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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 ...
A concretion is a volume of sedimentary rock in which a mineral cement fills the porosity (i.e. the spaces between the sediment grains). The image shows a Sandstone Concretion in the wall at the beach of Año Nuevo State Reserve. This concretion was too high in the wall to place a ruler, but I estimate it to be about 400 mm long.
The two major subunits of the Navajo are the Lamb Point Tongue (Kanab area) and the Shurtz Sandstone Tongue (Cedar City area). [8] The Navajo Sandstone was originally named as the uppermost formation of the La Plata Group by Gregory and Stone in 1917. [7] Baker reassigned it as the upper formation of Glen Canyon Group in 1936. [9]
Vaqueros Formation sandstone with concretions. The type locality of the Vaqueros is from Vaqueros Canyon in the Santa Lucia Mountains, about eight miles southwest of Greenfield. The formation was first described by Homer Hamlin in 1904, as part of a report on the water resources of the Salinas Valley. [4]
Sandstone modal compositions and detrital zircon U‐Pb analyses of the Wilcox Group indicate long‐distance sediment transport from primarily volcanic and basement sources to the west, northwest, and southwest. The Wilcox Group represents the earliest series of major post‐Cretaceous pulses of sand deposition along the western margin of the ...
The sandstone consists of more than 95 percent quartz sand. About 20 percent of the original sandstone, mostly feldspar grains, has been replaced by the calcite. Pyrite, which is now oxidized to goethite, occurs within the calcite cement of these concretions as microscopic crystals and very small, knobby concretions. The pyrite concretions ...
The Ozan marl is around 500 ft thick, and marine megafossils can be found. On top of the Ozan marl is two thin beds known as the Wolfe City Sandstone and Pecan Gap Chalk. The Wolfe City Sandstone is known in the city of Rockwall, Texas for its sandstone dikes that protrude into the surface, and gives a surface expression of a wall built of ...
Bäch Sandstone: by the Lake Zürich; Bern Sandstone: quarry sites near Bern in Ostermundigen, Krauchthal and by the Gurten; Bollingen Sandstone (also Buchberg Sandstone, Uznaberg Sandstone, Bollinger-Lehholz Sandstone and Güntliweid Sandstone): Rapperswil-Jona by the Upper Lake Zürich; Grès à cailloux roulés: near Avenches; Grès de ...