Term
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Definition
Glaciers form as snow accumulates year after year in regions cold enough and/or wet enough to have more snow fall in winter than melts in summer.
The excess snow accumulates year after year, becoming thicker and denser under its own weight.
Once pore spaces have become sealed off, ice crystals form an interlocking matrix capable of transmitting deforming stress, in the form of gravity acting on the tremendous weight of a large body of ice. This causes the ice to flow down-slope or outwards, and a glacier is born. |
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Term
| The orbital parameters that favor glaciations are: |
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Definition
| those that produce a minimum in summer radiation in the Northern Hemisphere, and low obliquity and precession such that Northern Hemisphere summer occurs when Earth is furthest from the Sun |
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Term
| Precession describes the: |
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Definition
| timing of the seasons with respect to the location of Earth in its orbit around the sun |
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Term
| The Malaspina Glacier in Alaska is an example of a: |
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Definition
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Term
| Formation of a glacier requires |
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Definition
| more accumulation than ablation |
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Term
| A kettle is a lake formed |
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Definition
| as blocks of ice buried by glacial sediment melt |
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Term
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Definition
| Basal(t) sliding, internal deformation and sometimes due to surges. |
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Term
| Exlain how a glacier's mass balance is measured, and how a glacier will respond to changes in mass balance (i.e, positive or negative). |
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Definition
| A glacier's mass balance is calculated as the amount of accumulation minus the amount of ablation. To measure the accumulation, the glacier is visited at the end of the winter and the thickness and water content of the winter snowpack is measured by digging or coring down to the previous summer surface. To measure the ablation, stakes are placed at this time and the surface of the glacier noted on the stake. The stakes are re-measured at the end of the summer to find the thickness of ice that melted over the summer. If a glacier has a positive mass balance, it means that there is more accumulation than ablation and the glacier will advance and/or thicken. If a glacier has a negative mass balance, it means that there is more ablation than accumulation, and the glacier will retreat and/or thin. |
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Term
| Glacier surges are though to result from |
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Definition
| damming of subglacial meltwate |
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Term
| Cold glaciers differ from temperate glaciers in that |
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Definition
| cold glaciers do not melt at their bed, cold glaciers cannot move by basalt sliding, and cold glaciers carry, erode, and transport less material |
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Term
| Describe each of the Milankovitch cycles. Be sure to explain how each cycle affects the amount and distribution of solar radiation received by the earth. Describe the orbital forcing that favors glaciations, and the orbital forcing that favors interglaciations. |
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Definition
| The first of the Milankovitch cycles is Eccentricity which is the change in the shape of the Earth's orbit from an elliptical path to a more circular path. This causes small changes in the total amount of solar radiation received by the Earth. The second cycle is obliquity which is the change in the tilt of the earth's axis from about 22 degrees to 24.5 degrees. This tilt changes the variation seen during the seasons and between seasons. The last cycle is Precession which is the orientation or wobble of the earth's rotational axis. Precession affects seasonality by changing the timing of summer and winter relative to the position of the earth in its orbit around the sun. When the orbital configuration is a small tilt this favors glaciations because it causes cool summers and ice growth. When there is a large tilt this causes warmer summers and ice retreat and favors interglaciations. When precession is such that northern hemisphere summer occurs during the time in earth’s orbit when we are furthers from the sun this also favors glaciation. |
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Term
| Which of the following landforms of glacial origin are not found in Glacier National Park? |
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Definition
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Term
| Features of mountainous regions affected by alpine glaciers include all of the following except: |
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Definition
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Term
| Explain the geologic evidence for sea floor spreading and subduction. |
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Definition
| Sea floor spreading can be backed up by the fact there are younger rocks at the mid ocean ridges and they get older the further away from the ridge they get. The sediments on the seafloor are thinner towards the ridges because they haven’t had the time to accumulate. The rocks on the seafloor show orderly distribution with the youngest rocks being closest to the mid-ocean ridges and older rocks being farther away. Sediments are thinner near the ridges as well giving more evidence to new ocean crust being made. Mapping in the 1950's showed clearly that the oceans were dominated by underwater mountain ranges. Because ocean crust was youngest at the ridges, older as distance increased from the ridges, and was no older than 200 million years, it was evident that new crust was being created as old crust was destroyed. Finally, rocks are magnetic recorders that preserve a record of the distribution of normal and reversed magnetic fields at specific times on the ocean floors. As new ocean floors are created at mid-ocean ridges, the rocks formed record the magnetic pattern. Magnetic patterns on the ocean floors show clear patterns of systematic normal and reversed magnetic activity and they show a distinct pattern of ocean floor construction. Also as the seafloor moves it moves the continents with it. The theory of subduction can be proven with the origin of earthquakes. These earthquakes become deeper along one side of the ocean trench and further away from the trench. This shows where the old ocean crust plummets into the mantle and is destroyed. |
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Term
| Earth differentiated into core, mantle, and crust based upon their differing |
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Definition
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Term
| How does the lithosphere differ from the asthenosphere? |
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Definition
| The lithosphere is strong and rigid while the asthenosphere is weak and plastic |
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Term
| Sources of earth's internal heat include |
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Definition
| Kinetic energy of planetary accretion, and Decay of radioactive elements |
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Term
| Which statement best describes the relationship between the age of rocks that make up oceanic crust and their distance from a mid-ocean ridge? |
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Definition
| the rocks become older with increasing distance from the mid-ocean ridge |
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Term
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Definition
| Concept that states that processes operating today also operated in the past |
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Term
| How did seafloor spreading revive Alfred Wegener’s ideas about continental drift? |
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Definition
| sea floor spreading provided a viable mechanism for moving the continents |
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Term
| Describe the Earth’s internal structure in terms of both chemical composition and physical properties. |
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Definition
