History
Sandstone From Wikipedia, the free encyclopedia Jump to: navigation , search This article is about the geological formation. For the conference center, see Sandstone retreat . For the town in Australia, see Sandstone, Western Australia . Red sandstone interior of Lower Antelope Canyon , Arizona , worn smooth due to erosion by flash flooding over millions of years 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. Because of the hardness of the individual grains, uniformity of grain size and friability of its structure, sandstone is an excellent material 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 Origins of Sandstone Sandstone near Stadtroda , Germany Millet-Seed Sandstone Macro ~ 4 cm in size 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 . Deposition from sand dunes can be recognized by irregular and fluidly shaped weathering patterns and wavy coloration lines when sectioned, while water deposition will form more regular blocks when weathered. 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 Sandstone composed mainly of quartz grains 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. 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 . 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, 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 USGS Minerals Yearbook: Stone, Dimension Clastic metamorphic and igneous rocks Clastic metamorphic rocks include breccias formed in faults , as well as some protomylonite and pseudotachylite . Occasionally, metamorphic rocks can be brecciated via hydrothermal fluids, forming a hydrofracture breccia. Clastic igneous rocks include pyroclastic volcanic rocks such as tuff , agglomerate and intrusive breccias , as well as some marginal eutaxitic and taxitic intrusive morphologies. Igneous clastic rocks are broken by flow, injection or explosive disruption of solid or semi-solid igneous rocks or lavas . Clastic sediments Clastic sedimentary rocks are rocks composed predominantly of broken pieces or ' clasts' of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size , clast and cementing material matrix composition, and texture. The classification factors are often useful in determining a sample's environment of deposition. Grain size determines the basic name of a clastic sedimentary rock. Grain size varies from clay in shales ; through silt in siltstones ; sand in sandstones ; and gravel , cobble , to boulder sized fragments in conglomerates and breccias . The Krumbein phi f scale numerically orders these terms in a logarithmic size scale. Composition includes the chemical and mineralogic make-up of the single or varied fragments and the cementing material matrix holding the clasts together as a rock. An example clastic environment would be a river system, in which the full range of grains being transported by the moving water consist of pieces eroded from solid rock upstream. Sedimentary breccias Sedimentary breccias are a type of clastic sedimentary rock which are composed of angular to subangular, randomly oriented clasts of other sedimentary rocks. They are formed by either submarine debris flows , avalanches , mud flow or mass flow in an aqueous medium. Technically, turbidites are a form of debris flow deposit and are a fine-grained peripheral deposit to a sedimentary breccia flow. The other derivation of sedimentary breccia is as angular, poorly sorted, very immature fragments of rocks in a finer grained groundmass which are produced by mass wasting. These are, in essence, lithified colluvium . Thick sequences of sedimentary colluvial breccias are generally formed next to fault scarps in grabens . In the field, it may at times be difficult to distinguish between a debris flow sedimentary breccia and a colluvial breccia, especially if one is working entirely from drilling information. Sedimentary breccias are an integral host rock for many SEDEX ore deposits . Igneous clastic rocks Basalt breccia, green groundmass is composed of epidote . Igneous clastic rocks can be divided into two classes Broken, fragmental rocks produced by intrusive processes, usually associated with plutons or porphyry stocks Broken, fragmental rocks associated with volcanic eruptions, both of lava and pyroclastic type Hydrothermal clastic rocks Hydrothermal clastic rocks are generally restricted to those formed by hydrofracture , the process by which hydrothermal circulation cracks and brecciates the wall rocks and fills it in with veins. This is particularly prominent in epithermal ore deposits and is associated with alteration zones around many intrusive rocks, especially granites . Many skarn and greisen deposits are associated with hydrothermal breccias. Impact breccias A fairly rare form of clastic rock is formed during meteorite impact. This is composed primarily of ejecta; clasts of country rock, melted rock fragments, tektites glass ejected from the impact crater and exotic fragments, including fragments derived from the impactor itself. Identifying a clastic rock as an impact breccia requires recognising shatter cones , tektites, spherulites , and the morphology of an impact crater , as well as potentially recognising particular chemical and trace element signatures, especially osmiridium . Yorkstone From Wikipedia, the free encyclopedia Jump to: navigation , search Yorkstone is a local variety of sandstone quarried in the county of Yorkshire in the United Kingdom . Known for its hard wearing and durable qualities Yorkstone has been used in a wide array of building, construction and landscaping applications around the world for many years. Yorkstone is a tight grained, Carboniferous sedimentary rock . The structure of the stone includes minerals such as quartz , mica , feldspar , clay and iron oxides . Yorkstone is popular in both new construction and restoration. Many quarries are still being worked in Yorkshire to provide new Yorkstone. The colour of Yorkstone depends on the minerals within its makeup and differs throughout the quarries from which it is mined. Newly quarried Yorkstone is usually available as slabs for paving, setts cobbles and walling stones. Sedimentology The Old Red Sandstone describes pretty much any sedimentary rock deposited after the Acadian Orogeny in the late Silurian , and before the Carboniferous . dubious – discuss The body of rock, or facies , is dominated by