The state of having little or no money and few or no material possessions. More than a fifth of the global population today live in poverty, subsisting on less than US $1 a day. There are clear links between poverty, population growth, and environmental problems. These are most evident at the level of individual households or communities, but they can also be detected at the national scale. Povert…
The rate at which energy is supplied, usually measured in watts. …
A North American term for a place where electricity is generated, either by burning fossil fuels, controlling nuclear reactions, tapping hot subsurface rocks (geothermal), or diverting water to turn turbines (hydroelectric). Also known as power station . …
A large area of flat or rolling grassland, dominated by grasses and wildflowers, with no or few trees, that often grows on fertile soil. See also dry prairie, hill prairie, mesic prairie, mixed grass prairie, sand prairie, shortgrass prairie, tallgrass prairie, wet prairie. …
A marsh type of vegetation dominated by small seasonally or permanently flooded depressions and emergent hydrophyte vegetation, that is found in North America on the prairies of the upper Midwest and the Canadian plains, and provides a habitat for the majority of North American ducks during migratory nesting and the breeding season. …
The earliest unit of geological time, which ended with the beginning of the Palaeozoic about 570 million years ago, and accounts for about 90% of geological time. The first living organisms appeared during the Precambrian. …
A proactive method of dealing with the environment based on the idea that if the costs of current activities are uncertain but are potentially both high and irreversible then society should take action before the uncertainty is resolved. The Convention for the Prevention of Marine Pollution by Dumping from Ships and Aircraft (Oslo Convention) ( 1972 ) is an early example of the use of the precauti…
An act or decision that can be used as an example in dealing with subsequent similar situations. …
The variation in the Earth's axis of rotation that traces out the path of a cone over a period of about 23?000 years. …
1 The process by which moisture (water vapour) in the atmosphere condenses and falls as rain, snow, sleet, or hail. 2 In chemistry, the action of causing a substance to be deposited in solid form from a solution. …
The process by which rain or snow removes particulates from the atmosphere and deposits them on the ground surface. See also rainout. …
An air pollution control devices that collect particles from an emission by mechanical or electrical means. …
A substance from which another substance is formed. …
An interaction between organisms in which one (the predator) eats the other (the prey). See also parasitism. …
A carnivore; an animal (such as a shark) that hunts and kills other animals (the prey) for food. …
An interaction between predator and prey in which the predator controls the size of the prey population. …
An indication in advance based on observation, experience, or scientific reason. Contrast projection. …
Plant species which are preferred by animals and are grazed out of choice. …
Dating back to before written historical records begin. In Europe this includes the Stone Age, the Bronze Age, and the Iron Age. In North America prehistory is usually taken to refer any time before ad 1540 . …
The initial step of a site assessment of Superfund sites, based on collecting and reviewing available records and information. See also Site Inspection. …
A death that occurs before the average age within that population and which is usually attributable to a specific cause (such as an accident or disease). …
The treatment of waste materials prior to composting, which includes grinding, shredding, sorting, and adding sewage sludge. …
In forest management, the removal of trees towards the end of a rotation in order to open the canopy so the crowns of seed‐bearing trees can enlarge, which improves seed production and encourages natural regeneration. …
All measures that are taken before an event occurs, that allow for prevention, mitigation, and readiness. See also contingency plan, disaster management. …
A planned fire in a predetermined area, in order to meet particular resource management objectives such as to improve silviculture, wildlife management, grazing, or reduction of fire hazard. Also known as controlled burn, prescribed fire . …
Written instructions or a written statement that defines management objectives. …
A way of comparing the value of something now with the value of it in the future, which is used to compare alternative projects that have different cost and revenue flows. Also known as present net worth . See also cost?benefit analysis, discount rate. …
The activity of protecting something (such as old and historic buildings, sites, structures, and objects) from loss or danger. Contrast conservation. …
A chemical substance used to protect organic material (such as food or wood) from decomposition or fermentation. …
1 To keep or maintain in an unaltered condition. 2 A reservation in which animals are protected. Also known as a reserve or nature reserve . …
Material that is made from wood veneers, particles, or fibres that are bonded together with an adhesive under heat and pressure, and is used in making buildings and furniture. …
The force that is applied per unit area. See also atmospheric pressure. …
The rate of change in atmospheric pressure between two points, which reflects the distance between isobars on a weather map, and affects wind speed (a steep pressure gradient produces strong winds). Also known as barometric gradient . …
