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32-599: The Sloan Canyon Formation consists of variegated reddish-brown, purple, and green mudstones , with some beds of siltstone and marl . It rests on the Travesser Formation and is overlain by the Sheep Pen Sandstone . Total thickness is 38–46 meters (125–151 ft). The formation is usually assigned to the Dockum Group . The proposal of Spencer G. Lucas and his collaborators to abandon

64-959: A further increase to the upper limit for the matrix size in order to bring it into line with the upper limit for silt (63 μm). On December 13, 2016, NASA reported further evidence supporting habitability on the planet Mars as the Curiosity rover climbed higher, studying younger layers, on Mount Sharp . Also reported, the very soluble element boron was detected for the first time on Mars. In June 2018 , NASA reported that Curiosity had detected kerogen and other complex organic compounds from mudstone rocks approximately 3.5 billion years old. Clay minerals Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin , Al 2 Si 2 O 5 ( OH ) 4 ), sometimes with variable amounts of iron , magnesium , alkali metals , alkaline earths , and other cations found on or near some planetary surfaces . Clay minerals form in

96-479: A hexagonal array in two dimensions. The fourth oxygen ion is not shared with another tetrahedron and all of the tetrahedra "point" in the same direction; i.e. all of the unshared oxygen ions are on the same side of the sheet. These unshared oxygen ions are called apical oxygen ions. In clays, the tetrahedral sheets are always bonded to octahedral sheets formed from small cations, such as aluminum or magnesium, and coordinated by six oxygen atoms. The unshared vertex from

128-400: A net negative charge and may be bonded together either by individual cations (such as potassium in illite or sodium or calcium in smectites) or by positively charged octahedral sheets (as in chlorites ). Clay minerals include the following groups: Mixed layer clay variations exist for most of the above groups. Ordering is described as a random or regular order and is further described by

160-452: A possible therapsid , and the reptile Rhynchosauroides . The beds now assigned to this unit were previously mistaken for Morrison Formation . The Sloan Canyon Formation was first named by B.H. Parker in 1930. Mudstones Mudstone , a type of mudrock , is a fine-grained sedimentary rock whose original constituents were clays or muds . Mudstone is distinguished from shale by its lack of fissility . The term mudstone

192-420: A traditional technique establishing fundamental occurrences or petrologic relationships. Clay minerals are common weathering products (including weathering of feldspar ) and low-temperature hydrothermal alteration products. Clay minerals are very common in soils, in fine-grained sedimentary rocks such as shale , mudstone , and siltstone and in fine-grained metamorphic slate and phyllite . Given

224-491: A variety of accessory minerals . In the Dunham classification (Dunham, 1962 ) system of limestones , a mudstone is defined as a mud-supported carbonate rock that contains less than 10% grains. Most recently, this definition has been clarified as a matrix-supported carbonate-dominated rock composed of more than 90% carbonate mud (<63 μm) component . A recent study by Lokier and Al Junaibi (2016) has highlighted that

256-540: A very common material, and is the oldest known ceramic . Prehistoric humans discovered the useful properties of clay and used it for making pottery . The chemistry of clay, including its capacity to retain nutrient cations such as potassium and ammonium , is important to soil fertility. Because the individual particles in clay are less than 4 micrometers (0.00016 in) in size, they cannot be characterized by ordinary optical or physical methods. The crystallographic structure of clay minerals became better understood in

288-478: Is also used to describe carbonate rocks ( limestone or dolomite ) that are composed predominantly of carbonate mud. However, in most contexts, the term refers to siliciclastic mudstone, composed mostly of silicate minerals. The NASA Curiosity rover has found deposits of mudstone on Mars that contain organic substances such as propane , benzene and toluene . There is not a single definition of mudstone that has gained general acceptance, though there

320-412: Is clay particles. Another definition is that mudstone is a sedimentary rock in which neither silt, clay, nor coarser grains is predominant. Rock of this composition that does show laminations or fissility is sometimes described as mudshale rather than mudstone . The lack of fissility or layering in mudstone may be due to either original texture or the disruption of layering by burrowing organisms in

