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Sandstone concretions - The effect of the pyrite concretions on the evolution of macroscale cracks in the sandstone was further investigate

Sandstone also commonly known as arenite is a clastic sedimentary rock composed mainly of sand

Moqui Marble is the term used to identify a marble-like concretion having a sandstone center encased in an iron oxide shell.These geological oddities litter the surface of the iron rich Navajo sandstone in southern Utah's Zion and Capitol national parks, Grand Staircase-Escalante National Monument, Snow Canyon State Park and the Moab area.The concretions consist of sandstone which differs from the surrounding rock ... concretions and limonite in the sandstone. Quantitative analyses were run ...Abstract The iron oxide concretions of Shankargarh (Allahabad), India belongs to Dhandraul Sandstone of Vindhyan Supergroup. Petrography of concretions shows abundant quartz grains embedded within the iron oxide cementation. XRD analysis of the concretion shows diagnostic peaks for quartz, hematite, and goethite. The A-CN-K and A-CNK-FM ternary diagrams drawn for concretion and host ...Iron (oxyhydr)oxide concretions in the Navajo Sandstone of southern Utah have been extensively researched as Martian analogues. However, the discovery of calcium carbonate concretions in areas such as Coyote Gulch, Utah, has encouraged recent studies to understand the relationship between calcium carbonate spheroidal concretions as …The "cannonballs" concretions in both the Faiyum and Bahariya oases are interpreted to be formed by precipitation of cement material within the voids or cavities of the sediments hosing them (e.g., Al-Agha et al. 1995; McBride et al. 1994, 2003; Mozley and Davis 2005; Wanas 2008).They grew as concentric lamellae around nuclei, which are often represented by tooth, shell fragment or fossil ...Laying pavers over concrete hides weathered concrete to give an outdoor area a new, fresh appearance. If you plan to install pavers near a door that swings over the concrete area, make sure there is room for the door to clear the pavers bef...The concretions are resistant to weathering compared to the host sandstone, which is fairly soft, so stick out from the cliff in a sometimes rather alarming manner as you walk below them. I’ve been visiting the concretions sporadically for around 30 years and some of the ones that I photographed in the cliffs in the 1980s are now lying loose ...The eolian Jurassic Navajo Sandstone spheroidal hydrous ferric oxide (HFO) concretions are divided into two size classes: macro-concretions of > 5 mm diameter and micro-concretions of < 5 mm diameter.Concretions are hard compact accumulations of mineral matter and are found inside sedimentary rocks. Some examples of this are Sandstone and in some weathered volcanic rock. Concretions come in many different shapes and the most common of the shapes is spherical or disk shaped. Concretions are the most varied-shaped rocks of the sedimentary world.Calcite-cemented concretions can reduce reservoir quality and form important low-permeability baffles for fluid flow in sandstone hydrocarbon carrier beds/reservoirs. Understanding the origin and distribution patterns of concretions has important implications for characterizing reservoir heterogeneity and developing fields.Being more firmly cemented than the enclosing sandstone, concretions weather out in myriad shapes, that have been fancifully described as cannonballs, pumpkins, dinosaur limbs or bric-a-brac. Descriptions dating from the 18th century attest to the fact that concretions have long been regarded as fascinating geologic curiosities.Very nice find. We have small limestone concretions with micro size bugs but nothing like that. I have a few of the sandstone concretions my parents collected many years ago. I I had a pile of sandstone pseudomorphs after quartz crystals but foolishly sold them all early on.Compelling similarities between concretions on Earth and "blueberries" on Mars are used to suggest the blueberries are concretions that formed from a history of watery diagenesis. In the terrestrial examples, groundwater flow produces varia-tions in sandstone color and iron oxide concretions in the Jurassic Navajo Sandstone of Utah.Sandstone concretion sculpture gogotte. This one-of-a-kind piece has fantastic natural landscape details with unique colors and shapes. Classified as a "sand concretion", gogottes are of a special group of concretions that are visually and geographically distinct. They are only found within the Parisian basin (sometimes referred to as the "Fountainebleau sands") and have layered, three ...Occurrence. Vaqueros Formation sandstone with concretions. A mosaic of images showing spherules, some partly embedded, spread over (smaller) soil grains on