Any group of people who share special interests, are politically active, and advocate particular policies or approaches. Examples include Friends of the Earth (FOE) and Greenpeace. Also known as an interest group or special interest group . See also environmentalism. …
An instrument that measures wind speed from the pressure exerted through a tube aligned to point into the wind. …
A type of light‐waternuclear reactor in which water is used as a coolant, but it is kept under enough pressure so that it does not boil. Electricity is generated by turbines which are turned by steam that is formed in a secondary cooling system. Contrast boiling water reactor. …
The dominant westerly winds that blow in middle latitudes on the poleward side of the subtropical high‐pressure areas. Also known as westerlies . …
The direction from which the wind blows most often. …
The number of individuals in a population who have a particular disease or condition at a given time. Contrast incidence. See also occurrence. …
A programme, specified in the US Clean Air Act, whose goal is to prevent air quality from deteriorating significantly in areas of the country that currently comply with ambient air quality standards. …
An animal that is killed and eaten by other animals (the predators). …
In commercial forestry, removing some of the trees from a stand that are too small to be sold (for lumber or house logs), so that the remaining trees will grow faster. …
In air pollutionemissions reduction, the period of time before the first Commitment Period under the Kyoto Protocol, when the operational framework is established and the involvement of signatories to the protocol is determined. …
Making purchasing decisions that will reduce waste. This includes buying goods with less packaging, choosing products that will last longer, and avoiding single‐use or disposable products, the most commonly cited example of disposable products being nappies. …
Land use that existed before particular planning constraints were introduced. …
A range of processes that are used to reduce, eliminate, or alter the nature of wastewater pollutants from non‐domestic sources before they are discharged into publicly‐owned treatment works. …
A measure of the sensitivity of supply and demand to changes in price. …
US legislation that established an insurance scheme for nuclear power that is backed by taxpayers. It limits the amount of insurance that nuclear power plant owners must carry, and shields nuclear power from free market forces by capping the liability of nuclear power plant owners in the event of a catastrophic accident or attack at levels which are significantly lower than likely costs. …
Air quality standards that are designed to protect human health. Contrast secondary ambient air quality standards. …
A herbivore, which eats primary producers and so sits above them in a food chain. Contrast secondary consumer. See also heterotroph. …
A regulation that applies in the US to public water systems and specifies a contaminant level which it is judged will not adversely affect human health. …
Agriculture and mining. Contrast secondary economic activities, tertiary economic activities. …
Energy that exists in natural resources (such as coal, crude oil, sunlight, uranium) that has not been converted or transformed by humans. …
A forest that is largely undisturbed by human activities. Contrast secondary forest. …
The marketplace into which shares are sold when they are first issued. Under the Kyoto Protocol, the exchange of emission reductions, offsets, or allowances between buyer and seller where the seller is the originator of the supply. Contrast secondary market …
Any compounds which occurs in all living organisms and are essential for life, such as carbohydrates, the essential amino acids, and polymers derived from them. …
1 A mineral such as feldspar or mica which occurs or occurred originally in an igneous rock. 2 Any mineral which occurs in the parent material of the soil. Contrast secondary mineral. …
The elements phosphorus, potassium, and sodium, which must be taken up and used by plants in sufficient quantities for them to complete their life cycles. Contrast secondary nutrient. …
Chemicals (such as carbon monoxide, hydrocarbons, nitrogen compounds, particulate matter, and sulphur dioxide) that are released directly into the air in a harmful form. Contrast secondary pollutant. …
An autotroph that captures energy from the environment and turns it into biomass through photosynthesis or chemosynthesis, and forms the base (lowest trophic level) of a food chain. Examples include green plants on land and phytoplankton in oceans. See also chemotroph. …
The amount of new plant biomass that is formed by photosynthesis or chemosynthesis in a given period of time. Primary productivity varies a great deal from one type of ecosystem to another. The estimated average net primary productivity for the world (in grams per square metre per year, g m-2 year-1) is 303; the average for major world biomes is reefs and estuaries 2000, forest 1290, freshwater 12…
A grazing area (range) which livestock prefers to use because it contains vegetation they like. When there is limited or no range management animals are likely to over‐graze these areas. …
The pollution limit for criteria air pollutants that is based on health effects. Contrast secondary standard. See also National Ambient Air Quality Standards. …
An ecological succession that begins on a newly formed soil or on a new surface that has been exposed for the first time (for example as the result of a landslide or volcanic eruption). Contrast secondary succession. …