alluvial sediments and conglomerates at its base, and progresses to a combination of dunes, lakes and river sediments. Its familiar red colour arises from the presence of iron oxide but not all the old red sandstone is red or sandstone - grey shales and conglomerates are common. History of study In the early 1800's, the paleotology of the formation was studied intensively by Hugh Miller , Henry Thomas De la Beche , Roderick Murchison , and Adam Sedgwick -- Sedgwick's interpretation was the one that placed it in the Devonian, and in fact it was he that coined that word. Many of the science of stratigraphy 's early debates were about the Old Red Sandstone. Old Red Sandstone can occur in conjunction with conglomerate formations, a noteworthy such cliffside exposure being the Fowlsheugh Nature Reserve , Aberdeenshire . Common Building Stone In regions where the formation is near the surface, many stone houses are built of the rocks quarried from it. Notable examples can be found in the area surrounding Stirling 1 , Stonehaven 2 , Perth 3 , and Tayside . The inhabitants of Caithness 4 at the north-eastern tip of Scotland also used the stone to a considerable extent. Note that in older geological works predating theories of plate tectonics , the United States ' Catskill Delta formation is sometimes referred to as part of the Old Red Sandstone. In the modern day, however, it is recognized that the two are not stratigraphically continuous but are very similar due to being formed at approximately the same time by the same processes. Based on the variation in composition and cementing material the sandstone has been categorized unto three major types, which are as follows: Quartz sandstone also called quartz arenite Arkose Litharenite or lithic sandstone commonly but imprecisely called graywacke Each type of sandstone has some implication about its depositional history - Quartz sandstone implies a long time in the depositional basin; Arkose implies a short time in the depositional basin because feldspar typically weathers quickly to clay. Also implies rapid erosion, arid climate, tectonic activity, steep slopes; Litharenite implies rapid erosion, temperate or arid not humid climate. Quartz sandstone or quartz arenite is dominated by quartz grains; arkose is dominated by feldspar grains usually potassium feldspar; and graywacke is dominated by rock fragment grains. Quartz Sandstone Quartz sandstone formed as a result of the extreme weathering and sorting of a sediment until everything that can be removed has been removed. The high content of quartz is a result of removal of feldspar and lithic. This is done by the complete chemical weathering and then the final removal of the clay takes placed in high energy environments. Tidal sand bars that accumulate large bodies of quartz sand is yet another situation that leads to formation of sandstone. Sand-sized quartz grains could come from the weathering of source area rocks such as granite, gneiss, or other sandstones which contain quartz. Arkose Sandstone Arkose, a sandstone derived from disintegration of granite or gneiss, and characterized by high feldspar content. This is thus the quartz sandstone containing over a quarter feldspar with iron oxide cement. Micas may also be present. Bedding is sometimes present, but fossils are rare. It effervesces slightly in dilute hydrochloric acid thus indicating calcite cement. Its color is usually in the shades of buff, brownish-gray or pink. Arkose sandstone finds its applications in building stone, and millstones for grinding corn. Litharenite or Lithic Sandstone Litharenite or lithic sandstone is commonly known by the name of graywacke. It is predominantly composed of dark sand-sized rock fragments, with some mica, quartz, and feldspar grains in a clay-rich matrix. A litharenite is composed of sand-sized rock fragments. The Sandstone Quarries The bedrock in the Runcorn area is sandstone, formed from deserts which covered the area 250 million years ago. Runcorn is perched at the end of an outcrop of this stone which looks out over the River Mersey. From the nature of the remains of Halton Castle and Norton Priory, this stone has been used since Norman times. During the 18th. C. the quarrying of the stone became a major industry of the area and large quarries were opened around the then small town. The high point of this industry may have been in the late 1800,s. Around 1850 A.D. some of the earlier quarries had been worked out, and new ones had been opened south of the older quarries towards the village of Weston.These latter continues in use until the outbreak of WWII in 1939, although by then they had become shadows of the industry of 50 years earlier. he spoil from the later quarries was dumped in the older earlier quarries and today these form the basis of the Runcorn Hill recreational area which was first laid down in the 1920,s. Many of the present day paths follow the lines of the old tramways which were used to carry the spoil down from the Weston quarries to these older ones. After 1939 the Weston quarries received the waste products from the nearby chemical works, and this dumping continued until the mid 1970,s. They were then finally topped out with soil and today they are used to graze horses on. In the 1990,s chemical vapours were discovered rising from buried chemicals which led to the abandoning of many houses local to the quarry sites, which had been built on waste rubble from the earlier quarrying. Where the solid sandstone had not been quarried proved impervious to this vapour and it had not reached the village of Weston itself. 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 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 may be strongly identified with certain regions. For instance, much of the North American West is well-known for its red sandstones. Some sandstones are resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material. Because of the hardness of the individual grains, uniformity of grain size, and somewhat friable nature, sandstone is an excellent material from which to make grindstones for sharpening blades and other implements. Non-friable sandstone can be used for grindstones grinding grain. 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 from seismic activity. Retrieved from " http://en.wikipedia.org/wiki/Sandstone "
