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Vaqueros Formation sandstone with concretions A mosaic of images showing spherules, some partly embedded, spread over (smaller) soil grains on the Martian surface. Concretions are found in a variety of rocks, but are particularly common in shales, siltstones, and sandstones. [30]
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 surface of these spherical concretions can range from being very rough to quite smooth. Some of the concretions are grooved spheres with ridges around their circumference. [5] [6] The abundant concretions found in the Navajo Sandstone consist of sandstone cemented together by hematite (Fe 2 O 3), and goethite (FeOOH).
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]
This concretion was too high in the wall to place a ruler, but I estimate it to be about 400 mm long. Please take a look at additional two images, which help you to see the settings of the image better: The first image shows the beach wall with two concretions and the second image is the wide angle image of the wall This same wall has lots of ...
Part of the hammer is embedded in a limey rock concretion, leading to it being regarded by some as an anomalous artifact. The tool is identical to late 19th-century mining hammers, and the most likely explanation for its encasement in rock is that a deposit of highly soluble travertine formed and hardened around it within a relatively short time.
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 About 20 percent of the original sandstone, mostly feldspar grains, has been replaced by the calcite.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 ...
Laingsburg Formation: Composed of four, massive sandstone units that are interbedded with planar-laminated shale and siltstones. Calcareous concretions and clay pebble clasts are often found in the massive sandstones. Coalified plant fragments are frequently found in the shale and siltstone layers. It grades laterally into the upper Ripon ...