6.2 Chemical Sedimentary Rocks. sands. "Clean" sandstones with open pore space (that may later be filled with matrix material) are called arenites. term that includes all varieties of rocks that are mostly composed of Conglomerates fragments are commonly deposited along the shoreline or stream channel and they are pea-sized or larger. In contrast to igneous and metamorphic rocks, a sedimentary rock usually contains very few different major minerals. For example, a quartz arenite would be composed of mostly (>90%) quartz grains and have little or no clayey matrix between the grains, a lithic wacke would have abundant lithic grains and abundant muddy matrix, etc. Both the cement and the clasts (including fossils and ooids) of a carbonate sedimentary rock usually consist of carbonate minerals. Sole markings, such as tool marks and flute casts, are grooves eroded on a surface that are preserved by renewed sedimentation. gray shales are common, but the rock can appear in any color. illite/montmorillonite clay minerals. Shale is In sag basins, the extra weight of the newly deposited sediments is enough to keep the subsidence going in a vicious circle. Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the Earths surface and within bodies of water. Generally, petroleum gas Chemical Rocks. mudstone. (deltaic or lagoon). [51], The kind of rock formed in a particular depositional environment is called its sedimentary facies. Among the three major types of rock, fossils are most commonly found in sedimentary rock. Kaolinite forms in hot and humid climate. rich in organic matter. Larger, heavier clasts in suspension settle first, then smaller clasts. [16], The 3D orientation of the clasts is called the fabric of the rock. What are the three broad categories of sedimentary environments? Chert breaks with a conchoidal fracture, often producing very sharp edges. Conglomerate consists largely of rounded gravel-size particles. Which texture is associated with all detrital rocks? may be used as a fossil fuel, although it is relatively dirty fuel because it In general, the greater the distance traveled, the smaller and more rounded the sediment particles will be. [41] Such traces are relatively rare. Normally, such material eventually decays by oxidation or bacterial activity. dioxide. Shale with deposits are less than 10m thick. Limestone is a sedimentary rock such as greater than 50% calcium carbonate ( calcite - CaCO three). [52], Facies can be distinguished in a number of ways: the most common are by the lithology (for example: limestone, siltstone or sandstone) or by fossil content. gneiss. liberates iron, magnesium and calcium, which can be used by the other forming Turbidity currents are sudden disturbances of the normally quiet deep marine environment and can cause the near-instantaneous deposition of large amounts of sediment, such as sand and silt. The opposite of cross-bedding is parallel lamination, where all sedimentary layering is parallel. is produced in high temperature/pressure, humic and plant dominant organic Deltaic deposits are generally paralic illite) is a major change that takes place in mudstones during the diagenesis. Clay minerals & quartz are most common. remainder is sand/clastic in most area. When a sedimentary layer is examined in cross section from one end to the other, each facies grades laterally into another that formed at the same time but that exhibits different characteristics . An example are the ice ages of the past 2.6 million years (the Quaternary period), which are assumed to have been caused by astronomic cycles. ), 17 Amazing Animals With Eyebrows (With Pictures), 15 Types of Fish With Legs And Can Walk (With Pictures), 15 Exceptional Water Diving Birds (With Pictures), 13 Different Big-lipped Animals (With Pictures), Causes and Effects of Ozone Layer Depletion, Causes and Effects to Environmental Pollution, Causes and Effects of Ocean Acidification, Causes and Effects of Marine Habitat Loss, 35+ Outstanding Facts About the Planet Earth. [10][8] Some biochemical processes, like the activity of bacteria, can affect minerals in a rock and are therefore seen as part of diagenesis. Under what circumstances does it accumulate? The latter category includes all kinds of sudden exceptional processes like mass movements, rock slides or flooding. Describe several varieties of each. precipitates; and various fresh water invertebrate organisms including Flood Plain, Lake (away from shore), Mid-continental Shelf, Delta, Tidal Flat, What is the primary basis for distinguishing among detrital rocks? calcium, magnesium, iron and water. crystals. water. Roegiers (1993) has it that about 75% of well drilling/completion problems are This further reduces porosity and makes the rock more compact and competent. A metamorphic rock Mudstone is a really pleasant-grained sedimentary rock consisting of a aggregate of clay and silt-sized particles. Turbidite is often composed of alternating silty and clayey layers. The subducting plate bends and forms a fore-arc basin in front of the overriding plate an elongated, deep asymmetric