GEO 100 Exam 2
hydrolysis
a chemical weathering process in which minerals chemically combine with water; a decomposition process that causes silicate minerals in rocks to break down and become altered
oxidation
a chemical weathering process in which oxygen dissolved in water oxidizes (combines with) certain metallic elements to form oxides; most familiar is the "rusting" of iron in a rock or soil, which produces a reddish-brown strain of iron oxide
spheroidal weathering
a chemical weathering process in which the sharp edges and corners of boulders and rocks are weathered in thin plates that create a rounded, spheroidal form
carbonation
a chemical weathering process in which weak carbonic acid (water and carbon dioxide) reacts with minerals that contain calcium, magnesium, potassium, and sodium (especially limestone), transforming them into carbonates
hydration
a chemical weathering process involving water that is added to a mineral, which initiates swelling and stress within the rock, mechanically forcing grains apart as the constituents expand
fog
a cloud, generally stratiform, in contact with the ground, with visibility usually reduced to less than 1 km (3300 ft)
ice sheet
a continuous mass of unconfined ice, covering at least 50,000 km^2. The bulk of glacial ice on Earth covers Antarctica and Greenland in two ice sheets
slopes
a curved, inclined surface that bounds a landform
kame
a depositional feature of glaciation; a small hill of poorly sorted sand and gravel that accumulates in crevasses or in ice-cased indentations in the surface
drumlins
a depositional landform related to glaciation that is composed of till (unstratified, unsorted) and is streamlined in the direction of continental ice movement- blunt end upstream and tapered end downstream with a rounded summit
delta (types of deltas)
a depositional plain formed where a river enters a lake or an ocean; named after the triangular shape of the Greek letter delta
drainage pattern (types of drainage patterns)
a distinctive geometric arrangement of streams in a region, determined by slope, differing rock resistance to weathering and erosion, climatic and hydrologic variability, and structural controls of the landscape
fjord
a drowned glaciated valley, or glacial trough, along a seacoast
floodplain
a flat, low-lying fluvial landform composed of alluvium along a stream or river channel, created by and subject to recurrent flooding
evaporation fog
a fog formed when cold air flows over the warm surface of a lake, ocean, or other body of water; forms as the water molecules evaporate from the water surface into the cold, overlying air; also known as steam fog or sea smoke
joints
a fracture or separation in rock that occurs without displacement of the sides; increases the surface area of rock exposed to weathering processes
denudation
a general term that refers to all processes that cause degradation of the landscape: weathering, mass movement erosion, and transport
roche mountonee
a glacial erosion feature; an asymmetrical hill of exposed bedrock; displays a gently sloping upstream side that has been smoothed and polished by a glacier and an abrupt, steep downstream side
alpine glacier
a glacier confined in a mountain valley or walled basin, consisting of three subtypes: valley glacier (within a valley), cirque glacier (forming at the head of a valley), and piedmont glacier (valley glaciers that coalesce at the base of a mountain range, spreading freely over nearby lowlands)
hydrograph
a graph of stream discharge over a period of time at a specific place on a stream
zone of saturation
a groundwater zone below the water table in which all pore spaces are filled with water
glacial ice
a hardened form of ice, very dense in comparison to normal snow or firn
flood
a high water level that overflows the natural riverbank along any potion of a stream
debris avalanches (snow avalanches)
a high-speed flow of rock and debris, sometimes fluidized by ice in steep mountain regions. A type of mass movement classified as a flow; may become a debris flow as it moves downslope
oxbow lake
a lake that was formerly part of the channel of a meandering stream; isolated when a stream eroded its outer bank, forming a cutoff through the neck of the looping meander. In Australia, known as a billabong
glacier
a large mass of dense, perennial ice resting on land, formed from the accumulation and recrystallization of snow, which then flows slowly under the pressure of its own weight and the pull of gravity
till plain
a large, relatively flat plain composed of unsorted glacial deposits behind a terminal or end moraine. Low-rolling relief and unclear drainage patterns are characteristic
natural levees
a long, low ridge that forms on both sides of a stream in a developed floodplain; a depositional product (coarse gravels and sand) of river flooding
stratocumulus clouds
a lumpy, grayish, low-level cloud, patchy with sky visible, sometimes present at the end of the day
drainage density
a measure of the overall operational efficiency of a drainage basin, determined by the ratio of combined channel lengths to the unit area
soil creep
a persistent mass movement of surface soil where individual soil particles are lifted and disturbed by the expansion of soil moisture as it freezes or by grazing livestock or digging animals
horn
