Iowa State Geology Practice Exam

In a syncline, the youngest rocks are located at the center of the fold. This is due to the way sedimentary layers are deposited and subsequently folded. When a syncline forms, the sediments that accumulate later in time end up in the lowest part of the fold structure. As the rocks are subjected to tectonic forces causing the fold, the younger layers are pushed downwards and become the innermost layers at the center. Thus, the age relationship shows that the rocks at the center of the syncline are younger compared to those on the outer sides, which are older due to the sequence of deposition and the geological processes involved. This layering reflects the principle of superposition, where younger strata are deposited on top of older strata.