| The earth is divided into three layers, a crust, a mantle and a core, that differ in their chemical composition. The crust is the thin outer layer, consisting primarily of oxygen, silicon and aluminum. It is further subdivided into continental and oceanic crust. The oceanic crust is thinner and denser, and is similar in composition to basalt (Si, O, Ca, Mg, and Fe). The continental crust is thicker and less dense, and is similar to granite in composition (Si, O, Al, K, and Na). The mantle is made of magnesium, iron and silicon. The core is almost exclusively iron and nickel. The outer core is liquid iron and the inner core is solid iron. The mantle and crust are further divided into the lithosphere, asthenosphere and mesosphere, depending on their physical properties, namely how close the material is to its melting point. The lithosphere is cold and rigid and includes the curst and uppermost part of the mantle where rocks are far below their melting point. Further down in the mantle is the asthenosphere where rocks are weak and can flow because they are close to their melting point. The deepest part of the mantle is the mesosphere where rocks are gain strong and below their melting point due to the high pressure. |
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Term
| According to plate-tectonic theory, plates of rigid __________ move over a weak ___________ below. |
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Definition
| lithosphere, asthenosphere |
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Term
| A scientific hypothesis that is extensively tested and continues to appear valid may be called a |
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Definition
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Term
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Definition
| Is made of alternating bands of normally and reversely magnetized rocks |
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Term
| Our understanding of what the interior of the Earth is made of comes from |
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Definition
| The composition of meteorites, The composition of lavas erupted from volcanoes, and Analysis of seismic waves |
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Term
| When two oceanic plates collide: |
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Definition
| The older plate will subduct |
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Term
| Accreted terranes are added to continents by: |
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Definition
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Term
| Transform plate boundaries are marked by |
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Definition
| two plates sliding past one another in different directions |
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Term
| Compare and contrast the geologic processes occurring at convergent and divergent plate boundaries, and provide a modern-day example of each of these types of plate boundaries. |
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Definition
| At convergent plate boundaries, two tectonic plates are pushing against one another. There are several ways in which plates collide at convergent boundaries. The first is a continent- oceanic plate convergence where the denser oceanic plate subducts beneath the lighter, more buoyant continental plate. The second is a continent-continent collision in which neither plate wants to subduct easily. The third is an oceanic-oceanic plate convergence where the older and more dense of the two plates will subduct beneath the other. Both oceanic-continental and oceanic- oceanic plate convergence cause melting of the mantle and subsequent volcanism, in the form of island or volcanic arcs, such as the Cascade Mountain range or the Japan volcanic island arc. Divergent plate boundaries occur where two plates are pulling apart and mantle wells up to form a volcanic ridge, such as the Mid-Atlantic Ridge. In both convergent and divergent boundaries, mantle rock is melted due to either decreasing pressure (divergent boundaries) or increased water content (convergent boundaries) which lowers the melting point of the mantle rock. In both cases as well, the plates move by process of convection within the interior of the earth. As the mantle convects, it carries the plates along on the surface of the earth. The motion of the plates form the divergent or convergent boundaries. |
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Term
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Definition
| increases with increasing silica content and decreases with increasing temperature |
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Term
| Which list of igneous rocks is in order of increasing silica content? |
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Definition
| gabbro, andesite, rhyolite |
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Term
| The type of magma most likely to form at an oceanic "hot spot" is |
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Definition
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Term
| An intrusive igneous rock is said to have a _______ texture. |
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Definition
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Term
| Melting of rocks to produce magma can be caused by |
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Definition
| Raising the temperature, Adding water, and Lowering the pressure |
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Term
| Which of the following plate boundaries is an example of an advanced stage of continental rifting that is developing into a new ocean basin? |
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Definition
| African Plate and Arabian Plate |
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Term
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Definition
| an area of volcanic activity with a deep magma source |
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Term
| Use Bowen's reaction series to explain how the composition of a magma changes due to fractional crystallization. |
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Definition
| Most magmas originate by partial melting of the mantle, and so are basaltic in composition to start (because the mantle is mafic). As the magma cools, different types of minerals crystallize in a specific sequence called Bowen's reaction series and cause the composition of the residual magma to change. This is because the first minerals to crystallize as the magma starts to cool are mafic minerals such as olivine and pyroxene, as well as calcium rich feldspar. There minerals are relatively rich in iron, magnesium, and calcium and poor in silica, sodium and potassium. Therefore, the crystallization of olivine, pyroxene, and calcium feldspar removes iron, magnesium, and calcium from the magma, leaving it enriched in silica, sodium, and potassium and making the magma more felsic in composition. As crystallization proceeds, amphiboles and biotite are formed next as the magma composition continues to become more felsic. Finally, the last minerals to form are muscovite, quartz, potassium and sodium feldspars, because by this time the magma has become rhyolitic in composition due to removal of iron, magnesium, and calcium by crystallization of olivine, pyroxene, and calcium feldspars early in the sequence, leaving the magma enriched in silica, sodium, and potassium. |
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Term
| In areas undergoing tectonic tension, such as the Great Basin, extension of the Earth's crust causes which type of fault to form? |
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Definition
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Term
| How does earthquake magnitude differ from intensity? |
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Definition
| magnitude reflects energy release, while intensity reflects the amount of damage |
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Term
| Which statement best describes our understanding of when to expect the next large Cascadia subduction zone earthquake? |
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Definition
| Although the average time between CSZ earthquakes is 500 years, radiocarbon dating of drowned coastal forests and tsunami sand layers in coastal marshes shows that the time between CSZ earthquakes has varied from 150 to 1000 years. Because it has been 300 years since the last CSZ earthquake, the next CSZ earthquake could occur today or not for another 700 years. |
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Term
| Which of the following Cascade volcanoes has the potential to erupt in the same way that Mount St. Helens did in 1980? |
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Definition
| They all have the potential to do so: Mount Rainier, Mount Hood, and Mount Shasta |
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Term
| The focus of an earthquake is |
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Definition
| Beneath the earth's surface, directly under the epicenter, the point of origin of seismic waves, and The primary point of rupture in the earth's crust |
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Term