a pyramidal, sharp-pointed peak that results when several cirque glaciers gouge an individual mountain summit from all sides
continental divides
a ridge or elevated area that separates drainage on a continental scale; specifically that ridge in North America that separates drainage to the Pacific on the west side from drainage to the Atlantic and Gulf on the east side and to Hudson Bay and the Arctic Ocean in the north
ice cap
a roughly circular glacier covering an area less than 50,000 km^2, completely burying the underlying landscape
cirque
a scooped-out, amphitheater-shaped basin at the head of a valley glacier in a mountain region; an erosional landform
aretes
a sharp ridge that divides two cirque basins. Derived from "knife edge" in French, these form serrated ridges in glaciated mountains
hydrologic cycle
a simplified model of the flow of water, ice, and water vapor from place to place. Water flows through the atmosphere and across the land, where it is stored as ice and as groundwater. Solar energy empowers the cycle
esker
a sinuously curving, narrow deposit of coarse gravel that forms along a meltwater stream channel, developing in a tunnel beneath a glacier
tarn
a small mountain lake, especially one that collects in a cirque basin behind risers of rock material or in an ice-gouged depression
stratus clouds
a stratiform (flat, horizontal) cloud generally below 2000 m (6500 ft)
braided stream
a stream carrying a high sediment load that becomes a maze of interconnected channels. Braiding often occurs with a reduction of discharge that reduces a stream's transporting ability or with an increase in sediment load
aquifer
a subsurface body of permeable rock or sediments through which water can flow in amounts adequate for wells and springs
"landslide"
a sudden rapid downslope movement under the influence of gravity of a cohesive mass of soil, regolith, or bedrock; often used as a catch-all term for mass-movement material that falls, slides, flows
snowline
a temporary line marking the elevation where winter snowfall persists throughout the summer; seasonally, the lowest elevation covered by snow during the summer
cumulonimbus clouds
a towering, precipitation-producing cumulus cloud that is vertically developed across altitudes associated with other clouds; frequently associated with lightning and thunder and thus sometimes called a thunderhead
abrasion
a type of erosion that breaks up rock particles and wears away bedrock, accomplished by the rolling and grinding of particles carried in a stream, removed by wind in a "sandblasting" action, or imbedded in glacial ice
debris flows
a type of mass movement that flows downslope in a slurry of unconsolidated material, specifically a mixture of water and sediment that is mainly gravels, boulders, and other rock fragments coarser than sand, but also includes mud, silt, and sand
traction
a type of sediment transport that drags coarser materials along the bed of a stream
crevasses
a vertical crack that develops in a glacier as a result of friction between valley walls, or tension forces of extension on convex slopes, or compression forces on concave slopes
water budget
a water accounting system for an area of Earth's surface using inputs of precipitation and outputs of evapotranspiration (evaporation from ground surfaces and transpiration from plants) and surface runoff. Preceipitation "income" balances evaporation, transpiration, and runoff "expenditures"; soil moisture storage acts as "savings" in the budget
zone of aeration
a zone above the water table where soil and rock are less than saturated and some pore spaces contain air rather than water
active layer
a zone of seasonally frozen ground that exists between the subsurface permafrost layer and the ground surface. The active layer is subject to consistent daily and seasonal freeze-thaw cycles
advection fog
active condensation formed when warm, moist air moves laterally over cooler water of land surfaces, causing the lower layers of the air to be chilled to the dew-point temperature
cloud
an aggregate of tiny water droplets and ice crystals suspended in the air and great enough in volume and concentration to be visible
unconfined aquifer
an aquifer that has a permeable layer of rock or sediment above and an impermeable layer of rock or sediment beneath
confined aquifer
an aquifer that is bounded above and below by impermeable layers of rock or sediment
drought
an extended period of dry conditions caused by lower precipitation and higher temperatures than normal
outwash plains
area of glacial stream deposits of stratified drift with meltwater-fed, braided, and overloaded streams; occurs beyond a glacier's morainal deposits
cumulus clouds
bright and puffy cumuliform clouds up to 2000 m (6500 ft) in altitude
bed load
coarse materials that are dragged along the bed of a stream by traction of by the rolling and bouncing motion of saltation; involves particles too large to remain in suspension
periglacial
cold-climate processes, landforms, and topographic features along the margins of glaciers, past and present; periglacial characteristics exist on more than 20% of Earth's land surface; includes permafrost, frost action, and ground ice
lateral moraine
debris transported by a glacier that accumulates along the sides of the glacier and is deposited along these margins
medial moraine
