Q&A Hero

Q: Explain how climate can affect the other four controls of soil formation.

Q: Using the order of crystallization on the Bowen's reaction Series, rate the resistance of silicate minerals to chemical weathering. In other words, which mineral(s) weather first and why? And last?

Q: Decades ago, a brick factory used to be located along a river. Waste materials and faulty bricks were piled along the banks of the river, and some of them fell into the water. Years later, some of these materials were removed. The bricks were still recognizable as bricks, some with the manufacturer's mark clearly visible on the front, but the edges and corners were rounded over. Why were the edges and corners of the bricks so rounded over while the faces of the bricks were largely untouched?

Q: How are humans agents of weathering and erosion?

Q: A burrowing animal is digging its tunnel through rocky soil, moving fresh material to the surface. How is this animal contributing to the weathering of that material?

Q: Because weathering involves the destruction of geologic materials, many people view the process as a bad thing. However, weathering can also be viewed as a positive process. Provide an example of one positive aspect of weathering that makes the processes not only important, but necessary. Explain.

Q: Match the phenomena associated with soil erosion in order from first to last. 1. First 2. Second 3. Third 4. Fourth 5. Fifth A) Formation of gullies B) Stream C) Impact of raindrops D) Sheet erosion E) Formation of rills

Q: Match the soil order with the environment in which it will form. 1. Oxisol 2. Histosol 3. Spodosol 4. Mollisols A) Tropics B) Wetlands/bog C) Humid/conifer forest D) Grasslands/prairie

Q: Match the soil horizon with the correct definition. 1. O horizon 2. E horizon 3. C horizon 4. A horizon 5. B horizon A) Accumulation of clay particles from upper layers B) Partially altered parent material that is easily identifiable C) Composed of a mixture of humus and mineral material D) Consists largely of organic material, still identifiable in uppermost layer E) Light-colored, depleted of soluble materials, little organic material

Q: Match the chemical weathering process with the correct definition. 1. Dissolution 2. Oxidation 3. Hydrolysis A) Minerals dissolved in acidic water. B) Positive ions lose electrons to oxygen. C) Positive ions are replaced with H+ or OH-.

Q: Match the mechanical weathering process with the correct definition. 1. Frost wedging 2. Salt crystal growth 3. Sheeting 4. Biological activity A) Expansion of ice forces a rock apart B) Mineral crystal development forces a rock apart C) Reduction of pressure on a pluton results in concentric layers breaking off D) Living materials break down a rock

Q: Mature soils are characteristic of steep slopes.

Q: A vertical succession of soil horizons is called a soil profile.

Q: Fine-grained particles or iron oxide accounts for red, yellow, and brown colors in soil horizons.

Q: A soil's parent material can consist of weathered mineral matter.

Q: Water expands when it freezes.

Q: Chemical weathering will break down a rock by changing the molecular compounds that make up the rock.

Q: Weathering is the transportation or removal of broken-down materials.

Q: Which of the following is a good method to reduce soil erosion as a result of strong winds? A) Planting grass in natural drainageways B) Creating terraces on steep slopes C) Planting rows of trees and shrubs D) Plant rows for crops that are oriented straight up the slope

Q: Which of the following is a good soil conservation method to reduce the loss of topsoil on gentle slopes that are farmed? A) Planting crops parallel to the contours of the slope. B) Leaving crop residues (i.e., stalks) in place in the field. C) Planting grass in natural drainageways on the slope. D) All of these choices are good for soil conservation.

Q: What is the definition of sheet erosion? A) The removal of soil particles by wind gusts B) Water moving in thin sheets, carrying dislodged soil particles C) Removal of sheets of rock through exfoliation D) Transportation of vegetation from rapidly eroding sediments

Q: Why is soil a nonrenewable resource? A) Because it forms very slowly B) Because there is a limited amount of soil on the Earth and it cannot be replaced C) Because it is not commonly used for human commerce D) Because it cannot be privately owned

Q: Which soil horizon can hold more water due to the accumulation of fine clay particles? A) A horizon B) B horizon C) O horizon D) E horizon

Q: The longer a soil has been forming, the ________ it becomes and the ________ it resembles the parent material. A) thinner; less B) thinner; more C) thicker; more D) thicker; less

Q: ________ is considered the most influential control of soil formation A) Parent material B) Plants C) Climate D) Time

Q: Can soils can be eroded from distant sources and deposited as soil in new locations? A) Yes, they are made of sediments and can be transported like sediments. B) No, soils develop in place through the complex weathering of sediments and other materials. C) Yes, the processes of transportation help to break down larger sediments to make soils. D) No, once a soil is created in a location, it cannot be weathered and eroded.