352-504: Is formed from a stack of layers interspaced with the interlayers. Clay minerals can be classified as 1:1 or 2:1. A 1:1 clay would consist of one tetrahedral sheet and one octahedral sheet, and examples would be kaolinite and serpentinite . A 2:1 clay consists of an octahedral sheet sandwiched between two tetrahedral sheets, and examples are talc , vermiculite , and montmorillonite . The layers in 1:1 clays are uncharged and are bonded by hydrogen bonds between layers, but 2:1 layers have

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384-400: Is known as corrensite , R1 illite-smectite is rectorite . X-ray rf(001) is the spacing between layers in nanometers, as determined by X-ray crystallography. Glycol (mg/g) is the adsorption capacity for glycol, which occupies the interlayer sites when the clay is exposed to a vapor of ethylene glycol at 60 °C (140 °F) for eight hours. CEC is the cation exchange capacity of

416-431: Is only one tetrahedral and one octahedral group in each layer the clay is known as a 1:1 clay. The alternative, known as a 2:1 clay, has two tetrahedral sheets with the unshared vertex of each sheet pointing towards each other and forming each side of the octahedral sheet. Bonding between the tetrahedral and octahedral sheets requires that the tetrahedral sheet becomes corrugated or twisted, causing ditrigonal distortion to

448-420: Is that a mudstone is a fine-grained clastic sedimentary rock that is not laminated or fissile . Most definitions also include a requirement that the rock contain significant amounts of both silt- and clay-sized grains. One common requirement is that a mudstone is a mudrock (a rock containing more than 50% silt- to clay-sized particles) in which between a third and two-thirds of the mud (silt and clay) fraction

480-467: Is wide agreement that mudstones are fine-grained sedimentary rocks, composed mostly of silicate grains with a grain size less than 0.063 millimetres (0.0025 in). Individual grains this size are too small to be distinguished without a microscope, which means that most classifications emphasize texture rather than mineral composition, and mudstones have historically received less attention from petrologists than have sandstones . The simplest definition

512-407: The polymerization of RNA in aqueous solution from nucleotide monomers, and the formation of membranes from lipids. In 1998, Hyman Hartman proposed that "the first organisms were self-replicating iron-rich clays which fixed carbon dioxide into oxalic acid and other dicarboxylic acids . This system of replicating clays and their metabolic phenotype then evolved into the sulfide rich region of

544-993: The 1930s with advancements in the x-ray diffraction (XRD) technique indispensable to deciphering their crystal lattice. Clay particles were found to be predominantly sheet silicate (phyllosilicate) minerals, now grouped together as clay minerals. Their structure is based on flat hexagonal sheets similar to those of the mica group of minerals. Standardization in terminology arose during this period as well, with special attention given to similar words that resulted in confusion, such as sheet and plane. Because clay minerals are usually (but not necessarily) ultrafine-grained, special analytical techniques are required for their identification and study. In addition to X-ray crystallography, these include electron diffraction methods, various spectroscopic methods such as Mössbauer spectroscopy , infrared spectroscopy , Raman spectroscopy , and SEM - EDS or automated mineralogy processes. These methods can be augmented by polarized light microscopy ,

576-649: The Dockum Group, possibly in favor of the Chinle Group , is highly controversial. A phytosaur skull was found in the Sloan Canyon Formation in 1939, establishing that it was a Triassic formation. The formation is part of one of the largest continuously mapped Triassic vertebrate tracksites, with the earliest studied exposures at Peacock Canyon. Ichnofossils (track fossils) include the archosaurs Brachychirotherium and Chirotherium ,

608-440: The applications of clays include drug delivery, tissue engineering, and bioprinting. Clay minerals can be incorporated in lime-metakaolin mortars to improve mechanical properties. Electrochemical separation helps to obtain modified saponite-containing products with high smectite-group minerals concentrations, lower mineral particles size, more compact structure, and greater surface area. These characteristics open possibilities for

640-571: The average pH level of 7.1 is reached at 30% of the pulp added and an experimental site with perennial grasses proved the efficacy of the technique. Moreover, the reclamation of disturbed lands is an integral part of the social and environmental responsibility of the mining company and this scenario addresses the community necessities at both local and regional levels. The results of glycol adsorption, cation exchange capacity, X-ray diffraction, differential thermal analysis, and chemical tests all give data that may be used for quantitative estimations. After

672-482: The clay. K 2 O (%) is the percent content of potassium oxide in the clay. DTA describes the differential thermal analysis curve of the clay. The clay hypothesis for the origin of life was proposed by Graham Cairns-Smith in 1985. It postulates that complex organic molecules arose gradually on pre-existing, non-organic replication surfaces of silicate crystals in contact with an aqueous solution. The clay mineral montmorillonite has been shown to catalyze