The initial treatment that is provided at a wastewater treatment plant, in which solids and liquids are separated from domestic sewage by screening and sedimentation. Also known as primary waste treatment . See also advanced wastewater treatment, primary waste treatment, secondary treatment. …
Any of the 195 species of mammal that belongs to the order Primates, which includes monkeys, apes, and humans. …
The best available land which is capable of producing acceptable yields of crops with acceptable inputs and minimal environmental damage. Also known as prime farmland . …
Having existed from the earliest times. See also primordial. …
A large tract of land within a US National Forest, that has been set aside for preservation in its natural condition with no alteration or development permitted except for measures to protect the spread of fire. Such areas were reclassified as Wilderness Areas under the 1964 Wilderness Act. …
A category of land defined within the recreation opportunity spectrum as an ?essentially unmodified natural environment of fairly large size?, with few interactions between users. Motor vehicles are not permitted, and the area is managed to be largely free from evidence of human control. …
In cladistics, a character that is shared among members of a large group (clade) and is thought to have arisen early in the evolution of the group. …
Those types of recreation activities that are associated with land having no roads, which includes hiking, backpacking, and cross‐country travel. …
A classification of wilderness and recreation opportunity on the ROS (recreation opportunity spectrum) scale, based on an unmodified environment, where trails may be present but structures are rare, and where contact with other people is unlikely. …
The principle that the factor (such as a particular nutrient, water, or sunlight) that is in shortest supply (the limiting factor) will limit the growth and development of an organism or a community. …
A small abnormal protein that is found in brain cell membranes, which is responsible for mad cow disease (Bovine Spongiform Eucaphalopathy) and causes new variant Creutzfeld?Jakob disease in humans. …
A doctrine of water law that allocates the rights to use a particular body of water on a first‐come first‐served basis. …
In the context of the international trade in hazardous chemicals, a procedure that seeks to share responsibility between exporting and importing countries in protecting human health and the environment by sharing information about the hazards associated with those chemicals, and encouraging importing countries not to proceed without agreement. …
A category in the EU Habitats Directive that is applied to habitats that are deemed to be of conservation importance within the European Union. …
A group of around 130 chemicals (of which about 110 are organics) that appear on a US Environmental Protection Agency list because they are toxic and relatively common in industrial discharges. …
Any species that is targeted in the UK Biodiversity Action Plan (BAP) for national conservation effort, and is the subject of a Species Action Plan or Species Statement in the UK BAP. …
The whole sequence of serecommunities in succession. …
Forest land that belongs to individuals and corporations. …
Any good or service whose consumption by one person excludes consumption by others. Contrast public good. …
Land that belongs to individuals and corporations. …
The opportunity cost of using a resource that is experienced by an individual, excluding any externalities. …
Things (property or goods) that belong to individuals as opposed to public ownership, which gives those individuals the exclusive right to possess, use, or dispose of those things. …
The value to an individual of using or not using a particular resource. …
The process of changing a government‐owned resource (such as a National Forest) to private control and ownership. …
Any toxic pollutant or combination of pollutants that is an unavoidable product from any manufacturing process. …
An organism that synthesizes food molecules from inorganic compounds using an external energy source, usually by photosynthesis. Contrast consumer. See also primary producer. …
A well that has a high enough yield that it can be used for public use, either for water supply or for industrial purposes. …
Describing an area that is to provide goods and services and to sustain ecological values. …
In general, the rate of output per unit of input, a measure of efficiency. In ecology, the rate of production of biomass. See also gross primary productivity, net primary productivity, primary productivity, secondary productivity, tertiary productivity. …
A product‐centred approach to environmental protection, which expects those in the product life cycle (manufacturers, retailers, users, and disposers) to share responsibility for reducing the environmental impacts of products. …
1 A cross‐section through topography or a landscape. 2 A vertical section through a soil from the surface into the relatively unaltered material. See also soil profile. 3 Variations in the physical and chemical properties of water at different depths within a waterbody. …
The bed of a body of deep water, where insufficient light penetrates for rooted plants to become established. …
Children or offspring, the immediate descendants of a plant or animal (including humans). …
The part of the potential yield of a crop that is planned for harvest in any particular year. …
Any land use zoning regulations which only allow particular types of use in certain kinds of areas, such as floodplain zoning that only allows uses which do not reduce the flood water storage capacity. …