| Volcanic gases have killed people in recent years at |
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Definition
| Mammoth Mountain, California |
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Term
| Seismic activity is closely monitored as a predictor of volcanic eruptions because: |
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Definition
| rising magma causes earthquakes |
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Term
| Explain the properties and sense of motion caused by seismic P, S, and surface waves. |
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Definition
| Primary waves (P-waves) travel the fastest, so they arrive at the recording station first (hence the name primary waves). P-waves produce alternating compression and relaxation parallel to the direction of wave propagation, and can travel through both solids and liquids. Secondary or shear waves (S-waves), produce up-and-down motion perpendicular to the direction of wave propagation. S-waves travel slower than P-waves, but faster than surface waves, so they arrive second (hence the name secondary waves). S-waves only propagate through solid materials, this provides one of the key pieces of evidence for a liquid outer core. Waves traveling along the surface are called surface waves. Surface waves travel the slowest, but cause most of the damage because they produce complex horizontal and rolling motion of the ground surface. There are tow types of surface waves. Love waves move the ground from side to side. Rayleigh waves roll along the ground like a wave on the surface of a body of water. |
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Term
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Definition
| is a more accurate estimate of the energy released in a very large earthquake |
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Term
| The deadliest hazard to the most people from future eruptions of Mount Rainier is |
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Definition
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Term
| Which of the following volcanoes is least likely to erupt in a violent and explosive style? |
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Definition
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Term
| Explain the relationships between magma composition (basalt, andesite, rhyolite), type of volcano (shield, cinder cone, composite, dome), silica content, viscosity, and style of eruptive activity. |
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Definition
| The three types of magma differ in silica content and, because viscosity is dependent in part on silica content, they also produce different styles of eruptive activity. Basaltic magma is relatively low in silica. If basaltic magma is gas poor it typically produces shield volcanoes that are broad and gently sloping due to the fluid, low viscosity nature of basaltic magma. The lack of gas produces a non explosive eruption. If basaltic magma is gas rich, it creates a much more explosive eruption. The gasses accumulate near the top of the magma chamber. When the volcano erupts, there is a frothy ejection of material through the air. As the material settles it creates a conical shape around the vent. Composite volcanoes are associated with andesitic magma which has intermediate silica content. These volcanoes are only found at subduction zones. The andesitic magma is formed by the partial melting of the subducted crust. Eruptions are explosive at first because of gas rich magma, but as the gas pressure decreases the explosive force decreases as well. The volcano is composed of alternating layers of pyroclastic material erupted through the air (when the magma is rich in gas) and thick pasty lava (when the magma is degassed). Rhyolitic magma is high in silica and therefore also high in viscosity. Eruptions of rhyolitic magma are typically explosive in nature and produce steep sided lava domes. |
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Term
| Of the clastic rocks listed below, which type is made of the largest grains? |
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Definition
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Term
| Soil differs from regolith in that |
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Definition
| Soil contains organic matter and can support plant life |
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Term
| The characteristics of a soil are controlled by |
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Definition
| all of the above:the composition of bedrock on which it forms, the climate, and the extent of chemical weathering |
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Term
| Which of these rocks is not foliated? |
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Definition
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Term
| Explain the formation and classification of sedimentary and metamorphic rocks. |
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Definition
| Sedimentary rocks consist of weathering products eroded, transported, and are deposited as sediment. Sediment is eventually lithified by burial, compaction, and cementation. Sediment rocks are divided into three groups based on the type of sediment: clastic sediment, chemical sediment, or biogenic sediment. Metamorphic rocks form by the recrystallization of pre-existing rocks at high temperature and pressures but without melting. Metamorphic rocks are divided into foliated metamorphic rocks formed by regional metamorphism and non-foliated rocks formed by contact metamorphism. Foliated rocks are classified by grain size (i.e., slate to schist) and non-foliated rocks by their composition (i.e., marble vs. quartzite). |
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Term
| Evaporites form in what type of environment? |
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Definition
| Seasonal lakes in closed basins |
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Term
| The Mesozoic Era is composed of the following periods |
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Definition
| Triassic, Jurassic, Cretaceous |
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Term
| Soil degradation can result from |
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Definition
| erosion of topsoil, salinization, and poor irrigation practices |
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Term
| Which of the following types of metamorphism occurs only in convergent tectonic settings? |
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Definition
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Term
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Definition
| a gap in the geologic record |
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Term
| Subjecting ____________ to metamorphism turns it into quartzite. |
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Definition
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Term
| Identify and describe the typical sequence of soil horizons observed in a well-developed soil profile. |
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Definition
| In a well-developed soil profile, there are horizons O, A, B, C, and R. The top horizon, O, is mostly organic material. The horizon below O is A, which is a topsoil consisting of a mixture of organic and mineral matter. A is also the Zone of Leaching, where clay, Ca Mg, and Fe are removed to lower levels. The next horizon is B, the accumulation zone, which consists of clay, Fe oxides, silica, carbonate and other materials from above are absorbed. The next horizon is C, which consists of partially altered parent material which is either rock or loose sediment. The lowest Horizon is R, which is unweathered or unaltered parent material, otherwise known as bedrock |
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Term
| The best way to distinguish halite from calcite is by their different |
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Definition
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Term
| Describe the different types of mass wasting, including the kinds of slopes and materials where each is likely to occur. |
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Definition
| The different types of mass wasting include falls, slumps, slides, flows, and creep. Falls involve the movement of material that has lost contact with the underlying surface, such as rock fall from a cliff. Occur on steeper slopes. Slumps and slides both involve the movement of a cohesive block of material. Slumps occur when there are planes of weakness in the slope, such as clay layer. The material moves downslope on this slip plane. Slumps occur in homogenous material without weak layers. Flows involve the loss of cohesion in the moving material. A slope failure may start as a slide or slump, and then becomes a flow as the block loses cohesion. Creep is a very slow flow, and may occur on slopes of only a few degrees. Repeated freezing and thawing or wetting and drying may cause creep to take place in soil. |
