Completar frases Relative rock datingVersión en línea Know how to compare rocks with one another and understand which is oldest and youngest. por Uko Nwa 1 A C B B horizontally D crosscutting younger A oldest superposition dating Relative C is determining whether an object or event is older or younger than other objects or events . Two basic rules for relative rock sequencing ; . one , layers will form on top of each other . This means the horizontal layers on top must be younger than the horizontal layers underneath it . This is called the law of . Second , for an igneous intrusion to break through a layer , it had to have existed at the time of the fault line . If a fault line / intrusion cuts through a layer , the intrusion or fault line is . This is called the law of . Therefore , if rock layer A is horizontally on top of rock layer B than rock layer B is . Furthermore , if an intrusion rock layer C cuts through both rock layer A and B then intrusion rock layer is the youngest , rock layer is the next youngest , and rock layer is the oldest . Lastly , a fault line D is made and all the rock layers shift . This tells us fault line is the youngest , intrusion rock layer is the next youngest , followed by rock layer , and rock layer is the oldest .