Page 70 - Atlas of Sedimentary Rocks Under The Microscope

Carbonate rocks

Limestone Porosity

Any description of a limestone should include an evaluation of the
amount and type of porosity in the sediment. Porosity may be primary,
having been present in the rock since deposi tion. or secondary, having
developed as a result of diagenesis. A classification of porosity types is
shown in Fig. F. The terminology of porosity types illustrated here
with limestones, is also applicable to sandstones.

Fabric selective

Interparticle lntraparticle lntercrystal Mouldic Fenestral Shelter Growth framework

Not fabric selective

Fracture Channel* Vug• Cavern*

• Cavern applies to man-sized or larger pores of channel or vug shapes

Fabric selective or not

Breccia Boring Burrow Shrinkage

Fig. F Basic porosiry rypes in sediments. Pores shaded hlack (af ter Choquelte and Pray, 1970)

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