A forecast that is based on historic and current information. Contrast prediction. …
The deliberate planning, control, and coordination of all aspects of a project (initiating, planning, executing, controlling, and closing), in order to achieve the agreed objectives. …
The emission forecast made in an emission reduction project, which is compared with the business‐as‐usual (baseline) scenario in order to determine the emission reductions that have been achieved. …
An organism that does not have a nucleus containing genetic information. See also eukaryote. …
A narrow strip of land that extends out into the sea. Also known as headland . …
1 To increase the number of plants of a particular population by means of cuttings. 2 The breeding of new lifestock through natural methods. …
Increasing or spreading of a plant or plants by natural reproduction. …
A part of a plant that can produce another plant which includes seeds, roots, and rhizomes. …
A colourless, heavy gaseous hydrocarbon that is found in crude oil and natural gas, and is used as fuel and in petrochemicals. …
Something that propels, such as a gas (such as butane, propane, and nitrogen oxides) that has a high vapour pressure and is used to force material out of aerosol spray cans. …
The pricing of natural resources at levels which reflect their combined economic values and environmental values. …
The rights of an owner of private property, which usually include the right to use the property as they see fit (within limits, such as zoning) and the right to sell it when and to whom they decide to. …
The concept that control measures or a response should generally be proportional to the risk. …
In the USA, any species of fish, wildlife, or plant that is proposed to be listed under the Endangered Species Act. …
1 To search for something useful or valuable. 2 The possibility of future success. …
The search for mineral deposits, for example by removing overburden, or by drilling cores to obtain subsurface samples. …
A study that follows a group (cohort) of individuals over time, in order to determine whether exposure to particular factors produces adverse effects on the group or on different subgroups. Also known as cohort study . …
A person who explores an area for useful or valuable resources, such as mineral deposits. …
A state in hermaphroditic organisms that is characterized by the development of the male stage before the appearance of the corresponding female feature, thus ensuring against self‐fertilization. Contrast protogyny. …
Land that is set aside, usually for conservation purposes, where development is banned or seriously restricted. There are many different types of protected areas, ranging from national parks (where conservation is one of a number of priorities) to nature reserves and biosphere reserves (where it is the main objective). …
An IUCN category of protected area, a strict Nature Reserve, which is a protected area managed mainly for scientific research or monitoring. …
An IUCN category of protected area, a Wilderness Area, which is a large area in an unmodified or slightly modified state which is protected and managed so as to preserve its natural condition. …
An IUCN category of protected area, a National Park, which is a protected area managed mainly for ecosystem conservation and recreation, which provides a foundation for scientific, educational, spiritual, recreational, and visitor opportunities, all of which must be environmentally and culturally compatible. …
A system that legally establishes protected areas and sites which are managed for conservation objectives. …
An IUCN Management Category (V) for protected areas, which is designed ?to maintain nationally significant natural landscapes that are characteristic of the harmonious interaction of man and land while providing opportunities for public enjoyment through recreation and tourism within normal life style and economic activity of these areas?. …
Defence against harm or danger: any activity (including insect and disease control, fire protection, and law enforcement) that reduces losses or risks, tends to maintain basic conditions and values, and reduces damage or injury to people and property. …
Plants that are grown to protect crops, soils, or land from environmental damage. …
A large organic molecule composed of one or more chains of amino acids in a specific order, which is required for the structure, function, and regulation of cells, tissues, and organs. Each protein has unique functions. Examples include hormones, enzymes, and antibodies. …
An aeon of geological time that followed the Archaean, extending from 2.5 billion years ago to about 570 million years ago (the start of the Phanerozoic). During this time period the first bacteria and fungi and primitive multicelled organisms appeared and developed. Proterozoic means ?early life?. …
A drug that inhibits the ability of a virus to make copies of itself. …
Any organism that belongs to the kingdom Protoctista. …
A code of correct conduct, or series of formal steps for conducting a test. See also Montreal Protocol. …
An international protocol that follows the principles of the International Convention on Oil Pollution Preparedness, Response and Co‐operation ( 1990 ), and seeks to ensure that ships carrying hazardous and noxious liquid substances are covered, or will be covered, by regimes similar to those already in existence for oil incidents. Also known as the HNS Protocol . …
In taxonomy, the kingdom that includes all of the single‐celled eukaryotes (the protozoa, slime moulds, and eukaryotic algae), as distinct from the multicelled Plantae, Fungi, and Animalia. Previously known as Protista. …
