Calcarenite is a sedimentary rock formed of calcareous particles that have been deposited mechanically from a solution. The particles which consist of fossil materials, pebbles and granules of carbonate rock and Oolites are transported and sorted by flowing water. When it is formed entirely of shell debris the rock is called coquina. (Robert 1768)
1.1. Composition of calcarenite
Calcarenite is a type of limestone composed mainly of above 50% of detrital sand of size 0.0625 to 3mm in diameter in carbonate grains which are extremely small. The grains consist of sand-sized grains of either corals, shells, Ooids, intraclasts, pellets, fragments of older limestone and dolomites, other carbonate grains or some combination of these.
Calcarenite
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1.4.1. Nodular Calcrete
This normally consists of carbonate-cementated and replaced Calcrete have irregular shape but the other 3 dimensions will be approximately equal. (Lintern, M., Roach, I. and Chen, X. 2002)
1.4.2. Tubular Calcrete
This Calcrete forms tube shaped carbonate concretions from indurated to soft and powdery. The conglutination may be separate or connected by size and content of carbonated by size and content of carbonate. Some are hallowed but other is solid or filled with materials other than carbonates. This Calcrete can be classified (Klappa 1980) and the common type is carbonated Rhizoliths or tubules. (Lintern, Roach, and Chen, 2002)
1.4.3. Laminar Calcrete
This develops as indurate sheets of carbonate overlying hardpan Calcrete or other hand surfaces. (Wright and Tucker, 1991). The laminae can be as thinner than 1mm and the total thickness of this Calcrete is normally even lesser than 250mm. this may occur as a thick layer without any underlying hard surface. (Lintern, M., Roach, I. and Chen, X. 2002)
1.4.4. Honeycomb Calcrete
This has a fabric of partly coalesced hard nodules with interstitial are of less-indurated calcareous material (Wright and Tucker 1991). The nodules seem to coalesce by development of overlaps. (Lintern, M., Roach, I. and Chen, X.
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If the calcium carbonate content of Calcrete is over 80%, Calcrete can be used to stabilize the soil while it is acting as lime. (Geocaching.com, 2016).
2. Geological history and stratigraphy
Calcarenite was introduced as calcarenite by Grabau in 1904 in his genetic classification of sedimentary rocks to show the two basic calcareous compositions, eremite grain size and clastic nature of the rock. (Orme, undated)
Calcarenite may quality the terms that show the dominate components just as colitic calcarenite; avoid calcarenite, and brachiopod calcarenite. In the serious watter, the term should not be applied to accumulation of reef rock and also con quinoid limestone (Orme, undated)
High wisconsinan costal dunes of Zululand and also Mozambique attain heights of close zome. The sands rest on a core of calcarenite and postdate development of sanngaman terrace. (Orme, 1973).
The most of the shapes of estuaries and lagoons along the coast wave established by river erosion and dune development during the wisconsinan lowering of sea level( Birch et al 1978). Langebaan lagoon is silicclastic- carbonate tidal mixed environment in a hot and on less water climate, Zululand lagoons have experience 60% reduction in the surface area, along shallowing as a result of Holocene sedimentation. (Orme,