which one of the following is an igneous rock? A) limestone B) rhyolite C) slate D) shale

Q: Rhyolite is the fine-grained equivalent of this igneous rock. A) basalt B) andesite C) granite D) diorite

Q: Granite and gabbro ________. A) have a similar mineral composition B) have a similar texture C) are similar in both texture and mineral composition D) are not similar in either texture or mineral composition

Q: Which igneous texture is characterized by two distinctively different crystal sizes? A) fine-grained B) glassy C) coarse-grained D) porphyritic

Q: Obsidian exhibits a ________ texture. A) fine-grained B) glassy C) coarse-grained D) porphyritic

Q: A porphyritic texture where large crystals are embedded in a matrix of small crystal may form when ________. A) climate change causes crystals to cool at different rates B) crystals of different compositions cool at different rates C) crystals of different compositions grow to different sizes D) a magma that has partially crystallized slowly moves to a different location where it then cools rapidly.

Q: Intrusive igneous rocks are often characterized as coarse-grained because ________. A) the pressures at depth cause them to have a rough texture B) the slow cooling at depth allows large crystals to grow C) the uplift process that exposes the rock fractures them and makes them rough D) small holes from escaping gases leave them rough and course

Q: Rocks that contain high amounts of silica typically also contain ________. A) iron, magnesium, potassium B) aluminum, magnesium, and potassium C) aluminum, sodium, and potassium D) calcium, magnesium, and potassium

Q: Which of the following is not true of peridotite? A) It is rarely found at the Earth's surface. B) It is denser than basaltic rocks. C) It is composed almost entirely of olivine and pyroxene. D) It is the main constituent of the Earth's crust.

Q: Igneous rocks with an andesitic composition ________. A) are denser than basaltic compositional rocks B) make up most of the sea floor C) are denser than granitic compositional rocks D) are found primarily in continental interiors

Q: Which of the following is not a dark silicate mineral? A) biotite B) amphibole C) quartz D) pyroxene

Q: If magma or lava cools quickly, the resulting igneous rock will have ________. A) more silicate minerals B) more variations in mineral types C) very small crystals D) very large crystals

Q: Why do crystals in a magma stop growing during cooling? A) They run out of space. B) They run out of heat. C) They become too dense to grow. D) The pressure from rocks above becomes too great and the magma stops growing crystals.

Q: Which of the following places is well known for its intrusive igneous rocks that were exposed by erosion? A) Mount St. Helens Volcano B) Hawaii C) Yosemite National Park D) Yellowstone National Park

Q: What is the difference between "magma" and "lava"? A) Magma is formed deep in the Earth and lava forms near the surface of the Earth. B) It is just a name change, and lava is what magma is called if it reaches the surface of the Earth. C) Magma makes igneous rocks and lava forms volcanoes. D) Magma is less dense than lava.

Q: What is the most common place for sediment to be deposited? A) rivers B) beaches C) mountains D) oceans

Q: What is required for an igneous rock to weather? A) It must move downslope under the influence of gravity. B) It must be exposed at the surface of the Earth. C) It must be uplifted from where it was emplaced. D) It must be deposited by water or ice.

Q: Why does magma rise toward the Earth's surface? A) because it is hot B) because it is a liquid C) because it is less dense than the material around it D) because it is immiscible and cannot combine with the material around it

Q: Joe Geologist discovers a vein made up primarily of quartz but also containing significant amounts of pyrite as well as chalcopyrite. He knows better than to fall for fool's gold, and decides to ignore the vein. Did he make the right decision? Explain.

Q: Gold is one of the rarest elements in the universe, yet it is extracted from ores on Earth. How is this possible?

Q: There are people who specialize in "cutting" diamonds, yet diamond is the hardest known substance. From your knowledge of minerals, which of the following describes what the diamond cutter does?

Q: Talc and graphite are two of the lowest minerals on the hardness scale. They are also described by terms like greasy or soapy. Both have a crystal structure characterized by sheet-structures at the atomic level, yet they don't behave like micas. What accounts for their unusual physical properties?

Q: A naturally occurring concentration of metallic minerals that can be extracted economically is called ________ whereas any occurrence of useful minerals that are formed in such quantities that eventual extraction is reasonably certain, but not necessarily profitable, are called ________ resources.

Q: Wood floats in water and rocks sink; thus, the density of ________ is the lower of the two.

Q: The physical property denoting a mineral's tendency to crack along parallel, planar surfaces is known as ________.

Q: What physical property denotes the color of a powdered mineral?

Q: The atomic particle that carries a positive charge is called a(n) ________.

Q: What is the smallest particle of matter that exhibits and defines the distinctive chemical characteristics of the individual elements?

Q: A compound is a stable chemical substance composed of two or more ________.

Q: Quartz sand is a useless commodity unless you want to rebuild a beach.

Q: Many metals are extracted from ores that contain sulfide minerals.

Q: Building stone, sand and gravel, and fertilizers are industrial materials that are a special class ore deposits but are usually subject to the same regulations as other ores.

Q: Nonmetallic minerals like halite and gypsum have no industrial uses.

Q: Although fluorite and native sulfur are not metallic minerals, deposits of these materials are still called ore deposits.

Q: Diamond and quartz are both minerals composed of a single element.

Q: Quartz forms at a lower temperature than olivine.

Q: In the silicon-oxygen tetrahedron, there are more silicon atoms than oxygen atoms.

Q: Silicon-oxygen bonds are weak and cause cleavage to be common in silicate minerals.

Q: Cleavage is related to the internal structure of a mineral.

Q: A minerals luster is produced by its ability to transmit light. Opaque minerals always have a metallic luster because they do not transmit any light.

Q: A brown mineral specimen and a green mineral specimen have identical hardness; therefore, they are the same mineral, but just happen to be different color