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