Real rocks can be tilted, overturned, eroded or redeposited, so geologists establish the structural context before applying simple rules. The activity deliberately keeps its layers upright and leaves out missing intervals. Its numbered construction steps show a possible history, not measured durations or dates for a real outcrop.
Earth and geology · Discover & try
What happened first in these rock layers?
Reading level 4 of 5 · FluentChange
Word help
Superposition
In an upright undisturbed stack, lower sedimentary layers are older.
Intrusion
Rock formed when magma enters and solidifies within existing material.
Cross-cutting relationship
A feature is younger than the material it cuts.
Watch · Try · Explain
See how it works
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Original upright-layer reconstruction; no real outcrop dates, overturned beds or missing-time estimates are implied.
What to look for
- Build the bottom layer first.
- Check which layers a feature actually cuts.
- Keep event order separate from elapsed years.
Explain what you noticed
In another outcrop, a fault cuts beds M and N, but an undisturbed bed P covers the fault. Which sequence fits?
Keep this idea: Relative dating puts events in order without assigning ages in years.
Follow the sources
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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