Q: Oxidation is an effective method to weather iron in olivine. However, what must happen first to free the iron? A) Root wedging to break up the olivine B) Melting of the olivine C) Dissolution of olivine D) Hydrolysis acting on the olivine

Q: Organic acids can chemically weather a rock. Where would these acids originate? A) Decay of granite B) Thermal reaction between water and limestone C) Secretion from and decay of vegetation D) Leaching from the E horizon

Q: What effect will roots have on a sedimentary rock? A) Root tips will promote cementation, making the rock stronger. B) Roots will weaken the cement, splitting the rock apart. C) Roots will wrap around the sediments, holding them tight as the rock cements. D) Roots will add cement to unconsolidated sediments to create a rock.

Q: Which horizons make up the topsoil? A) C horizon B) O and A horizons C) E, B, and C horizons D) O, A, E, and B horizons

Q: Which horizons make up the solum? A) C horizon B) O and A horizons C) E, B, and C horizons D) O, A, E, and B horizons

Q: What is the definition of eluviation? A) Decayed organic material B) Accumulation of fine clay particles in a soil column C) Downward transportation of fine clay particles in a soil column D) The collective term for the O, A, E, and B horizons

Q: ________ are the primary source of organic matter in soils. A) Earthworms B) Microorganisms C) Plants D) Mammals

Q: ________ is a soil that has unconsolidated sediment as its parent material. A) Humus B) Residual soil C) Regolith D) Transported soil

Q: ________ is a soil that has bedrock as its parent material. A) Humus B) Residual soil C) Regolith D) Transported soil

Q: ________ is decayed remains of plant and animal life. A) Regolith B) Gravel C) Amino Acids D) Humus

Q: Which of the following components makes up the largest percentage of most soils? A) Mineral portion B) Pores filled with water C) Organic portion D) Pores filled with air

Q: Soil develops in response to interactions between which Earth spheres? A) Hydrosphere and atmosphere B) Geosphere, atmosphere, and biosphere C) Geosphere, hydrosphere, and atmosphere D) Biosphere, atmosphere, geosphere, and hydrosphere

Q: A(n) ________ is a common boundary where different parts of a system interact. A) sphere B) interface C) delineation D) geosphere

Q: ________ is the upper few feet of regolith that contains minerals and organic matter, water, and air and is capable of sustaining life. A) Horizon B) Humus C) Soil D) Sediment

Q: ________ weathering occurs when differences in resistance or environmental factors produce uneven surfaces on rocks. A) Chemical B) Differential C) Spheroidal D) Mechanical

Q: Which climate contains the optimum environment for chemical weathering? A) Cold and dry B) Warm and dry C) Cold and wet D) Warm and wet

Q: Which of the following rocks will be most resistant to weathering? A) Solid bedrock B) Jointed bedrock C) Bedrock with solution weathering D) Bedrock with sheeting

Q: During hydrolysis, ________ commonly decompose into clay minerals, silica, and soluble constituents. A) feldspars B) halides C) ferromagnesians D) carbonates

Q: ________ and ________ are chemical weathering products created in many metal and coal mining regions and pose serious environmental hazards. A) Carbonic acid; slag B) Nitric acid; coal dust C) Hydrochloric acid; bicarbonate D) Sulfuric acid; iron oxide

Q: Rainwater will combine with which atmospheric gas in order to create carbonic acid? A) Methane B) Oxygen C) Carbon dioxide D) Carbon monoxide

Q: Which chemical weathering process is the primary method of weathering for feldspars? A) Dissolution B) Oxidation C) Frost Wedging D) Hydrolysis

Q: Which acid is commonly responsible for the dissolution of limestone? A) Nitric B) Carbonic C) Sulfuric D) Hydrochloric

Q: What is the most important agent of chemical weathering? A) Salt B) Heat C) Wind D) Water

Q: What environmental condition is reduced on a batholith in order to generate weathering via sheeting? A) Heat B) Moisture C) Pressure D) Mineral content

Q: Which of the following regions has the least likelihood of experiencing weathering via salt crystal growth? A) Arid deserts B) Rocky shorelines along the ocean C) Subterranean cave passages D) Roadways cleared of snow by the spread of halite

Q: Which of the following is not an agent of erosion? A) Running water B) Heat C) Ice D) Wind

Q: ________ weathering is when there is a chemical transformation of rock into other compounds. A) Mechanical B) Chemical C) Spheroidal D) Differential

Q: ________ weathering is when physical forces break solid rock into smaller sediments. A) Mechanical B) Chemical C) Spheroidal D) Differential

Q: An example of a volcanic caldera that formed from the collapse of a magma chamber after large volumes of material were erupted is ________. A) Parcutin B) Yellowstone C) Mount Fujiyama D) Mount Rainier