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704-433: The dwarf planet Ceres , asteroid 101955 Bennu , and comet Tempel 1 , as well as Jupiter's moon Europa . Like all phyllosilicates, clay minerals are characterised by two-dimensional sheets of corner-sharing SiO 4 tetrahedra or AlO 4 octahedra. The sheet units have the chemical composition (Al, Si) 3 O 4 . Each silica tetrahedron shares three of its vertex oxygen ions with other tetrahedra, forming

736-454: The hexagonal array, and the octahedral sheet is flattened. This minimizes the overall bond-valence distortions of the crystallite. Depending on the composition of the tetrahedral and octahedral sheets, the layer will have no charge or will have a net negative charge. If the layers are charged this charge is balanced by interlayer cations such as Na or K or by a lone octahedral sheet. The interlayer may also contain water. The crystal structure

768-425: The hot spring acquiring the ability to fix nitrogen . Finally phosphate was incorporated into the evolving system which allowed the synthesis of nucleotides and phospholipids." The structural and compositional versatility of clay minerals gives them interesting biological properties. Due to disc-shaped and charged surfaces, clay interacts with a range of drugs, protein, polymers, DNA, or other macromolecules. Some of

800-452: The manufacture of high-quality ceramics and heavy-metal sorbents from saponite-containing products. Furthermore, tail grinding occurs during the preparation of the raw material for ceramics; this waste reprocessing is of high importance for the use of clay pulp as a neutralizing agent, as fine particles are required for the reaction. Experiments on the histosol deacidification with the alkaline clay slurry demonstrated that neutralization with

832-454: The most common problems encountered when describing a mudstone is to incorrectly estimate the volume of 'grains' in the sample - in consequence, misidentifying mudstone as wackestone and vice versa. The original Dunham classification (1962) defined the matrix as clay and fine-silt size sediment <20 μm in diameter. This definition was redefined by Embry & Klovan (1971 ) to a grain size of less than or equal to 30 μm. Wright (1992 ) proposed

864-400: The presence of water and have been important to life, and many theories of abiogenesis involve them. They are important constituents of soils , and have been useful to humans since ancient times in agriculture and manufacturing . Clay is a very fine-grained geologic material that develops plasticity when wet, but becomes hard, brittle and non–plastic upon drying or firing . It is

896-455: The quantities of organic matter, carbonates, free oxides, and nonclay minerals have been determined, the percentages of clay minerals are estimated using the appropriate glycol adsorption, cation exchange capacity, K20, and DTA data. The amount of illite is estimated from the K20 content since this is the only clay mineral containing potassium. Argillaceous rocks are those in which clay minerals are

928-597: The requirement of water, clay minerals are relatively rare in the Solar System , though they occur extensively on Earth where water has interacted with other minerals and organic matter . Clay minerals have been detected at several locations on Mars , including Echus Chasma , Mawrth Vallis , the Memnonia quadrangle and the Elysium quadrangle . Spectrography has confirmed their presence on celestial bodies including

960-486: The sediment prior to lithification . Mudstone looks like hardened clay and, depending upon the circumstances under which it was formed, it may show cracks or fissures, like a sun-baked clay deposit. When the mineral composition of mudstones has been determined, using such techniques as scanning electron microscopy , electron probe microanalysis , or X-ray diffraction analysis , they have been found to be composed primarily of clay minerals , quartz , and feldspars , with

992-437: The term reichweite , which is German for range or reach. Literature articles will refer to an R1 ordered illite-smectite, for example. This type would be ordered in an illite-smectite-illite-smectite (ISIS) fashion. R0 on the other hand describes random ordering, and other advanced ordering types are also found (R3, etc.). Mixed layer clay minerals which are perfect R1 types often get their own names. R1 ordered chlorite-smectite

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1024-402: The tetrahedral sheet also forms part of one side of the octahedral sheet, but an additional oxygen atom is located above the gap in the tetrahedral sheet at the center of the six tetrahedra. This oxygen atom is bonded to a hydrogen atom forming an OH group in the clay structure. Clays can be categorized depending on the way that tetrahedral and octahedral sheets are packaged into layers . If there

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