Final answer:
Clastic sedimentary rocks are formed through the accumulation and cementation of weathered rock fragments or clasts. The three types of sandstone are quartz arenite, arkose, and graywacke.
Step-by-step explanation:
Clastic sedimentary rocks are formed through the accumulation and cementation of weathered rock fragments or clasts. The three types of sandstone are described as follows:
- Quartz Arenite: This type of sandstone is composed almost entirely of quartz grains. It is well-sorted, meaning that the grains are similar in size, and typically forms in environments with high energy, such as beaches and dunes.
- Arkose: Arkose is a sandstone that contains a significant amount of feldspar grains. It is often poorly-sorted and can indicate that the sediment was deposited close to the source rock and not transported far.
- Graywacke: Graywacke is a sandstone with a mix of quartz, feldspar, and rock fragments. It is typically poorly-sorted and often forms in environments with high energy, such as turbidity currents in the ocean.