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Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.. Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.
Sodium and magnesium salts are the most effective at producing salt weathering. Salt weathering can also take place when pyrite in sedimentary rock is chemically weathered to iron(II) sulfate and gypsum, which then crystallize as salt lenses. [9] Salt crystallization can take place wherever salts are concentrated by evaporation.
Deposition is the geological process in which sediments, soil and rocks are added to a landform or landmass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment.
A clast is a fragment of geological detritus, [1] chunks, and smaller grains of rock broken off other rocks by physical weathering. [2] Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport, whether in suspension or as bed load, and in sediment deposits.
[2] [3] [4] The dike rock is usually more resistant to weathering than the surrounding rock, so that erosion exposes the dike as a natural wall or ridge. [3] It is from these natural walls that dikes get their name. [5] Dikes preserve a record of the fissures through which most mafic magma (fluid magma low in silica) reaches the surface. [4]
Spheroidal or woolsack weathering in granite on Haytor, Dartmoor, England Spheroidal weathering in granite, Estaca de Bares, A Coruña, Galicia, Spain Woolsack weathering in sandstone at the Externsteine rocks, Teutoburg Forest, Germany Corestones near Musina, South Africa that were created by spherodial weathering and exposed by the removal of surrounding saprolite by erosion.
Horizontal joints in the sedimentary rocks of the foreground and a more varied set of joints in the granitic rocks in the background. Image from the Kazakh Uplands in Balkhash District, Kazakhstan. Orthogonal joint sets on a bedding plane in flagstones, Caithness, Scotland Joints in the Almo Pluton, City of Rocks National Reserve, Idaho.
These rocks are fine-grained and sometimes cool so rapidly that no crystals can form and result in a natural glass, such as obsidian, however the most common fine-grained rock would be known as basalt. Any of the three main types of rocks (igneous, sedimentary, and metamorphic rocks) can melt into magma and cool into igneous rocks. [2]