Question

Select all of the answers that apply.

Examine the following rock strata. Using the laws of biostratigraphy, which of the following statements are true about
the relative ages of the rock layers and intrusion?
E
D
с
B
Intrusion A is older than all of the rock layers.
Layer Bis older than intrusion A
Layers C, D, and E are older than intrusion A.
Intrusion A is older than layers C, D, and E.
Without additional information, you cannot tell the relative ages of Intrusion A and rock layers C, D, and E.
Layer B is older than layers C, D, and E.

Answer 1

Answers: Layer B is older than intrusion A , intrusion A is older than layers C, D, and E, and layer B is older than layers C, D, and E.

Answer 2

Layer B is older than intrusion A

Intrusion A is older than layers C, D, and E.

Layer B is older than layers C, D, and E.

Step-by-step explanation:

The laws of biostratigraphy can be applied to this lithological section in order to ascertain the relative ages of the beds.

Some of these laws that are applicable to this problem are:

• Principle of superposition of strata : the oldest layer is always at the bottom of sequence while the youngest is on top in an undisturbed rock sequence.
• Law of cross-cutting: when faults and fractures cuts through a rock sequence, they are younger than the rock they cross through.
• Law of intrusions: Intrusions are younger than the rock layers they cut through

The geologic history of the beds here can be interpreted as thus:

• Lithology B was first deposited
• Then an intrusion A occurred and terminated at B
• Layers C, D and E were then deposited.

The oldest layer here is B followed by the intrusion A and successful deposition of C, D and E in that order.