Mesozoic

Mesozoic
Name	Mesozoic
Start	252.17 Ma
End	66.0 Ma
Primary locations	Laurasia, Gondwana, Tethys Ocean

Mesozoic The Mesozoic was an era of deep time marked by dramatic shifts in Paleozoic aftermath, continental reconfiguration, and the rise and turnover of dominant faunas and floras. Spanning from the aftermath of the Permian–Triassic extinction event to the threshold of the Cretaceous–Paleogene extinction event, it witnessed the diversification of Archosauria, the evolution of modern Angiosperms, and major plate reorganizations that set the stage for Cenozoic Earth systems. This era is central to studies in paleontology, stratigraphy, geochronology, and natural resource exploration.

Overview

The era follows the Permian and precedes the Paleogene of the Cenozoic. Paleontologists and geologists commonly subdivide it into three chronostratigraphic systems tied to global biotic and lithologic changes observed in sections like the GSSP-defined boundaries at locations such as the Meishan Section and sections in the Gubbio Basin. Key figures whose work shaped Mesozoic research include Charles Darwin (influence on evolutionary framework), Othniel Charles Marsh and Edward Drinker Cope (vertebrate paleontology), and later stratigraphers like Alfred Wegener (continental drift) and Arthur Holmes (geochronology).

Geological subdivisions

The era is divided into the Triassic, Jurassic, and Cretaceous systems, each with characteristic faunal assemblages and lithostratigraphic markers used by institutions such as the International Commission on Stratigraphy and museums like the Natural History Museum, London. The Early Triassic records recovery strata after the Permian–Triassic extinction event, while the Late Cretaceous includes formations sampled by expeditions to localities like Laramidia and Iberia. Geological stages within those systems—such as the Carnian, Oxfordian, and Maastrichtian—are correlated worldwide using radiometric ages from labs like the US Geological Survey and isotope work associated with researchers at Caltech and ETH Zurich.

Paleogeography and climate

Paleogeographic reconstructions show the breakup of Pangaea into northern Laurasia and southern Gondwana, with seaways like the Tethys Ocean expanding between continental fragments documented in maps by teams at Paleomap Project. Rift-related basins formed passive margins along regions that now include North America, South America, Africa, and Eurasia', with volcanic provinces such as the Karoo-Ferrar and Deccan Traps (the latter at the Cretaceous–Paleogene boundary). Climate varied from anoxic events and greenhouse phases to regional aridity recorded in sedimentary sequences in the Newark Basin, fossil floras from Antarctica expeditions, and isotopic paleothermometry developed at institutions like Lamont–Doherty Earth Observatory.

Major life and evolutionary events

The era saw the radiation of Archosauria into dominant roles, including lineages that produced Dinosaurs, Pterosaurs, and early Crocodylomorpha, documented in classic localities such as Solnhofen and Hell Creek Formation. Marine ecosystems hosted diverse Ammonoidea, Belemnites, and Marine Reptilia like Ichthyosaurs and Plesiosaurs, recovered by field teams associated with museums including the American Museum of Natural History and the Natural History Museum, London. Floral evolution progressed from gymnosperm-dominated biotas—conifers and cycads evident in collections at Royal Botanic Gardens, Kew—to the explosive appearance of Angiosperms during the Cretaceous, revolutionizing pollination systems alongside insect groups studied by entomologists at Smithsonian Institution. Vertebrate paleontology milestones include the discovery and interpretation of feathered theropods from Liaoning deposits investigated by researchers affiliated with Chinese Academy of Sciences and the reappraisal of avian origins influenced by work at University of Kansas and American Museum of Natural History.

Tectonics and mass extinctions

Tectonic processes—rifting, seafloor spreading, and orogeny—reshaped ocean basins and continental climates across the era, with mountain-building episodes later preserved in orogens like the early phases of the Andes and Cordillera. Mass extinction episodes bracket the era: the terminal Permian–Triassic extinction event opened ecological space, while the terminal Cretaceous–Paleogene extinction event led to the extinction of non-avian dinosaurs and many marine taxa. Proposed drivers for these crises include large igneous provinces (e.g., Siberian Traps, Deccan Traps), the impact event linked to the Chicxulub crater identified by teams from institutions including UNAM and MIT, and climatic perturbations analyzed in studies at NASA and USGS laboratories.

Economic and scientific significance

Mesozoic successions host major energy and mineral resources: hydrocarbon reserves in North Sea, Gulf of Mexico, and North Africa basins, and mineral deposits explored historically by corporations such as BP and ExxonMobil. Fossil sites drive tourism and outreach at institutions like the Field Museum, Smithsonian National Museum of Natural History, and the Royal Tyrrell Museum. Scientifically, the era provides a foundation for modern evolutionary theory, biogeographic models used by researchers at University of Cambridge and Harvard University, and stratigraphic frameworks maintained by the International Commission on Stratigraphy. Ongoing interdisciplinary studies combine data from paleoclimatology groups at Scripps Institution of Oceanography and molecular clock research at Max Planck Institute for Evolutionary Anthropology to refine timelines and causal mechanisms underlying Mesozoic change.

Category:Geologic eras