The Ìgbà Ẹlẹ́fun tabi Ìgbà Ẹfun (Cretaceous) ( /krɪˈteɪʃəs/), derived from the Latin "creta" (chalk), usually abbreviated K for its German translation Kreide (chalk), is a geologic period and system from circa 145.5 ± 4 to 65.5 ẹgbẹgbẹ̀rún ọdún sẹ́yìn million years (Ma) ago. In the geologic timescale, the Cretaceous follows the Jurassic Period and is followed by the Paleogene Period of the Cenozoic Era. It is the youngest period of the Mesozoic Era, and at 80 million years long, the longest period of the Phanerozoic Eon. The end of the Cretaceous defines the boundary between the Mesozoic and Cenozoic eras. Image:Sauerstoffgehalt-1000mj.svg Image:Phanerozoic Carbon Dioxide.png Image:All palaeotemps.png