Before separation, there was unity. Not the unity of harmony, but the unity of things that have not yet learned they are different.
The Fold existed outside of sequence, outside of causality. All elements occupied the same conceptual space without intersection or reaction. Fire contained no heat because heat required something else to burn. Water held no depth because depth required somewhere else to be.
Duration is the wrong word. The Fold persisted in a state that predated the necessity of persistence.