199.6 – 145.5 MILLION: JURASSIC

  • Pangea supercontinent begins to split with significant mountain-building and volcanism;
  • seas fill rift zones, Panthalassa and Tethys oceans begin shrinking;
  • Climate warm and humid with vast tropical forests;
  • The plankton that lived in the Jurassic period made our crude oil;
  • Dinosaurs dominate the land;
  • First birds arise from small dinosaurs;
  • Marine reptiles flourish;
  • Gymnosperm trees form global forests with vast ‘prairies’ of ferns.
The Jurassic  is a geologic period and system that extends from 201.3± 0.6 Ma (million years ago) to 145± 4 Ma.
Name Diameter (km) Age (megayears) Dating method Morphological type Notes
Viewfield, Saskatchewan 2.5 190 ± 20 Geological dating CONFIRMED Simple Jurassic-Triasic post-impact deposit
Cloud Creek, Wyoming 7 ~190 ± 30 Geological dating CONFIRMED Complex Chronostratigraphic
Hartney, Manitoba 6 <190 ± 20 Geological dating PROBABLE Complex? Structurally uplifted centre
Upheaval Dome, Utah 2.57 <170 Geological dating PROPOSED Younger than the Jurassic Navajo Sandstone