How do exposed layers of sedimentary rock in the Grand Canyon reveal clues about the geologic time scale?
A)The chemical composition of each layer indicates the conditions on Earth when the layer was deposited.
B)Fossils of soft-bodied animals are prevalent in sedimentary rock.
C)Radiometric dating using 14C of fossils in each layer can accurately predict their age up one million years ago.
D)The chemical composition of each layer can be determined by radiometric dating.
E)The oldest fossils are found near the surface, while the most recent fossils are found at deeper layers.

Question

How do exposed layers of sedimentary rock in the Grand Canyon reveal clues about the geologic time scale?  
A)The chemical composition of each layer indicates the conditions on Earth when the layer was deposited.
B)Fossils of soft-bodied animals are prevalent in sedimentary rock.
C)Radiometric dating using 14C of fossils in each layer can accurately predict their age up one million years ago.
D)The chemical composition of each layer can be determined by radiometric dating.
E)The oldest fossils are found near the surface, while the most recent fossils are found at deeper layers.

Quizplus · Accepted Answer

The chemical composition of each layer in exposed sedimentary rock can reveal clues about the conditions on Earth when the layer was deposited. For example, layers containing high amounts of iron oxide suggest that the atmosphere was rich in oxygen when they were formed. In addition, the presence of certain minerals can indicate the type of environment in which the layer was deposited, such as a shallow sea or a river delta. These clues can provide insight into the geologic time scale, as different periods in Earth's history were characterized by distinct environmental conditions.

How Do Exposed Layers of Sedimentary Rock in the Grand