Understanding Porosity: Well-Sorted Gravel vs Silty Sandstone

Which material is likely to have greater porosity: well-sorted gravel or silty sandstone?

a. Well-sorted gravel

b. Silty sandstone

Answer:

b. Silty sandstone

Porosity refers to the percentage of void space in a material, indicating its ability to hold fluids. Well-sorted gravel typically has larger and more uniform grain sizes, resulting in lower porosity compared to a silty sandstone that contains a mixture of sand and silt-sized grains.

The presence of fine-grained particles, such as silt-sized grains in a sandstone, can contribute to higher porosity due to their smaller size and ability to fill the void spaces between larger grains. Therefore, a silty sandstone is more likely to exhibit greater porosity compared to a well-sorted gravel.