basin. The Coal. Sedimentary rocks are formed on or near the Earths surface, in contrast to metamorphic and igneous rocks, which are formed deep within the Earth. The composition of sediments provides us with clues as to the original rock. Compaction takes place as the sediments come under increasing overburden (lithostatic) pressure from overlying sediments. Cherts are of dull brown or gray in color and are often found as nodules firmly enclosed in limestone which protrude out of the limestone when the limestone is slowly immersed in water. shales were deposited in anoxic, reducing environments, such as in stagnant It will yield hydrocarbons on distillation. This structure forms when fast flowing water stops flowing. Concretions are roughly concentric bodies with a different composition from the host rock. The process of illitization (smectite is transformed to Sediments are typically saturated with groundwater or seawater when originally deposited, and as pore space is reduced, much of these connate fluids are expelled. Secondary sedimentary structures are those which formed after deposition. The petroleum oil or gas What might have happened at the end of the Precambrian Eon and the beginning of the Phanerozoic Eon to allow geologists to mark this boundary on the time scale? Shales are needed to extract the hydrocarbons, leading to waste products that raise Tidal flats and shoals are places that sometimes dry because of the tide. 6.3 Depositional Environments and Sedimentary Basins. However, any type of mineral may be present. When sedimentary rocks have no lamination at all, their structural character is called massive bedding. Erosion removes most deposited sediment shortly after deposition.[60]. tiles and Portland cement. has various subdivisions. Examples include: Chemical sedimentary rock forms when mineral constituents in solution become supersaturated and inorganically precipitate. [26] Imprints of organisms made while they were still alive are called trace fossils, examples of which are burrows, footprints, etc. with a high natural gas content has recently been used as an energy source. its fine lamination or fissility. The same process can form mud volcanoes on the surface where they broke through upper layers. These deposits form underwater as a mixture [8], Unroofing of buried sedimentary rock is accompanied by telogenesis, the third and final stage of diagenesis. Mud is further divided into silt (1/16 to 1/256mm diameter) and clay (<1/256mm diameter). Dolomite. Shales of marine depositional environment bookmarked pages associated with this title. Shales are fissile clastic sedimentary rocks formed from Lighter hydrocarbons These include clastic, chemical, and organic sedimentary rocks. [12], Lithification follows closely on compaction, as increased temperatures at depth hasten the precipitation of cement that binds the grains together. calcite or lime. ferruginous or calcareous (sometimes also called limy), respectively. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) A chaotic mass of Alternatively, sedimentary rocks can be subdivided into compositional groups based on their mineralogy: Sedimentary rocks are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. crushed and heated with limestone to make cement for the construction industry. Tiny debris from the rock masses and mountains are eroded together with soils, sand, and other granite pieces that are normally washed from highlands to low areas. now free to migrate upwards. source rocks because of their organic carbon contents. What minerals are most abundant in detrital sedimentary rocks? metamorphic rock that can be split into thin sheets (has slaty cleavage). Finergrained rocks. Removing #book# Explain how you arrived at your answer. Shale is frequently used to explain mudstones that are difficult and fissile (wreck along bedding planes). requires little processing besides crushing and mixing with water. Rich enough in carbon to burn, coal is an organic sedimentary rock that is a widespread and important fuel source. effectively. The finergrained clastic sedimentary rocks are called shale, siltstone, and mudstone. The common cementing materials are silica, iron oxide and The weathering and erosion is normally due to the forces of water, thermal expansion, gravity, wind, and salt crystal expansion that breaks down the pre-existing rocks into small pieces and then carried away to some distance low areas. occur in the playas, rivers, basins and oceans. Amber is simply a hardened tree sap and its colors ranges from transparent yellow to creamy yellow or red to dark brown. Iron(II) oxide (FeO) only forms under low oxygen (anoxic) circumstances and gives the rock a grey or greenish colour. [61], Rock formed by the deposition and subsequent cementation of material, For an overview of major minerals in siliciclastic rocks and their relative stabilities, see, For an explanation about graded bedding, see, For a short description of trace fossils, see, For an overview of different sedimentary environments, see, For a definition of shallow marine environments, see, For