Early Jurassic

The Early Jurassic (201–174 Ma) occurs after the Rhaetian Age (Late Triassic), and before the Aalenian Age (Middle Jurassic) of the Mesozoic Era

Geologic Age

  • 201.3174.1 million years ago

Subdivisions

Eon / Era / Period / Epoch

What happened during this time?

  • Gondwanan floras start to resemble northern continents

  • Cordaites, gigantopterids, and glossopterids no longer dominate

  • Five distinct vegetative biomes exist by this time (Rees et al. 1999)

    • Cool temperate

      • Low diversity of flora: 70 genera, 120 species

      • High proportion of deciduous and seasonal plants with growth rings

    • Warm temperate: below 60 degrees latitude and centered on 40 degrees

      • High in diversity

      • Ferns

      • Equisetophytes

      • Macrophyllous cycads

      • Macrophyllous conifers

        • woody and herbaceous members of Pinaceae, Taxodiaceae, Podocarpaceae

      • Ginkgoes were less common; first appearance of the genus Ginkgo

    • Winterwet

    • Subtropical desert

    • Summerwet tropical