A state in hermaphroditic systems that is characterized by the development of female reproductive organs before the appearance of the corresponding male feature, thus ensuring against self‐fertilization. Contrast protandry …
A subatomic particle that is found in all atoms and has a positive electric charge. See also electron, neutron. …
A term previously used to describe the components of living tissues. See also cytoplasm. …
A plant, bacterial, or fungal cell that has had its cell wall removed. …
Microscopic, usually single‐celled micro‐organisms that are larger and more complex than bacteria, live in the soil or freshwater, and are non‐photosynthetic and feed upon dead or live bacteria and fragments of organic matter. Some protozoa cause human disease, including malaria and sleeping sickness. A member of the kingdom Protoctista. …
Deposits of a mineral resource (such as a fossil fuel) whose location and extent are known, as opposed to potential but unproved (discovered) deposits, and which can be extracted economically. …
A political or administrative region within a country. …
Increased diversity of species caused by geographical isolation. …
The conservation status rank of a species, subspecies, or variety of plant or animal within a country, based largely on the total number of known sites within that country and the degree to which they are potentially or actively threatened with destruction. See also global rank. …
The special or effective cause of a particular change, such as the combustion of fossil fuel, which causes increased levels of carbon dioxide in the atmosphere, which in turn causes global warming. …
The general cause of a particular change, such as variations in day length, which affects the behaviour or organisms in various ways. Contrast ultimate factor. …
The principle that wastes should be treated close to where they arise (ideally within the boundary of the plant or community in which they are generated), in order to avoid exporting them to other places. …
Data that are used to represent a situation, phenomenon, or condition for which no direct information (such as instrumental records) is available. …
An indicator that is used to provide proxy data. There are four main types of proxy climate indicator, for example, which are historical (oral or written records), biological (records of faunal and floral growth and distribution), geological (terrestrial deposits and features, and marine ocean sediment cores), and glaciological (ice cores). …
The area adjacent to (usually in front of) a glacier. …
A lake in front of a retreating glacier or ice sheet, which is usually fed by meltwater. See also glacial lake. …
Cutting live or dead branches from plants (particularly the branches of trees, or the sides and tops of hedges), in order to improve the quality of the growth. See also thinning out. …
The vegetation succession that occurs on moving sand such as also sand dunes. …
An instrument consisting of a wet‐bulb and a dry‐bulb thermometer that is used to measure the amount of water vapour in the air. …
An insect with wings or a wingless insect that is believed to have evolved from winged ancestors. Contrast apterygote. …
Forest land in the USA that belongs to municipal, state, and federal governments. …
Any good or commodity whose benefits are available to everyone, from which no one can be excluded, and from which no single individual can enjoy all of the benefits. …
The health or physical well‐being of a whole community. …
Land that is owned in common by all and is managed by the government (town, county, state, or federal). Also known as public estate . …
US legislation that amended the Federal Land Policy Management Act ( 1976 ) to provide the US Bureau of Land Management and the US Forest Service with additional direction and authorities in managing public rangelands. …
US legislation that requires utilities to buy power from eligible cogeneration sources, small hydro, or waste‐fuelled facilities, under contracts, at an agreed cost. It also requires utilities to provide a backup supply of electricity to customers who choose self‐generation. …
1 A small shallow area of water on the ground surface. 2 To destroy the structure of the surface soil by physical methods such as the impact of raindrops, poor cultivation with implements, and trampling by animals. …
A dense soil that is almost impervious to air and water, having been puddled when wet. …
Raw material (cellulose fibres) that is made from trees and used in producing paper products. …
Low quality softwood that is harvested for use as a source of fibre in the manufacture of pulp, for making products such as paper and textiles. …
A light‐coloured volcanic rock that contains many trapped gas bubbles formed by the explosive eruption of magma, is light enough to float on water, and can develop as layers to form tuff when hardened. …
A treatment method in which contaminated water is pumped out of the ground and then treated before being discharged back into the environment. …
A hydroelectric scheme in which the water that flows though the turbines is recycled by pumping it back to the upper storage reservoir during off‐peak periods, where it can be used again to produce electricity during peak periods. …
The level of the water surface in a well when pumping is in progress. …
A test that is conducted in a well in order to determine the characteristics of the aquifer or well. …
