Sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions.

Some sandstones are resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material. However, some that have been used in the past, such as the Collyhurst sandstone used in the north of England, have been found less resistant, necessitating repair and replacement in older buildings. [ [http://www.sci-eng.mmu.ac.uk/manchester_stone/images.asp?page1=2&vartype=building&id=&offset=0# Edensor, T. & Drew, I. "Building stone in the City of Manchester: St Ann's Church"] ] Because of the hardness of the individual grains, uniformity of grain size and friability of their structure, some types of sandstone are excellent materials from which to make grindstones, for sharpening blades and other implements. Non-friable sandstone can be used to make grindstones for grinding grain, e.g., gritstone.

Rock formations that are primarily sandstone usually allow percolation of water and are porous enough to store large quantities, making them valuable aquifers. Fine-grained aquifers, such as sandstones, are more apt to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestones or other rocks fractured by seismic activity.

Origins of Sandstone

Sandstones are "clastic" in origin (as opposed to "organic", like chalk and coal, or "chemical", like gypsum and jasper). They are formed from cemented grains that may either be fragments of a pre-existing rock or be mono-minerallic crystals. The cements binding these grains together are typically calcite, clays and silica. Grain sizes in sands are in the range of 0.1 mm to 2 mm (clays and rocks with smaller grain sizes including siltstones and shales are typically called "argillaceous" sediments; rocks with larger grain sizes including breccias and conglomerates are termed "rudaceous" sediments).

The formation of sandstone involves two principal stages. First, a layer or layers of sand accumulates as the result of sedimentation, either from water (as in a river, lake, or sea) or from air (as in a desert). Typically, sedimentation occurs by the sand settling out from suspension, i.e., ceasing to be rolled or bounced along the bottom of a body of water (e.g., seas or rivers) or ground surface (e.g., in a desert or sand dune region). Finally, once it has accumulated, the sand becomes sandstone when it is compacted by pressure of overlying deposits and cemented by the precipitation of minerals within the pore spaces between sand grains. The most common cementing materials are silica and calcium carbonate, which are often derived either from dissolution or from alteration of the sand after it was buried. Colors will usually be tan or yellow (from a blend of the clear quartz with the dark amber feldspar content of the sand). A predominant additional colorant in the southwestern United States is iron oxide, which imparts reddish tints ranging from pink to dark red (terra cotta), with additional manganese imparting a purplish hue. Red sandstones are also seen in the Southwest and West of England and Wales, as well as central Europe and Mongolia. The regularity of the latter favors use as a source for masonry, either as a primary building material or as a facing stone, over other construction.

The environment where it is deposited is crucial in determining the characteristics of the resulting sandstone, which, in finer detail, include its "grain size", "sorting" and "composition" and, in more general detail, include the rock geometry and sedimentary structures. Principal environments of deposition may be split between terrestrial and marine, as illustrated by the following broad groupings:

* Terrestrial environments
# Rivers (levees, point bars, channel sands)
# Alluvial fans
# Glacial outwash
# Lakes
# Deserts (sand dunes and ergs)

* Marine environments
# Deltas
# Beach and shoreface sands
# Tidal flats
# Offshore bars and sand waves
# Storm deposits (tempestites)
# Turbidites (submarine channels and fans)

Types of sandstone

Once the geological characteristics of a sandstone have been established, it can then be assigned to one of three broad groups:
* arkose or "arkosic" sandstones, which have a high (>25%) feldspar content and a composition similar to granite.
* "quartzose" sandstones, also known as "beach sand", which have a high (>90%) quartz content. Sometimes these sandstones are termed "orthoquartzites", e.g., the Tuscarora Quartzite of the Ridge-and-valley Appalachians.
* "argillaceous" sandstones, such as greywacke or bluestone, which have a significant clay or silt content.

Aeolian sandstone is a term used for a rock which is composed of sand grains that show signs of significant transportation by wind. These have usually been deposited in desert environments.

According to the USGS, U.S. sandstone production in 2005 was 192,000 metric tons worth $24.3 million, the largest component of which was the 121,000 metric tons worth $9.75 million of flagstone or dimension stone.

