Based on the size and shape of the clasts in the sedimentary rock shown in the image, which classification would geologists most likely apply to the rock?

Question

Question 4 options:

A)

Breccia

B)

Sandstone

C)

Conglomerate

D)

Mudrock

Answer 1

To accurately classify the sedimentary rock based on the size and shape of the clasts, you would generally consider the following:

• Breccia: Composed of large, angular clasts.
• Sandstone: Made primarily of sand-sized particles (0.063 to 2 mm) and has a granular texture.
• Conglomerate: Contains larger, rounded clasts.
• Mudrock: Generally has very small particles (clay and silt) and may include shale.

If the clasts are large and angular, the rock would likely be classified as A) Breccia. If the clasts are rounded and larger, then it would be classified as C) Conglomerate. If the rock is composed of sand-sized particles, then it would be B) Sandstone. If it is primarily small particles, then it would fit into D) Mudrock.

Without seeing the image, if the clasts are large and angular, go with A) Breccia. If they are rounded, choose C) Conglomerate.