an overview of continental environments, see, For an overview over facies shifts and the relations in the sedimentary rock record by which they can be recognized, see, For an overview of sedimentary basin types, see, For a short explanation of Milankovitch cycles, see, 10.1306/5D25C98B-16C1-11D7-8645000102C1865D, 10.1306/74D71109-2B21-11D7-8648000102C1865D, "Heat, time, pressure, and coalification", 10.1130/0016-7606(1971)82[3395:SFOEAS]2.0.CO;2, "Experimental diagenesis of organo-mineral structures formed by microaerophilic Fe(II)-oxidizing bacteria", 10.1130/0016-7606(1978)89<19:DIFDAO>2.0.CO;2, Sedimentary Rocks Tour, introduction to sedimentary rocks, https://en.wikipedia.org/w/index.php?title=Sedimentary_rock&oldid=1118168039, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License 3.0, Quartz sandstones have >90% quartz grains, Feldspathic sandstones have <90% quartz grains and more feldspar grains than lithic grains, Lithic sandstones have <90% quartz grains and more lithic grains than feldspar grains. Typically sediments depositing on the ocean floor are fine clay or small skeletons of micro-organisms. minerals. Sediment transported by wind is called aeolian and is almost always very well sorted, while sediment transported by a glacier is called glacial till and is characterized by very poor sorting. The shale permeability). (S2). Chemical sedimentary rocks are formed when the water components evaporate, leaving dissolved minerals behind. This Mudcracks are a bed form caused by the dehydration of sediment that occasionally comes above the water surface. Who are the famous geologists in history. shale is. [14], The presence of organic material can colour a rock black or grey. porous rock from where it continues moving or migrating until it is trapped or black colour of some shales may also be due to presence of iron sulphide. [43] In carbonate rocks such as limestone or chalk, chert or flint concretions are common, while terrestrial sandstones sometimes contain iron concretions. Besides transport by water, sediment can be transported by wind or glaciers. and structural traps. Fissility of the clay is its main distinguishing characteristic from other sedimentary rocks. bookmarked pages associated with this title. The sedimentary Sandy shale, Mineralogical Composition: Generally typically crey color. Where the lithosphere moves downward (tectonic subsidence), a basin forms and sediments are deposited. Are you sure you want to remove #bookConfirmation# that are able to move out of the shale and migrate upwards. water columns. It Unlike textures, structures are always large-scale features that can easily be studied in the field. On the other hand, the burrowing activity of organisms can destroy other (primary) structures in the sediment, making a reconstruction more difficult. Quartz and These are not visible to the unaided eye. much less), do meet the particle size definition and are organic rich. Examples of sag basins are the regions along passive continental margins, but sag basins can also be found in the interior of continents. With continued They can also be deposited in sedimentary basins and on the continental What is the "raw material" for coal? Shale is a hydraulic fracturing (fracking). of clay, silt and water sliding down the continental slope (in most cases). Imagine that you are standing on a beach but cannot swim. a. Deposits of marine environment are characterized by homogenous rock yellow), or micaceous minerals (chlorite, biotite and illite greens). conditions, contain reduced free carbon along with ferrous iron (Fe2+) and sulfur carbonaceous and bituminous shales are important source rocks for generation of This is the organic material that usually occurring in the rocks as kerogen (a mixture of organic compounds with high molecular weight). Clastic Sedimentary Rocks - result from the cementation of loose fragments of pre-existing rock. shales are probably high in calcium due to the fossils they contain. Amber is an organic sedimentary rock and is naturally plastic and is light-weight compared to the majority of the typical stones. about 50-100C3. trapped in the reservoirs can then be exploited by drilling wells into the Black shale be consolidated but in this case it is often named marlstone. Here is the process described specially for the diagenesis of sand into sandstone Imagine a large deposit of loose sand sediment along a shoreline Over a great amount of time, the sand is compacted as more 2. A bed is defined as a layer of rock that has a uniform lithology and texture. Biochemical sedimentary rocks are created when organisms use materials dissolved in air or water to build their tissue. The material is then transported from the source area to the deposition area. Shale is This preserves the form of the organism but changes the chemical composition, a process called permineralization. Other shales are stronger in Non-Clastic Sedimentary Rocks has two types ; Coal is a non-clastic sedimentary rock. main criterion for subdividing the detrital rocks is particle size, whereas the primary basis for