Geology Final Review

Front 1

Soil (engineering definition)

Back 1

"Any unconsolidated material, regardless of origin Any material that can be excavated with a shovel.

Soils classified based on:
1) Particle Size 2) Particle size distribution 3) Plasticity of Material

Term 'regolith' also used

Examples: Actual Soil, Weathered residual material, Large clasts on a talus slope, glacial deposits, a beach
"

Front 2

Soil (geological definition)

Back 2

'the scum that covers the good stuff'

Front 3

Soil Horizons

Back 3

"distinct layers within the soil profile that form as a result of chemical weathering processes in addition to physical and biological processes

Descriptions of the soil profile are done by recognizing master horizons"

Front 4

Master Horizons

Back 4

"set of horizons found worldwide in lots of different places

Not all master horizons will form in a soil profile
Factors that impact formation of master horizons:
Physical conditions, chemical environment, biological activity, climate (Temperature and Precipitation), parent material and TIME

Master Horizons to Know:
O-->surface accumulation of mostly organic matter
A-->mixed mineral material and partly
decomposed organic material (humus)
E-->usually underlies O and A, less organic
matter, zone of eluviation (or leaching) of
metal oxides and clays
B-->underlies O, A and E, substances leached
from E accumulate in B (illuvial zone)
(several subdivisions within B horizon
based on substance that accumulates)
K-->very strongly impregnated CaCO3 layer
Carbonate makes up 50% or more by volume
C-->horizon containing parent material from which
the soil formed (parent material that has
undergone some weathering
R-->consolidated bedrock underlying the soil"

Front 5

Cohesionless Soils

Back 5

"coarse-grained soils with little clay content
No interparticle bonding, friction (ALONE)
determines shear strength
Important Index Properties:
1)Particle-size distribution, 2) Shape of particles, 3) Clay
content, 4) In-place density and relative density"

Front 6

Cohesive Soils

Back 6

"fine-grained soils that contain high amounts of silt and clay
both interparticle bonding and friction contribute to
overall shear strength
Important Index Properties:
1)Consistency, 2) Water content, 3) Atterberg limits, 4) Type and amount of clay, 5) Sensitivity"

Front 7

Well-graded

Back 7

containing a variety of particle sizes (similar to poorly sorted)

Front 8

Poorly-graded

Back 8

containing a narrow range of particle sizes (similar to well sorted)

Front 9

Consistency

Back 9

"index property of cohesive soils
(def) strength and resistance to penetration of the soil in its in-place condition
(i.e.: resistance to jabbing a pencil into the soil)

Determined by:
Fabric-->arrangement of soil particles, particularly clays
Flocculated-->lots of edge to edge, non-ordered
contact of clay particles
Dispersed-->parallel arrangement of clay particles
Flocculated-->much stronger than dispersed
Remolding-->process of going from flocculated to
dispersed"

Front 10

Sensitivity

Back 10

"index property of cohesive soils

ratio of the unconfined compressive strength in the undisturbed state to strength in the remolded state

St = (strength in undisturbed condition)/(strength in remolded
state)
High sensitivity = highly unstable and dangerous"

Front 11

Flocculated Soils

Back 11

"arrangement of soil particles in clay soils
lots of edge to edge, non-ordered contact of clay particles

randomly, loosely oriented, not compacted
Flocculated orientation much stronger than
dispersed
"

Front 12

Dispersed Soils

Back 12

"parallel arrangement of clay particles (compacted)

Weaker than flocculated arrangement
Remolding = process of going from flocculated to dispersed"

Front 13

Atterberg Limits

Back 13

"Water content values at which a soil changes physical state
Liquid Limit: water content level at which soil passes
from a liquid to a plastic state
Plastic Limit: decreasing water content limit at which the
soil passes into a semisolid state
Shrinkage Limit: continued decreasing water content, limit
at which the soil becomes a solid and
no longer shrinks in volume with
decreasing water contact
(at SL, all soil particles are in contact with one another)"

Front 14

Angle of Internal Friction

Back 14

"Measure of the shear strength of cohesionless soils
Successive direct shear tests with increasing normal
stress are conducted on a sample of cohesionless soil

For Cohesionless soils: plot of shear stress vs. normal stress from these tests results in a straight line

The angle of inclination of the line with respect to the horizontal axis is the angle of internal friction.

