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Biosparite
Fossiliferous limestone is a type of limestone that contains noticeable quantities of fossils or fossil traces. If a particular type of fossil dominates, a more specialized term can be used as in " Crinoidal", "Coralline", "Conchoidal" limestone. If seashells, shell fragments, and shell sand form a significant part of the rock, a term " shell limestone" is used. The fossils in these rocks may be of macroscopic or microscopic size. The sort of macroscopic fossils often include crinoid stems, brachiopods, gastropods, and other hard shelled mollusk remains. In some cases, microfossils such as siliceous diatom shells in deposition may convert over time to opal and chert, providing the only inferred evidence of bioactivity preserved in limestone. Fossiliferous limestone is termed biosparite under the Folk classification of sedimentary rocks. Lagerstätte are a class of fossil bearing rocks that includes fossiliferous limestone. Use Fossils in general provide geologic clues to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Folk Classification
The Folk classification, in geology, is a technical descriptive classification of sedimentary rocks devised by Robert L. Folk, an influential sedimentary petrologist and Professor Emeritus at the University of Texas. Folk's sandstone (clastic) classification Folk's philosophy is that the name of a rock must convey as much information as possible without being a complete description. For this, he proposed five important properties of sandstones to use as defining characteristics. These five properties are: grain size, chemically precipitated cements, textural maturity, miscellaneous transported constituents, and clan designation. Folk's fivefold name must be in the following format: :(Grain size): (chemically precipitated cements) (textural maturity) (miscellaneous transported constituents) (clan designation) However, Folk stated that cements and miscellaneous transported constituents are optional categories as they are not always observed. The other three properties should always ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Fossiliferous Limestone
Fossiliferous limestone is a type of limestone that contains noticeable quantities of fossils or trace fossil, fossil traces. If a particular type of fossil dominates, a more specialized term can be used as in "Ames Limestone, Crinoidal", "Coralline", "Conchoidal" limestone. If seashells, shell fragments, and shell sand form a significant part of the rock, a term "shell limestone" is used. The fossils in these rocks may be of macroscopic or microscopic size. The sort of macroscopic fossils often include crinoid stems, brachiopods, gastropods, and other hard shelled mollusk remains. In some cases, microfossils such as siliceous diatom shells in deposition may convert over time to opal and chert, providing the only inferred evidence of bioactivity preserved in limestone. Fossiliferous limestone is termed biosparite under the Folk classification of sedimentary rocks. Lagerstätte are a class of fossil bearing rocks that includes fossiliferous limestone. Use Fossils in general pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 precipitation (chemistry), chemical precipitate or a diagenesis, diagenetic replacement, as in petrified wood. Chert is typically composed of the petrified remains of siliceous ooze, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms, Dictyochales, silicoflagellates, and radiolarians. Precambrian cherts are notable for the presence of fossil cyanobacteria. In addition to Micropaleontology, microfossils, chert occasionally contains macrofossils. However, some chert is devoid of any fossils. Chert varies greatly in color, from white to black, but is most often found as gray, brown, grayish brown and light green to rusty redW.L. Roberts, T.J. Campbell, G.R. Rapp Jr., ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Lithographic Limestone
Lithographic limestone is hard limestone that is sufficiently fine-grained, homogeneous and defect-free to be used for lithography. Geologists use the term "lithographic texture" to refer to a grain size under 1/250 mm. The term "sublithographic" is sometimes used for homogeneous fine-grained limestone with a somewhat coarser texture. Origin The generally accepted theory for the origin of lithographic and sublithographic limestones is that they were formed in shallow, stagnant, hypersaline, and anoxic lagoons. The combination of mild hypersalinity and low oxygen content is believed to have inhibited the formation of microbial mats and prevented the invasion of bottom dwelling organisms. Microbial mats and bottom dwelling organisms would have left fossils, and bottom dwelling organisms would have churned the accumulating sediment, producing a less homogeneous rock. Stagnancy was required to avoid churning or sculpting of the sediment by currents or wave action.Walte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Shelly Limestone