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Term
| Hydrothermal ore deposits are |
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Definition
| formed by deposition of dissolved minerals from hot fluids, and associated with contact metamorphism |
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Term
| Slumps are characterized by |
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Definition
| somewhat coherent pieces of earth that rotate on a curved surface |
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Term
| Why are silicate minerals the most common group of minerals in the crust? |
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Definition
| because oxygen and silicon are the most common elements in the crust |
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Term
| The minimum concentration necessary for profitable mining of an ore deposit depends on |
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Definition
| the metal's average concentration in crustal rock, and the price of the metal being recovered |
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Term
| The factor of safety used in slope stability studies is |
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Definition
| the ratio of resisting to driving forces |
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Term
| Some minerals have crystal structures with distinct weaknesses. These minerals tend to break into distinct shapes that reflect their crystalline structure. These types of minerals are said to possess good ______. |
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Definition
|
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Term
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Definition
| increase slope stability because roots help hold soil in place, decrease slope stability by adding weight, and increase slope stability by taking up moisture |
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Term
| The fact that mineral resources are formed slowly over time means that mineral resources are: |
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Definition
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Term
| Identify and briefly define five properties of minerals that are useful for identification of a mineral sample. Explain which of these properties are most reliable and which are not. |
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Definition
| Luster- the quality and intensity of light reflected from a mineral. Somewhat reliable for mineral identification. A good first step. Color- the color of the mineral itself to the naked eye. Not very reliable due to many different minerals having the same color and the fact that the same type of mineral can be different colors. Streak- When a mineral is rubbed on a ceramic plate it leaves a powdery substance of a particular color. This is much more reliable than color when identifying minerals. Many minerals can have the same color as each other but might have different streak colors. Hardness- Minerals can be tested on how hard or soft they are as indicated by their ability to scratch and resistance to being scratched. . This can be tested by knowing the relative hardness of other objects as well as other minerals and comparing the two. This is a very reliable method for mineral identification. Cleavage- Cleavage has to do with how a mineral breaks. Many minerals break along preferred directions. Different minerals have cleavage in different angles, allowing for identification. Cleavage is studied by both the number of directions as well as the angles. This is a reliable means of identification because cleavage is a result of the type of chemical bonding present in a mineral and is thus a fundamental property of that mineral. All of these must be considered when identifying minerals. No one test stands by itself as a method for mineral identification. |
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Term
| What adverse effect do groins and jetties both have on coastal erosion? |
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Definition
| they stop longshore transport and starve down-drift areas of sand |
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Term
| Why do waves expend so much energy on a rocky headland? |
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Definition
| waves refract toward the headland on both sides |
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Term
| A cut-off meander is also known as |
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Definition
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Term
| Tsunami are most common in the Pacific Ocean because: |
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Definition
| Most subduction zones are located in the Pacific Ocean |
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Term
| Entrenched meanders along the Colorado River indicate that: |
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Definition
| the Colorado River had once eroded down near its base level, and was rejuvenated by uplift of the Colorado Plateau, leading to renewed erosion |
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Term
| Which type of flood is typically caused by intense rainfall in an area with impervious groundcover? |
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Definition
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Term
| A region has just had a 100-year flood. That means that |
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Definition
| a flood event of that size has a 1 percent probability of occurrence in the next year |
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Term
| The _________ is the time it takes for successive wave crests to pass a point. |
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Definition
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Term
| A stream's load consists of |
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Definition
| the amount of sediment carried by the stream |
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Term
| How are flood recurrence intervals and the discharge associated with floods of different recurrence intervals estimated from records of peak annual discharge? |
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Definition
| Records of peak annual discharge are collected over a certain amount of time, in this case, say 10 years. Each of the peak annual discharges is then ranked from high to low, #1 being the largest, #2 being the second largest, etc. Next, the Recurrence interval for each peak annual discharge is calculated using (n+1)/m where N is the number of years in the data set (in this case, 10) and m is the rank of the peak discharge for a particular year. Then you plot the recurrence intervals with the peak flood discharges, on the x and y-axis respectively. When plotted on a semi-log scale, there is an approximate linear relationship between discharge and recurrence interval. This linear relationship allows us to estimate the discharge expected for a flood of a given recurrence interval, say the 100-year flood used for flood insurance purposes. |
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Term
| In the continuity equation (Q = V *A), the Q stands for: |
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Definition
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Term
| What is the difference between local and eustatic sea level change? Provide examples of processes that cause local and eustatic sea level change. |
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Definition
| The difference between local and eustatic sea level change is that eusatic change happens when there is a global change in sea level due to a change in the volume of water in the ocean or the volume of the ocean basin whereas local sea level change is when local tectonic uplift or substance of the land surface. Eustatic sea level change occurs with global warming (i.e. glaciers melting) and local sea level change occurs when there is topographic uplift or subsidence along a particular coastline. |
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Term
| Around an actively pumped well in an unconfined aquifer, a ____________ may develop in the water table. |
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Definition
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Term
| Which of the following would likely serve as an aquitard? |
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Definition
|
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Term
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Definition
| is a site of groundwater discharge, and is also known as a gaining stream |
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Term
| Describe the process of eutrophication and the consequences for aquatic ecosystems. Be sure to identify specific pollution sources that can result in eutrophication. |
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Definition