Angle of internal friction is determined by the material
(common values on slide 3 of Lecture 18 (03/21))

Stress plots for cohesive soils will also be linear, but they don't pass through the origin (angle of internal friction still defined with respect to horizontal)"

Front 15

Settlement

Back 15

"vertical subsidence of a building foundation as soil compresses under load

Uneven settlement is a potentially serious problem"

Front 16

Compressibility

Back 16

"tendency for the soil to decrease in volume under load

can be measured by consolidation test
soil sample placed under a compressive load and void
space measured at various loads
Compression Index--slope of plot of decrease in void
space vs. normal pressure
(CI is used to predict amount of settlement)"

Front 17

Consolidation

Back 17

"process of soil compression

Rate of consolidation varies with soil properties

VERY SLOW in SATURATED CLAY-rich soils due to
very low permeability and high water content (drain
slowly---process can take a few years)

Total decrease in void ratio can be quite high in clay rich
soils, although it may take many years for equilibrium to
be reached (i.e.: lots of void spaces in flocculated
clays...once all the water gets out, the soil is
compacted a lot)"

Front 18

Hydrocompaction

Back 18

"Soil Hazard common in arid regions

particles held in a loose arrangement by the presence of weak clay, water or precipitant bonds in an UNsaturated state

If the soil becomes water saturated, then these bonds are broken and the soil collapses on itself

Results in foundation settlement, utility line rupture, etc."

Front 19

Liquifaction

Back 19

"Soil Hazard that results from conversion of a saturated soil to a liquid state under a rapid or cyclic stress

Commonly occur during earthquakes

Increased stress upon the soil from earthquakes can be great enough to suspend the soil particles in the pore water rather than driving the pore water from the soil

(load applied so rapidly water doesn't have time to escape

Results in total loss of shear strength and liquid behavior of the soil

Once the stress is removed, soil rapidly regains its strength"

Front 20

Sinkholes

Back 20

"roughly circular pits resulting from surface collapse of soils into subsurface cavities

Regions commonly affected by surface collapse are:
Coal mining regions (i.e.: Pennsylvania)
Karst limestone regions
(Groundwater passing through limestone dissolves the
limestone resulting in subsurface voids)

Examples: Winter Park Sinkhole; Lake Jackson, FL
"

Front 21

Metamorphism

Back 21

Mineralogical, chemical and structural adjustments of solid rocks in response to physical and chemical conditions different from the conditions under which the rocks originated

Front 22

Contact Metamorphism

Back 22

"alteration of the country rock by intruding magma
(Note: country rock is whatever the pre-existing rock was)

Characterized by High Temperature/Low Pressure
(Occurs deep in the earth, there is some pressure but
relatively low with respect to other types of metamorphism)"

Front 23

Burial Metamorphism

Back 23

"alteration of rocks due to the increase in pressure and temperature associated with increasing depth in the Earth's crust

Characterized by Moderate Temperature and Pressure
(Caused by accumulation of sediments on top of the rocks as in the formation of sedimentary basins)"

Front 24

Regional Metamorphism

Back 24

"alteration of a region of rocks in response to tectonic compression
(i.e.: at convergent plate margins/formation of mountain belts)

Moderate to High Temperature and Pressure"

Front 25

Dynamic Metamorphism

Back 25

"alteration of rock due to extremely high pressures

Low Temperature/High Pressure (Fault Zones)"

Front 26

Country Rock

Back 26

whatever the pre-existing rock was that's being metamorphosed

Front 27

Protolith

Back 27

"the original rock before metamorphism (same as country rock?)
""Metamorphic processes result in a change in the protolith""

Protolith composition plays a major role in determining composition of the resulting metamorphic rock

In a CLOSED system, new mineral creation by metamorphic processes is limited by composition of protolith

OPEN system--metamorphic process can introduce new minerals"

Front 28

Foliated

Back 28

"One of 2 main metamorphic textures

A metamorphic rock is foliated if it has a parallel orientation of grains within the rock

Usually has a banded or layered look that superficially resembles sedimentary rock

Engineering Properties similar to sedimentary rocks (susceptible to failure along foliation planes)

2 Common Cases:
1) Foliation is a relic of sedimentary bedding (i.e.: protolith was a sedimentary rock)
2) Protolith may have no bedding, but metamorphic rock has strong foliation due to directed stress
Common in regional metamorphic terrains
Tectonic forces applied in one direction
Growth of new minerals (micas) with long axis
perp. to directed stress
Where high temps. are present, shearing of
existing minerals, elongated parallel to applied force
"

