The Red Hills , also referred to as Gypsum Hills , is the name of a physiographic region located mostly in Clark , Comanche and Barber counties in southern and central Kansas . This undulating terrain of red-tinted sediments, a product of the underlying geology, does not fit the conventional description of the Great Plains landscape of Kansas.
23-590: The red bed sediments of the Red Hills were deposited in an arid continental closed basin that formed within the Pangaean supercontinent during the Permian Period. Water often flooded this basin forming ephemeral playas of somewhat acidic waters. The shallow playas were intermittently flooded then dried leaving a mixture of lacustrine sediments and gypsum evaporites . The red color derives from
46-745: A location in Clark County, Kansas is a stub . You can help Misplaced Pages by expanding it . This article about a location in Barber County, Kansas is a stub . You can help Misplaced Pages by expanding it . Red bed Red beds (or redbeds ) are sedimentary rocks , typically consisting of sandstone , siltstone , and shale , that are predominantly red in color due to the presence of ferric oxides . Frequently, these red-colored sedimentary strata locally contain thin beds of conglomerate , marl , limestone , or some combination of these sedimentary rocks. The ferric oxides, which are responsible for
69-410: Is buried during sedimentation, the constituent organic molecules ( lipids , proteins , carbohydrates and lignin - humic compounds) break down due to the increase in temperature and pressure . This transformation occurs in the first few hundred meters of burial and results in the creation of two primary products: kerogens and bitumens . It is generally accepted that hydrocarbons are formed by
92-508: Is extensively used in geology . However, this term has filtered into the field of anthropology , archaeology and paleontology to describe the changes and alterations that take place on skeletal (biological) material. Specifically, diagenesis "is the cumulative physical, chemical, and biological environment; these processes will modify an organic object's original chemical and/or structural properties and will govern its ultimate fate, in terms of preservation or destruction". In order to assess
115-628: Is not specific to a particular depositional environment . However, the favourable conditions for diagenetic red bed formation i.e. positive Eh and neutral-alkaline pH are most commonly found in hot, semi-arid areas, and this is why red beds are traditionally associated with such climates. Secondary red beds are characterized by irregular color zonation, often related to sub- unconformity weathering profiles. The color boundaries may cross-cut lithological contacts and show more intense reddening adjacent to unconformities. Secondary reddening phases might be superimposed on earlier formed primary red beds in
138-458: Is simply accompanied by a reduction in porosity and water expulsion ( clay sediments), while their main mineralogical assemblages remain unaltered. As the rock is carried deeper by further deposition above, its organic content is progressively transformed into kerogens and bitumens . The process of diagenesis excludes surface alteration ( weathering ) and deep metamorphism . There is no sharp boundary between diagenesis and metamorphism , but
161-486: Is the intrastratal alteration of ferromagnesian silicates by oxygenated groundwaters during burial. Walker's studies show that the hydrolysis of hornblende and other iron-bearing detritus follows Goldich dissolution series . This is controlled by the Gibbs free energy of the particular reaction. For example, the most easily altered material would be olivine : e.g. A key feature of this process, and exemplified by
184-471: Is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition . Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust . In the early stages, the transformation of poorly consolidated sediments into sedimentary rock ( lithification )
207-489: Is the relative scarcity of red-colored source sediments of suitable age close to an area of red-bed sediments in Cheshire , England. Primary red beds may also form by in situ (early diagenetic ) reddening of the sediment by the dehydration of brown or drab colored ferric hydroxides. These ferric hydroxides commonly include goethite (FeO-OH) and so-called "amorphous ferric hydroxide" or limonite . Much of this material may be
230-427: Is used to understand the geologic history they have undergone and the nature and type of fluids that have circulated through them. From a commercial standpoint, such studies aid in assessing the likelihood of finding various economically viable mineral and hydrocarbon deposits. The process of diagenesis is also important in the decomposition of bone tissue. The term diagenesis, literally meaning "across generation",
253-586: The Carboniferous of the southern North Sea . Post-diagenetic alteration may take place through reactions such as pyrite oxidation: and siderite oxidation: Secondary red beds formed in this way are an excellent example of telodiagenesis . They are linked to the uplift , erosion and surface weathering of previously deposited sediments and require conditions similar to primary and diagenetic red beds for their formation. Diagenesis Diagenesis ( / ˌ d aɪ . ə ˈ dʒ ɛ n ə s ɪ s / )
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#1732776825417276-826: The oxidation of iron contained within the deposits. The region is also known as the Gypsum Hills, because of the large natural deposits of gypsum in this area. The dissolution of underlying gypsum beds has led to the formation of sinkholes which are common features within the Red Hills region. Big Basin and Little Basin are two well-known sinkholes in western Clark County. The Red Hills have scenic vistas and some small steep canyons. High points include Mount Nebo (2,441 feet (744 m)), Mount Jesus (2,340 feet (710 m)) and Mount Lookout (2,320 feet (710 m)), in Clark County, Kansas . 37°20′30″N 99°04′46″W / 37.34169°N 99.079551°W / 37.34169; -99.079551 This article about
299-503: The dissolution-precipitation mechanism. These models have been intensively studied and applied in real geological applications. Diagenesis has been divided, based on hydrocarbon and coal genesis into: eodiagenesis (early), mesodiagenesis (middle) and telodiagenesis (late). During the early or eodiagenesis stage shales lose pore water, little to no hydrocarbons are formed and coal varies between lignite and sub-bituminous . During mesodiagenesis, dehydration of clay minerals occurs,
322-400: The form of hydroxyapatite ) renders its diagenesis more complex. Alteration occurs at all scales from molecular loss and substitution, through crystallite reorganization, porosity, and microstructural changes, and in many cases, to the disintegration of the complete unit. Three general pathways of the diagenesis of bone have been identified: They are as follows: When animal or plant matter
345-691: The latter occurs at higher temperatures and pressures . Hydrothermal solutions, meteoric groundwater, rock porosity, permeability , dissolution/ precipitation reactions , and time are all influential factors. After deposition, sediments are compacted as they are buried beneath successive layers of sediment and cemented by minerals that precipitate from solution . Grains of sediment, rock fragments and fossils can be replaced by other minerals (e.g. calcite , siderite , pyrite or marcasite ) during diagenesis. Porosity usually decreases during diagenesis, except in rare cases such as dissolution of minerals and dolomitization . The study of diagenesis in rocks
368-441: The main development of oil genesis occurs and high to low volatile bituminous coals are formed. During telodiagenesis, organic matter undergoes cracking and dry gas is produced; semi- anthracite coals develop. Early diagenesis in newly formed aquatic sediments is mediated by microorganisms using different electron acceptors as part of their metabolism. Organic matter is mineralized, liberating gaseous carbon dioxide (CO 2 ) in
391-423: The mineral ferrihydrite (Fe 2 O 3 H 2 O). This dehydration or "aging" process has been found to be intimately associated with pedogenesis in alluvial floodplains and desert environments. Goethite (ferric hydroxide) is normally unstable relative to hematite and, in the absence of water or at elevated temperature, will readily dehydrate according to the reaction: The Gibbs free energy (G) for
414-470: The porewater, which, depending on the conditions, can diffuse into the water column. The various processes of mineralization in this phase are nitrification and denitrification , manganese oxide reduction, iron hydroxide reduction, sulfate reduction , and fermentation . Diagenesis alters the proportions of organic collagen and inorganic components (hydroxyapatite, calcium, magnesium) of bone exposed to environmental conditions, especially moisture. This
437-418: The potential impact of diagenesis on archaeological or fossil bones , many factors need to be assessed, beginning with elemental and mineralogical composition of bone and enveloping soil, as well as the local burial environment (geology, climatology , groundwater ). The composite nature of bone, comprising one-third organic (mainly protein collagen ) and two thirds mineral ( calcium phosphate mostly in
460-521: The reaction goethite → hematite (at 250 °C) is −2.76 kJ/mol and G becomes increasingly negative with smaller particle size. Thus detrital ferric hydroxides, including goethite and ferrihydrite, will spontaneously transform into red-colored hematite pigment with time. This process not only accounts for the progressive reddening of alluvium but also the fact that older desert dune sands are more intensely reddened than their younger equivalents. Red beds may form during diagenesis . The key to this mechanism
483-425: The reaction, is the production of a suite of by-products which are precipitated as authigenic phases. These include mixed layer clays ( illite – montmorillonite ), quartz , potassium feldspar and carbonates as well as the pigmentary ferric oxides . Reddening progresses as the diagenetic alteration becomes more advanced, and is thus a time-dependent mechanism. The other implication is that reddening of this type
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#1732776825417506-540: The red color of red beds, typically occur as a coating on the grains of sediments comprising red beds. Classic examples of red beds are the Permian and Triassic strata of the western United States and the Devonian Old Red Sandstone facies of Europe. Primary red beds may be formed by the erosion and redeposition of red soils or older red beds, but a fundamental problem with this hypothesis
529-431: The thermal alteration of these kerogens (the biogenic theory). In this way, given certain conditions (which are largely temperature-dependent) kerogens will break down to form hydrocarbons through a chemical process known as cracking , or catagenesis . A kinetic model based on experimental data can capture most of the essential transformation in diagenesis, and a mathematical model in a compacting porous medium to model
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