ABSTRACT

The proposed classification of carbonate cement precipitated in quartzose sandstones is based upon two major characteristics: (1) crystallization of carbonate in available intergranular pores without modification in the arrangement of the detrital grain framework, or in the shape of such grains; (2) crystallization of cement involving expansion of the intergranular space and consequent rearrangement in the packing of detrital grains; or, crystallization of cement involving replacement and mineral substitution of detrital grains.

The simple cement fills pores only and serves as a lithifying agent to preserve the fabric of the uncemented sediment. Cementation which is accompanied by volume expansion modifies grain-supported fabrics, can cause rupture of porous grains such as glauconite, can crystallize as concretions around grains, or as large, single poikilitic crystals, can replace grains of silicate minerals, or modify an original framework of carbonate grains by recrystallization.