A model of evolution in which change occurs in short, relatively rapid phases, followed by longer periods of stability (stasis). This model helps to explain some important discontinuities in the fossil record, including mass extinctions (in which many different species appear to have died out at roughly the same time), and the lack of intermediate forms (fossil evidence of the existence of transit…
In an insect, the stage of metamorphosis between being a larva and an adult, during which the body is transformed. …
An animal (usually a horse) that has been bred for many generations from members of the same breed or strain. …
The process of making something pure; free from anything that debases, pollutes, or contaminates. …
A long fishing net used at sea to encircle and trap fish, but which also often catches dolphins and other marine species. …
The biological decomposition of organic matter under anaerobic conditions, which produces offensive smells. See also butyric fermentation. …
Material (usually waste) that is able to rot quickly enough to cause offensive smells and attract flies. …
A layer in the ocean where the water density increases rapidly with depth, which acts as a strong barrier to vertical mixing of seawater. …
An ecological pyramid that shows the relationship between total biomass (weight of organic matter) and trophic level within a food web: biomass usually decreases at higher levels, because whilst the individual organisms are larger, there are fewer of them. …
An ecological pyramid that shows the relationship between energy (in calories per unit of area (square metres) over a given period of time, usually a year) and trophic level within a food web, as energy is lost through respiration so that relatively little of the original energy is ultimately available to the top carnivores. …
An ecological pyramid which shows the relationship between the number of individuals and their trophic level within a food web. The number of individuals usually decreases at each level; a large number of primary producers supports a small number of larger consumers. …
An instrument which is used to measure diffuse and direct solar radiation. …
A form of organicinsecticide which is derived from certain species of chrysanthemums and breaks down in sunlight in a few days. In high doses it kills many garden insect pests, but many insects can recover from exposure to low doses. …
Broken fragments of rock that are thrown out during a volcanic eruption, including lapilli, pumice, volcanic ash, and volcanic bombs. …
A hot, dense mixture of ash, pumice, rock fragments, and gas that is formed during an explosive volcanic eruption and flows downhill at great speed. …
A rock that is formed by the accumulation of fragments of volcanic rock scattered by a volcanic explosion. …
The chemical decomposition of a substance by heat in the absence of oxygen, which produces various hydrocarbon gases and a carbon‐like residue. …
A type of seismic wave, caused by an earthquake, which is refracted (bent) as it passes through the liquid outer core of the Earth and can be detected and measured at seismograph stations. Also known as primary wave . Contrast S‐wave. …
See Quantified Emissions Limitation and Reduction Commitment. …
A sampling frame or square that is marked out for quantifying the number or percentage cover of a particular species within a given area. See also transect. …
Relating to or expressed in terms of quality, rather than quantity. Contrast quantitative. …
A programme or set of procedures and activities that are designed to ensure an acceptable level of quality. …
The level of well‐being of life style, and the physical conditions in which people live. Contrast standard of living. …
Legally binding targets and timetables defined under the Kyoto Protocol for the limitation or reduction of greenhouse gas emissions for developed countries. Also known as Quantified Emissions Limitation and Reduction Objectives (QELROS). …
See Quantified Emissions Limitation and Reduction Commitment (QELRC). …
Relating to or expressed in terms of quantity (numbers), rather than quality. Contrast qualitative. …
Enforced isolation or restriction of free movement of individuals, usually imposed to prevent the spread of a contagious disease. …
1 A surface excavation from which clay, stone, or minerals are extracted. See also mine. 2 An animal that is hunted or caught for food. …
1 A process of physical/mechanical weathering that involves repeated freeze?thaw cycles at the base of a glacier or ice cap, weakening the underlying rock, fragments of which are plucked out by the ice as it flows over it. Also known as plucking . 2 Industrial scale surface extraction, using machinery, of minerals such as limestone for aggregates in road building or china clay for the pottery ind…
The most common rock‐forming mineral, composed of crystals of silicon dioxide (SiO2), which may be glassy or opaque. …
A resistant metamorphic rock in which individual sand grains are cemented together by quartz, formed by applying great heat and pressure to sandstone. …
The most recent period of geological time, covering the last 2 million years, which includes the Pleistocene and the Holocene. Also known as Pleistogene . …
Short for ?radiation absorbed dose?. A unit of measurement that was used for the absorbed dose of radiation. It has been replaced by the gray (1 rad = 0.01 joules per kilogram = 0.01 gray). …
Short for radio detection and ranging, an instrument that is used to detect and determine the range to distant objects (including rainstorms) by measuring the strength of the electromagnetic signal reflected back from it. …
A drainage pattern in which the rivers radiate outwards from a central high point, such as the dome of a uniform rock outcrop or the centre of a volcano. …