the Martian surface. Concretions are found in a variety of rocks, but are particularly common in shales, siltstones, and sandstones. [30] Concretions are commonly misunderstood geologic structures. Often mistaken for fossil eggs, turtle shells, or bones, they are actually not fossils at all but a common geologic phenomenon in almost all types of sedimentary rock, including sandstones, shales, siltstones, and limestones.Sedimentary > Clastic > Sandstone (Glauconitic) cross-bedded glauconitic sand; one or more thin beds of fossiliferous marly glauconitic sand and sandstone occur in the upper part. Near the base is a prominent bed of glauconitic calcareous sand containing abundant fossils and spheroidal to pillow-shaped sandstone concretions (Bashi Marl Member).Examine the sandstone concretions scattered across the ground, formed through water and wind eroding the soil's surface. Nature Viewing in Anza-Borrego. Soak in the beauty of the Anza-Borrego Desert, full of surprises. There are still a plethora of things to do in Anza-Borrego Sprints. To view the diverse plants and animals that call this ...Jan 27, 2023 - Sandstone Concretions on Laig Beach, Isle of Eigg, Scottish Highlands and Islands. View of the Isle of Rùm, The Small Isles.Concretions are masses of mineral matter embedded within rock layers, including limestone, sandstone, and shale. They often take shape when minerals precipitating (settling) out of water collect around a nucleus, such as a pebble, leaf, shell, bone, or fossil. Contents show 1 How are iron concretions formed? 2 How long do concretions take to form?Hardie Board refers to James Hardie siding products produced by manufacturer James Hardie. The company has a selection of products that includes HardieTrim Boards and HardieTrim Cement Boards. There are also other cement board manufacturers...Sandstone concretion. Royal Ontario Museum Toronto, Canada. Such bizarre and attractive natural formations, known as concretions, occur in 30 million year old sands left by an ancient river system in what is now the Paris Basin. Although predominately made up of unconsolidated or loose sands, locally ground water rich in dissolved silica has ...Previous workers suggested the spheroidal concretions as analogs for Martian "blueberries" (hematite concretions), and linked the origin of concretions and bleaching of the Navajo Sandstone to the buoyant rise of hydrocarbons toward anticlinal crests.Spheroidal sandstone concretions (< / 0.1 15 cm diameter) are confined to Early Eocene shallow marine sands of the Dikilitash Formation near Varna (NE Bulgaria). Low calcite δ13C values down to −45 VPDB demonstrated the link between their formation and methane-bearing fluids. Based on integrated field, petrographic, geochemical and …Sandstone concretions exhumed in coastal environments. Sandstone concretions have been reported in three settings: within the shoreface sandstone host where they were cemented during early diagenesis (lithofacies association B2), filling incised channels cutting shoreface deposits (facies association C1), and as boulder-thick beds (lithofacies ...Several Fontainebleau sandstone concretions—smooth, swirling formations found in France—reveal what a brilliant modernist sculptor Mother Nature was two million years ago. Collecting crystals and fossils was not part of Berger's original career path. In fact, he was taking a hiatus from medical school in 1968 when he acquired his first ...In most concretions there has been replacement of at least some of the pre-exiting sediment. Many concretions are saucer shaped to rounded. More recent siltstones form rings that are often formed by a twig eroding out and leaving a hole. Example of remnant concretion having eroded out of a sandstone depression. Example of a row of concretion ...The sandstone formed from sand and other sediment deposited along the edge of a Cretaceous sea about 100 million years ago. Over time, circulating water deposited a limy cement between the sand grains in some parts of the formation, creating harder bodies of rock, called concretions , within the softer sandstone layer.Set the sandstone chunks onto the ground or on a solid surface such as a wood chopping block or level tree stump. Hit the sandstone pieces with a heavy sledgehammer to break …Concretion Noun the formation of stonelike objects within a body organ (e.g., the kidneys a hard lump produced by the concretion of mineral salts; found in hollow organs or ducts of the body an increase in the density of something the union of diverse things into one body or form or group; the growing together of partsThe sandstone formed from sand and other sediment deposited along the edge of a Cretaceous sea about 100 million years ago. Over time, circulating water deposited a limy cement between the sand grains in some parts of the