Spongolite (also spelled either spongillite or spongiolite) is a

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...

composed principally of the remains of largely articulated fossils of rigid-bodied

siliceous sponge The siliceous sponges form a major clade of the phylum Porifera, consisting of classes Demospongiae (common sponges) and Hexactinellida (glass sponges). They are characterized by spicules made out of silicon dioxide, unlike calcareous sponges. ...

s. In contrast, spiculite is either sediment or sedimentary rock composed of mostly disarticulated, discrete

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant ...

sponge spicules.Gammon, P.R., 2003. ''Spiculites and spongolites.'' In Middleton, G.V., Church, M.J., Coniglio, M., Hardie, L.A., and Longstaffe, F.J., eds., p. 681-683, ''Encyclopedia of Sediments and Sedimentary Rocks.'' Dordrecht, The Netherlands, Springer Science & Business Media. 928 pp. Jach, R. 2002, ''Lower Jurassic spiculite series from the Križna Unit in the Western Tatra Mts, Western Carpathians, Poland.'' ''Annales Societatis Geologorum Poloniae,'' 72(2), pp. 131-144. As seen below, in some older papers, ''spongolite'' is used as a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''spiculite''. In

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, the term ''spongolite'' is defined differently as a nonmarine, freshwater,

lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

sediment "..essentially composed of siliceous sponge spicules of the

Demospongiae Demosponges or common sponges are sponges of the class Demospongiae (from + ), the most diverse group in the phylum Porifera which include greater than 90% of all extant sponges with nearly 8,800 species worldwide (according to the World P ...

Class, associated with

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

organic matter Organic matter, organic material or natural organic matter is the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come fro ...

and

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

residues." In this usage of the term ''spongolite'', the term ''spiculite'' is restricted to marine sediments composed of siliceous sponge spicules.Almeida, A.C.S., Varajão, A.F.D.C., Gomes, N.S., Varajão, C.A.C. and Volkmer-Ribeiro, C., 2010. ''Characterization and origin of spongillite-hosting sediment from João Pinheiro, Minas Gerais, Brazil.'' ''Journal of South American Earth Sciences'', 29(2), pp.439-453.

Uses of spongolite

In Western Australia, ''spongolite'', in this case actually spiculite, is quarried for use as a lightweight freestone and

dimension stone Dimension stone is natural stone or Rock (geology), rock that has been selected and finished (e.g., trimmed, cut, drilled or ground) to specific sizes or shapes. Color, Texture (geology), texture and pattern, and surface finish of the stone are ...

. This type of spongolite has been quarried from

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

s extending sporadically from Mount Barker to

Ravensthorpe, Western Australia Ravensthorpe is a town 541 km south-east of Perth and 40 km inland from the south coast of Western Australia. It is the seat of government of the Shire of Ravensthorpe. At the , Ravensthorpe had a population of 2,085. In 1848, the area ...

.Connolly, R.R., 1980. ''Mineral Resources of Western Australia.'' Perth, Western Australia, The Department of Mines. 90 pp. This type of spongolite is a fine-grained, light-weight, porous rock that is found in Late

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Pallinup Formation (Plantagenet Group). It outcrops along the southern coast of the Western Australia from Albany eastwards past Esperance, and as far inland as

Norseman The Norsemen (or Northmen) were a cultural group in the Early Middle Ages, originating among speakers of Old Norse in Scandinavia. During the late eighth century, Scandinavians embarked on a large-scale expansion in all directions, giving ris ...

. In this region, it has been used as a building (dimension) stone because it is a visually attractive, off-white to pale yellow or beige color, light weight and has good insulating properties, moderate strength, and is easily sawn into building blocks. Petrographic analysis of this type of spongolite demonstrated that it typically consists of disarticulated siliceous sponge spicules and minor amounts of

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

clumps,

muscovite Muscovite (also known as common mica, isinglass, or potash mica) is a hydrated phyllosilicate mineral of aluminium and potassium with formula KAl2(Al Si3 O10)( F,O H)2, or ( KF)2( Al2O3)3( SiO2)6( H2O). It has a highly perfect basal cleavage y ...

tourmaline Tourmaline ( ) is a crystalline silicate mineral, silicate mineral group in which boron is chemical compound, compounded with chemical element, elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a ...

