Question

practice: applying geologic principles
for each diagram, order the rock layers from oldest to youngest and identify the geologic principle(s) that you are using.
hint: a is an unconformity due to erosion, and d is the fault line
hint: m is the fault line

Explanation:

Step1: Understand superposition principle

In undisturbed rock - layer sequences, the oldest layers are at the bottom and the youngest at the top.

Step2: Analyze first diagram

Layer C is at the bottom, so it's the oldest. Then E, D, and B is on top. Intrusion A cuts through layers C, E, D, so A is younger than those layers but older than B as B is undisturbed by A. Order: C, E, D, A, B. Principle: Superposition and cross - cutting relationships.

Step3: Analyze second diagram

Layer I is at the bottom, so it's the oldest. Then B, F. Fault M cuts through I, B, F. Magma intrusion H cuts through M and other layers. Then M is older than H. Layer R is on top undisturbed. Order: I, B, F, M, H, R. Principle: Superposition, cross - cutting relationships.

Step4: Analyze third diagram

Layer E is at the bottom (oldest). Then G, B. Fault D cuts through E, G, B. Intrusion C cuts through D and other layers. Layer A is on top. Order: E, G, B, D, C, A. Principle: Superposition, cross - cutting relationships.

Step5: Analyze fourth diagram

Layer A is the oldest as it's at the bottom. Then B, C. Fault M cuts through A, B, C. Layer D is above C and cut by M. Then E, F, G are above D. Layer H is on top. Order: A, B, C, M, D, E, F, G, H. Principle: Superposition, cross - cutting relationships.

Answer:

First diagram: C, E, D, A, B
Second diagram: I, B, F, M, H, R
Third diagram: E, G, B, D, C, A
Fourth diagram: A, B, C, M, D, E, F, G, H