No. 1688, Gaoke East Road, Pudong new district, Shanghai, China.
No. 1688, Gaoke East Road, Pudong new district, Shanghai, China.
A concretion is a hard, compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. [1] Concretions are often ovoid or spherical in shape, although irregular shapes also occur. The word 'concretion' is derived from the Latin concretio "(act of) compacting, condensing, congealing, uniting", itself from con …
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 me by a fellow who found it while gardening in his yard in Kauai, Hawaii. I asked a colleague who lives in Kauai whether or not hematite concretions were found there.
These particles were broadly classified into two types: (1) a morphology resembling a clump of tangled fibrous strands of manganese and iron minerals (~0.2 µm in diameter and ~1 µm long; Mn ...
(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).
These nodules are commonly referred to as concretions, which are cemented mineral masses. The size of concretions typically ranges from millimeters to centimeters (Fig. …
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 …
These nodules are com-monly referred to as concretions, which are cemented mineral masses. The size of concretions typically ranges from millimeters to centimeters (Fig. 1A), while the...
The second model suggested that ferruginous concretions were developed from the dissolution and oxidation of siderite nodules 10 ... R. Rinded, iron-oxide concretions in Navajo sandstone along the ...
Iron oxide concretions occur in the Dhandraul Sandstone of Manikpur Formation, Kaimur Group, Vindhyan Supergroup (figure 1).Its formation history involves varying sedimentary environments including fluvial, aeolian, and nearshore (Chakraborty 1996).The study area represents an area near Biharia and Janma Village (25°3.524′N; 81°31.517′E), Shankargarh, …
The amorphous iron oxides (Feo) represented more than 50% of the crystalline Fe oxides (Fed-Feo), indicating that the studied concretions contained high amounts of poorly crystalline Fe oxides. Similar results were also reported by Richardson and Hole (1979), who found that iron in concretions was largely extractable by oxalate suggesting a low ...
Iron oxide concretions on both Mars and Earth are valuable records of diagenetic, postdepositional changes in sedimentary units because they preserve evidence of ancient groundwater flow (Chan et al., 2004, 2005; Ormö et al., 2004; McLennan et al., 2005), fluid-rock interactions, element cycling, and the presence of redox boundaries. The ...
Bench tests with extreme chemical solutions produce immediate formation of iron precipitates. (A) An initial distinct, soft, greenish 'nodule' forms. Its rind turns red as pH …
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 ...
Concretions most commonly result from carbonate precipitation, although a variety of minerals also can form concretions, including pyrite, apatite, iron oxides, and silica (as opal, chert, or chalcedony). Of the carbonate minerals, calcite most commonly forms concretions, followed by dolomite, and siderite.
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 are just above
Environ Chem Lett (2013) 11:1–9 DOI 10.1007/s10311-012-0386-y REVIEW Sequestration of heavy metals from soil with Fe–Mn concretions and nodules Dionisios Gasparatos Received: 27 August 2012 / Accepted: 18 September 2012 / Published online: 27 September 2012 Ó Springer-Verlag Berlin Heidelberg 2012 Abstract In recent years, heavy metal contamination has …
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 …
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 …
The resultant laterite is rich in hydrated iron and aluminium oxides, and low in humus, silica, lime, silicate clays, and most other minerals. Laterites are red and argillaceous in appearance, but often possess a nodular pisolitic texture. ... early diagnetic concretions (nodules) formed around the fossil and protected it from later compaction ...
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, southwestern Utah.Nodule formation is superimposed on eolian laminae and has periodic banding (insert).B
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 by Fe and Mn oxides …
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.
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 ...
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 minerals ...
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 diagenetic events.
march 1, 2020 what are lake iron nodules? • an iron-enriched concretion, often containing more than 30 percent iron by weight. there are both oxic and anoxic forms. oxic iron nodules form at the sediment/water interface (swi). they are commonly composed of the minerals goethite and hematite. anoxic iron nodules form in anoxic sediment pore-space.
demonstrate that concretions with iron-oxide rinds and iron-poor cores are the hallmarks of altered siderite masses. Because this insight pro-vides a view back in time, beyond the most recent …
Redox concentrations are defined as zones of apparent accumulation of Fe-Mn oxides that include nodules and concretions, masses and pore linings (Fig. 1A) (Soil Survey Staff, 2014). Redox concentrations form when reduced Fe has accumulated and is then oxidized. ... Iron oxide in wells part 1, genesis, mineralogy and geochemistry. Appl. Geochem ...
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 ...
Analyses of small iron oxide nodules found within certain sandstones of the U.S. Southwest could shed light on how similar spherules may have formed on Mars. ... Some hematite concretions from ...