| Eutrophication takes place when an increase of nutrients in water cause a bloom of algae or other plant life. When the plants or algae die, it uses oxygen to decompose the matter, which it takes from the water. This decreases the oxygen content in the water and can suffocate other species found in the area. Feedlots can be a source of excess nutrients, since the waste from livestock is high in nutrients and can run off into streams and other water bodies. Wastewater treatment plants can also contribute to eutrophication through the release of nitrogen and phosphorous into nearby water bodies. |
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Term
| Accessible and usable water is found mostly as |
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Definition
|
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Term
| In the western U.S. the use of surface water is governed by the |
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Definition
| prior appropriation doctrine |
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Term
| Point sources of pollution include all of the following except |
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Definition
|
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Term
| Explain the importance of porosity, permeability, and hydraulic gradient in determining the volume, speed, and direction of groundwater flow in an aquifer. |
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Definition
| Porosity is the total volume of empty pore space and is affected by size, shape, sorting and arrangement of particles. Porosity is also expressed as a fraction or percent. Porosity determines how much water can be held in a solid, and thus affects the volume of groundwater flow. Permeability is how easily a solid allows a liquid to flow through it. It is determined by how large or small the pore spaces are and the connectivity of them. There will be low permeability if the pore spaces are not connected. Permeability affects the rate at which groundwater flows, because a solid with a high level of permeability permits the passage of water easier, allowing for swifter flow. The hydraulic gradient si the change in pressure over some horizontal distance. For an unconfined aquifer the hydraulic gradient is simply the slope of the water table. Because water always flows from high to low pressure, the hydraulic gradient determines the direction of groundwater flow. |
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Term
| The rate of groundwater flow is proportional to the |
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Definition
|
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Term
| Eutrophication of water is caused by |
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Definition
| discharge of raw sewage into the water, excess fertilizer runoff from farmland, and phosphate detergent residue in wastewater |
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Term
| The level of water in Mono Lake has decreased in recent years because of |
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Definition
| diversion of surface streams that once flowed into Mono Lake |
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Term
| To be useful as a source of water (an aquifer), a rock must be |
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Definition
| both porous and permeable |
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Term
| Most oil exported from the Persian Gulf region goes to |
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Definition
|
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Term
| Explain the trends in global use of each of the three fossil fuel types since the Industrial Revolution. |
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Definition
| Coal was the first fossil fuel to go into wide use after the industrial revolution because coal was abundant in England and the NE US, areas that were first industrialized. Prior to electricity coal was used to power steam generated machinery. Coal is still widely used today because it is plentiful and a highly concentrated source of energy. The use of oil increased after WWII due to the proliferation of cars. Oil use has leveled off since the 1970's due to declining oil production, improved energy efficiency, and shifts to natural gas and nuclear energy. Oil still dominates in the transportation sector. There has been a dramatic increase in the use of natural gas since the 1960's. It is the fastest growing energy resource because it is a cleaner burning fuel, meaning it gives off less acidic pollution, but still emits greenhouse gases. |
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Term
| At peak rates of production, the oil supplied by drilling in the Arctic National Wildlife Refuge (ANWR) would be equivalent to |
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Definition
| the amount of oil that would be saved by raising the average fuel economy of American cars by 1 to 2.5 miles per gallon |
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Term
| Which of the following statements is NOT true? |
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Definition
| Rainfall would not be acidic if burning of sulfur-rich coal were stopped |
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Term
| In what ways do the radiative forcing effects of anthropogenic greenhouse gas emissions and aerosol emissions differ? |
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Definition
| greenhouse gas emissions trap terrestrial radiation, while aerosol emissons reflect solar radiation, greenhouse gas emissions remain in the atmosphere for decades to centuries, while aerosol emissions remain in the atmosphere for days to weeks, and greenhouse gas emissions result in global warming, while aerosol emissions result in regional cooling |
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Term
| Global average temperatures remained steady or decreased slightly between about 1945 and 1975 due to |
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Definition
| large emissions of sulfur aerosols prior to regulation by the Clean Air Act |
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Term
| How has glacial ice aided the study of climate change? |
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Definition
| glacial ice contains trapped air bubbles that archive former atmospheric carbon dioxide concentrations |
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Term
| Discuss what happens to incoming solar radiation in term’s of the Earth’s radiation budget. Be sure your answer explains the following: shortwave (solar) radiation, longwave (terrestrial) radiation, albedo, and the greenhouse effect. |
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Definition
| Earth's radiation budget is the difference between incoming solar radiation and departing terrestrial radiation. The earth's albedo is the percentage of solar energy that is reflected back into space without being used (30%). The reamining incoming solar radiation (shortwave radiation), about 70%, is absorbed by the earth and is re-emitted as terrestrial radiation (longwave radiation). Most solar radiation is visible to the eye while longwave radiation is not. The greenhouse effect is what happens when gases such as carbon dioxide, methane, and water vapor trap the departing longwave radiation and reflect it back to earth. |
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Term
|
Definition
| are involved in the production of photochemical smog, emitted primarily from mobile sources such as cars and trucks, and converted to nitric acid droplets in the atmosphere |
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Term
| The formation of photochemical smog involves |
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Definition
| a variety of primary pollutants reacting with sunlight |
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Term
|
Definition
| the remains of land plants |
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Term
| The United States presently |
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Definition
| imports nearly ¾ of the oil it uses from foreign countries |
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Term
| Nuclear fission is the process of |
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Definition
| splitting of heavy atoms to make light atoms |
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Term
| The loss of two protons and two neutrons from the nucleus is ___________ decay. |
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Definition
|
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Term
| Identify three alternative energy sources and explain one advantage and one disadvantage of each. |
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Definition
| Wind power is cheap and creates no pollution, however a backup or storage system is needed to provide power when winds are too weak to generate electrcity. Solar power is also cheap and creates no pollution. However, solar collectors are expensive and take up a lot of space. Nuclear energy, especially fusion, is a nearly limitless energy source. However, the techonology to use nuclear fusion on a commercial scale does not yet exist and the problem of what to do with radioactive waste from nuclear fission has yet to be solved. |
