Changes

===Porosity===

===Porosity===

Identification of porosity type and a qualitative estimate of porosity abundance should be made in the column labeled “Porosity.” For carbonate rocks, the porosity classification scheme discussed by Choquette and Pray<ref name=pt05r34>Choquette, P. W., Pray, L. C., 1970, [http://archives.datapages.com/data/bulletns/1968-70/data/pg/0054/0002/0200/0207.htm Geological nomenclature and classification of porosity in sedimentary carbonates]: AAPG Bulletin, v. 54, p. 207–250.</ref> is recommended. For siliciclastic rocks, four types of porosity are common:

Identification of porosity type and a qualitative estimate of porosity abundance should be made in the column labeled “Porosity.” For carbonate rocks, the porosity classification scheme discussed by Choquette and Pray<ref name=pt05r34>Choquette, P. W., and L. C. Pray, 1970, [http://archives.datapages.com/data/bulletns/1968-70/data/pg/0054/0002/0200/0207.htm Geological nomenclature and classification of porosity in sedimentary carbonates]: AAPG Bulletin, v. 54, p. 207–250.</ref> is recommended. For siliciclastic rocks, four types of porosity are common:

* Intergranular

* Intergranular

* Intragranular or moldic

* Intragranular or moldic

* Microporosity

* Microporosity

* [[Fracture]] (Pittman<ref name=Pittman>Pitman, E. D., 1979, Porosity, diagenesis, and productive capability of sandstone reservoirs, in Scholle, P. A., and P. R. Schluger, eds., Aspects of Diagenesis: Society Economic Paleontologists and Mineralogists Special Publication 26, p. 159-173</ref>)

* [[Fracture]] (Pittman<ref name=Pittman>Pitman, E. D., 1979, Porosity, diagenesis, and productive capability of sandstone reservoirs, in P. A. Scholle, and P. R. Schluger, eds., Aspects of Diagenesis: Society Economic Paleontologists and Mineralogists Special Publication 26, p. 159-173</ref>)

Of these, microporosity is the most difficult to recognize with a binocular microscope. The existence of microporosity is suggested by the presence of detrital or authigenic clays in sandstones. Accurate laboratory or thin section determinations of porosity types and percentages should always augment the estimates made during core logging. (For more on porosity classification schemes, see [[Porosity]].)

Of these, microporosity is the most difficult to recognize with a binocular microscope. The existence of microporosity is suggested by the presence of detrital or authigenic clays in sandstones. Accurate laboratory or thin section determinations of porosity types and percentages should always augment the estimates made during core logging. (For more on porosity classification schemes, see [[Porosity]].)