debris transported by a glacier that accumulates down the middle of the glacier, resulting from two glaciers merging their lateral moraines; forms a depositional feature following glacial retreat
chemical weathering
decomposition and decay of the constituent minerals in rock through chemical alteration of those minerals. Processes include hydrolysis, oxidation, carbonation, and solution
erosion
denudation by wind, water, or ice, which dislodges, dissolves, or removes surface material
till
direct ice deposits that appear unstratified and unsorted; a specific form of glacial drift
karst topography
distinctive topography formed in a region of chemically weathered limestone with poorly developed surface drainage and solution features that appear pitted and bumpy; originally named after the Krs Plateau in Slovenia
terminal moraine
eroded debris that is dropped at a flacier's farthest extent
suspended load
fine particles held in suspension in a stream. The finest particles are not deposited until the stream velocity nears zero
icebergs
floating ice masses
mudflows
fluid downslope flows of material of smaller size and higher water content than a debris flow
talus slope
formed by angular rock fragments that cascade down a slope along the base of a mountain; poorly sorted, cone-shaped deposits
radiation fog
formed by radiative cooling of a land surface, especially on clear nights in areas of moist ground; occurs when the air layer directly above the surface is chilled to the dew-point temperature, thereby producing saturated conditions
col
formed by two headward-eroding cirques that reduce an arete (ridge crest) to form a high pass or saddlelike depression
kettle
forms when an isolated block of ice persists in a ground moraine, an outwash plain, or a valley floor after a glacier retreats; as the block finally melts, it leaves behind a steep-sided hole that frequently fills with water
permafrost
forms when soil or rock temperatures remain below 0 degrees Celsius for at least 2 years in areas considered periglacial; criterion is based on temperature and not on whether water is present
rockfalls
free-falling movement of debris from a cliff or steep slope, generally falling straight or bounding downslope
alluvium
general descriptive term for clay, silt, sand, gravel, or other unconsolidated rock and mineral fragments transported by running water and deposited as sorted or unsorted sediment on a streambed, floodplain, delta
latent heat
heat energy that is "hidden" within the structure of water's physical states- ice, water, or water vapor- and when absorbed or released during a phase change does not produce a change in temperature. Heat energy is absorbed as the latent heat of melting, vaporization, or sublimation. Heat energy is released as the latent heat of freezing, condensation, and deposition
artificial levees
human-built earthen embankments along river channels, often constructed on top of natural levees
point bar
in a stream, the inner portion of a meander, where sediment fill is redeposited
solifluction
in polar regions and at high elevations, the downslope movement of saturated soil during the summer months after seasonal thaw has occurred
internal drainage
in regions where rivers do not flow into the ocean, the outflow is through evaporation or subsurface gravitational flow. Portions of Africa, Asia, Australia, and the western United States have such drainage
undercut bank (cutbank)
in streams, a steep bank formed along the outer portion of a meandering stream; produced by lateral erosive action of a stream; sometimes called a cutbank
surplus
in terms of the water balance, the condition that occurs when all water demands are met and extra water remains; often takes the form of surface runoff that feeds lakes and streams and recharges groundwater
deficit
in the water balance, a natural water shortage; the amount of unmet (unsatisfied) potential evapotranspiration (PE)
alluvial terraces
level areas composed of alluvium that appear as topographic steps above a stream, produced by erosion as the stream downcuts into its floodplain after stream rejuvenation
ablation
loss of glacial ice through melting and evaporation, sublimation, or the calving of blocks of ice at the glacier's toe
moraines
marginal glacial deposits (lateral, medial, terminal, ground) of unsorted and unstratified material
dissolved load
materials carried in chemical solution in a stream, derived from minerals such as limestone and dolomite or from soluble salts
altocumulus clouds
middle-altitude clouds composed of ice and water that occur in several forms: patchy rows, wave patterns, a "mackerel sky," or lens-shaped "lenticular" clouds
sinkholes
nearly circular depression created by the weathering of karst landscapes with subterranean drainage; also known as a doline in traditional studies; may collapse through the roof of an underground space
paternoster lakes
one of a series of small, circular, stair-stepped lakes formed in individual rock basins aligned down the course of a glaciated valley; named because they look like a string of rosary (religious) beads
regolith
partially weathered rock overlying bedrock, whether residual or transported
adiabatic
pertaining to the change in temperature of a vertically moving parcel of air-cooling by expansion as it rises or heating by compression as it sinks- occurring without any exchange of heat between the air parcel and the surrounding environment
groundwater mining