|
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Term
| Geothermal power generation |
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Definition
| uses hot water or steam produced where groundwater comes in contact with hot rocks or magma beneath the surface |
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Term
| What factors make Yucca Mountain a favorable location for long-term storage of radioactive waste? What factors make Yucca Mountain a poor location for this purpose? Explain. |
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Definition
| Yucca Mountain is a good location for long-term storage of radioactive waste primarily because of its hydrology and climate. Yucca Mountain is in a very dry climate with low precipitation and a deep water table. Groundwater discharges into closed hydrologic basins, minimizing the potential for any contaminants that escape to spread. The volcanic rock of the area contains zeolites, a type of mineral that absorbs contaminants, further minimizing the potential for contamination to spread. The site is also located on sparsely populated federal land that was used for nuclear weapons testing during the Cold War. However, Yucca Mountain is in a geologically active region, with geologically recent earthquakes and volcanic activity. Future earthquake or volcanic activity may occur and breach the facility. Most Nevada residents strongly oppose the facility (although local opposition is likely anywhere a facility of this type is proposed), and the radioactive waste must be brought to Yucca Mountain from across the country. |
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Term
| Nuclear fuel reprocessing is not used in the United States because |
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Definition
| of national security concerns over the Plutonium that is recovered by this process |
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Term
| In commercial nuclear reactors |
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Definition
| the energy released is harnessed by heating water to turn turbines and generate electricity |
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Term
| Which of the following renewable energy sources currently generates the greatest share of energy consumed in the U.S.? |
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Definition
|
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Term
| Solar energy is presently used for |
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Definition
| speace heating, generating electricty, and heating water for home use |
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Term
| What limitation(s) do wind and solar energy share? |
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Definition
| need for a storage or backup system to meet demand when generating capacity is low and a large collection system that takes up a lot of space |
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Term
| Yucca Mountain, Nevada is a potentially viable site for nuclear waste disposal because |
|
Definition
| it is sparsely populated federal land in a very dry climate |
|
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Term
| A breeder reactor differs from a burner reactor in that |
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Definition
| a breeder reactor produces more nuclear fuel than it burns |
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Term
| The fact that mineral resources are formed slowly over time means that mineral resources are: |
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Definition
|
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Term
| Organic matter in soil is found principally in the |
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Definition
|
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Term
| Which group of igneous rocks is all extrusive? |
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Definition
|
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Term
| Why are landslides more common on steep slopes? |
|
Definition
| slope angle determines the relative magnitude of driving forces |
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Term
| Numerical ages can be assigned to a rock using: |
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Definition
| Using known rates of radiocative decay of elements within the rock |
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Term
| Which of the following minerals are iron oxides that can be mined as iron ore? |
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Definition
|
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Term
| A __________ is an area along an active fault zone that is likely to produce large earthquakes, but has not done so recently. |
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Definition
|
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Term
|
Definition
| are rocks changed through the effects of heat and pressure |
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|
Term
| A strike-slip fault has what type of motion? |
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Definition
|
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Term
| Explain how records of seismic waves made by seismographs are used to locate and earthquake epicenter and determine its Richter magnitude. |
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Definition
| The distance from the epicenter is determined from the seismograph based on the difference in arrival times between the faster P waves and the slower S waves. If three or more seismographs are available, the location of the epicenter can be pinpointed by triangulation. Each seismograph defines a circle whose radius is the distance to the epicenter. Although you don’t know the direction to the epicenter, if you have three or more seismographs the circles will interest at a single point, the epicenter. The Richter magnitude is determined from the maximum amplitude of seismic waves recorded on a seismograph and the distance of that seismograph from the epicenter. |
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Term
| An igneous rock with a felsic composition and a coarse texture would be called |
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Definition
|
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Term
| Melting of rocks to produce magma can be caused by |
|
Definition
| Raising the temperature and Adding water and Lowering the pressure |
|
|
Term
| List the three main types of rocks and describe the processes by which they are formed and the characteristics by which they are classified. |
|
Definition
| Igneous rocks are formed by cooling and crystallization of magma. Classification is based on the composition; the relative abundance of minerals present, and texture; the size, shape and arrangement of minerals present. They can be either intrusive or extrusive. Sedimentary rocks consist of weathering products eroded, transported, and re-deposited as sediment. Sediment is eventually lithified by burial, compaction, and cementation. Sediment rocks are divided into three groups based on the type of sediment: clastic sediment, chemical sediment, or biogenic sediment. Metamorphic rocks form by the recrystallization of pre-existing rocks at high temperature and pressures but without melting. Metamorphic rocks are divided into foliated metamorphic rocks formed by regional metamorphism and non-foliated rocks formed by contact metamorphism. Foliated rocks are classified by grain size (i.e., slate to schist) and non-foliated rocks by their composition (i.e., marble vs. quartzite). |
|
|
Term
| During fractional crystallization |
|
Definition
| iron, magnesium, and calcium is removed from the magma and the magma becomes enriched in silica, sodium, and potassium and the composition of the magma becomes more felsic |
|
|
Term
| The deadliest volcanic eruption in recorded history, with nearly 100,000 people killed, was the eruption of |
|
Definition
| Tambora, Indonesia in 1815 |
|
|
Term
| The oldest continental rocks are nearly as old as the earth, but the oldest oceanic rocks are only about 200 million years old. This is because: |
|
Definition
| of subduction of oceanic lithosphere |
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|
Term
| The minimum concentration factor necessary for profitable mining of an ore deposit depends on |
|
Definition
| the metal's average concentration in crustal rock and the price of the metal being recovered |
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|
Term
| In a clastic sedimentary rock, looking at ______ tells you about conditions of transportation and deposition, while looking at _______ tells you about their source. |
|
Definition
| particle size, particle composition |
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Term
| A broad bulge in the ground surface several inches high that formed in the past 5 years just west of ________ has scientists concerned about the potential for future volcanic activity there. |
