Mesozoic

The Mesozoic Era ( /ˌmɛz.əˈz.ɪk, ˌmɛz.-, ˌmɛs-, ˌm.zə-, -z-, ˌm.sə-, -s-/ mez-ə-ZOH-ik, mez-oh-, mess-, mee-zə-, -zoh-, mee-sə-, -soh-)[1][2], also called the Age of Reptiles and the Age of Conifers,[3] is the second-to-last era of Earth's geological history, lasting from about 252 to 66 million years ago and comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic.

Mesozoic
251.902 ± 0.024 – 66.0 Ma
Chronology
Etymology
Name formalityFormal
Nickname(s)Age of Reptiles, Age of Conifers
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEra
Stratigraphic unitErathem
Time span formalityFormal
Lower boundary definitionFirst appearance of the Conodont Hindeodus parvus.
Lower boundary GSSPMeishan, Zhejiang, China
31.0798°N 119.7058°E / 31.0798; 119.7058
GSSP ratified2001
Upper boundary definitionIridium enriched layer associated with a major meteorite impact and subsequent K-Pg extinction event.
Upper boundary GSSPEl Kef Section, El Kef, Tunisia
36.1537°N 8.6486°E / 36.1537; 8.6486
GSSP ratified1991

The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs, pterosaurs, mosasaurs, and plesiosaurs. The Mesozoic was a time of significant tectonic, climatic, and evolutionary activity. The era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. Dinosaurs first appeared in the Mid-Triassic, and became the dominant terrestrial vertebrates in the Late Triassic or Early Jurassic, occupying this position for about 150 or 135 million years until their demise at the end of the Cretaceous. Archaic birds appeared in the Jurassic, having evolved from a branch of theropod dinosaurs, then true toothless birds appeared in the Cretaceous. The first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg (33 lb)—until the Cenozoic. The flowering plants appeared in the early Cretaceous Period and would rapidly diversify throughout the end of the era, replacing conifers and other gymnosperms as the dominant group of plants.


Share this article:

This article uses material from the Wikipedia article Mesozoic, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.