Iron oxide concretions result from a series of chemical oxidation and reduction steps, and the nucleation, 2 M. A. CHAN et al. NAVAJO SANDSTONE CONCRETIONS Iron mobilization and precipitation The Lower Jurassic Navajo Sandstone of southern Utah contains color variations and diagenetic iron oxide concretion mineralization (Fig. 1) …
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1971, 1981). Displacive siderite nodules are com-mon in peaty, methanic soils that develop within poorly drained, floodplain sediments (Ho & Coleman, 1969; Moore et al., 1992; Bailey et al., ... Rinded iron-oxide concretions 1771 2012 The Authors. Journal compilation 2012 International Association of Sedimentologists, Sedimentology, 59, 1769 ...
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Iron-oxide concretions and nodules 2. page 2. ... This concretion appears to have started as a mass of pyrite crystals (iron sulfide, cubic) and is in the process of oxidizing to iron oxide. This photo was sent to …
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Iron oxide concretions on both Mars and Earth are valuable records of diagenetic, postdepositional changes in sedimentary units because they preserve …
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Jurassic Navajo Sandstone examples of very small (<1 cm-scale) and 'mini' (mm-scale) spherical iron-oxide concretions are common and are expected as a result …
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The discovery of iron oxide spherules by the Opportunity rover on Meridiani Planum (Mars) (Squyres et al., 2004) prompted a revival of interest in terrestrial concretionary iron oxide cementation.Among the occurrences of iron oxide cementation that received the most immediate interest were concretions from southern Utah (Fig. 1) …
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Iron-oxide concretions and nodules 4. page 4. back to Some Meteorite Realities. I was given the stones above as a child by my grandmother. I do not know where she got them, but she was from New York state. ... The stones are hematite concretions used by Native Americans to paint their faces. The blunt end of the stone in the upper left could be ...
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The Jurassic Navajo Sandstone, host for the iron oxide concretions in this study, averages (volume % ± one standard deviation) 74 ± 2 % quartz, 5.6 ± 0.6 % K …
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A large deposit of ferromanganese oxide coated sands and scattered manganese nodules occurs in the northern portion of Lake Ontario. The Mn and Fe contents of the concretions are similar to those in concretions from other environments, while their Ni, Cu, and Co contents are lower than in deep-sea nodules, but higher than in most previously …
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The majority of studies have shown that the primary minerals of the Fe–Mn concretions and nodules were quartz, feldspars and micas. The mineralogical similarity between the Fe–Mn concretions and nodules and the surrounding soil matrix indicates their pedogenetic origin and their in situ formation due to cementation of soil materials …
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(A) Iron oxide concretions (several cm in diameter) in cross-bedded host rock at Snow Canyon, southwestern Utah. Nodule formation is superimposed on eolian laminae and has periodic banding (insert).
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of manganese nodules 1.1 Manganese nodules are mineral concretions made up of manga-nese and iron oxides. They can be as small as golf balls or as big as large potatoes. The nodules occur over extensive areas of the vast, sediment-covered, abyssal plains of the global ocean in water depths of 4 000 to 6 500 metres, where temperatures …
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Jurassic Navajo Sandstone: (A) examples of different sizes of common spherical iron oxide concretions: (B–C) common concretion accumulations, (D) in situ concretions, (E) mixed populations of ...
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One previous model for the Fe-oxide concretions in Utah suggested that Fe-oxide concretions formed by mixing between reducing fluids and oxygenated water, which caused precipitation of iron as ferric oxide cement in the bleached host rock (1, 2, 4–8).Mobilization and transport of chemically reduced Fe 2+ in solution are thought to …
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The formation of ferric oxide concretions in a quartz arenite is thought to proceed via a three-step process (Chan et al. 2000, 2004, 2007; see Fig. 7): (1) reduction and mobilization of Fe from hematite grain coatings; (2) transport of Fe 2+ to the site of precipitation; and (3) precipitation of Fe to form iron sulfide or hydrous ferric oxides ...
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Fe-rich concretions commonly occur in Greek soils with alternating drying and waterlogging periods. This study was conducted to characterize the iron oxides in Fe-rich concretions from the upper ...
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The formation of hydraulically isolated compartments along hard-linked strike-slip faults promotes: (1) the development of Liesegang bands in a reaction zone dominated by pore-water molecular diffusion of O 2 into Fe 2+-rich stagnant water, and (2) the precipitation of iron-oxide impregnations and concretions in the fault-core–mixed zone ...
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Iron oxide cements have δ 56 Fe values that are typically negative and as low as −0.74‰. In contrast, iron oxide-stained Navajo Sandstone in close proximity to a rinded iron oxide concretion has δ 56 Fe values that are 0.9 to 1‰ greater than the δ 56 Fe value of the associated iron oxide concretion
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Iron oxide concretions result from a series of chemical oxidation and reduction sttif, and the nucleation, precipitation and maturation of polynuclear gels, metastable phases, the role of pH, and stability of different mineralogy are still poorly understood. ... amorphous nodules of iron-hydroxide. It is not clear how these …
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North Dakota, especially in the wondrously sculpted badland areas of the west, has a fantastic variety of concretions and nodules. Some are the size and shape of petrified logs, while others, perched atop pedestals of softer sediments that they shield from erosion, have lens or disk shapes. ... Surface films of iron oxides are common on clay ...
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In addition to bleaching, iron concretions (also known as iron-oxide concretions, iron-rich concretions, concretionary nodules) are the remarkable products of interaction between reducing CO 2-bearing …
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marbles (iron concretions) collecting in small depressions, like puddles of ball bearings. These natural spherical balls have been called various names such as iron nodules, iron sandstone balls, or moki marbles. However, we use the name "iron concretion" to describe both the composition (iron oxide that is the dark mineral which cements ...
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Stereoscopic and optical microscopy observations show that the concretions and nodules contain skeletal grains of primary minerals (like quartz, feldspar etc.), pores cemented together with a brown or dark matrix which is consisted of Fe-Mn oxides, hydroxides and oxyhydroxides (for the sake of brevity all are called oxides) and clay …
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One previous model for the Fe-oxide concretions in Utah suggested that Fe-oxide concretions formed by mixing between reducing fluids and oxygenated water, which caused precipitation of iron as ...
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(A) Iron oxide concretions (several cm in diameter) in cross-bedded host rock at Snow Canyon, southwestern Utah. Nodule formation is superimposed on eolian laminae and has periodic banding …
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The SR-mCT images reveal that the large nodules (2–3, 3–5, and 5–8 mm in diameter) have distinct Fe and Mn concentric ring structure, while the small nodule (1–2 mm) exhibits a homogeneous fabric. The μ-XRF maps show that Mn is concentrated near the nucleus of the nodule, while Fe is more concentrated in the exterior of the nodule.
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First, the iron oxide concretions initiate or nucleate on a single seed. This hypothesis will be tested by petrographic analysis to identify nucleation sites and a conceptual model that accounts for rinds of iron oxide cemented sandstone that surrounds uncemented sandstone. Second, the concretions form quickly and record brief …
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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, …
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Still, the table identifies the principal characteristics of many types of concretions and nodules and gives one an idea of the diversity of types to be found in the Hell Creek Formation. Table 1. Classification and characteristics of concretions and nodules of the Cretaceous Hell Creek Formation in Slope and Bowman Counties.
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Formation of iron oxide concretion nodules, bands and scallops in Navajo eolian sandstone. (A) Iron oxide concretions (several cm in diameter) in cross-bedded host rock at Snow Canyon ...
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