The Great Unconformity

a huge gap in the geological record that shows up across the world

The unconformity shows up around the world when sedimentary rock that is about 500 million years old lies directly on top of far more ancient “basement” rock that can be often over 1.7 billion years old. The missing layers can represent anywhere from several million to more than a billion years, making this feature “arguably the most iconic but enigmatic gap in Earth’s stratigraphic record,” according to the new study.

https://www.404media.co/great-unconformity-gap-geological-record-study-columbia/