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Cherts can cause several problems when used as concrete aggregates. Deeply weathered chert develops surface pop-outs when used in concrete that undergoes freezing and thawing because of the high porosity of weathered chert. The other concern is that certain cherts undergo an alkali-silica reaction with high-alkali cements.
In geology and particularly in sedimentology, a nodule is a small, irregularly rounded knot, mass, or lump of a mineral or mineral aggregate that typically has a contrasting composition from the enclosing sediment or sedimentary rock. Examples include pyrite nodules in coal, a chert nodule in limestone, or a phosphorite nodule in marine shale.
Concretions in Torysh, Western Kazakhstan Concretions with lens shape from island in Vltava river, Prague, Czech Republic Marlstone aggregate concretion, Sault Ste. Marie, Michigan, United States A concretion is a hard and compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary ...
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, [1] [2] categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start fires. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.
Here radiolarian cherts overlie spilites and volcanic rocks. Radiolarites are also found in the nearby Southern Uplands where they are associated with pillow lava. The Scottish radiolarites are followed by deposits in Newfoundland from the Middle and Upper Ordovician. The red Strong Island Chert for instance rests on ophiolites.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
Feb. 14—The Mower County Board of Commissioners on Tuesday approved a resolution that will lead to the beginning of a project at the Wanhi Yukan Trail-Grand Meadow Chert Quarry Arch & Cultural ...
Rhynie chert; S. Siliceous ooze; V. Vigla Formation This page was last edited on 29 December 2013, at 10:45 (UTC). Text is available under the Creative Commons ...