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High Surface Areas: Caves are generally located in areas known as karst lands. Karst is the surface expression of the subterranean solution of limestone that develops caverns. Karst landscapes are pitted with sinkholes, vertical shafts, and long Blind valleys that lack surface outlets. Karst soils are usually thin, and bare bands of limestone, known as karren or lapiez, form much of the surface. Most of the streams that drain karst areas flow underground through cavernous passages, often reaching the surface in the form of large springs.
Glass microfibre papers are made from 100% borosilicate glass or a very pure quartz. Their mechanical strength stems in part from the very high surface areas of the sub-micron fibres, and from entanglement of the very long fibres. They are particularly suitable for quantitative work, and may be used at temperatures as high as 500°C or at low temperatures without embrittlement.
Maps and charts are representations in miniature, on a plane surface, of a portion of the earth's surface. A chart emphasizes water areas and features that are of particular interest to a skipper. A map focuses primarily on land areas, with different types of maps emphasizing physical features, roads, structures, or political boundaries. |
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