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37-466: The estate encompasses numerous ancient Native American sites, including an earthwork platform mound , now known as Biltmore Mound , that is located south of the Swannanoa River. Based on evidence from excavations conducted there in the early 21st century, the mound was started by indigenous people between 400 and 550CE, with the second to last stage of the mound built about 580-600CE. It was built over

74-482: A 200-year period. Some of the terraces and aprons on the mound seem to have been added to stop slumping of the enormous mound. Although the mounds were primarily meant as substructure mounds for buildings or activities, sometimes burials did occur there. Intrusive burials occurred when a grave was dug into a mound and the body or a bundle of defleshed, disarticulated bones was deposited into it. Mound C at Etowah has been found to have more than 100 intrusive burials into

111-581: A Connestee Phase habitation (built during the Pisgah phase ) in the Middle Woodland period. The historic Cherokee people occupied this area, which is part of their traditional homeland in this region. The mound has been identified as an area of feasting. The Cherokee called this site near the confluence Untokiasdiyi , meaning "where they race." They used it as a meeting place and area of competitive ritual games. Under pressure from European-American settlers,

148-575: A gel of orthosilicic acid ).) The clay minerals formed depend on the composition of the source rock and the climate. Acid weathering of feldspar -rich rock, such as granite , in warm climates tends to produce kaolin. Weathering of the same kind of rock under alkaline conditions produces illite . Smectite forms by weathering of igneous rock under alkaline conditions, while gibbsite forms by intense weathering of other clay minerals. There are two types of clay deposits: primary and secondary. Primary clays form as residual deposits in soil and remain at

185-836: A great capacity to take up water, and they increase greatly in volume when they do so. When dried, they shrink back to their original volume. This produces distinctive textures, such as mudcracks or "popcorn" texture, in clay deposits. Soils containing swelling clay minerals (such as bentonite ) pose a considerable challenge for civil engineering, because swelling clay can break foundations of buildings and ruin road beds. Clay minerals most commonly form by prolonged chemical weathering of silicate-bearing rocks. They can also form locally from hydrothermal activity. Chemical weathering takes place largely by acid hydrolysis due to low concentrations of carbonic acid , dissolved in rainwater or released by plant roots. The acid breaks bonds between aluminium and oxygen, releasing other metal ions and silica (as

222-402: A major challenge in civil engineering . The defining mechanical property of clay is its plasticity when wet and its ability to harden when dried or fired. Clays show a broad range of water content within which they are highly plastic, from a minimum water content (called the plastic limit ) where the clay is just moist enough to mould, to a maximum water content (called the liquid limit) where

259-431: A new layer of fill added, along with a new structure on the now higher summit. Sometimes the surface of the mounds would get a several inches thick coat of brightly colored clay. These layers also incorporated layers of different kinds of clay, soil and sod, an elaborate engineering technique to forestall slumping of the mounds and to ensure their steep sides did not collapse. This pattern could be repeated many times during

296-539: A river in North Carolina is a stub . You can help Misplaced Pages by expanding it . Platform mound A platform mound is any earthwork or mound intended to support a structure or activity. It typically refers to a flat-topped mound, whose sides may be pyramidal. The indigenous peoples of North America built substructure mounds for well over a thousand years, starting in the Archaic period and continuing through

333-437: A variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide . Clays develop plasticity when wet but can be hardened through firing . Clay is the longest-known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery . Some of the earliest pottery shards have been dated to around 14,000 BCE, and clay tablets were

370-452: Is Armenian bole , which is used to soothe an upset stomach. Some animals such as parrots and pigs ingest clay for similar reasons. Kaolin clay and attapulgite have been used as anti-diarrheal medicines. Clay as the defining ingredient of loam is one of the oldest building materials on Earth , among other ancient, naturally occurring geologic materials such as stone and organic materials like wood. Between one-half and two-thirds of

407-527: Is 22 miles or 35 kilometers long, and it flows entirely within the geographical boundaries of Buncombe County . It is a valuable resource to the county, providing drinking water to the Asheville metropolitan area, and numerous recreational opportunities. In September 2004, extremely heavy rains from the remnants of Hurricane Frances and Hurricane Ivan caused the Swannanoa to flood , causing major damage to

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444-620: Is a unique type of marine clay indigenous to the glaciated terrains of Norway , North America , Northern Ireland , and Sweden . It is a highly sensitive clay, prone to liquefaction , and has been involved in several deadly landslides . Modelling clay is used in art and handicraft for sculpting . Clays are used for making pottery , both utilitarian and decorative, and construction products, such as bricks, walls, and floor tiles. Different types of clay, when used with different minerals and firing conditions, are used to produce earthenware, stoneware, and porcelain. Prehistoric humans discovered

