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Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology (1995)

Chapter: APPENDIX D - GLOSSARY OF TERMS

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Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×

Appendix D
Glossary of Terms1


alluvium

-general term for unconsolidated material (clay, sand, silt, gravel) deposited by streams


bajada

-a broad alluvial slope extending from the base of a mountain range into a basin.,. formed by joining of a series of alluvial fans; occurs in add and semiarid conditions

base level

-theoretical lowest level toward which erosion of the Earth's surface constantly progresses; lowest level to which a river flows - locally could be into another river or lake; ultimately, into the ocean. Sea level is called the ultimate base level.

batholith

-a large mass of hardened molten rock with more than 100 km2 of surface exposure with no known lower limit

berm

-a relatively narrow horizontal man-made shelf, ledge, or bench which breaks the continuity of a slope

breccia

-a coarse-grained rock composed of angular rock fragments held together by mineral cement

brittle deformation

-deformation in which rocks behave rigidly, by cracking and breaking, when a force or stress is applied


caliche

-secondary calcareous material found in layers on or near the surface in arid and semi-add regions, composed of soluble calcium salts with varying amounts of gravel, silt, clay, and sand; a carbonate layer produced by soil-forming (pedogenic) processes

capillary force

-the action by which a fluid, such as water, is drawn up in small interstices as a result of surface tension of other droplets of water

clast

-a grain or fragment of rock, such as silt, sand, pebble or boulder

Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×

clastic

-pertaining to a rock or sediment composed of fragments of pre-existing rocks

compression

-a system of forces or stresses which result in the decrease in volume or shortening of the crust

cone of depression

-a cone-shaped depression in the water table around a well which develops when water is withdrawn from the well

conglomerate

-a coarse-grained sedimentary rock composed of rock fragments larger than 2 mm in diameter and a fine grained matrix and/or cement of silt, sand, or calcium carbonate; the rock fragments usually are rounded, as pebbles, rather than angular as in a breccia

continental crust

-the crust which underlies the continents; mainly granite, a light colored, low density rock, high in silica and aluminum, low in iron and magnesium

continental margin

-edge of the continent which is between the shoreline and the abyssal ocean floor

continental shelf

-the part of the continental margin between the shoreline and the continental slope; the fiat, gently sloping extension of the continent under the ocean

correlative

-belonging to the same stratigraphic position or level, generally implies strata of the same age, having formed at the same time in the geologic past

crust

-the outermost layer of the earth

crustal extension

-pulling apart of the outermost layer of the Earth's surface as a result of strain

crystalline rock

-a rock consisting wholly of relatively large mineral grains, refers generally to highly metamorphosed rocks


Darcy's Law

-a formula for calculating the rate of flow of fluids through a matrix of soil or porous rock on the assumption that flow is laminar and that inertia can be neglected

deep sod water flux

-deep percolation of water in the unsaturated zone

deformation

-the process of folding, faulting, shearing, compression, or extension of rocks as a result of earth forces

deposition/sedimentation

-the process of accumulation of loose rock material into layers or masses on the earth's surface above or below the sea

Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×

detachment fault

-a low-angle fault formed at the base of a horizontal or gently dipping body of rock; can be a thrust fault as a result of compression, or a normal fault as a result of extension.

dike

-an igneous intrusion which cuts across the layered structure of the surrounding rock; magma that fills a crack in the crust and hardens

dilution

-reduction in the concentration of a solution by addition of more solvent

dip

-an angle down from the horizontal that a sloping structural surface, e.g., a bed or a fault plane, makes

dispersion

-distribution of a substance outward in all directions

drainage system

-the network of surface streams, including a main stream and all of its tributaries, which drains a particular region

drawdown

-in a body of water, the difference between the water-surface elevation at a constriction, and what the elevation would be with no constriction

ductile deformation

-deformation in which rocks behave like a viscous substance


erosional exhumation

-the uncovering or exposure by erosion of a surface, landscape, or feature that has been buried beneath other rocks

evaporite

-a non-clastic sedimentary rock composed of minerals produced from a saline solution, mainly the ocean or salt lake, due to evaporation, such as salt (sodium chloride) or gypsum

evapotranspiration

-loss of water from a land area through transpiration by plants and evaporation from the soil

extension

-a strain term signifying pulling apart the crust resulting in an increase in length


flux

-the rate of water movement through the unsaturated zone, regardless of direction

fold

-a curve or bend of a rock strata or other planar feature resulting from explosive volcanic activity that pulverizes rock as it blasts it out of the volcano


ground water

-subsurface water located in the saturated zone below the water table

Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×

hydraulic conductivity

-a measure of the unsaturated zone's transmission of water

hydraulic gradient

-in an aquifer, the rate of change of total head per unit of distance in a given direction


infiltration

-the movement of water downward into soil or porous rock

island arc

-a chain of near shore islands rising from deep sea floor, produced by the down-plunge of oceanic crust beneath a continental margin