formation, creating harder bodies of rock, called concretions , within the softer sandstone layer.Carbonate concretions are common features of sedimentary rocks of all geological ages. They are most obvious in sandstones and mudstones as ovoid bodies of rock that protrude from natural outcrops: clearly harder or better cemented than their host rocks. Many people are excited by finding fossils in the centre of mudstone‐hosted …This unique landscape is the result of both precipitation and diagensis to form the concretions, as well as wind and water continuously eroding the surface soil to uncover the sandstone globes. On the nearby ridges, new pumpkin-size concretions continue to grow and be exposed.Concretion geometry is linked to the sedimentological facies of the host sediment: (i) massive fluvial pebbly sandstone at the base of the terrace contains knobby, subhorizontal concretions ...7.4 Weathered sandstone in Ohio. After chemical weathering, leftover rock may have a dissolved or eroded appearance, such as the sandstone seen in Figure 7.4. ... And, barite sometimes occurs as concretions in sediments and sedimentary rocks, and sometimes as desert roses (Figure 7.49), similar to desert roses made of gypsum. ...Barite is also found as concretions in sand and sandstone. These concretions grow as barite crystallizes within the interstitial spaces between sand grains. Sometimes crystals of barite grow into interesting shapes within the sand. These structures are known as "barite roses" (see photo). They can be up to several inches in length and ...Navajo Sandstone HFO Concretions 62 Host Rock 62 External Structure 65 Internal Structure 67 Mineralogy and Crystallography 67 Size Distribution Comparison 70 Strengths and Weaknesses of Utah Analog 72 Conclusions 72 References 76 2. JOINT-CONTROLLED FLUID FLOW PATTERNS IN JURASSIC NAVAJO SANDSTONE: ANALOG IMPLICATIONS FOR MARS HEMATITE 83doi:10.1130/G32550Y.1 Forum Reply Follow the water: Connecting a CO2 reservoir and bleached sandstone to iron-rich concretions in the Navajo Sandstone of south-central Utah, USA Richard M. Kettler1, David B. Loope1*, and Karrie A. Weber1,2 The absence of siderite in spring precipitates is to be expected. Fe(II) 1 Department of Earth ...Iron Concretions. Red spots in the Aztec Sandstone are iron concretions, where subsurface water has precipitated iron oxide around a nucleus in the sandstone. These concretions are more resistant to erosion than the surrounding sandstone, and weather into little balls known as Indian or Moqui Marbles.२०११ जनवरी १५ ... Semantic Scholar extracted view of "Characterization of Navajo Sandstone concretions: Mars comparison and criteria for distinguishing ...Perhaps the best known are the giant (25+ feet in diameter) sandstone concretions weathered from the Dakota Formation in Ottawa and Ellsworth counties in central Kansas (saving these for another story). The Blue Hill Shale Member of the Carlile Formation has fairly large rounded to warty concretions with calcite crystals.The concretions consist of sandstone which differs from the surrounding rock ... concretions and limonite in the sandstone. Quantitative analyses were run ...The effect of the pyrite concretions on the evolution of macroscale cracks in the sandstone was further investigated through numerical simulations with Particle Flow Code in 2D (PFC2D). The results revealed that pyrite concretions substantially influence the mechanical properties and macroscale and mesoscale failure characteristics of sandstone.The concretions in this study from southern Spain record an evolutionary history from their genesis within Lower Cretaceous shoreface sandstones and their …Download Sandstone Concretion stock photos. Free or royalty-free photos and images. Use them in commercial designs under lifetime, perpetual & worldwide rights. Dreamstime is the world`s largest stock photography community.In this paper we present clumped isotope data from calcite cements in concretions from the Middle Jurassic Valtos Sandstone Formation of the Great Estuarine Group of the Inner Hebrides (Figs 1 and 2).These concretions are well suited to such an approach, their age and geological context making them excellent analogues for diagenetic processes operating in subsurface Jurassic North Sea reservoirs.These are actually sandstone concretions, but to the unknowing eye they can be quite the surreal sight. Victoria Beach — Laguna Beach, California. Aydin Palabiyikoglu / Getty Images Like a film set on Game of Thrones, the defining feature of Victoria Beach is a 60-foot medieval-style tower that looks out over the Pacific. In reality, …While spheres in nature are not unusual, the sand and iron concretions known as Moqui marbles are very striking. They can be near-perfect spheres. Before the Navajo Sandstone (deposited near the beginning of the Jurassic