It is not that the rocks have been at the surface for two billion years; they have been through enormous geological changes in that time.

What the two-billion-year age represents is the age of the original depositional event — when the sediments were first laid down — not the age of the current surface exposure.

This distinction, while it might seem pedantic, is actually part of what makes the geological story interesting.

The journey of these rocks from ancient seabed to mountaintop is a story of geological processes operating across two billion years — burial, lithification, uplift, erosion — and that story is as remarkable as the age itself.

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