481-459: Is clay with visible annual layers that are formed by seasonal deposition of those layers and are marked by differences in erosion and organic content. This type of deposit is common in former glacial lakes . When fine sediments are delivered into the calm waters of these glacial lake basins away from the shoreline, they settle to the lake bed. The resulting seasonal layering is preserved in an even distribution of clay sediment banding. Quick clay

518-674: Is important to soil fertility. Clay is a common component of sedimentary rock . Shale is formed largely from clay and is the most common of sedimentary rocks. However, most clay deposits are impure. Many naturally occurring deposits include both silts and clay. Clays are distinguished from other fine-grained soils by differences in size and mineralogy. Silts , which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. There is, however, some overlap in particle size and other physical properties. The distinction between silt and clay varies by discipline. Geologists and soil scientists usually consider

555-524: Is the most common sedimentary rock. Although many naturally occurring deposits include both silts and clay, clays are distinguished from other fine-grained soils by differences in size and mineralogy. Silts , which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. Mixtures of sand , silt and less than 40% clay are called loam . Soils high in swelling clays ( expansive clay ), which are clay minerals that readily expand in volume when they absorb water, are

592-512: Is used in many industrial processes, such as paper making, cement production, and chemical filtering . Bentonite clay is widely used as a mold binder in the manufacture of sand castings . Clay is a common filler used in polymer nanocomposites . It can reduce the cost of the composite, as well as impart modified behavior: increased stiffness , decreased permeability , decreased electrical conductivity , etc. Traditional uses of clay as medicine go back to prehistoric times. An example

629-524: The Biltmore Village section of Asheville, and to the other communities that it flows through. In September of 2024, the river overflowed into Asheville resulting in devastating floods due to Hurricane Helene . (Not necessarily in order.) This article about a location in Buncombe County , North Carolina is a stub . You can help Misplaced Pages by expanding it . This article related to

666-536: The Woodland period . Many different archaeological cultures ( Poverty Point culture , Troyville culture , Coles Creek culture , Plaquemine culture and Mississippian culture ) of North Americas Eastern Woodlands are specifically well known for using platform mounds as a central aspect of their overarching religious practices and beliefs. These platform mounds are usually four-sided truncated pyramids , steeply sided, with steps built of wooden logs ascending one side of

703-563: The earthworks . When Europeans first arrived in North America, the peoples of the Mississippian culture were still using and building platform mounds. Documented uses for Mississippian platform mounds include semi-public chief 's house platforms, public temple platforms, mortuary platforms, charnel house platforms, earth lodge /town house platforms, residence platforms, square ground and rotunda platforms, and dance platforms. Many of

740-476: The Cherokee ceded their land here in 1819. This site near the Swannanoa River was later abandoned and became overgrown. At one time there was plowing in the area, reducing the height of the mound, but it is distinguished by a much wider, oval-shaped base. The mound was rediscovered in 1984. It was first excavated in a more than two-year project by a team from Appalachian State University , beginning in 2000. The river

777-415: The cohesion that makes it plastic. In kaolinite clay, the bonding between plates is provided by a film of water molecules that hydrogen bond the plates together. The bonds are weak enough to allow the plates to slip past each other when the clay is being moulded, but strong enough to hold the plates in place and allow the moulded clay to retain its shape after it is moulded. When the clay is dried, most of

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814-439: The final layer of the mound, with many grave goods added, such as Mississippian copper plates ( Etowah plates ), monolithic stone axes, ceremonial pottery and carved whelk shell gorgets . Also interred in this mound was a paired set of white marble Mississippian stone statues . A long-standing interpretation of Mississippian mounds comes from Vernon James Knight , who stated that the Mississippian platform mounds were one of

851-399: The first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering . Between one-half and two-thirds of the world's population live or work in buildings made with clay, often baked into brick, as an essential part of its load-bearing structure. Clay is a very common substance. Shale , formed largely from clay,

888-516: The first known writing medium. Clay was chosen due to the local material being easy to work with and widely available. Scribes wrote on the tablets by inscribing them with a script known as cuneiform , using a blunt reed called a stylus , which effectively produced the wedge shaped markings of their writing. After being written on, clay tablets could be reworked into fresh tablets and reused if needed, or fired to make them permanent records. Purpose-made clay balls were used as sling ammunition . Clay

925-565: The life of a site. The large amounts of fill needed for the mounds left large holes in the landscape now known by archaeologists as " borrow pits ". These pits were sometimes left to fill with water and stocked with fish. Some mounds were developed with separate levels (or terraces) and aprons, such as Emerald Mound , which is one large terrace with two smaller mounds on its summit; or Monks Mound , which has four separate levels and stands close to 100 feet (30 m) in height. Monks Mound had at least ten separate periods of mound construction over

962-404: The material. The clay mineral kaolinite is transformed into a non-clay material, metakaolin , which remains rigid and hard if moistened again. Further firing through the stoneware and porcelain stages further recrystallizes the metakaolin into yet stronger minerals such as mullite . The tiny size and plate form of clay particles gives clay minerals a high surface area. In some clay minerals,