Notes

References

* Boggs, J.R., 2000, "Principles of sedimentology and stratigraphy", 3rd ed. Toronto: Merril Publishing Company. ISBN 0-13-099696-3
* Folk, R.L., 1965, [http://www.lib.utexas.edu/geo/folkready/folkprefrev.html "Petrology of sedimentary rocks" PDF version] . Austin: Hemphill’s Bookstore. 2nd ed. 1981, ISBN 0-914696-14-9
* Pettijohn, F.J., P.E. Potter and R. Siever, 1987, "Sand and sandstone", 2nd ed. Springer-Verlag. ISBN 0-387-96350-2
* Scholle, P.A., 1978, "A Color illustrated guide to constituents, textures, cements, and porosities of sandstones and associated rocks", American Association of Petroleum Geologists Memoir no. 28. ISBN 0-89181-304-7
* Scholle, P.A., and D. Spearing, 1982, "Sandstone depositional environments: clastic terrigenous sediments ", American Association of Petroleum Geologists Memoir no. 31. ISBN 0-89181-307-1
* [http://minerals.usgs.gov/minerals/pubs/commodity/stone_dimension/dstonmyb05.pdf USGS Minerals Yearbook: Stone, Dimension]

Gallery



See also

* Bargate stone
* Beaver river sandstone
* Brownstone
* Dimension stone
* Geology
* Hummelstown brownstone
* List of minerals
* List of stone
* Old Red Sandstone
* New Red Sandstone
* Sarsen
* Sedimentary basins
* Yorkstone
* Wisconsin Dells
* Uluru


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Sandstone — Sand stone , n. A rock made of sand more or less firmly united. Common or siliceous sandstone consists mainly of quartz sand. [1913 Webster] Note: Different names are applied to the various kinds of sandstone according to their composition; as,… …   The Collaborative International Dictionary of English

  • Sandstone — bezeichnet: Operation Sandstone, die dritte Serie US amerikanischer Kernwaffentests Sandstone (Minnesota), eine Stadt im Bundesstaat Minnesota in den Vereinigten Staaten Sandstone (Western Australia), eine Stadt im australischen Bundesstaat… …   Deutsch Wikipedia

  • Sandstone — Sandstone, MN U.S. city in Minnesota Population (2000): 1549 Housing Units (2000): 634 Land area (2000): 5.296212 sq. miles (13.717125 sq. km) Water area (2000): 0.139947 sq. miles (0.362461 sq. km) Total area (2000): 5.436159 sq. miles… …   StarDict's U.S. Gazetteer Places

  • Sandstone, MN — U.S. city in Minnesota Population (2000): 1549 Housing Units (2000): 634 Land area (2000): 5.296212 sq. miles (13.717125 sq. km) Water area (2000): 0.139947 sq. miles (0.362461 sq. km) Total area (2000): 5.436159 sq. miles (14.079586 sq. km) FIPS …   StarDict's U.S. Gazetteer Places

  • sandstone — (n.) 1660s, from SAND (Cf. sand) (n.) + STONE (Cf. stone) (n.). So called from its composition …   Etymology dictionary

  • sandstone — ► NOUN ▪ sedimentary rock consisting of sand or quartz grains cemented together, typically red, yellow, or brown in colour …   English terms dictionary

  • sandstone — [sand′stōn΄] n. a common bedded sedimentary rock much used for building, composed largely of sand grains, mainly quartz, held together by silica, lime, etc …   English World dictionary

  • sandstone — (Roget s IV) n. Varieties of sandstone include: arkrose, freestone, brownstone, flagstone, bluestone, grit, novaculite, Triassic brownstone, Berea sandstone, Medina sandstone, Potsdam quartzite, Old Red Sandstone, New Red Sandstone; see also… …   English dictionary for students

  • sandstone — [[t]sæ̱ndstoʊn[/t]] sandstones N MASS Sandstone is a type of rock which contains a lot of sand. It is often used for building houses and walls. ...the reddish sandstone walls. ...sandstone cliffs …   English dictionary

  • sandstone — /sand stohn /, n. a common sedimentary rock consisting of sand, usually quartz, cemented together by various substances, as silica, calcium carbonate, iron oxide, or clay. [1660 70; SAND + STONE] * * * Sedimentary rock formed from sand sized… …   Universalium


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.