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Definition
|
|
Term
| Which of the following is a consequence of differentiation? |
|
Definition
| Light elements rose to form the crust and Heavy elements sank to form the core and Light lithosphere floating on denser asthenosphere |
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|
Term
| Biogenic sedimentary rocks include |
|
Definition
| organically precipitated components cemented together and organically formed materials compressed together |
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Term
| Volcanoes can kill people in a number of different ways. Considering that Mount Rainier is a stratovolcano what types of hazards would be associated with an eruption of Mount Rainier? Which of these hazards poses the greatest threat to the most people? Why? |
|
Definition
| Typical hazards from stratovolcanoes such as Mount Rainier are pyroclastic flows, ash fall, and lahars. Pyroclastic flows are mixutures of hot rock, ash, and gases that sweeps down a mountain side. Ash fall is another real danger. It has the potential to burry things very quickly and blocks sunlight from getting through. Large accumulations of ash can result in roof collapse. Lahars are mixtures of water and loose volcanic debris produced as hot rocks quickly melt snow and ice. Lahars pose the greatest threat from Mount Rainier because of the large volume of snow and ice on Mount Rainier and the ability of lahars to travel great distances down river valleys from the volcano and sweep through populated areas. |
|
|
Term
| Addition of water to soil on slopes may |
|
Definition
| Destabilize the slope by adding mass. |
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|
Term
| A ____________ is an unconformity between parallel layers of sediment. |
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Definition
|
|
Term
| Ore deposits of dense minerals concentrated by stream action are called |
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Definition
|
|
Term
| The sedimentary rock called limestone is made of calcium carbonate |
|
Definition
| precipitated from seawater and from shells from ancient organisms |
|
|
Term
| Why are silicate minerals the most common group of minerals in the crust? |
|
Definition
| because oxygen and silicon are the most common elements in the crust |
|
|
Term
| Because earth is a closed system: |
|
Definition
| There is a finite supply of resources, and All waste and pollutants generated on Earth stay on Earth |
|
|
Term
| On what basis are Mercalli intensity values assigned to locations? |
|
Definition
| qualitative perceptions of and damage caused by the earthquake |
|
|
Term
| Viscosity of magma is controlled by |
|
Definition
| temperature and silica content of the magma |
|
|
Term
| A volcanic feature formed by the accumulation of pyroclastic material around a vent is called a: |
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Definition
|
|
Term
| Describe the processes of physical and chemical weathering. How does physical weathering enhance chemical weathering? |
|
Definition
| Physical weathering is the breaking down of rocks into smaller fragments without changing the chemical makeup. There are different types such as frost wedging which breaks up rocks by freezing the cracks and thermal expansion and contraction which makes rocks get bigger and smaller. Chemical weathering is the breakup of rocks by chemical processes such as dissolving them, and oxidation to iron materials to create rust. Physical weathering promotes chemical weathering because it breaks the rocks into smaller pieces that are easier to alter chemically by exposing more surface area. |
|
|
Term
| Evidence that the earth has a liquid outer core includes: |
|
Definition
| earth’s strong magnetic field and the observation that earthquake S waves do not travel through the core |
|
|
Term
| Typical rates of plate movement are |
|
Definition
| 2 to 3 centimeters per year. |
|
|
Term
| The color of a soil is useful as an indicator of |
|
Definition
| the amount of organic matter and iron |
|
|
Term
| Which of the following volcanic eruptions produced a tsunami? |
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Definition
|
|
Term
| Which of the following does NOT meet all the criteria to be considered a mineral? |
|
Definition
| volcanic glass (obsidian) |
|
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Term
|
Definition
| is also high in viscosity and tends to erupt explosively and can be formed by fractional crystallization of basaltic magmaQuestion 43 |
|
|
Term
| The discovery that oceanic crust is destroyed at subduction zones came with the recognition that |
|
Definition
| Earthquakes become deeper with distance from deep-sea trenches |
|
|
Term
| A volcanic rock of intermediate composition, characteristic of subduction-zone volcanoes like those of the Cascade Range, is |
|
Definition
|
|
Term
| Composite volcanoes are found only in which tectonic setting? |
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Definition
|
|
Term
| Rocks that were heated and metamorphosed by hot magma that was intruded nearby have undergone ________ metamorphism. |
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Definition
|
|
Term
| Which of the following minerals is a sheet silicate with excellent cleavage in one direction? |
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Definition
|
|
Term
| Paleomagnetic studies are based on the fact that |
|
Definition
| When iron-bearing minerals crystallize, they align themselves parallel to the lines of force of the earth's magnetic field. |
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|
Term
| Lava with low viscosity is found at which volcano? |
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Definition
|
|
Term
| A mass movement in which materials move in a disorganized, chaotic fashion as it loses cohesion is a |
|
Definition
|
|
Term
| Physical weathering includes all of the following except: |
|
Definition
| dissolution of limestone by acidic rainwater. |
|
|
Term
| The locations and ages of islands in the Hawaiian Island chain can be used to show |
|
Definition
| the rate of movement of the Pacific Plate. |
|
|
Term
| Which of the following is not a feature of divergent plate boundaries? |
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Definition
|
|
Term
| The principle of _______________ states that the oldest layers are on the bottom of a sequence of sediment layers. |
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Definition
|
|
Term
| Wegner's evidence for continental drift includes all |
|
Definition
| the shape of the continents and similar fossils on the southern continents |
|
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Term
|
Definition
| found in mountainous regions, their shape and flow pattern is strongly influenced by the topography. |
|
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Term
|
Definition
| occupy bowl shaped depressions on mountainsides formed by glacial erosion |
|
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Term
|
Definition
| occupy mountain valleys and many extend 100s of km from cirque headwalls; often represent the coalescence of many smaller cirque and valley glaciers |
|
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Term
|
Definition
| valley glaciers that emerge from confining valleys and spread laterally to form fan shaped lobes |
|
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Term
|
Definition
| cover highland areas and flow outward from a central dome |
|
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Term
|
Definition
| cover large sections of a continent |
|
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Term
|
Definition
| floating margins of an ice cap or ice sheet that extends into the sea |
|
|
Term
| True or False: Polar glaciers are more common. |
|
Definition
| False. Temperate glaciers are more common. |
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|
Term
| True or False: Glaciers flow fastest near their middle. |
|
Definition
| True! Frictional resistance from bedrock along the valley walls and floor results in slower movement along the sides and bottom of a glacier. This causes cracks in the glacier surface called crevasses to open and close to accommodate different flow rates within the glacier. |
|
|
Term
| Longest glacier in North America |
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Definition
|
|
Term
| In what country was the fastest glacier ever recorded? |
|
Definition
|
|
Term
|
Definition
| valley glaciers that reach the sea |
|
|
Term
| How do tidewater glaciers lose mass? |
|
Definition
| Calving icebergs from their terminus, which often forms a near-vertical ice cliff. |
|
|
Term
| Why are Glaciers Good Indicators of Climate Change? |
|
Definition
| Glaciers, because their formation and continued existence are due to more snow falling in winter than melts during summer, are sensitive indicators of climate and climate change. Glaciers advance and retreat in response to changes in mass balance, in other words in response to climate changes. |