999-724: The moulded clay is just dry enough to hold its shape. The plastic limit of kaolinite clay ranges from about 36% to 40% and its liquid limit ranges from about 58% to 72%. High-quality clay is also tough, as measured by the amount of mechanical work required to roll a sample of clay flat. Its toughness reflects a high degree of internal cohesion. Clay has a high content of clay minerals that give it its plasticity. Clay minerals are hydrous aluminium phyllosilicate minerals , composed of aluminium and silicon ions bonded into tiny, thin plates by interconnecting oxygen and hydroxide ions. These plates are tough but flexible, and in moist clay, they adhere to each other. The resulting aggregates give clay

1036-532: The mounds were the result of multiple episodes of mound construction, with the mound becoming larger with each event. The site of a mound was usually a site with special significance, either a pre-existing mortuary site or civic structure. This site was covered with a layer of basket-transported soil and clay known as mound fill, and a new structure constructed on its summit. At periodic intervals, averaged about twenty years, these structures would be removed, possibly ritually destroyed as part of renewal ceremonies, and

1073-467: The plates carry a negative electrical charge that is balanced by a surrounding layer of positive ions ( cations ), such as sodium, potassium, or calcium. If the clay is mixed with a solution containing other cations, these can swap places with the cations in the layer around the clay particles, which gives clays a high capacity for ion exchange . The chemistry of clay minerals, including their capacity to retain nutrient cations such as potassium and ammonium,

1110-696: The separation to occur at a particle size of 2 μm (clays being finer than silts), sedimentologists often use 4–5 μm, and colloid chemists use 1 μm. Clay-size particles and clay minerals are not the same, despite a degree of overlap in their respective definitions. Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils' Atterberg limits . ISO 14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. Mixtures of sand , silt and less than 40% clay are called loam . Some clay minerals (such as smectite ) are described as swelling clay minerals, because they have

1147-571: The site layout replicate cosmology . Mound rebuilding episodes are construed as rituals of burial and renewal, while the four-sided construction acts to replicate the flat earth and the four quarters of the earth. The use of platform mounds is documented elsewhere in the world, including: Clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite , Al 2 Si 2 O 5 ( OH ) 4 ). Most pure clay minerals are white or light-coloured, but natural clays show

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1184-841: The site of formation. Secondary clays are clays that have been transported from their original location by water erosion and deposited in a new sedimentary deposit. Secondary clay deposits are typically associated with very low energy depositional environments such as large lakes and marine basins. The main groups of clays include kaolinite , montmorillonite - smectite , and illite . Chlorite , vermiculite , talc , and pyrophyllite are sometimes also classified as clay minerals. There are approximately 30 different types of "pure" clays in these categories, but most "natural" clay deposits are mixtures of these different types, along with other weathered minerals. Clay minerals in clays are most easily identified using X-ray diffraction rather than chemical or physical tests. Varve (or varved clay )

1221-537: The three "sacra", or objects of sacred display, of the Mississippian religion – also see Earth/fertility cult and Southeastern Ceremonial Complex . He based his theory on analogy to ethnographic and historic data on related Native American tribal groups in the Southeastern United States. Knight suggests a microcosmic ritual organization based around a "native earth" autochthony , agriculture, fertility, and purification scheme, in which mounds and

1258-542: The useful properties of clay. Some of the earliest pottery shards recovered are from central Honshu , Japan . They are associated with the Jōmon culture, and recovered deposits have been dated to around 14,000 BCE. Cooking pots, art objects, dishware, smoking pipes , and even musical instruments such as the ocarina can all be shaped from clay before being fired. Ancient peoples in Mesopotamia adopted clay tablets as

1295-426: The water molecules are removed, and the plates hydrogen bond directly to each other, so that the dried clay is rigid but still fragile. If the clay is moistened again, it will once more become plastic. When the clay is fired to the earthenware stage, a dehydration reaction removes additional water from the clay, causing clay plates to irreversibly adhere to each other via stronger covalent bonding , which strengthens

1332-493: The world's population, in both traditional societies as well as developed countries, still live or work in buildings made with clay, often baked into brick, as an essential part of their load-bearing structure. Also a primary ingredient in many natural building techniques, clay is used to create adobe , cob , cordwood , and structures and building elements such as wattle and daub , clay plaster, clay render case, clay floors and clay paints and ceramic building material . Clay

1369-461: Was used as a mortar in brick chimneys and stone walls where protected from water. Clay, relatively impermeable to water, is also used where natural seals are needed, such as in pond linings, the cores of dams , or as a barrier in landfills against toxic seepage (lining the landfill, preferably in combination with geotextiles ). Studies in the early 21st century have investigated clay's absorption capacities in various applications, such as

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