Front 29

Non-foliated

Back 29

"One of 2 main metamorphic textures

Occurs when there is little or no directed stress

Common in contact and burial metamorphism where there is no preferred direction of growth (constant pressure from all sides)

Engineering properties similar to igneous rocks (strong, no planes of weakness)"

Front 30

Marble

Back 30

"Non-foliated metamorphic rock that forms from a limestone protolith

Re-crystallization process results in interlocking grains of calcite or dolomite

Example of a rock that forms from thermal metamorphism (i.e.: in response to high temperatures)"

Front 31

Quartzite

Back 31

"Non-foliated metamorphic rock that forms from a sandstone protolith
High Temps of metamorphism homogenize crystal structure, get rid of void spaces
One of the hardest rock's on the Earth's surface"

Front 32

Schist

Back 32

"well-foliated metamorphic rocks with coarser grains and higher metamorphic grade than slate
(often have visible alignment of micas)
Many types of igneous and sedimentary rocks can be metamorphosed to form schist

Metamorphic grade refers to degree of metamorphism
High grade is high degree of metamorphism
Low grade is low degree of metamorphism

Schist is 'mid-grade' metamorphism (more than slate less than gneiss)
"

Front 33

Gneiss

Back 33

"well-foliated rock that develops under high-grade metamorphic conditions

Coarse-grained, coarse banded rock that consists of alternate bands of light and dark-colored minerals

Form from silicic igneous and various types of sedimentary rocks"

Front 34

Slate

Back 34

"well-foliated rock produced by low-grade metamorphism of shale (usually directed pressures and low temps)

Foliation planes are planes of weakness"

Front 35

Permeability

Back 35

"rate at which fluids will move through a saturated material
Determined by size and connectedness of the voids AND
the properties of the fluid (temperature, viscosity, density)"

Front 36

"Intrinsic Permeability (k)
(units: cm^2 or darcys)"

Back 36

"permeability defined by the properties of the material
INDEPENDENT OF FLUID PROPERTIES
Depends on:
size, shape, packing of the grains
degree of cementation
degree of fracturing"

Front 37

"Hydraulic Conductivity (K)
(units: m/s)"

Back 37

"measure of the ability of a rock or soil to transmit water
Equation: K= k*(ρg/µ)
k = intrinsic permeability
ρ = density of water
µ = viscosity of water
g = acceleration due to gravity
Hydraulic conductivity combines k with the properties of the fluid...can change dramatically if fluid properties change (i.e.: hydrocarbon contamination)"

Front 38

Elastic

Back 38

"Type of ideal deformation response characterized by:
Linear plot of stress vs. strain
Slope is the modulus of elasticity (E)
E = σ/ε
Strain (ε) is the change in length vs the original length
Strain in elastic systems is recoverable"

Front 39

Unsaturated Zone

Back 39

partial filling of void spaces by water (aka vadose zone)

Front 40

Saturated Zone

Back 40

complete filling of void spaces with water

Front 41

Phreatic Zone

Back 41

below the water table

Front 42

Capillary Zone

Back 42

above the water table

Front 43

Water Table

Back 43

point at which the fluid pressure is equal to atmospheric pressure

Front 44

Equipotential lines

Back 44

(black lines) lines that connect points of equal head (i.e. there is
no hydraulic gradient along an equipotentail line)

Front 45

Flow lines

Back 45

(curved lines with arrows) water will always flow from greatest head
to lowest head in a direction perpendicular to equipotential lines

Front 46

Recharge

Back 46

addition of water to the groundwater system through rainfall or
snowmelt

Front 47

Discharge

Back 47

removal of water from the groundwater system

Front 48

Aquifer

Back 48

saturated body of rock or soil that transmits economically significant quantities of
groundwater

Front 49

Aquitards

Back 49

unit of rock that does not transmit groundwater at economically
feasible rates (Impermeable layers, dense non-fractured rock units)

Front 50

Aquicludes

Back 50

unit of rock that does not transmit groundwater (uncommon to
absent in nature--all rocks tend to transmit some water)