distinguishing among different rocks in the chemical group is their mineral composition. They are the fossilized remains of plants and are in flammable black and brownish-black tones. Dolomites are chemical sedimentary rocks that almost resemble calcite. In some environments, beds are deposited at a (usually small) angle. Oil shale Grain size is largely a function of the distance the particle was transported. Examples include rocks such as coal, some limestone, and some dolomites. concerns about environmental impact. Details of the positive as well as the negative This is also the reason why some of the formed hydrocarbons All three types of rocks (igneous, sedimentary and metamorphic rocks) can be the source of sedimentary detritus. Sedimentary environments usually exist alongside each other in certain natural successions. Fore-arc basins are filled with deep marine deposits and thick sequences of turbidites. This means that coarser sediment particles can be transported and the deposited sediment can be coarser than in deeper environments. Outline the steps that would transform an exposure of granite in the mountains into various sedimentary rocks. modifier (calcilutite is a very fine-grained limestone). Mudrocks are sedimentary rocks composed of at least 50% silt- and clay-sized particles. Black color is given to these rocks by organic matter. result presenced of greater than one percent carbonaceous material and Shales are generally deposited in lacustrine This burrowing is called bioturbation by sedimentologists. An indurated mud fine-grained sedimentary rocks like shale. Clastic sedimentary rocks are subdivided according to the dominant particle size. shale which owes its color to organic matter (>5%). When sedimentary strata accumulate through time, the environment can shift, forming a change in facies in the subsurface at one location. Deep marine usually refers to environments more than 200m below the water surface (including the abyssal plain). To describe such a texture, only the average size of the crystals and the fabric are necessary. [33] Cross-bedding is characteristic of deposition by a flowing medium (wind or water). Salt is colorless or white and might be colored when mixed with impurities such as clay or iron oxide. The fossil, in the end, consists of a thin layer of pure carbon or its mineralized form, graphite. The compaction effect due to the weight of the piling layers of materials reduces the porosity of the rocks formed and intensifies the cohesion between the grains. Distinguish between conglomerate and breccia. Most of these cyclic changes are caused by astronomic cycles. The common types of limestone include fossiliferous limestone rich in fossils, lithographic limestone that is very fine-grained, coquina limestone composed of broken shell fragments, encrinal limestone composed of crinoid fragments, and travertine deposited by the forces of moving surface water. It is usually white in color and is used to produce plaster of Paris. [34] Differences in laminations are generally caused by cyclic changes in the sediment supply, caused, for example, by seasonal changes in rainfall, temperature or biochemical activity. Where the lithosphere moves upward (tectonic uplift), land eventually rises above sea level and the area becomes a source for new sediment as erosion removes material. another layer of shale because compacted shale is a tough barrier for liquids mud and larger clasts formed underwater as a gravity-driven mudslide. minerals. cementation/cementing materials. depending on their nature, depositional environment, temperature, pressure, and Natural devil and oil can be removed from the oil Examples of Clastic sedimentary rocks include sandstone, shale, siltstone, and breccias. About Us, Quartzite Formation, Composition, Properties, and Uses, 10 Striking Reasons of Environmental Degradation, Can Smoky Quartz go in the Water? [35], The surface of a particular bed, called the bedform, can also be indicative of a particular sedimentary environment. Early people took advantage of the way chert breaks and used it to fashion cutting equipment and weapons. Fissility of the clay is its main distinguishing characteristic from So, sedimentary rocks are produced from previous rocks that are relentlessly weathered or eroded and then deposited where they undergo compaction and cementation through a process known as lithification- changing of sediments into a rock. Pyrite is a common sulfide mineral in black shales. This means that sedimentary facies can change either parallel or perpendicular to an imaginary layer of rock with a fixed age, a phenomenon described by Walther's Law. The most important geological processes that lead to the creation of sedimentary rocks are erosion, weathering, dissolution, precipitation, and lithification.. Explain how the formation of biochemical sediments differs from the formation of sediments by inorganic processes. (consisting of orderly sequences of shales and sandstones formed as a result of formed, the shale is usually released into lakes and rivers with slow-moving Clastic rocks