pumping an aquifer beyond its capacity to flow and recharge; an overuse of the groundwater resource
nimbostratus clouds
rain-producing, dark, grayish stratiform clouds characterized by gentle drizzle
stratified drift
sediments deposited by glacial meltwater that appear sorted; a specific form of glacial drift
firn
snow of a granular texture that is transitional in the slow transformation from snow to glacial ice; snow that has persisted through a summer season in the zone of accumulation
fluvial
stream-related processes; from the Latin fluvius meaning "river"
sheetflow
surface water that moves downslope in a thin film as overland flow; not concentrated in channels larger than rills
surface runoff
surplus water that flows across the ground surface toward stream channels when soils are saturated or when the ground is impermeable; also called overland flow
overland flow
surplus water that flows across the land surface toward stream channels. Together with precipitation and subsurface flows, it constitutes the total runoff from an area
permeability
the ability of water to flow through soil or rock; a function of the texture and structure of the medium
actual evapotranspiration
the actual amount of evaporation and transpiration occurring at any given location; derived in the water balance by subtracting the deficit from potential evapotranspiration (PE)
potential evapotranspiration
the amount of moisture that would evaporate and transpire under optimum moisture conditions where adequate precipitation and soil moisture are present. PE is the total water demand, which if not satisfied results in a deficit, or moisture shortage
angle of repose
the angle at which a slope if inclined and beyond which downslope movement (slope failure) will occur. It is the limit of steepness on a slope, measured from a horizontal plane, and depends on the size, texture, and water content of the slope materials
soil-moisture zone
the area of water stored in soil between the ground surface and the water table. Water in this zone may be available or unavailable to plant roots, depending on soil texture characteristics
drainage basin
the basic spatial geomorphic unit of a river system; distinguished from a neighboring basin by ridges and highlands that form divides, marking the limits of the catchment area of the drainage basin
physical weathering (mechanical weathering)
the breaking up and disintegrating of rock without any chemical alteration; sometimes referred to as mechanical or fragmentation weathering
phase change
the change in state among the solid, liquid, and gas phases of water (ice, water, and water vapor). Each ____ ____ involves the absorption or release of latent heat
cone of depression
the depressed shape of the water table around a well after active pumping. The water table adjacent to the well is drawn down by the water removal
mass movement (mass wasting)
the downslope movement of a body of material (soil, sediment, or rock) propelled by the force of gravity; also called mass wasting
gradient
the drop in elevation from a stream's headwaters to its mouth, ideally forming a concave slope
differential weathering
the effect of different resistances in rock, couples with variations in the intensity of physical and chemical weathering
firn line
the elevation on a glacier above which winter snow and ice remain intact throughout the summer melt season but below which summer melting occurs
hydraulic action
the erosive work accomplished by the turbulence of water; causes a squeezing and releasing action in joints in bedrock; capable of prying and lifting rocks
soil-moisture utilization
the extraction of soil moisture by plants for their needs; efficiency of withdrawal decreases as the soil-moisture storage is reduced
cryosphere
the frozen portion of Earth's waters, including ice sheets, ice caps and fields, glaciers, ice shelves, sea ice, and subsurface ground ice and frozen ground (permafrost)
aggradation
the general building of a land surface because of deposition of material; opposite of degradation. When the sediment load of a stream exceeds the stream's capacity to carry it, the stream channel accumulates material through this process
glacial drift
the general term for all glacial deposits, both unsorted (till) and sorted (stratified drift)
latent heat of sublimation
the heat energy absorbed (680 calories for one gram of ice) in the phase change from ice to water vapor- no liquid phase. The change from water vapor to ice is deposition, which releases a comparable amount of heat
latent heat of vaporization
the heat energy absorbed from the environment in a phase change from liquid to water vapor at the boiling point; under normal sea-level pressure, 540 calories must be added to each gram of boiling water to achieve a phase change to water vapor
latent heat of condensation
the heat energy released to the environment in a phase change from water vapor to liquid; under normal seal-level pressure, 540 calories are released from each gram of water vapor that changes phase to water at boiling, and 585 calories are released from each gram of water vapor that condenses at 20 degrees Celcius (68 degrees Fahrenheit)
ice field
the least extensive form of a glacier, with mountain ridges and peaks visible above the ice; less than an ice cap or ice sheet
base level
the level below which a stream cannot erode its valley; the ultimate base level is sea level
