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Concretion. 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.
Apr 20, 2018 · 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 ...
- Hidekazu Yoshida, Koshi Yamamoto, Masayo Minami, Nagayoshi Katsuta, Sirono Sin-ichi, Richard Metcalf...
- 2018
Mar 18, 2013 · 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 concretions ...
- Jim D. Marshall, Duncan Pirrie
- 2013
Sep 15, 2015 · Stable isotope data from cogenetic pyrite (δ 34 S) and silica (δ 18 O) phases provide insight into the evolution of biogeochemical processes during concretion growth, and suggest that concretions were formed almost entirely during sulphate reduction, with only minor modification thereafter. Concretions of the Wheeler Formation appear to represent an end-member system of concretion formation ...
- Robert R. Gaines, John S. Vorhies, John S. Vorhies
- 2016
Nov 1, 1996 · EARTH-SCIENCE REVIEWS ELSEVIER Earth-Science Reviews 41 (1996) 177-210 Concretion morphology, classification and genesis J. Sellés-Martínez Dep. Ciencias Geologicas, Fac. Ciencias Exactas, Universidad de Buenos Aires, Pa6ellon 2 Ciudad Universitaria, 1428 Buenos Aires, Argentina Received 10 October 1995; accepted 17 April 1996 Abstract A ...
- J. Sellés-Martínez
- 1996
May 2, 2018 · Generalized conditions of spherical carbonate concretion formation around decaying organic matter in early diagenesis. Scientific Reports , 2018; 8 (1) DOI: 10.1038/s41598-018-24205-5 Cite This Page :
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Jul 1, 1993 · An attempt to create an overall mass balance of the relevant species is shown in Table 3. This calcula- tion integrates all the possible processes which might contribute during the period of growth of the concretion. It obviously is crude since there will not be a perfectly closed system containing the concretion and its host sediment.
