Carbonate grains detrital

The sand grains that make up aeolian dunes can include detrital biogenic carbonate grains (e.g. Ward, 1973, 1975), ooids (e.g. Budd, 1988) and... 

Cementation occurred chiefly by diffusive supply of Ca " and HCOj" derived from detrital carbonate grains uniformly distributed in sandstone beds and, in formations with mudrock interbeds, from detrital and biogenic carbonate in mudrocks. Local factors, many of which remain unidentified, influenced the cementation process and resulted in substantial heterogeneity in the distribution and form of calcite cement (Fig. 2). 

Detrital carbonate grains, including limestone, bioclasts and rare dolomite, are important components of the sandstones, except for the Loiano, Macigno and M. Modino formations. These strata contain less than 5% detrital carbonate, whereas the other formations contain from 8 to 30% detrital carbonate. 

The carbonate content of mudrock interbeds averaged by formation ranges from 17 to 59% (the latter are more properly clayey limestones) (Table 3), about 3-10 times the amount of carbonate in sandstones. There is no correlation between the amount of carbonate in sandstones and associated mudrocks, but formations whose sandstones have abundant detrital carbonate grains generally have... 

Fontana, D. (1991) Detrital carbonate grains as provenance indicators in the Upper Cretaceous Pietraforte Formation (northern Apennines). Sedimentology, 38, 1085-1095. 

Fig. 4. Photomicrographs of carbonate cements in sandstones of the San Joaquin basin. (A) Siderite rhombs (arrows) in pore space (dark areas). Well NCL 88-29, 2746.5 m (9010.8 ft). White bar is 0.25 mm. (B) Dolomite pore-filling sandstone from the central basin. Note high cement volume and undeformed detrital biotite (dark grains). Detrital grains are chiefly quartz and feldspar. Well NCL 88-29, 2717 m (8913 ft). White bar is 0.5 mm. (C) Calcite pore-filling cement from central basin. Note relatively high cement volume and partially crushed biotite. Well NCL 487-29,...

Very simply, a sandstone has a grain composition of stone detritus (quartz, feldspar, detritic mica/clays) and a binder that may be clayey, quartzitic, or carbonatic (or mixtures thereof) [51, 55]. The mineral composition of limestone is mostly calcium carbonate, often derived fi om precipitated calcium carbonate and fossil shell remnants fi-om marine organisms and a calcitic binder matrix [51, 56, 57]. 

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