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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
Marlstone aggregate concretion, Sault Ste. Marie, Michigan, United States. 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
Concretion. In subject area: Earth and Planetary Sciences. Concretions are masses of rock that form when minerals grow around organic debris, commonly found in black shales and occasionally in gray shales. They can occur as individual concretions or clusters and may be loosely bonded to the surrounding shale.
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
Jun 20, 2021 · Moreover, based on the above observations and the literature (Levy, 1998; Pardi, 1984; Sheldon, 1900; Tarr, 1935), the appearance, distribution, and morphology of concretions in the CVVC sediments possess a series of remarkable characteristics: (1) concretions only occur in specific (or preferred) zones within the varved sediments, but are not dispersed homogeneously throughout the entire ...
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Apr 3, 2020 · 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. Concretions form inside sediments before they harden into ...
