1. The correct sequence is Outcrop 3, Outcrop 1, Outcrop 2, Outcrop 4.
2. This order is determined by applying the Law of Superposition, which states that in an undisturbed sequence of sedimentary rocks, the oldest layers are at the bottom and each successive layer is younger than the one below it.
3. In Outcrop 3, the lowest layer contains only a single type of fossil (a coiled shell), indicating it is the oldest.
4. In Outcrop 1, a new fossil type (a fan-shaped shell) appears in the middle layer, suggesting this layer is younger than the bottom layer in Outcrop 3.
5. In Outcrop 2, the top layer contains both fossil types, indicating it is the youngest layer among the first three outcrops.
6. In Outcrop 4, the topmost layer contains no fossils and is capped by a distinct, dark, horizontal line, which represents an unconformity or erosion surface. This indicates a period of non-deposition or erosion, making it the youngest event in the sequence.
Parent Tip: Review the logic above to help your child master the concept of index fossils worksheet.
