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===Glacial sandstones===

===Glacial sandstones===

Glacial sandstones are poorly sorted matrix-bouldery sand deposits consisting of sands, lenses left by melt water streams with reservoir potential and other glacial deposits left by retreating glaciers as moraine deposits. Examples of these glacial sandstones include tillites, with little value as a reservoir due to low porosity. Glacial sandstones may also be deposited in marine areas, giving rise to muddy sediments with dispersed boulders. These may however be locally reworked by wave action in shallow area resulting into potential reservoir sand bed for example Ordovician oil- bearing glacial sands found in Algeria and Permo-carboniferous hydrocarbon glacial sands in southern Oman.

Glacial sandstones are poorly sorted matrix-bouldery sand deposits consisting of sands, lenses left by melt water streams with reservoir potential and other glacial deposits left by retreating glaciers as moraine deposits. Examples of these glacial sandstones include tillites, with little value as a reservoir due to low porosity. Glacial sandstones may also be deposited in marine areas, giving rise to muddy sediments with dispersed boulders. These may however be locally reworked by wave action in shallow area resulting into potential reservoir sand bed for example Ordovician oil- bearing glacial sands found in Algeria and Permo-[[carboniferous]] hydrocarbon glacial sands in southern Oman.

[[File:Sandstone-Fig-8.png|thumb|300px|Figure 8: glacial Devonian Sandstone at Suur Taevaskoda, Põlva County, Estonia (Source: [http://www.Clastic Depositional Environments.htm]).]]

[[File:Sandstone-Fig-8.png|thumb|300px|Figure 8: glacial Devonian Sandstone at Suur Taevaskoda, Põlva County, Estonia (Source: [http://www.Clastic Depositional Environments.htm]).]]