- published: 25 Mar 2016
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Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.
Clay minerals are typically formed over long periods of time by the gradual chemical weathering of rocks, usually silicate-bearing, by low concentrations of carbonic acid and other diluted solvents. These solvents, usually acidic, migrate through the weathering rock after leaching through upper weathered layers. In addition to the weathering process, some clay minerals are formed by hydrothermal activity. Clay deposits may be formed in place as residual deposits in soil, but thick deposits usually are formed as the result of a secondary sedimentary deposition process after they have been eroded and transported from their original location of formation. Clay deposits are typically associated with very low energy depositional environments such as large lakes and marine basins.
A van is a kind of vehicle used for transporting goods or people.
In British English usage, it can be either specially designed or based on a saloon or sedan car, the latter type often including derivatives with open backs (such as pick-up trucks). There are vans in all shapes and sizes, ranging from the classic van version of the tiny Mini to the five metre long (LWB) variants of the Mercedes Sprinter van. Vehicles larger than this are classified as lorries (trucks).
The word van is a shortened version of the word caravan, which originally meant a covered vehicle.
The word van has slightly different, but overlapping, meanings in different forms of English. While the word always applies to boxy cargo vans, the most major differences in usage are found between the different English-speaking countries.
British English speakers will generally refer to a passenger minivan as a people-carrier or MPV, or multi-purpose vehicle, and a larger passenger van as a minibus. Ford makes a distinct line of vans with short bonnets (hoods) and varying body sizes. Minivans are the same vans but smaller. The driver's mate of a delivery van was sometimes referred to as a "vanguard." The Sun newspaper introduced the idea of "White Van Man", a typical working class man or small business owner who would have a white Ford Transit, Mercedes Sprinter or similar panel van. The Top Gear TV programme did a piece where the presenters had to buy a cheap panel van and then perform a series of tests. In reference to the reputation of van drivers' style of driving on British roads, one of the tests was to tailgate a car travelling at 60 mph as closely as possible.