Front 51

Unconfined aquifers

Back 51

lack an overlying aquitard or aquiclude; water table is upper
boundary

Front 52

Confined aquifer

Back 52

bounded above and below by aquitards or aquicludes

Front 53

Potentiometric surface

Back 53

contours defined by the hydraulic head in wells of confined aquifers define potent surf;
if rises above land surface, artesian wells occur

Front 54

Perched aquifer

Back 54

form when lenses of impermeable material form smallish localized
aquitards in the unsaturated zone; small aquifers can develop above
these lenses; usually have low yields

Front 55

Residence time

Back 55

amount of time water spends in an aquifer (important bc length of
time it takes contaminants into deep confined aquifers)

Front 56

Cone of depression

Back 56

when water is pumped from an unconfined aquifer, this is formed

Front 57

Sustainability

Back 57

balance of discharge and recharge; discharge=recharge ->
equilibrium; discharge < recharge -> also in good shape; discharge
> recharge -> TROUBLE

Front 58

Karst

Back 58

limestone and dolomite are readily soluble by groundwater; over
time surface flow will transfer from surface runoff and drainage to
subsurface drainage with hardly any surface runoff; over time
surface will develop into a sinkhole plain

Front 59

Diffuse flow

Back 59

initial stages of Karst development; flow follows minute cracks and
joints in the rock, similar to usual groundwater movement

Front 60

Mixed flow

Back 60

second stage of Karts development; the minute cracks and joints
enlarge due to solution of the limestone and these become
preferential conduits but still some aspects of diffuse flow

Front 61

Secured Landfill

Back 61

used for disposal of hazardous wastes; requires engineered
leachate barriers; regular monitoring of unsaturated/saturated zones

Front 62

Sanitary Landfill

Back 62

used for disposal of less hazardous wastes; modern design tends
to try to isolate the waste into "cells" within the overall landfill

Front 63

Acid mine drainage

Back 63

sulfide minerals oxidize to produce sulfuric acid; very low pH, helps
mobilize metals

Front 64

Injection wells

Back 64

first used to dispose of brines brought up with oil; now used by
chemical industry to dispose of hazardous chemicals; commonly
very deep (hundreds of thousands of meters); typically try to inject
waste into permeable layer that doesn't contain useable
groundwater that is overlain by one or more aquitards

Front 65

Aqueous-phase liquids

Back 65

contaminant is dissolved in water

Front 66

Nonaqueous-phase liquids (NAPLs)

Back 66

contaminant is non-immiscible in water

Front 67

DNAPL

Back 67

dense non-aqueous phase liquid; denser than water

Front 68

LNAPL

Back 68

light non-aquesous phase liquid; less dense than water (includes
the petroleum products)

Front 69

Pendular Zone

Back 69

fluid pressure << atmospheric pressure and pores only slightly
saturated, air dominates pore space, no more reducation in
saturation level; matric potential << 0, results in thin films and
narrow capillaries filled with water

Front 70

Funicular Zone

Back 70

fluid pressure < atmospheric pressure and pores are only partially
saturated, but water dominates pore space; matric potential << 0

Front 71

Advection

Back 71

transport by the bulk movement of flowing water in response to the
hydraulic gradient; rate of movement = average linear velocity; why
average? Lots of different paths that the flow can take, each will
have a different velocity; v = KI/n where K = hydraulic conductivity,
I = hydraulic gradient, n = porosity

Front 72

Hydrodynamic dispersion

Back 72

results in spreading of the contaminated zone along the flow path;
higher flow rates in the center of the plume that the margins; more
rapid flow through the larger pores; lateral expansion of the
contaminant due to having a flow around aquifer grains; results in
the fixed mass of contaminants being spread over larger area =
reduction in concentration

Front 73

Oil layer

Back 73

Gasoline = LNAPL; begins to pool at the top of the capillary fringe
in a layer termed the "free product"; will migrate along the top of the
capillary fringe in the direction of the slope in the water table; top
of the free product forms the "oil layer"

Front 74

Viscous

Back 74

a type of ideal material; in a linear plot of stress vs. strain viscosity is the slope; it is non-recoverable

Front 75

Plastic

Back 75

a type of ideal material; no strain until some critical stress value has been reached and then continuous deformation after that

Front 76

Brittle

Back 76

respond in a mostly elastic fashion until failure (breakage of the rock, usually results in earthquakes)

Front 77

Ductile

Back 77

respond in a mostly plastic fashion until failure (folding of the rock)

