how does cross-cutting relations establish relative dates?
Answered by The Community. Making the world better, one answer at a time. Cross cutting relations are used in relative dating because you can see which layers were deposited before or after the fault occured.The same way, when a fault cuts through a rock, or when magma intrudes and crystallizes, we can assume that the fault or intrusion is younger than the rocks affected.nswered by The Community. Making the world better, one answer at a time. Cross cutting relations are used in relative dating because you can see which layers were deposited before or after the fault occured.