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Concretions form within layers of sedimentary strata that have already been deposited. They usually form early in the burial history of the sediment, before the rest of the sediment is hardened into rock. This concretionary cement often makes the concretion harder and more resistant to weathering than the host stratum.
Beachrock is a type of carbonate beach sand that has been cemented together by a process called synsedimentary cementation. Beachrock may contain meniscus cements or pendant cements. As the water between the narrow spaces of grains drains from the beachrock, a small portion of it is held back by capillary forces, where meniscus cement will form ...
This figure describes the geological aspects and processes of the carbonate silicate cycle, within the long-term carbon cycle. The carbonate–silicate geochemical cycle, also known as the inorganic carbon cycle, describes the long-term transformation of silicate rocks to carbonate rocks by weathering and sedimentation, and the transformation of carbonate rocks back into silicate rocks by ...
Carbonatation is a slow process that occurs in concrete where lime (CaO, or Ca(OH) 2 ) in the cement reacts with carbon dioxide (CO 2) from the air and forms calcium carbonate. The water in the pores of Portland cement concrete is normally alkaline with a pH in the range of 12.5 to 13.5.
In reinforced concrete, the chemical reaction between carbon dioxide In the air and calcium hydroxide and hydrated calcium silicate in the concrete is known as neutralisation. The similar reaction in which calcium hydroxide from cement reacts with carbon dioxide and forms insoluble calcium carbonate is carbonatation.
Silicified carbonates can appear as silicified carbonate rock layers, [3] or in the form of silicified karsts. The Paleogene Madrid Basin in Central Spain is a foreland basin resulted from the Alpine uplift, an example of silicified carbonates in rock layers. The lithology consists of carbonate and detritus units that were formed in a ...
The clasts and matrix are typically cemented by calcium carbonate, iron oxide, silica, or hardened clay. Conglomerates form when rounded gravels deposited by water or glaciers become solidified and cemented by pressure over time. They can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of ...
Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone , which is composed of calcite or aragonite (different crystal forms of CaCO 3 ), and dolomite rock (also known as dolostone), which is composed of dolomite (CaMg(CO 3 ) 2 ).