Front 78

Rock Mass Rating System

Back 78

system to quantify many factors to determine the quality of a rock mass (Table 7.8-7.10)

Front 79

Strike & Dip

Back 79

method to measure the orientation of planar elements within a rock body

Front 80

strike

Back 80

direction of the line formed by intersection of the plane and the horizontal (measured in degrees from north)

Front 81

dip

Back 81

amount of slope on the plane, always measured on a vertical plane perpendicular to strike, measured in degrees from horizontal

Front 82

Anticline

Back 82

a type of fold - upward bending, shaped like an arch

Front 83

Syncline

Back 83

a type of fold - downward bending, shaped like a U

Front 84

Symmetrical

Back 84

a type of fold - limbs dip in opposite directions at the same angle

Front 85

asymmetrical

Back 85

a type of fold - limbs dip in opposite directions in different angles

Front 86

overturned

Back 86

limbs dip in same direction

Front 87

recumbent folds

Back 87

axial plane nearly horizontal

Front 88

axial plane

Back 88

a plane containing the axis that divides the fold into two equal sections

Front 89

joint

Back 89

evidence of a brittle deformation (difference btwn joint/fault - joints have no had movement occur along the failure plane); produced by cooling of igneous rocks, unloading durin erosion, compressional tensile and shearing stresses (these tend to form in sets of parallel planes throughout the rock body); are planes of weakness and the overall stability of the rock body will be controlled by the orientation and spacing of the join

Front 90

fault

Back 90

fractures that movement has occurred along; classified by the type of movement (slip) that has occurred

Front 91

dip-slip

Back 91

movement has occurred in the direction of the dip of the fault plane

Front 92

strike-slip

Back 92

movement has occurred in the direction of the strike of the fault plane (transform, strike-slip)

Front 93

hanging wall

Back 93

the "top wall" if a miner attached himself to one this wall he would "hang" from it

Front 94

foot wall

Back 94

the "bottom wall" if a miner attached himself to this wall, he could stand on it (without falling)

Front 95

normal fault

Back 95

hanging wall has moved down, extensional

Front 96

reverse fault

Back 96

hanging wall has moved up, compressional

Front 97

thrust fault

Back 97

low angle reverse fault, compressional

Front 98

fault scarp

Back 98

the exposed and eroded fault plane

Front 99

horst

Back 99

paired dip-slip faults result in this; specifically - 2 reverse faults result in this

Front 100

graben

Back 100

paired dip-slip faults result in this; specifically - 2 normal faults result in this

Front 101

right and left lateral strike-slip faults

Back 101

determine by facing the fault and noting in which direction the movement appears to have gone relative to you (right or left)

Front 102

hypocenter/focus

Back 102

where the strain release actually occurs along the fault

Front 103

epicenter

Back 103

point on the Earth's surface directly above the hypocenter; point where seismic waves first reach the surface, usually most severe ground motion

Front 104

P wave

Back 104

primary waves, compressional; travel trhough Earth's interior, travel the fasest of all waves

Front 105

S wave

Back 105

secondary (or shear) waves, shear; travel through Earth's interior, next fastest wave (after primary)

Front 106

Rayleigh wave

Back 106

a type of surface wave (long periods, slow, travel only on surface); like ocean waves, vertical displacement

Front 107

Love wave

Back 107

a type of surface wave (long periods, slow, travel only on surface); horizontal ground motion, result from S waves reaching surface at epicenter

Front 108

seismograph

Back 108

instrument used to measure the intensity of the seismic waves

Front 109

seismogram

Back 109

chart of the wave vibrations

Front 110

Modified Mercalli Scale

Back 110

measure of the intensity - subjective measurement based on damage and personal interviews (12 different divisions - see Table 16.2); the same earthquake results in different divisions depending upon the location of the person recording it

Front 111

Fundamental Period

Back 111

a natural vibration that both buildings and geological materials have (bedrock and stiff soils <1s, soft soils = several seconds, tall buildings = several seconds, short stiff buildings <1s); if the building and ground have similar fundamental periods - resonance occurs and more damage is the usual result ALSO tall building built on soft soilds tend to suffer the greatest damage due to similarities in fundamental period

Front 112

Groundwater

Back 112

a fundamental natural resource (used for drinking water, sanitation, irrigation/agriculture, livestock water, industry, recreation)