Q: What kind of viscosity would flood basalts have? A) Low viscosity B) Medium viscosity C) High viscosity

Q: Which of the following is not a method of caldera formation? A) Collapse of magma chamber after large volumes of material are erupted B) Collapse of a composite cone summit following an explosive eruption C) Collapse of the flank of a cinder cone volcano after an effusive lava flow D) Collapse of summit of a shield volcano after draining of magma chamber

Q: What kind of volcano is most closely associated with pyroclastic flows? A) Shield B) Cinder cone C) Composite cone D) Caldera

Q: What is the driving force behind pyroclastic flows? A) Directed explosion B) Gravity C) Water D) Earthquakes

Q: What kind(s) of lava generate a cinder cone? A) Andesite B) Andesite and rhyolite C) Basalt D) Basalt and andesite E) Andesite, basalt, and rhyolite

Q: What kind(s) of lava are most closely associated with composite cones? A) Andesite B) Rhyolite C) Basalt D) Rhyolite and basalt

Q: The ring of fire is a narrow zone of composite cone volcanoes rimming the ________ Ocean. A) Pacific B) Atlantic C) Indian D) Arctic

Q: Lavas erupting from composite cones are generally ________-rich, making them very viscous. A) magnesium B) iron C) aluminum D) silica

Q: In what year did Parcutin form in a Mexican cornfield? A) 1935 B) 1939 C) 1943 D) 1952

Q: Based on the structure of the cone and the rock making it up, what interpretations can be made about the gas content of eruptions from cinder cone volcanoes compared to those of shield volcanoes? A) Less gas than shield volcanoes B) Same gas content as shield volcanoes C) More gas than shield volcanoes D) Gas is not found in volcanoes

Q: Which volcanoes have flanks with the steepest angle of repose (between 30 and 40)? A) Shield volcanoes B) Cinder cones C) Composite cones D) Lava domes

Q: A ________ is a submarine volcano. A) seamount B) caldera C) scoria cone D) dome

Q: In order to cover such large expanses of seafloor, shield volcanoes erupt ________ lava. A) rhyolitic B) andesitic C) porphyritic D) basaltic

Q: With the exception of volcanoes associated with a subduction zone, most volcanic islands are ________ volcanoes. A) cinder cone B) shield C) composite cone D) caldera

Q: What interpretations can be made about the maturity of a volcano where most eruptions occur from basal fissures and there are a number of parasitic cones along the volcano's flanks? A) It is a mature volcano. B) It is in the early stages of growth.

Q: Which of the following choices best explains the difference between a crater and a caldera? A) A crater is a very large circular depression over 1 km across; a caldera is a small funnel-shaped depression. B) A crater is a small, funnel-shaped depression; a caldera is a large depression that has a diameter of over 1 km. C) A crater is a fissure in the crust; a caldera is a collapsed summit. D) A crater is a large circular depression over 1 km across; a caldera is a small, parasitic cone growing on the flank of the volcano.

Q: A ________ is a cone-shaped structure created by successive eruptions of volcanic materials such as lava or pyroclastic materials. A) caldera B) volcanic cone C) crater D) fumarole

Q: Which type of magma(s) will produce scoria? A) Basaltic B) Andesitic C) Rhyolitic D) Basaltic and andesitic E) Andesitic and rhyolitic

Q: Around which volcano is a scientist likely find pillow basalts? A) Mount St. Helens B) Parcutin C) Fujiyama D) Kilauea

Q: What is the name of the small holes created by gas bubbles on the surface of scoria? A) Lapilli B) Pumice C) Vesicles D) Volatiles

Q: ________ is pulverized rock, lava fragments, and ash erupted from a volcano. A) Pahoehoe B) Pyroclastic material C) Basalt D) Lapilli

Q: Which of the following lavas make up 90 percent of the total volume of lava on Earth? A) Basaltic B) Andesitic C) Rhyolitic

Q: ________ is a material's resistance to flowing. A) Viscosity B) Volatiles C) Composition D) Quiescent

Q: Define magma. A) Dissolved gases in molten rock B) A material's resistance to flowing C) Molten rock that has been erupted D) Molten rock found at depth that contains dissolved gases and some crystals

Q: Using the choices below, select the statement that best explains how dissolved gases drive volcanic eruptions. A) As the magma rises, gas bubbles contract, fragmenting the material and expelling it from the vent. B) As the magma rises, gases reduce silicate mineral chains by breaking silicon-oxygen bonds; the result is an explosion. C) Confining pressure decreases on a rising magma, allowing gas bubbles to expand and fracture the magma. This process further decreases pressure on the magma and will result in an explosive event. D) Decreases in confining pressure result in decreasing viscosity of the magma, allowing the magma to ooze from the volcano.