Changes

[[file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig1.png|thumb|left|{{figure number|1}}Dunham's<ref name=pt06r29>Dunham, R. J., 1962, [http://archives.datapages.com/data/specpubs/carbona2/data/a038/a038/0001/0100/0108.htm Classification of carbonate rocks according to depositional texture], in, Classifications of Carbonate Rocks—A Symposium: AAPG Memoir 1, p. 108–121.</ref> classification of carbonate rocks according to depositional texture.<ref name=pt06r138>Swanson, R. G., 1981, Sample examination manual: [http://store.aapg.org/detail.aspx?id=603 AAPG Methods in Exploration 1], 65 p.</ref>]]

[[file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig1.png|thumb|left|{{figure number|1}}Dunham's<ref name=pt06r29>Dunham, R. J., 1962, [http://archives.datapages.com/data/specpubs/carbona2/data/a038/a038/0001/0100/0108.htm Classification of carbonate rocks according to depositional texture], in, Classifications of Carbonate Rocks—A Symposium: AAPG Memoir 1, p. 108–121.</ref> classification of carbonate rocks according to depositional texture.<ref name=pt06r138>Swanson, R. G., 1981, Sample examination manual: [http://store.aapg.org/detail.aspx?id=603 AAPG Methods in Exploration 1], 65 p.</ref>]]

The majority of carbonate sediments are produced in shallow, warm ocean waters by extraction of calcium carbonate from seawater by organisms to form their shells or skeletal material. The sediments are composed of a spectrum of sizes and pore geometries. The [[Carbonate classifications|Dunham classification]] ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig1.png|Figure 1]]) describes depositional textures in a manner that can be related to pore geometries. The grain-supported textures tend to have larger pore sizes than do mud-supported textures. The textures have different geometries in different depositional environments.

The majority of carbonate sediments are produced in shallow, warm ocean waters by extraction of [[Carbonate|calcium carbonate]] from seawater by organisms to form their shells or skeletal material. The sediments are composed of a spectrum of sizes and [[pore geometries]]. The [[Carbonate classifications|Dunham classification]] ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig1.png|Figure 1]]) describes depositional textures in a manner that can be related to [[Pore system shapes|pore geometries]]. The [[Grain-supported carbonates|grain-supported]] textures tend to have larger pore sizes than do [[Mud-supported carbonates|mud-supported]] textures. The textures have different geometries in different depositional environments.

[[file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|thumb|{{figure number|2}}Carbonate depositional environments. (Diagram by R. G. Loucks and C. R. Handford, unpublished.)]]

[[file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|thumb|{{figure number|2}}Carbonate depositional environments. (Diagram by R. G. Loucks and C. R. Handford, unpublished.)]]

There are five basic carbonate depositional environments. From shore to basin, they are ''peritidal'' (tidal flat), ''shallow shelf interior, shelf margin complex, slope'', and ''basin'' ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]).

There are five basic carbonate depositional environments. From shore to basin, they are ''[[peritidal]]'' (tidal flat), ''[[shallow shelf interior]], [[shelf margin complex]], [[slope]]'', and ''[[basin]]'' ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]).

The peritidal depositional environment is complex ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]). Sediments deposited between mean high and mean low tide are called ''intertidal sediments'', sediments deposited above mean high tide are called ''supratidal sediments'', and sediments deposited below mean low tide are called ''subtidal sediments''. In arid and semi-arid climates, evaporite flats (sabkhas) are present from which [[gypsum]] and [[halite]] are deposited. [[Sand dunes|Eolian sand dunes]] composed of siliciclastic or carbonate grains may form on the supratidal surface.

The peritidal depositional environment is complex ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]). Sediments deposited between mean high and mean low tide are called ''[[intertidal sediments]]'', sediments deposited above mean high tide are called ''[[supratidal sediments]]'', and sediments deposited below mean low tide are called ''[[subtidal sediments]]''. In arid and semi-arid climates, evaporite flats ([[sabkhas]]) are present from which [[gypsum]] and [[halite]] are deposited. [[Sand dunes|Eolian sand dunes]] composed of siliciclastic or carbonate grains may form on the supratidal surface.

The shallow shelf interior environment ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]) is dominated by low-energy waters that allow lime mud to accumulate. [[Storm deposits and currents|Storms]], however, churn the sediment into suspension, winnowing out the fine-sized material and concentrating the coarse material. Near shorelines, the shelf environment may be composed of offshore [[bars]] and [[spits]] oriented parallel to shoreline. Shorelines that face heavy wave action accumulate carbonate sand or gravel. Tidal currents are concentrated in channels between islands and produce [[tidal deltas]] on the lee side of the island.

The shallow shelf interior environment ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]) is dominated by low-energy waters that allow lime mud to accumulate. [[Storm deposits and currents|Storms]], however, churn the sediment into suspension, winnowing out the fine-sized material and concentrating the coarse material. Near shorelines, the shelf environment may be composed of offshore [[bars]] and [[spits]] oriented parallel to shoreline. Shorelines that face heavy wave action accumulate carbonate sand or gravel. Tidal currents are concentrated in channels between islands and produce [[tidal deltas]] on the lee side of the island.