- The Miocene (/ˈmaɪ.əsiːn, -oʊ-/ MY-ə-seen, -oh-) is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words μείων (meíōn, “less”) and καινός (kainós, “new”) and means “less recent” because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene.