Question

the image shows cross - cutting relationships. b, w, e, and k represent rock layers, and q represents a fault. which statement describes the geologic features?
○ layer k is the oldest.
○ layer w is the youngest.
○ fault q occurred before layer k was deposited.
○ layers b, w, and e were deposited after fault q occurred.

Explanation:

To determine the correct statement, we analyze the cross - cutting relationships and the principle of superposition (older layers are generally below younger layers, and a fault that cuts through layers must be younger than the layers it cuts).

1. Analyze "Layer K is the oldest": Layer B is below W, E, and K. So B is older than W, E, K. So this statement is wrong.
2. Analyze "Layer W is the youngest": Layer K is on top of W, E. So K is younger than W? No, K is on top, so K is younger than W? Wait, no, the principle of superposition: in undisturbed sedimentary layers, the oldest layers are at the bottom. But here, fault Q cuts through B, and then W, E, K are deposited. Wait, K is the topmost layer, so K is the youngest among B, W, E, K? Wait, no, let's re - examine. The fault Q cuts through layer B. Then, above the fault, we have W, E, K. Wait, no, looking at the diagram, layer B is the bottom - most (the brick - like layer), then W (yellow), E (blue with ovals), K (green). But the fault Q cuts through B, and also cuts through the lower W and E? Wait, no, the left side: B, then W, then E, then K. The right side: B, then W, then (the blue layer, maybe E? Wait, the diagram: left side has B (brick), W (yellow), E (blue with ovals), K (green). Right side has B (brick), W (yellow), a blue layer (maybe E), and K (green). The fault Q cuts through B, and the lower W and E on the left? Wait, no, the fault is a diagonal line. So the layers B, W, E, K: the order from bottom to top (oldest to youngest in undisturbed case) would be B, W, E, K. But the fault Q cuts through B, and also cuts through the W and E on the left? Wait, no, the fault is a break. So the fault Q must have occurred after B was deposited, because it cuts B. Then, W, E, K were deposited? Wait, no, on the left side, below E is W, below W is B. On the right side, below the blue layer (E) is W, below W is B. The fault cuts through B, and the W and E on the left? Wait, maybe the correct way: the principle of cross - cutting relationships: a fault that cuts through rock layers is younger than the layers it cuts. Also, the principle of superposition: in horizontal layers, the oldest is at the bottom.

Now let's check each option:

• Option 1: "Layer K is the oldest." No, because K is the topmost layer. In undisturbed sedimentary layers, the top layer is the youngest. So K is the youngest among B, W, E, K? Wait, no, maybe the layers were deposited as B, then W, then E, then K. So B is oldest, then W, then E, then K. So K is the youngest, not the oldest. So this option is wrong.
• Option 2: "Layer W is the youngest." No, because K is on top of W, so K is younger than W. So this option is wrong.
• Option 3: "Fault Q occurred before layer K was deposited." Let's see: Fault Q cuts through B, W, and E (because the fault line goes through B, the lower W, and the lower E on the left). Then layer K is deposited on top, covering the fault. So the fault Q occurred before K was deposited. This makes sense. Let's check the other option to be sure.
• Option 4: "Layers B, W, and E were deposited after fault Q occurred." But the fault Q cuts through B, W, and E, which means that B, W, and E must have been deposited before the fault Q occurred (because a fault can't cut through layers that haven't been deposited yet). So this option is wrong.

Answer:

Layers B, W, and E were deposited after fault Q occurred. (Wait, no, earlier analysis for option 3: Fault Q occurred before layer K was deposited. Wait, let's re - do the analysis.

Wait, the fault Q cuts through layers B, W, and E (because the fault line intersects B, W, and E). Then layer K is on top, not cut by the fault. So the sequence of events:

1. Deposition of B, W, E (in order: B first, then W, then E, as per superposition - oldest at bottom).
2. Fault Q occurs, cutting through B, W, E.
3. Deposition of K, which is not cut by the fault, so K is younger than the fault Q.

So:

• "Layer K is the oldest": Wrong, K is the youngest among B, W, E, K.
• "Layer W is the youngest": Wrong, K is younger than W.
• "Fault Q occurred before layer K was deposited": Correct, because K is deposited after the fault (since the fault doesn't cut K).
• "Layers B, W, and E were deposited after fault Q occurred": Wrong, because the fault cuts them, so they must be deposited before the fault.

So the correct answer is "Fault Q occurred before layer K was deposited."