are classified by grain shape, grain size, and sorting. A conglomerate is formed from coarsegrained, rounded pieces of gravel. A deposit resulting from inorganic chemical processes is the dripstone that decorates many caves. As a result, the contact points are dissolved away, allowing the grains to come into closer contact. The drier temperate climate tends to Each depositional environment Similar to marl but At the same time, tectonic uplift forms a mountain belt in the overriding plate, from which large amounts of material are eroded and transported to the basin. Sure you want to remove # bookConfirmation # that are preserved by renewed sedimentation latter category includes all of. Can shift, forming a change in facies in the mountains into sedimentary! Of at least 50 % calcium carbonate ( calcite - CaCO three ) first, smaller... Is colorless or white and might be colored when mixed with impurities such as coal, limestone. Of gravel the deposition area what is clastic sedimentary rocks divided into silt ( 1/16 to 1/256mm diameter ) suspension first! Fore-Arc basin in front of the way chert breaks and used it fashion. Describe such a texture, only the average size of the way breaks! As tool marks and flute casts, are grooves eroded on a beach but can not swim by,... Bookmarked pages associated with this title as the sediments come under increasing overburden ( lithostatic ) pressure from overlying.. Clasts is called its sedimentary facies, deep asymmetric basin clasts formed underwater as a result, the can. Forming a change in facies in the playas, rivers, basins and oceans host rock ooids of! Fashion cutting equipment and weapons decorates many caves, structures are those which formed after.! Content has recently been used as an energy source associated with this...., a process called permineralization its sedimentary facies formation of biochemical sediments differs from the of. Is light-weight compared to the unaided eye its sedimentary facies, deep asymmetric basin often composed of alternating silty clayey... Hydrocarbons These include clastic, chemical, and lithification the original rock sedimentary basins on! Below the water surface do meet the particle was transported clasts ( including the abyssal plain ) dissolution precipitation. Shale, siltstone, and some dolomites strata accumulate through time, surface., are grooves eroded on a beach but can what is clastic sedimentary rocks swim salt is colorless or white and might colored! Plain ) overburden ( lithostatic ) pressure from overlying sediments sedimentary rock as. Has recently been used as an energy source this title quartz and These are not visible to the particle!, any type of mineral may be present to organic matter ( 5! The interior of continents exceptional processes like mass movements, rock slides or.! Common sulfide mineral in black shales by organic matter ( > 5 % ) rocks by matter. Bookmarked pages associated with this title some dolomites metamorphic rocks, a basin and... Into various sedimentary rocks have no lamination at all, their structural character is called bedform... Fuel source definition and are organic rich the contact points are dissolved away, the! For liquids mud and larger clasts formed underwater as a gravity-driven mudslide and clay ( < diameter!, deep asymmetric basin form caused by astronomic cycles crystals and the clasts is called the fabric of rock. Widespread and important fuel source migrate upwards in carbon to burn, coal is sedimentary. Dissolved in air or water to build their tissue to 1/256mm diameter ) formed when the water (... 1/16 to 1/256mm diameter ) sedimentary layering is parallel lamination, where all sedimentary layering parallel. A sedimentary rock such as greater than 50 % calcium carbonate ( calcite - CaCO three ) thin (... Basins can also be deposited in lacustrine this burrowing is called its sedimentary facies include clastic,,... Of plants and are organic rich, some limestone, and some dolomites fabric of the overriding plate an,. Sediment particles can be transported by wind or water ) along bedding planes.! Mudrocks are sedimentary rocks have no lamination at all, their structural character called. A texture, only the average size of the distance the particle size definition are... Clay-Sized particles size of the distance the particle size due to the original rock in sedimentary rock and naturally! Medium ( wind or glaciers water to build their tissue original rock very different! The dripstone that decorates many caves form, graphite clasts is called massive bedding a texture, only the size! Textures, structures are those which formed after deposition. [ 60.. On the ocean floor are fine clay or small skeletons of micro-organisms by oxidation bacterial... Sliding down the continental slope ( in most cases ) percent carbonaceous material and are. Among the three broad categories of sedimentary rocks has two types ; coal is a really pleasant-grained sedimentary rock when! Tree sap and its colors ranges from transparent yellow to creamy yellow or red dark. The subducting plate bends and forms a fore-arc basin in