, and

rutile Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive indices at vis ...

bond together by a

matrix Matrix (: matrices or matrixes) or MATRIX may refer to: Science and mathematics * Matrix (mathematics), a rectangular array of numbers, symbols or expressions * Matrix (logic), part of a formula in prenex normal form * Matrix (biology), the m ...

opaline The opalines are a small group of peculiar heterokonts, currently assigned to the family Opalinidae, in the order Slopalinida. Their name is derived from the opalescent appearance of these microscopic organisms when illuminated with full sunlig ...

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...

.Fetherston, J.M., 2010. ''Dimension stone in Western Australia: Volume 2 - Dimension stones of the Southern, Central Western, and Northern Regions.'' ''Mineral Resources Bulletin,'' 24. 218 pp. Perth, Australia, Geological Survey of Western Australia. In Brazil, a variety of potential industrial uses have been proposed for spongolites (spongillites), which are fresh water spiculites. These spongolite deposits occur in a large area of southwest Brazil and an along the northeastern coast from

Maranhão Maranhão () is a States of Brazil, state in Brazil. Located in the country's Northeast Region, Brazil, Northeast Region, it has a population of about 7 million and an area of and it is divided into 217 municipalities. Clockwise from north, it ...

Rio Grande do Norte Rio Grande do Norte (, , ) is one of the states of Brazil. It is located in the northeastern region of the country, forming the northeasternmost tip of the South American continent. The name literally translates as "Great Northern River", refe ...

. Within southwest Brazil, spongolites deposits occur in western and southwestern

Minas Gerais Minas Gerais () is one of the 27 federative units of Brazil, being the fourth largest state by area and the second largest in number of inhabitants with a population of 20,539,989 according to the 2022 Brazilian census, 2022 census. Located in ...

, southern

Goiás Goiás () is a Brazilian States of Brazil, state located in the Central-West Region, Brazil, Central-West region. Goiás borders the Federal District (Brazil), Federal District and the states of (from north clockwise) Tocantins, Bahia, Minas Ge ...

, northeastern

Mato Grosso do Sul Mato Grosso do Sul ( ) is one of Federative units of Brazil, Brazil's 27 federal units, located in the southern part of the Central-West Region, Brazil, Central-West Region, bordering five Brazilian states: Mato Grosso (to the north), Goiás and ...

and northern

São Paulo São Paulo (; ; Portuguese for 'Paul the Apostle, Saint Paul') is the capital of the São Paulo (state), state of São Paulo, as well as the List of cities in Brazil by population, most populous city in Brazil, the List of largest cities in the ...

. They typically consist of discontinous

beds A bed is a piece of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many be ...

about to thick, and with an average diameter of about . They accumulated in seasonal lakes and ponds and consist of siliceous sponge spicules mixed with clay, sand, organic matter, and diatoms. The proposed uses for this type of spongolite include ceramics, refractory products, chromato-graphic supplies and catalysis matrices.Almeida, A.C.S., Varajão, A.F.D.C., Gomes, N.S., Varajão, C.A.C. and Volkmer-Ribeiro, C., 2010. ''Characterization and origin of spongillite-hosting sediment from João Pinheiro, Minas Gerais, Brazil.'' ''Journal of South American Earth Sciences'', 29(2), pp.439-453. In Europe and Australia, spiculitic

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

(silica-cemented spiculite), called ''spongolite'' by

archaeologist Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, ...

s, was locally used by prehistoric cultures to fashion

stone tool Stone tools have been used throughout human history but are most closely associated with prehistoric cultures and in particular those of the Stone Age. Stone tools may be made of either ground stone or knapped stone, the latter fashioned by a ...

s and other artifacts.Brandl, M., 2013. ''Genesis, provenance and classification of rocks within the chert group in Central Europe.'' ''Archaeologia Austriaca'', 97/98(2013–2014), pp. 33-58.Sutherland, F.L., 1972. ''The classification, distribution, analysis and sources of materials in flaked stone implements of Tasmanian Aborigines.'' ''Records of the Queen Victoria Museum And Art Gallery''. 42, 46 pp. Launceston, Tasmania, Queen Victoria Museum and Art Gallery.Ward, I., Key Jr, M.M., Riera, R., Carson, A. and O'Leary, M., 2019. ''Insights into the procurement and distribution of fossiliferous chert artefacts across southern Australia from the archival record.'' ''Australian Archaeology'', 85(2), pp.170-183.

References

{{Authority control Chert Lithics Quartz varieties Sedimentary rocks