specific humidity
the mass of water vapor (in grams) per unit mass of air (in kilograms) at any specified temperature. The maximum mass of water vapor that a kilogram of air can hold at any specified temperature is termed its maximum specific humidity
discharge (Q=wdv)
the measured volume of flow in a river that passes by a given cross section of a stream in a given unit of time; expressed in cubic meters per second or cubic feet per second
evapotranspiration
the merging of evaporation and transpiration water loss into one term
evaporation
the movement of free water molecules away from a wet surface into air that is less saturated; the phase change of water to water vapor
sediment transport
the movement of solid particles (sediment), typically by the action of gravity or the movement of a fluid, such as water, in which the sediment is entrained
transpiration
the movement of water vapor out through the pores in leaves; the water is drawn by the plant roots from soil-moisture storage
sublimation
the phase change of ice, a solid, directly to water vapor, a gas. The opposite process is deposition, in which water vapor changes directly to ice
frost wedging
the physical weathering process driven by frost action, or freeze-thaw action, that breaks rocks apart; a type of physical weathering
exfoliation (sheeting)
the physical weathering process that occurs as mechanical forces enlarge joints in rock into layers of curved slabs or plates, which peel or slip off in sheets; also called sheeting
saturation
the point at which air is holding the maximum amount of water vapor possible at that temperature, and beyond which point any addition of water vapor will cause net condensation; also known as saturation equilibrium, the point at which evaporation and condensation are in balance
nickpoint (waterfull)
the point at which the longitudinal profile of a stream is abruptly broken by a change in gradient; for example, a waterfall, rapids, or cascade
estuary
the point at which the mouth of a river enters the sea, where freshwater and seawater are mixed; a place where tides ebb and flow
percolation
the process by which water permeates the soil or porous rock into the subsurface environment
calving
the process in which pieces of ice break free from the terminus of a tidewater glacier or ice sheet to form floating ice masses (icebergs) where glaciers meet an ocean, bay, or fjord
degradation
the process occurring when sediment is eroded along a stream, causing channel incision
deposition
the process whereby weathered, wasted, and transported sediments are laid down by gravity, wind, water, and ice
weathering
the processes by which surface and subsurface rocks disintegrate, dissolve, or are broken down. Rocks at or near Earth's surface are exposed to physical and chemical weathering processes
relative humidity
the ratio of water vapor actually in the air (content) to the maximum water vapor possible in air (capacity) at that temperature; expressed as a percentage
soil-moisture storage
the retention of moisture within soil. In the water balance, this is the savings account that can accept deposits (soil-moisture recharge) or allow withdrawals (soil-moisture utilization) as conditions change
bedrock
the rock of Earth's crust that lies below the soil and regolith, and is sometimes exposed at the surface as an outcrop
hydrology
the science of water, including its global circulation, distribution, and properties- specifically water at and below Earth's surface
geomorphology
the science that analyzes and describes the origin, evolution, form, classification, and spatial distribution of landforms
meandering stream
the sinuous, carving pattern common to graded stream, with the energetic outer portion of each curve subjected to the greatest erosive action and the lower-energy inner portion receiving sediment deposits
porosity
the spaces, or voids, between particles in a material such as soil or rock
ground ice
the subsurface water that is frozen in regions of permafrost. The moisture content of areas with ground ice may vary from nearly absent in regions of drier permafrost to almost 100% in saturated soils
dew-point temperature
the temperature at which a given mass of air becomes saturated, holding the maximum amount of water vapor possible. Any further cooling or addition of water vapor results in active condensation
saltation
the transport of sand grains by stream or wind, bouncing the grains along the ground in asymmetrical paths
parent material
the unconsolidated material, from both organic and mineral sources, that is the basis of soil development
water table
the upper surface of groundwater; that contact point between the zone of saturation and the zone of aeration in an unconfined aquifer
infiltration
water access to subsurface regions of soil moisture storage through penetration of the soil surface
groundwater
water beneath the surface that is beyond the soil-root zone; a major source of potable water
soil-moisture recharge
water entering available soil storage spaces
humidity
water vapor content of the air. The capacity of the air for water vapor is mostly a function of the temperature of the air and the water vapor
cirrus clouds
wispy, filamentous ice-crystal clouds that occur above 6000 m (20,000 ft); appear in a variety of forms, from feathery hairlike fibers to veils of fused sheets