Changes

Sandstone is most significant type of petroleum reservoir rock in over 60% of the world’s giant fields; composed of mainly [[quartz]] and/or feldspars and typically deposited by relatively high- energy processes, which winnow out much of the fine particle size fraction while transporting and depositing the coarser (sand-sized) particles. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, grey, pink, white and black. However, since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions depending on the for example red sandstone Red sandstone found in interior of Lower Antelope Canyon, Arizona.

Sandstone is most significant type of petroleum reservoir rock in over 60% of the world’s giant fields; composed of mainly [[quartz]] and/or feldspars and typically deposited by relatively high- energy processes, which winnow out much of the fine particle size fraction while transporting and depositing the coarser (sand-sized) particles. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, grey, pink, white and black. However, since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions depending on the for example red sandstone Red sandstone found in interior of Lower Antelope Canyon, Arizona.

[[File:Sandstone-Fig-1.png|thumb|300px|Figure 1: Red sandstone in interior of Lower Antelope Canyon, Arizona. (Modified from Pettijohn et al.<ref name=Pettijohn>Pettijohn F. J., P.E. Potter and R. Siever. (1987). Sand and sandstone. (2nd edition), Springer-Verlag. ISBN 0-387-96350-2.</ref>).]]

[[File:Sandstone-Fig-1.png|thumb|300px|{{Figure number|1}}Red sandstone in interior of Lower Antelope Canyon, Arizona. (Modified from Pettijohn et al.<ref name=Pettijohn>Pettijohn F. J., P.E. Potter and R. Siever. (1987). Sand and sandstone. (2nd edition), Springer-Verlag. ISBN 0-387-96350-2.</ref>).]]

==Composition of sandstone==

==Composition of sandstone==

[[File:Sandstone-Fig-2.png|thumb|300px|{{Figure number|2}}A microscopic photograph of a Nubia sandstone under the polarizing microscope. It is composed of entirely of monocrystalline, subrounded, medium grained detrital quartz grains (Q) cemented with clays and iron oxides. Although they can also be cemented by zircon crystals (Z). (Modified from Folk<ref>Folk, R.L. (1965). Petrology of sedimentary rocks PDF version. Austin: Hemphill’s Bookstore. 2nd edition. ISBN 0-914696-14-9.</ref>).]]

 

[[File:Sandstone-Fig-2.png|thumb|300px|Figure 2: A microscopic photograph of a Nubia sandstone under the polarizing microscope. It is composed of entirely of monocrystalline, subrounded, medium grained detrital quartz grains (Q) cemented with clays and iron oxides. Although they can also be cemented by zircon crystals (Z). (Modified from Folk<ref>Folk, R.L. (1965). Petrology of sedimentary rocks PDF version. Austin: Hemphill’s Bookstore. 2nd edition. ISBN 0-914696-14-9.</ref>).]]

* '''Rock grains.''' The grains that make up the bulk of sandstones can be classified into several different categories based on their mineral composition:

* '''Rock grains.''' The grains that make up the bulk of sandstones can be classified into several different categories based on their mineral composition: