Classification of Carbonate Rocks According to Depositional Textures

Three textural features seem especially useful in classifying those carbonate rocks that retain their depositional texture (1) Presence or absence of carbonate mud, which differentiates muddy carbonate from grainstone; (2) abundance of grains, which allows muddy carbonates to be subdivided into mudstone, wackestone, and packstone; and (3) presence of signs of binding during deposition, which characterizes boundstone. The distinction between grain-support and mud-support differentiates packstone from wackestone—packstone is full of its particular mixture of grains, wackestone is not. Rocks retaining too little of their depositional texture to be classified are set aside as crystalline carbonates.