2.1.3 Sedimentary Rocks (OCR A-Level Geology)

Which is the smallest grain size

• Clay

• Silt

• Sand

• Pebble

Name the sedimentary rock photographed

• Limestone

• Breccia

• Coal

• Conglomerate

Sedimentary rocks are formed by...

• Cooling of lava or magma

• Heat and pressure

• Compaction and cementation

• Extrusive volcanic events

The process of grains "sticking together" to form a sedimentary rock is termed

• Plastering

• Pressuring

• Cementation

• Deposition

Using the Hjulstrom Curve a pebble at 5cms^-1 would be...

• Desposited

• Transported

• Eroded

• Cemented

Which description matches the term traction

• Wearing down of grains due to collisions with other grains

• Erosion and transportation of sediment

• Wearing down of grains due to collisions with bed / surface

• Transport by sliding and / or rolling

Describe the texture of breccia

• Vesicular

• Siliclastic

• Crystalline

• Bioclastic

The grain size analysis shows a sediment which is...

• Poorly sorted

• Moderately Sorted

• Very Poorly Sorted

• Well Sorted

Which sample has the lowest porosity?

• A

• B

• C

• A and B

Which agent of erosion is unlikely to result in attrition

• Water

• Ice

• Wind

• Gravity