GEOLOGY

Previous
Next

EARTH SCIENCE

FOSSILS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Some students made a model to show one of the first steps in the formation of sedimentary rock. The students pour 2 cm of light-colored sand into a clear plastic box. Then they add 1 cm of gravel. Finally, they pour 2 cm of dark-colored sand on top of the gravel. Which characteristic of sedimentary rock does this model best show?
A
Sedimentary rock is made of layers.
B
Sedimentary rock is cemented bits of rock.
C
Sedimentary rock is often limestone.
D
Sedimentary rock is common in Texas.
Explanation: 

Detailed explanation-1: -Pieces of rock are loosened by weathering, then transported to some basin or depression where sediment is trapped. If the sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock. Clastic sedimentary rocks may have particles ranging in size from microscopic clay to huge boulders.

Detailed explanation-2: -Sedimentary rocks are the product of 1) weathering of preexisting rocks, 2) transport of the weathering products, 3) deposition of the material, followed by 4) compaction, and 5) cementation of the sediment to form a rock. The latter two steps are called lithification.

Detailed explanation-3: -Sedimentary rocks and fossil fuels are related because fossil fuels are trapped in some sedimentary rocks. Fossil fuels form when organic matter and sediment accumulate on top over time. With heat and pressure, the organic matter goes through a chemical change converting them into coal, petroleum, or natural gas.

There is 1 question to complete.
Previous
Next