isothermal

-maintaining a constant temperature during any process or procedure


lateral flow

-flow of water across a sloping surface or through a matrix because of gravity

lateral subsurface flow

-water infiltrating the surface soil and moving laterally in the subsurface following a shallow slope or gradient


magma

-molten rock, formed deep in the earth's crust, from which igneous rocks solidify

magmatism

-the development and movement of magma

matric potential

-is a measure of how tightly water is held by the soil matrix

matrix

-the fine-grained material enclosing, or filling the interstices between, the larger grains of a sediment or sedimentary rock

metamorphism

-the chemical, mineralogical, and/or structural change of rocks as a result of change in temperature and/or pressure

mountain building

-the formation of mountains through the process of thrusting, folding, and faulting of layers of the earth resulting from continental collisions. Deeper layers of the crust also undergo metamorphism during this process.


oceanic crust

-the crust which underlies the ocean basins; mainly basalt, a dark, dense rock, low in silica and aluminum, high in iron and magnesium

osmotic potential

-the energy required to remove dissolved salts from soil water


paleosol

-a buried soil horizon of the geologic past

perched water

-accumulated water trapped in the unsaturated zone by either some impermeable layer or some structural feature

Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×

pereolation

-the downward movement of water through small openings within a porous material, such as in the unsaturated zone

permeability

-the property or capacity of a porous rock, sediment or soil for transmitting a fluid; the interconnected pore spaces that allow movement of water from one place to another

piston flow

-the uniformly distributed downward movements of water in the unsaturated zone

playa

-a dry, vegetation-free fiat area at the lowest part of an undrained desert basin; a dry lake bed in the desert

pluton

-an igneous intrusion; a large amorphous mass of magma formed deep within the earth, moved upward, and hardened before reaching the surface

potential

-refers to energy as function of position or of condition

precipitation

-the solidification of dissolved particles and settling out of solution by gravity

probable maximum precipitation (PMP)2

-the theoretical greatest depth of precipitation for a given duration that is physically possible over a given size storm area at a particular geographical location

probable maximum flood (PMF)2

-the most severe flood that is considered reasonably possible at a site as a result of meteorologic and hydrologic conditions

preferential flow

-movement of water downward through the unsaturated zone, along non-uniformly distributed pathways

Proterozoic

-the period of time before the Cambrian period, prior to macroscopic life


recharge

-the process of adding water to the saturated zone

regional uplift

-large-scale, long-term upward movement of an area of the crust

relief

-the vertical difference in elevation between hilltops or mountain summits and lowlands or valleys in a particular area. An area of high relief has great vertical variation and an area of low relief has little variation in elevation.

root zone

-area in the sediment in which living plant roots are found

Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×

saturation

-the point at which the interstices of a material, such as a rock, contain the maximum possible amount of water; all pores are filled with water

sill

-an igneous intrusion which parallels the planar structure of the surrounding rock; magma that forces its way between layers and then parallels the layered structure when it hardens.

soil-water potential

-a measure of how tightly water is held by the soil matrix as result of capillary and other forces

sorption

-the taking up of a fluid or solution by a porous medium

standard deviation

-a quantification of the error range (±) of values about the average of a number of measurements

storage capacity

-the ability of a soil to hold water; the amount of water that can be held in the unsaturated zone


texture

-the general physical appearance or character of a rock; the pattern or interconnection of rock particles

tuff

-a general term for unconsolidated ash and fine fragments of rocks, resulting from explosive eruptions of volcano.


unconfined aquifer

-ground water that has a free water table, i.e. water not confined by pressure beneath impermeable rocks

unsaturated zone

-a subsurface zone including the soil that may contain water under pressure less than that of the atmosphere, including water held by capillary forces; it is the zone above the water table


vadose zone

-another term for unsaturated zone

volcanism

-the processes by which magma and its associated gases rise into the crust and are extruded onto the surface as lava flows and into theatmosphere


water table

-the surface between the saturated zone and the unsaturated zone, the uppermost part of ground water

water table divide

-a ridge or elevated zone in the water table from which ground water moves away in both directions


xeroriparian

-refers to species typically found in or along washes

in arid environments

Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×
Page 219
Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×
Page 220
Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×
Page 221
Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×
Page 222
Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×
Page 223
Suggested Citation:"APPENDIX D - GLOSSARY OF TERMS." National Research Council. 1995. Ward Valley: An Examination of Seven Issues in Earth Sciences and Ecology. Washington, DC: The National Academies Press. doi: 10.17226/4939.
×
Page 224
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The book examines specific scientific and technical safety issues related to the proposed low-level radioactive waste site at Ward Valley, California. It includes, among other issues, evaluation of the potential for infiltration by shallow subsurface water, contamination of ground water and the Colorado River, damaging effects on the desert tortoise habitat, and restoration of the native vegetation.

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