Shelly limestone is a highly fossiliferous limestone, composed of a number of fossilized organisms such as brachiopods, bryozoans, crinoids, sponges, corals and mollusks. It varies in color, texture and hardness. Coquina is a poorly indurated form of shelly limestone. Shelly limestone is a sedimentary rock because it is made up of fragments. To be shelly, it is full of broken shells which are "glued" together with calcite. Calcium carbonate often makes up around 10% of the volume, whilst many varied sized shells from granular to very large pebbles. Its color is gray. Formation Each shelly limestone is unique in its own way, where every stone of this type is composed of different fossilized organism and shell fragments. Shelly limestones are mainly found near where marine life live or where marine life once occupied. The unique qualities of a shelly limestone are formed with the help of calcite, acting as a sticking agent for small shell fragments, dead marine organism and oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Keystone (limestone)
Keystone is a type of limestone, or coral rag, quarried in the Florida Keys, in particular from Windley Key fossil quarry, which is now a State Park of Florida. The limestone is Pleistocene in age, and the rock primarily consists of scleractinian coral, such as Elkhorn coral and Brain coral. The Hurricane Monument, commemorating victims of the Labor Day Hurricane of 1935, and located at mile marker 82 on U.S. Route 1 near Islamorada, is constructed of keystone, as is the David W. Dyer Federal Building and United States Courthouse. See also *List of types of limestone This article lists types of limestone arranged according to generic type and location. Generic limestone categories This section is a list of generic types of limestone. * * * * * * * * Marble – Metamorphic limestone * * * * ... Limestone Paleontology {{geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Fossil Beach
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of ''Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before print. The ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Coral Sand
Coral sand is a form of aragonite sand particles originating in tropical and sub-tropical marine environments primarily from bioerosion of limestone skeletal material of marine organisms. Often, this is due to corallivores, such as parrotfish, which excrete sand after digestion. However, the term "coral" in ''coral sand'' is used loosely in this sense to mean limestone of recent biological origin; corals are not the dominant contributors of sand particles to most such deposits. Rather, coral sand is a mix of coral and/or remnant skeletal fragments of foraminifera, calcareous algae, molluscs, and crustaceans . Because it is composed of limestone, coral sand is acid-soluble. Environmental issues Coral sand mining is a significant industry in some areas, and can have damaging environmental effects. Over 500,000 tons of coral sand were mined annually from Mauritius until being banned in October 2001. Many Comoros beaches have been scarred by sand mining. Over 250 tons of shells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Coral Rag
Coral rag is a rubbly limestone composed of ancient coral reef material. The term also refers to the building blocks quarried from these strata, which are an important local building material in areas such as the coast of East Africa and the southeastern United States littoral (e.g. Florida, Bermuda). It is also the name of a member—the Coral Rag Member—of the Upper Oxfordian Coralline Oolite Formation of North Yorkshire. "Calne Freestone And Coral Rag" is a former name for the Stanford Formation, which stretches from Westbury in Wiltshire to Waddesdon in Buckinghamshire. Varieties * Corallian Limestone * Keystone (limestone) See also * Coral Rag Formation *Coral sand Coral sand is a form of aragonite sand particles originating in tropical and sub-tropical marine environments primarily from bioerosion of limestone skeletal material of marine organisms. Often, this is due to corallivores, such as parrotfish ... * List of types of limestone Notes Limestone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Coquina
Coquina () is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically sorted fragments of mollusks, trilobites, brachiopods, or other invertebrates. The term ''coquina'' comes from the Spanish language, Spanish word for "cockle (bivalve), cockle" and "shellfish". For a sediment to be considered to be a coquina, the particles composing it should average or greater in size. Coquina can vary in hardness from poorly to moderately cementation (geology), cemented. Incompletely consolidated and poorly cemented coquinas are considered grainstones in the Dunham classification system for carbonate sedimentary rocks. A well-cemented coquina is classified as a biosparite (fossiliferous limestone) according to the Folk classification, Folk classification of sedimentary rocks. Coquinas accumulate in high-energy marine and Lacustrine deposits, lacustrine environments where currents and waves result in the vigorous winnowing, abrasion, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Index Fossils
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. "Biostratigraphy." ''Oxford Reference: Dictionary of Biology'', 8th ed., Oxford University Press, 2019. The primary objective of biostratigraphy is ''correlation'', demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to help identify biozones, as they make up the basic biostratigraphy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
