With a increased portion of other minerals one calls the rock arcose (with feldspars) or Grauwacke (with rock break bits). If most grains are larger than 2 mm, one speaks of a conglomerate (with rounded off grains) and/or. of a Brekzie (with angular grains).
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sandstone develops by cementing (cementation) of loose sand and has therefore the same developing conditions as these. It is contrary to chemical and biogenous(of organism deposited) rocks such as limestone or coal of klastischen origin, consists thus of rubble of weathered and threadbare rocks. Since quartz is a relatively decomposition-resistant mineral, which occurs in addition in very many rocks, it enriches itself with the decomposition and transportation process strongly, while other mineral grains disintegrate.Therefore the sandstones consist completely predominantly of this mineral.
The most important developing areas for sandstones are the seas, thereby above all the offshore flat seas, the shelves. The sand comes from the mainland and by rivers and Meeresströmungen to its final deposit place is however usually transported. Itin addition, gives numerous sandstone occurrences, which developed on the mainland. The fluvialen, i.e. the sandstones deposited by rivers outweigh clearly over from the wind the deposited.
By the load pressure of the recent, overlaying deposits, with the pressure and the natural chemicals of the sea or groundwater and partly also by admixtures in the sandstone it comes to the solidification (dia. genesis)the sand. This process runs off differently fast and lasts between few decades and several millions years.
kinds of cementing (cementation)
cementing or cementation one calls the natural solidification of the sand by the precipitation and/or. Storage of minerals around the Sandkörneraround. Depending upon kind of the cement (bonding agent) one differentiates different kinds:
- Quartz sand stones owe their solidification of the pressure solution and the reprecipitation of quartz, which interconnect the Sandkörner. This kind of the cement is called also kieseliges bonding agent.
- Tonsandsteine contain clay/tone minerals as bonding agents.
- Ferritic one Sandstones contain ferric oxides (Eisensandstein) as bonding agents.
- With lime sandstones (with the artificially manufactured lime sandstones to be confounded may not) Kalzit fills out the areas between the Sandkörnern.
- A special case on are sandstones without cements, with those it with strong pressure for cementing the Sandkörnerthe grain surfaces comes.
The different kinds of the bonding agents arise partially also mixed. In a sandstone present as golden Stone in the trade for example handplate-large pieces of quartz sand stone are stored into a Tonsandstein.
sandstone is on the earth's surface very far pickling width unitsRock and occurs practically on all continents. There it arises preferentially on geologically older platforms, which were however in their history once basin areas. A further important spreading and developing area are the current shelf seas and Kontinentalränder. Within very old continental Schilden, young mountains and in the deep ocean basins he withdraws however.
characteristics as building material
sandstone a common building material is and for paving or for sculptures was often used. One finds buildings of sandstones for example in Nuremberg or in Dresden, where the majoritythe buildings of baroque of sandstone consists. In Dresden one used the soft Tonsandstein for the decorative internal area and for basic parts the quartz sand stone of the Elbe, as he is diminished today still from a company in Pirna. The color of sandstone can, exactly the same as of , Vary sand, are grey usual colors (without admixtures such as z. B. Ruhr sandstone from Hohensyburg, yellow Ibbenbürener sandstone (by contained Limmonit), brown, red by Hämatit as with red Weser sandstone and knows (as with grey only surface reflection is another), example Rackwitzer sandstone. That is green in former times south the westfälischen Soest diminished green sandstone, the Glaukonitkalkstein diminished today with Anröchte is somewhat darker than the medieval sandstone.
Tonsandstein is easy mostly a comparatively soft rock material and to work on, if it is break fresh. Quartz sand stones are “embossment hard” against it and z.T. more badly to work on than granite. All sandstones the missing de-icing salt resistance is common. The frost firmness is different depending upon sort. By the deposit direction one differentiates “with respect to the camp” cut, if it parallel to the layering and “against the camp”, if it is cut orthogonal for layering. Thosedeveloping textures at the Sichtfächen can be very strongly different thereby.
generally nutrient-poor soils
in Central Europe from sandstone, which are inclined in addition to the acidification, develop for soil formation on sandstone due to prevailing quartz. Depending upon water offer and development depth of theSoil finds one Ranker, brown ground connection or Podsole. Usually these soils are forest-economically used (for example in the Thüringer wood country).
Exceptions form however sandstones with a kalkigen or strongly tonus towards bonding agents as well as sandstones, into which kalkige or tonige layers are stored. The soils upthese rocks are then usually more nutrient-rich and can be used also agriculturally. An example are sandstones of the Keupers in South Germany.
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