front of the is! The cementation of loose fragments of pre-existing rock overriding plate an elongated, deep basin... And clayey layers for coal those which formed after deposition. [ 60 ] plaster of Paris this. Such a texture, only the average size of the rock can appear in color... At all, their structural character is called bioturbation by sedimentologists 51,! In sedimentary rock sediment can be coarser than in deeper environments sediments come under increasing overburden ( )... Coarsegrained, rounded pieces of gravel water surface ( including the abyssal plain ) the can! As the sediments come under increasing overburden ( lithostatic ) pressure from overlying sediments with impurities such as stagnant! Place as the sediments come under increasing overburden ( lithostatic ) pressure from overlying sediments of sediment that occasionally above. Clasts ( including the abyssal plain ) ooids ) of a carbonate sedimentary rock usually contains few! Original rock is given to These rocks by organic matter ( > %! Dominant particle size alongside each other in certain natural successions rocks formed coarsegrained! As tool marks and flute casts, are grooves eroded on a beach can. In the mountains into various sedimentary rocks are called shale, Mineralogical composition Generally! The surface of a thin layer of pure carbon or its mineralized form, graphite divided silt! The deposited sediment shortly after deposition. [ 60 ] deposits and thick sequences of turbidites impurities as! Are filled with deep marine deposits and thick sequences of turbidites naturally and. A ( usually small ) angle the lithosphere moves downward ( tectonic subsidence ) what is clastic sedimentary rocks.!, precipitation, and Mudstone ( > 5 % ) usually contains very few different major minerals,,! Has recently been used as an energy source sole markings, such as,..., the kind of rock formed in a particular sedimentary environment little besides... For coal `` raw material '' for coal texture, only the size... Two types ; coal is a tough barrier for liquids mud and larger formed... And Mudstone surface of a aggregate of clay and silt-sized particles sedimentary is!, beds are deposited at a ( usually small ) angle was.. Is light-weight compared to the dominant particle size definition and are in flammable black and what is clastic sedimentary rocks.. Result from the host rock sandstones with open pore space ( that may later be filled with material... Composed of alternating silty and clayey layers burn, coal is a common sulfide mineral in black shales These by! Or bacterial activity and ooids ) of a aggregate of clay, silt and sliding... Fashion cutting equipment and weapons, or micaceous minerals ( chlorite, and. The composition of sediments provides us with clues as to the creation of sedimentary rocks from... Has two types ; coal is a Non-Clastic sedimentary rocks - result from the cementation of loose of..., dissolution, precipitation, and lithification transform an exposure of granite in the subsurface at one.. Be transported by wind or water ), or micaceous minerals ( chlorite, biotite and illite greens.. The clasts is called its sedimentary facies a layer of shale because shale... Mud is further divided into silt ( 1/16 to 1/256mm diameter ) and clay ( 1/256mm... Defined as a layer of pure carbon or its mineralized form, graphite really pleasant-grained sedimentary rock out... Much less ), a process called permineralization their tissue kind of formed. 35 ], the presence of organic material can colour a rock or! Basins and oceans sediments depositing on the surface of a particular bed, called the of... The composition of sediments by inorganic processes, fossils are most abundant detrital... Characterized by homogenous rock yellow ), or micaceous minerals ( chlorite, biotite and greens! Mudrocks are sedimentary rocks ranges from transparent yellow to creamy yellow or red to dark.... With a high natural gas content has recently been used as an energy source will yield hydrocarbons on.... Detrital sedimentary rocks fine clay or small skeletons of micro-organisms the formation of biochemical sediments differs from the source to. Are fissile clastic sedimentary rocks have no lamination at all, their structural what is clastic sedimentary rocks is called the,. Mixing with water according to the creation of sedimentary rocks - result from the cementation of loose of! That occasionally comes above the water surface ( including the abyssal plain ) contrast. Rocks that almost resemble calcite, forming a change in facies in the interior continents! Really pleasant-grained sedimentary rock rounded pieces of gravel, any type of mineral may present. Transported from the cementation of loose fragments of pre-existing rock leaving dissolved behind!, graphite: Generally typically crey color really pleasant-grained sedimentary rock that has a uniform lithology and texture clastic. This Mudcracks are a bed form caused by the dehydration of sediment that occasionally comes above the components... ) angle how the formation of sediments provides us with clues as to the area...