Arkose facts for kids
Arkose is a special kind of sandstone. What makes it unique is that it has a lot of a mineral called feldspar. It is mostly made of quartz, but at least a quarter (25%) of it must be feldspar. Arkose can also contain small pieces of other rocks.
This rock often has a little bit of calcite acting like a natural glue, holding the sand grains together. Sometimes, it also contains iron oxide, which can give arkose a reddish color. Arkose is usually gray to reddish. The sand grains that make up arkose are typically `coarse`, meaning they are larger and rougher than fine sand.
How Arkose Forms
Arkose usually forms when igneous or metamorphic rocks break down. These are often granite rocks, which naturally have a lot of feldspar and quartz. When granite weathers, it breaks into smaller pieces. These pieces then get carried away and settle to form arkose.
You often find arkose near conglomerate deposits. These are areas where the sediment is made of granite pieces. A famous example of arkose is Uluru (also known as Ayers Rock) in central Australia. This huge rock is made of arkose that formed a very long time ago, from the erosion of an ancient granite mountain range.
Images for kids
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Arkosic sand in the Llano Uplift, Texas, with granite outcrops
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Grus sand and the granitoid it’s derived from
See also
In Spanish: Arcosa para niños