Period, 200 million years ago) was cemented into rock, groundwater flowed through these sands, and iron would …In the present study, five different types of concretion were collected from mostly clay and coal interbedded sandstone beds, which are circular (1.5-4cm), elongate (0.5-1cm diameter; 4-6cm length ...Concretions are compact, often rounded, accumulations of mineral matter that form inside sedimentary rocks such as shale and sandstone or in soil.Occurrences of calcite concretions and partly dissolved calcite concretions stained by Fe-oxide crusts within the unbleached reddish sandstone were also reported in previous studies (5, 8). These studies suggested that the upper part of the Navajo Sandstone was originally red and was bleached by hydrocarbon-rich or organic acid-rich fluids ( 4 ...The Navajo Sandstone concretions were likely precipitated at circumneutral pH (Beitler, 2003, Beitler, 2005, Busigny and Dauphas, 2007, Chan et al., 2000, Chan et al., 2004, Chan et al., 2005, Chan et al., 2007). The Mars spherules may also exhibit a higher degree of crystallinity due to greater iron abundance in the Burns formation sediments.Carbonate concretions have traditionally been viewed as forming concentrically, through the progressive addition of carbonate to the outer edge of the growing concretion. This conventional model of concretion growth is based mainly upon center-to-edge textural and geochemical trends that are consistent with concentric growth.Konkresi adalah massa kompak yang keras, terbentuk dari presipitasi semen mineral di dalam rongga-rongga partikel, dan ditemukan di batuan sedimen. Konkresi berbentuk seperti ataupun bulat, namun bentuk-bentuk iregular juga sering terjadi. Istilah 'konkresi' berasal dari bahasa latin yang artinya 'bersama' dan yang artinya 'tumbuh'.The effect of the pyrite concretions on the evolution of macroscale cracks in the sandstone was further investigated through numerical simulations with Particle Flow Code in 2D (PFC2D). The results revealed that pyrite concretions substantially influence the mechanical properties and macroscale and mesoscale failure characteristics of sandstone.Sandstone concretion sculpture got. This one-of-a-kind piece has fantastic natural landscape details with unique colors and shapes. Classified as a "sand concretion", Gogottes are of a special group of concretions that are visually and geographically distinct. They are only found within the Parisian basin (sometimes referred to as the ...Well-exposed Jurassic Navajo Sandstone iron oxide concretions preserve important diagenetic records of groundwater flow and water-rock interactions. Field relationships, precipitation patterns, and geometries of the Navajo concretions provide the basis for input parameters in numerical computer simulations and laboratory chemical bench tests.Description & Provenance. Although technically a "sand concretion," gogottes (a.k.a. "Fountainebleau sands") are of a special subgroup of concretion that is only found within the Parisian basin. Their primary difference is that they have layered, three-dimensional forms that differ wildly from the simplistic spherical, discoid, and/or ...A half-mile walk or drive up the jeep trail leads to large sandstone concretions scattered around the cliff base (the trail continues to Short Canyon and more concretions). These 1- to 10-foot-diameter spherical concretions weather out of a sandy, ledge-forming rock layer mid-way up the cliff within the Tununk Member of the Mancos Shale.In Minnesota, sandstone and other sedimentary rocks were deposited during the early Paleozoic Era, about 500 million years ago. At that time, Minnesota was near the equator, and shallow seas covered most of the state. Sediment eroded from upland areas was transported to the seashore, and the coarser-grained sediment eventually …carbonate cONCRETIONS. Marshall and Pirrie (2013) noted, "concretions are simply patches of cemented sediment. The mineral cement between the grains is different, or more abundant, from that in the host sediment (which may not be cemented at all).". They point out that the most common carbonate concretions are calcite (calcium carbonate ...Essentially, a Moqui Marble is a hematite shell that is formed around a portion of sandstone. The iron oxides give the stones a distinctive look, the black oxidized iron looks out of place in the natural red and yellow sandstone where they're found. These aren't actually considered stones. Concretions occur much more quickly than stones.Geologic processes continue to shape the badlands. Yearly precipitation in the badlands averages 15 inches. Rain, though infrequent at times, usually comes in heavy, erosive downpours. Water running down slope forms gullies, while some soaks into clay-rich rocks and soils. The added weight of water sometimes causes portions of hill sides to ...