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The Mesozoic Era [3] is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods.It is characterized by the dominance of gymnosperms such as cycads, ginkgoaceae and araucarian conifers, and of archosaurian reptiles such as the dinosaurs; a hot greenhouse climate; and the tectonic break-up of Pangaea.
An era is the second largest geochronologic time unit and is equivalent to a chronostratigraphic erathem. [ 14 ] [ 13 ] There are ten defined eras: the Eoarchean , Paleoarchean , Mesoarchean , Neoarchean , Paleoproterozoic , Mesoproterozoic , Neoproterozoic , Paleozoic , Mesozoic and Cenozoic , with none from the Hadean eon.
An approximate timescale of key Mesozoic events. Vertical axis scale: Millions of years ago This page was last edited on 9 December 2024, at 05:49 (UTC). Text ...
c. 251.9 Ma ± 0.024 Ma – Mesozoic era and Triassic Period begin. Mesozoic Marine Revolution begins. c. 245 Ma – First ichthyosaurs. c. 240 Ma – Cynodonts and rhynchosaurs diversify. c. 225 Ma – First dinosaurs and teleosti evolve. c. 220 Ma – First crocodilians and flies. c. 215 Ma – First turtles.
Permian period, end of Paleozoic era beginning of Mesozoic era, Triassic period (252–201 Ma) Cycads, seed ferns. First therapsids. Oxygen in atmosphere peaks, around 30%. [33] Gorgonopsians and other therapsids (forerunners of mammals) displace pelycosaurs as dominant land animals. First gorgonopsia, apex predators of the Late Permian.
The Paleozoic era spanned roughly (Ma) [39] and is subdivided into six geologic periods: from oldest to youngest, they are the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. Geologically, the Paleozoic starts shortly after the breakup of a supercontinent called Pannotia and at the end of a global ice age.
Of all the phases Earth has been through, the Mesozoic Era stands out among the rest—even from off-world. Skip to main content. Sign in. Mail. 24/7 Help. For premium support please call: 800-290 ...
The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at 66 million years, [2] with radiometric dating yielding a more precise age of 66.043 ± 0.043 Ma. [3]