Smithsonian National Museum of Natural History Geologic Time The Story of a Changing Earth
Presented by the Department of Paleobiology.
The Triassic
Contents
Overview
Extinction and Recovery
Origin of Mammals
Origin of the Dinosaurs
Climate and Plate Tectonics
Evidence
Skull of Coelophysis
learn more
sample
Dicynodont
Dicynodont
Cynodont
Skull of Cynognathus
Skull of Buettneria
Phytosaur
Nothosaur
Bennettitalean 1
Bennettitalean 2
Cycadophyte
Trilophosaurus
references and links
Foundational Concepts
Dating Methods
Earth Processes
Life Processes
Privacy Statement Copyright
Glossary Credits Email Us


Climate and Plate Tectonics
Pangea was maximally developed at the start of the Triassic, with Panthalassia (“all ocean”) occupying the other side of the globe, and the Tethys Ocean forming an enormous gulf on the eastern margin of Pangea. Even as the assembly of Pangea was completed, however, it began to rift apart. By the end of the Triassic, rifting in the center of Pangea had begun. North America began to pull away from Europe and Africa, and blocks of crust sank to create rift valleys. During the Late Triassic and Early Jurassic, these valleys were associated with the initial formation of the Atlantic Ocean. The sediments that filled these rift valleys are preserved along the eastern margin of North America and the western edges of Africa and Europe, and they contain important evidence of Late Triassic organisms and their environments.

Early Triassic climate was quite similar to that at the end of the Permian. Much of Pangea was warm and dry, and the interior of this supercontinent was particularly arid. These environments were often dominated by conifers and other gymnosperms. However, the Triassic also saw an increase in seasonality, as well as prominent monsoon weather cycles. Provincial biotas developed as well. In the north (Laurasia), these ecosystems included ginkgoes, bennettitalians, cycads, and tree ferns. In contrast, southern (Gondwanan) environments were dominated by seed ferns, most prominently one called Dicroidium.



=

Overview | Extinction and Recovery | Origin of Mammals
Origin of the Dinosaurs | Climate and Plate Tectonics



Department of Paleobiology Home | National Museum of Natural History Home
Smithsonian Institution Home