An anticline is a type of fold in sedimentary strata that is arch-like in shape, with its oldest rocks located at the core of the fold. The limbs of an anticline dip away from the center, creating a convex-upward structure. Anticlines are important in petroleum geology because they can serve as traps for oil and natural gas, accumulating hydrocarbons in the crest of the fold.
Reference: Twiss, R. J., & Moores, E. M. (2007). Structural Geology. W.H. Freeman and Company.