|
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Term
| Why are Glaciers Valuable as Resources? |
|
Definition
| Glaciers are valuable as resources of freshwater. Approximately 2/3 of the worlds freshwater is stored in mountain glaciers and polar ice caps. Mountain glaciers act as natural reservoirs of freshwater, releasing water as they melt during hot, dry weather when the water is needed the most. Glacier meltwater can be a significant portion of the water flowing in streams. |
|
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Term
|
Definition
| the breaking off of large chunks of rock from the down-glacier side of rock outcrops along pre-existing joints or fractures in the rock |
|
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Term
|
Definition
| the crushing and grinding of rock into fine particles called glacial flour |
|
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Term
|
Definition
| long, parallel scratches in bedrock produced as glacier ice drags rock fragments across a bedrock surface. |
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Term
|
Definition
|
|
Term
|
Definition
| the smoothing of bedrock surfaces by the abrasive action of ice containing rock flour, producing a smooth, reflective surface |
|
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Term
|
Definition
| bowl shaped depressions formed as a glacier cuts into the side of a mountain; have a broad, gently sloping bottom and a steep headwall |
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Term
|
Definition
| alpine lakes partially filling the bowl-shaped depression at the bottom of a cirque |
|
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Term
|
Definition
| narrow, knife edge ridge that is left standing in nearly sheer relief as glaciers erode from opposite sides of a mountain ridge |
|
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Term
|
Definition
| where glaciers have cut completely through a ridge leaving a u-shaped notch behind |
|
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Term
|
Definition
| pyramid-shaped mountain peak left by cirque glaciers cutting into three or more sides of a mountain |
|
|
Term
| What glacial landscape feature is the Matterhorn in Switzerland? |
|
Definition
|
|
Term
|
Definition
| straight, wide valley with steep sides and a flat bottom; formed when a glacier straightens and widens a narrow, v-shaped river valley originally formed by stream erosion |
|
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Term
|
Definition
| where smaller tributary glaciers join the main trunk glacier this valley is left perched high above the main valley floor because smaller tributary glaciers have less erosive power than the main glacier; often end in waterfalls |
|
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Term
|
Definition
| u-shaped valley partially drowned by seawater |
|
|
Term
| What glacial landscape feature is Chasm Lake in Longs Peak, CO? |
|
Definition
| It is a tarn nestled at the bottom of a huge cirque |
|
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Term
|
Definition
| piles of till that accumulates at the edge of a glacier when it remains in one place for some period of time |
|
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Term
|
Definition
| deposited along the side of the glacier |
|
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Term
|
Definition
| form when one glacier flows into another, turning two lateral moraines into a single medial moraine |
|
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Term
|
Definition
| till shaped into streamlined hills |
|
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Term
|
Definition
| deposited at the end of a glacier |
|
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Term
|
Definition
| small depressions filled with melted glacial ice |
|
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Term
|
Definition
| man most credited with discovering the Ice Ages |
|
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Term
|
Definition
| any body of water that flows in a channel |
|
|
Term
| What cycles are streams apart of? |
|
Definition
| Hydrologic and Rock Cycles |
|
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Term
|
Definition
| aka watershed, is the area drained by a single river or river system |
|
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Term
|
Definition
| a stream flowing into a larger stream |
|
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Term
|
Definition
| separates drainage basins by the ocean they ultimately flow to; runs the length of the Rocky Mountains and separates streams flowing west and eventually reaching the Pacific Ocean from those flowing east or north to the Atlantic and Arctic Oceans, respectively. |
|
|
Term
| Eastern Continental Divide |
|
Definition
| aka Hudson Bay Divide, runs east from the Rock Mountains and separates streams flowing south and east to the Gulf of Mexico and Atlantic Ocean from those flowing north to Hudson Bay and the Arctic Ocean |
|
|
Term
| Where do the Hudson Bay Divide and the Continental Divide meet? |
|
Definition
| Triple Divide Peak in Montana's Glacier National Park |
|
|
Term
|
Definition
| streams do not reach the ocean, instead they end in basins with dry or saline lakes where the water leaves the basin by evaporation. |
|
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Term
|
Definition
| average width of channel, average depth of channel, average velocity of channel, discharge or volume of water carried per unit time, stream gradient, sediment load carried by the stream |
|
|
Term
| Continuity Equation: what does each letter mean? |
|
Definition
Q = A * V
Q is the discharge in cubic meters per second
A is the cross-sectional area of the channel in square meters
V is the velocity in meters per second |
|
|
Term
| True or False: the continuity equation factors are independent of one another. |
|
Definition
| False! The factors are interdependent, meaning that when one changes, one or more of the others also changes. |
|
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Term
|
Definition
| the lowest point to which the river or stream can flow and erode |
|
|
Term
| What will happen to Lake Erie when Niagara Falls cuts back the dolomite completely? |
|
Definition
| Lake Erie will be partially drained to the lower base level of the nearby Lake Ontario. |
|
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Term
|
Definition
| Steep gradient, fast velocity, high eroding power, coarse sediment load |
|
|
Term
| Mature (Meandering) Stream |
|
Definition
| Shallow gradient, slower velocity, low eroding power, finer sediment load |
|
|
Term
|
Definition
| erode at high discharge and fill with fine sediment at low discharge |
|
|
Term
|
Definition
| fill with coarse sediment at high discharge and erode at low discharge |
|
|
Term
| How does a stream become rejuvenated? |
|
Definition
| A drop in base level can reinvigorate a mature stream by steepening its gradient, leading to a renewed pulse of erosion. The Colorado River is a classic example of a formerly mature stream that has been rejuvenated. Uplift of the Colorado Plateau rejuvenated the Colorado River by steepening its gradient, leading to renewed erosion. |
|
|
Term
|
Definition
| occur where a stream's flow divides into multiple and interconnected channels; allows the stream to carry more sediment as bed load; develop in areas with highly variable discharge and abundant coarse sediment |
|
|
Term
| What are the three ways sediment is carried in streams? |
|
Definition
| The bed load consists of coarse clastic (rock) materials moved along the channel bed by rolling, sliding, or bouncing. The suspended load is clastic materials carried within the water column by turbulent flow. Suspended sediment givers river water its muddy appearance and typically accounts for about 90% of the total sediment load.The dissolved load is the chemical weathering products carried in dissolved form by chemical solution. The dissolved load carried to the sea by rivers gives ocean water its saltiness. The dissolved load in closed basins evaporates to form salt deposits. |
|
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Term
|
Definition
| landscapes resulting from the deposition of sediment by streams |
|
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Term
|
Definition
| the flat area adjacent to a stream channel; develop where streams periodically over-top their banks during periods of high discharge |
|
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Term
|
Definition
| formed floodplain surfaces abandoned when the river cuts down to a new base level in response to a change in gradient, discharge or sediment load. |
|
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Term
|
Definition
| piles of coarse sediment deposited where a stream emerges from a narrow canyon into a broad valley due to the drop in velocity as the channel spreads out |
|
|
Term
|
Definition
| forms as sediment is deposited where river velocity drops rapidly as it enters an ocean or lake |
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