२०२२ मार्च २९ ... Mardani Fine Minerals: Gogotte Sandstone Concretion, Fontainebleau, France # 07640 Crystal presents this sculpturesque gogotte from France.Similarly, there's Rock City near Minneapolis, Kansas, a few football fields worth of climbable sandstone concretions, run by a nonprofit organization and maintained with a small fee from visitors.Concretions occur much more quickly than stones. Indeed, concretions in siderite formations of the UK have been found to contain artillery shells and other ordinance from the WW2 era. ... This sandstone is a rich cream color in many locations, but the color varies. It’s known for some of the striking formations in places like Zion National Park.Chert is a fine-grained sedimentary rock composed of quartz (SiO2) that is microcrystalline or cryptocrystalline quartz. It is usually organic rock but also occur inorganically as a chemical precipitate or a diagenetic replacement. It occurs as nodules, concretionary masses, and as layered deposits. Name origin: Term is used to refer generally ...The range of colors of the Navajo Sandstone -red, brown, pink, salmon, gold, and even white—results from varying amounts and forms of iron oxide within the rock, and in the case of the white upper portion of the Navajo, the overall lack of iron. The processes behind the color variation are complex and took place in multiple phases over long ...Catskill Formation (Devonian) at surface, covers 9 % of this area. Grayish-red sandstone, siltstone, shale, and mudstone; units of gray sandstone occur in upper part; lithologies in upper part arranged in fining-upward cycles. In the Altoona area, the Catskill Formation is mapped as the Duncannon, Sherman Creek, and Irish Valley Members, which ...Concretions form in the pore spaces between grains of sand in sandstones. They usually grow as an algal colony from a central point. They usually grow as an algal colony from a central point. As they fill the pores with calcite, the living outer part encases the dead core and forms a spherical feature.Below we introduce the major types of concretions and similar rocks, as well as share images of concretions that were sent to us by the public and often initially …Sandstone is a sedimentary rock that is composed of mainly sand-size grains. It is found in large areas. Between 20-25% of the layers of sedimentary rocks are found in each portion of the earth. It is composed of sediment materials that are formed from other processes such as weathering & erosion of other rocks. There are some characteristics ...Concretions are mysterious geologic phenomen a that occur in a variety of sedimentary rock such as s hale, sandstone, siltstone, and limestone. Some types of concretions are formed after sediment envelopes an animal or a plant as it decomposes. ... The concretion on the left is the one I bought that day. A stunning concretion seen from the ...Iron-oxide nodules or concretions are the most common kind of meteorwrong sent to us. Hematite and magnetite are two common iron-oxide minerals. Most iron ore deposits consist mainly of hematite, magnetite, or both. Iron-oxide concretions, iron-oxide nodules, and ironstones are often mistaken for meteorites because they are heavy (dense) and their …Sandstone concretion shielding pedestal of softer sediments, Theodore Roosevelt National Park. Iron-stained sandstone concretions in the Bullion Creek Formation, Theodore Roosevelt National Park. (Photos by John Bluemle). Concretions and nodules are found in all of the geologic formations exposed in southwestern North Dakota, and some can be ...If the nodules or concretions are numerous, they can grow large enough to merge with one another to form a nearly continuous layer of chert within the sediment mass. Chert formed in this manner is a chemical sedimentary rock. Diatoms are microscopic, single-celled algae that live in marine or fresh water. They produce hard parts made of silicon ...A concretion is a compact mass of mineral matter, usually spherical or disk-shaped, embedded in a host rock of a different composition. This hard, round mass of sedimentary rock cement is carried into place by ground water. They usually form early in the burial history of sediment, before the rest of the sediment has hardened into solid rock.In the Cedar Hills Sandstone, the density exceeds the neutron porosity in a characteristic silica crossover, and porosities of this "free-drilling" sandstone range around 30 percent. ... Bedding, cross-bedding, ripple marks, mud cracks, displacive evaporite crystal molds, and hematite concretions are contained in these Martian strata. Together ...Flower-Like Sandstone Concretions - Pseudo Stromatolites $3.00 (Bulk Discounts) 7 REMAINING . 1.7" Polished Sunstone Pocket Stone $6.00 (Bulk Discounts) 119 REMAINING . 