Arkosic sandstone is a term primarily used to describe sandstone that contains a significant proportion of feldspar minerals, particularly potassium feldspar. The presence of these feldspar minerals gives arkosic sandstone its distinctive color and composition. See also Arkose.
Arkosic sandstone is commonly composed of grains of sand-sized particles, primarily quartz, and feldspar. The term “arkosic” originates from the Greek word “arkos,” which means “pertaining to feldspar.” This highlights the significance of feldspar content in this type of sandstone.
Due to its mineral composition, arkosic sandstone typically exhibits a range of colors, often including shades of pink, reddish-brown, and yellow. These colors stem from the iron oxide pigments associated with feldspar and other minerals.
Arkosic sandstone is commonly found in sedimentary environments where the weathering and erosion of granitic or other feldspar-rich rocks have occurred. The feldspar-rich parent rocks break down into smaller fragments through processes like physical weathering, leading to the creation of sand-sized grains that accumulate and eventually become arkosic sandstone. This type of sandstone can be an important indicator of the geologic history of an area. It suggests the presence of source rocks with significant feldspar content and can help geologists infer past environmental conditions. Arkosic sandstone may also serve as a reservoir rock for groundwater or oil and gas due to its porosity and permeability characteristics.