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Raised rock slabs or plates of varying thickness, mostly resulting from the buckling of laminae, plates, and slabs. These forms are generally cracked by tectonic activity, although decreases in lithostatic pressure through unloading, or, more rarely, from surficial expansion of plates caused by intense heat. Smaller plates and slabs may be changed in part through freeze-thaw. A-tents are also known as pop-ups, but ...

Not living, non-biological, usually describing factors in an ecosystem: atmospheric gases, humidity, salinity, soil mineral particles, water, and so on. An ...

Loss of snow and ice from a glacier by *sublimation, melting, and evaporation; and from the *calving of icebergs, and avalanches. In temperate and subpolar regions melting is the major form of ablation; in the Antarctic, it is calving. The rate of loss varies with air temperature, relative humidity, wind speed, insolation, aspect, and the nature of the surface. In snowfields, ablation includes snow removed by the wind, and is affected by aspect, depth of snow, and the nature of the underlying surface....

A member of an indigenous people existing in a land before invasion or colonization from outside. For Canadian aboriginal peoples, see ...

Also known as corrasion, this is the grinding away of bedrock by fragments of rock which may be incorporated in ice (...

The density of the water vapour present in a mixture of air and water vapour. Cold air cannot contain as much water vapour as warm air, so has a lower absolute humidity than warm air. Low absolute humidity results in more evaporation than in air with high absolute humidity....

The movement of a crustal plate in relation to a fixed point, such as a hot spot, or latitude and longitude....

The selection and conceptualization of a phenomenon, or some aspect of it; a way of viewing a real world object, usually a simplification—such as a ...

The total number of individuals of a certain species present in an area, generally estimated by sampling methods (such as capture–recapture), and which may vary according to competition, predation, and resources....

Of or belonging to the ocean depths, especially below 2000 m. The abyssopelagic zone is that part of deep lakes, oceans, or seas characterized by specific forms of plankton and nekton which inhabit open water, and the ...

A factor which increases the momentum of a boom or slump in an economy, so that a small change in demand, for example, may lead to a greater industrial growth (or decline)....

Connection or entry to a service. A. Sen (1999) measures access to advantage by one’s access to basic needs: satisfying goods—like food; freedoms—as in a labour market; and capabilities. S. W. Allard (...

The ease of approach to one location from other locations: in terms of the distance travelled, the cost of travel, or the time taken. The improvement of infrastructures produces an increase in accessibility that positively affects the competitiveness of the economic system and favours the appearance of specialization benefits and scale economies. In fact, regions with high levels of accessibility to the locations of input materials and markets tend to be more productive and competitive than peripheral and remote regions; see Gutiérrez in R. Kitchin and N. Thrift, eds (...

Complying with; thus, accordant drainage has evolved in conformity with the underlying geological structure: domes show a radial pattern, for example. The ...

1 The growth of land by the offshore deposition of sediment, forming *spits and *tombolos. Accretion is most active in ...

The adaptation to, and adoption of, a new culture. This may occur simultaneously as two cultures meet, but occurs more often as an immigrant group takes to the behaviour patterns and standards of the receiving group. A major example is acculturation among African Americans; see H. Landrine and E. Klonoff (...

One of the key factors for crop growth, this is the length of time, from a specific date, for which mean daily temperatures have been above, or below, a stated temperature; the total time for which temperatures varied from that standard....

1 The input of ice to a glacier. Weaver (1975) Arct. & Alpine Res. 7, 3 suggests that it is greatest in shaded uplands. The ...

A soil-forming process whereby organic acids (from humus) increase hydrogen ion concentration, as in the transformation of *brown-earth soils into acid brown earth, in humid temperate forest regions. For the Model of Acidification of Groundwaters in Catchments (MAGIC), see ...

When *fossil fuels are burned, dioxides of sulphur and nitrogen are released into the air; these dissolve in atmospheric water to form acid rain. In addition, nitrogen oxides combine with volatile organic compounds to form ground-level smog. These pollutants lead to the acidification of lakes and streams (making some of them incapable of supporting aquatic life), impair visibility, weaken forests, and degrade buildings....