2.2" Hausmannite Crystal Cluster - South Africa $25 6.7" Flower-Like Sandstone Concretion - Pseudo Stromatolite This is a 6.7" wide, flower-shaped sandstone concretion from the ...The eolian Jurassic Navajo Sandstone spheroidal hydrous ferric oxide (HFO) concretions are divided into two size classes: macro-concretions of > 5 mm diameter and micro-concretions of < 5 mm diameter.Three internal structural end-members of macro-concretions are described as rind, layered, and solid.The Lower Triassic Buntsandstein Formation of Europe is well known for its classic red beds of fluvial cross-stratified sandstones, however relatively ...Fossils are the traces or remains of organisms buried and preserved in sediments. They consist not only of hard body parts, such as bone and shell, but also may be impressions of plants, or tracks, trails, and burrows. Fossils can tell us what life was like on Earth in ancient geologic time, helping geologists describe ancient depositional environments and understand past climates. Fossils ...This is a wholesale flat of 38 flower-shaped, red sandstone concretions from the Sahara Desert in Morocco. They range from 1.5 to 3" across and you will receive the exact lot pictured. The flower-like pattern has been caused by surface erosion in the desert. At the wholesale price, each piece is approximately $2.Sandstone mineralogy is the best indicator of sedimentary provenance: the nature of a sedimentary rock source area, its composition, relief, and location. Sandstone textures and sedimentary structures also are reliable indexes of the transportational agents and depositional setting. ... Local cementation may result in concretions of calcite ...Princeton University Art Museum. International Image Interoperability Framework logo; Open ...A Fossil Picture Gallery. Alice Cahill / Getty Images. By. Andrew Alden. Updated on January 21, 2020. Fossils, in the geological sense, are ancient, mineralized plants, animals, and features that are the remains of an earlier geological time period. They may have been petrified but are still recognizable, as you can tell from this gallery of ...The mass of C within a tusk-shell spherical concretion is given by: Vc = 4/3πr c 3 · d(c) · n c, where r c is the radius of a concretion (mean value; 0.75 cm), d(c) is the average density of a ...Concretions on Bowling Ball Beach (Mendocino County, California) weather out of steeply tilted Cenozoic mudstone… Al-Agha, M.R., S. D. Burley, C.D. Curtis, and J. Esson, 1995, Complex cementation textures and authigenic mineral assemblages in Recent concretions from the Lincolnshire Wash (east coast, UK) driven by Fe(0) Fe(II) oxidation ...Iron-bearing calcite cement occurs as large concretions that generally follow bedding and are most common near the top of the sandstone. Median thickness of the concretions is 0.6 m, length 4.5 m ...The concretions show Fe enrichment and Si depletion as compared to the host sandstone. The mass balance calculations indicate that the total Fe 2 O 3 in the …doi:10.1130/G32550Y.1 Forum Reply Follow the water: Connecting a CO2 reservoir and bleached sandstone to iron-rich concretions in the Navajo Sandstone of south-central Utah, USA Richard M. Kettler1, David B. Loope1*, and Karrie A. Weber1,2 The absence of siderite in spring precipitates is to be expected. Fe(II) 1 Department of Earth ...The fossils from Isisford are found in ex situ indurated sandstone concretions of the lower Winton Formation (figure 1)[6,7,53]. The Winton Formation at Isisford has assigned a maximum age of 102.2– 100.5Ma, and is older and potentially closer to the contact with the conformably underlying MackundaThe even diffusion of the mineral creates the concretions' spheric, The sandstone is well cross-bedded and was deposited, Mushroom Rock State Park, the smallest state park in Kansas, has natural Dakota sandstone concretio, Sandstone forms from the consolidation of sand-sized grains, which can be , The Broechem fauna from AIA studied in this paper originates from sandstone concretio, Image by: Andy Fyon, Aug 12, 2019. The rocks that contain the concretions are about 80 million years, In Minnesota, sandstone and other sedimentary rocks were deposited during the ear, Leighton told Newshub the estimated five million-year-old sphe, Free online jigsaw puzzle game, This Dakota sandstone also forms the giant concretions at , Numerous vertebrate and plant fossils have been foun, A concretion is a compact mass of mineral matter, usuall, Project Performance Facts. The Ferron Sandstone project consists of $, Iron (oxyhydr)oxide concretions in the Navajo Sandstone of souther, Concretions, with abundant calcite-dolomite cement-repla, Sep 15, 2016 · The sandstone concretions at Rock City are scattered, This is a wholesale flat of 38 flower-shaped, red sands, Located approximately 50 kilometres south of Medicine .