Front 113

Free product layer

Back 113

The pool of gasoline that forms at the top of the capillary fringe

Front 114

Glacier

Back 114

sufficiently massive body of interlocking snow and ice crystals that flows downslope under its own weight

Front 115

Firn

Back 115

dense granular snow/ice resulting from compaction of snow, eventually compaction of the firn results in the total recrystallization and formation of glacial ice

Front 116

Snow line

Back 116

elevation above which snow more or less remains all year long

Front 117

Zone of Accumulation

Back 117

area of glacier that snowfall exceeds melting/sublimation

Front 118

Zone of Ablation

Back 118

area of glacier that melting/sublimation exceeds snowfall

Front 119

Equilibrium Line

Back 119

area where snow fall equals melting/sublimation

Front 120

Basal sliding

Back 120

tendency of the glacier to slide as a block above its bed

Front 121

Cold-based glacier

Back 121

moves only by visco-plastic deformation

Front 122

Wet-based glacier

Back 122

moves both by visco-plastic deformation and by basal sliding

Front 123

Deforming Bed Hypothesis

Back 123

When moving over a bed of weathered rock/weak sedimentary rock/old glacial sediments, the glacier may couple to the bed and deform it so that the bed material is moving at some velocity

Front 124

Crevasse

Back 124

large glacial cracks, in the brittle zone/upper part of the glacier

Front 125

Brittle Zone

Back 125

upper portion of the glacier

Front 126

Visco-plastic Zone

Back 126

portion of the glacier below brittle zone where crevasses do not form, ice deforms 'in a visco-plastic way'

Front 127

Glacial striations

Back 127

elongated grooves caused by abrasion of the bed by traveling rocks; form parallel to the direction of ice flow, only occurs in wet-based glaciers

Front 128

Plucking

Back 128

process of incorporation of large block of bedrock into the glacier

Front 129

Ice thrusting

Back 129

ice freezes to bedrock and shearing of the bed results in large slabs being mobilized into the glacier, occurs in cold-based regions

Front 130

Roche Moutonnes

Back 130

a rock hill shaped by the passage of ice to give a smooth up-ice side and a rough, plucked and cliff-girt surface on the down-ice side

Front 131

U-shaped valley

Back 131

valley formed by erosions of glaciers; characteristic steep, straight sides, and a flat bottom, ice flows tend to form U-shaped valleys whereas streams and rivers form V-shaped valleys

Front 132

Horn

Back 132

point where aretes coalesce; sharply pointed pinnacle that forms when 2 or more glaciers erode headward at the base of a mountain peak

Front 133

Arete

Back 133

narrow ridge that separates two glaciated valleys and is often quite steep and sharp

Front 134

Col

Back 134

a gap produced in a ridge by the headward erosion of glaciers in two cirques from opposite sides of the ridge

Front 135

Cirque

Back 135

bowl-shaped depression at the base of a mountain peak where glaciers form and begin to flow downvalley

Front 136

Hanging Valley

Back 136

tributary glacial valley with the floor at higher relief than the valley into which it flows, most commonly associated with U-shaped valleys when a tributary glacier flows into a glacier of larger volume

Front 137

Drift

Back 137

catch-all term for any glacial deposits

Front 138

Till

Back 138

nonsorted, nonstratified sediment deposited by glacial ice

Front 139

Basal till

Back 139

deposited at the base of wet-based glaciers, dense and compact

Front 140

Ablation till

Back 140

originates as debris from ice thrusting or plucking that is transported from the base to the glacier to the ablation area

Front 141

Ice-contact stratified drift

Back 141

debris deposited by meltwater moving around, through, or on top of glacier

Front 142

Moraine

Back 142

ridge of drift

Front 143

Lateral moraine

Back 143

narrow ridge of drift that is deposited along the lateral edge of valley glaciers and of outlet glaciers against the valley wall

Front 144

Medial moraine

Back 144

longitudinal debris bands in the glacier in the main valley formed from lateral moraines from glaciers that formed in tributary valleys

Front 145

End moraine (terminal moraine)

Back 145

ridge of drift deposited by the glacier at its point of maximum advance

Front 146

Ice sheet/ice cap

Back 146

large expanses of ice with a dome-shaped profile
ice sheets are greater than 50,000 km^2 while caps less than 50,000 km^2

Front 147

Outwash

Back 147

gravel, sand, and silt deposited in front of the glacier