The Chulec Formation (Ki-chu) is a geological formation in Peru whose strata date back to the Albian. The formation has a thickness of about 100 to 200 metres (330 to 660 ft) and comprises limestones, marls and calcareous sandstones that were deposited during a marine transgression from the west. Pterosaur remains and ammonites are among the fossils that have been recovered from the formation.