Carnian Stage

What happened during this time?

Geophysical

• There is a turning point for a number of key environmental variables:

  • Carbon dioxide was reaching a local maximum (at 250-300% of modern levels), 

  • Oxygen is at a local minimum (at about 50% of modern levels). 

  • Sea levels had been extremely low and quite stable since the end of the Permian, but by the end of the Carnian, we see the first hints of a long-term rise in sea level which would last for a hundred million years, cresting in mid-Cretaceous times. 

  • Relatively stable, dry climates of the Early and Middle Triassic were shifting to the more strongly zonal, monsoonal climates of the Late Triassic.

Biological

Flora

• Caytoniales, a possible sister group to the angiosperms, appear on the landscape.

• Obscure seed plant groups, Iraniales and Czekanowskiales, also appear during this time.

• Also on the landscape are Ferns, Conifers, Cycads, Bennettitaleans, Ginkgoes, and Corystosperms

  • Conifers in the Late Triassic include Voltziaceae, Majoniacaceae, Araucariaceae, and Podocarpaceae as well as some of the earliest evidence of the Pinaceae, Cupressaceae, Taxaceae, and Cheirolepidiaceae

  • Ferns in the Late Triassic include the ancient tree ferns, Marattiales, and the modern tree ferns, Dicksoniaceae, as well as the Osmundaceae, Gleicheniaceae, Matoniaceae, Dipteridaceae, and Hymenophyllaceae.

• There is a "burst" of amber during the middle Carnian during the Carnian Pluvial Event

Fauna

• Dicynodonts indicate that they were feeding on Ferns, Conifers, and Corystosperms from coprolites including wood, cuticle debris, spores, and pollen grains (Perez Loinaze et al. 2018)

  • Dicynodonts mostly disappear at the end of the Carnian

• Dinosaurs diversified explosively in the mid-Carnian (Bernardi et al. 2018)

  • The mid-Carnian extinction (known as the Carnian Pluvial Episode, or CPE) marks this radiation of dinosaurs

  • Climates shuttled from dry to humid and back to dry again

  • There were massive eruptions in western Canada, represented today by the great Wrangellia basalts

  • These eruptions drove bursts of global warming, acid rain, and killing on land and in the oceans