FIRE AND ICE: SUPER-ERUPTIONS, VOLCANIC WINTERS, THE END-TRIASSIC EXTINCTION, AND THE RISE OF DINOSAUR-DOMINANCE
Under Triassic high-CO2 there was no polar ice, and CO2doublings from CAMP produced a few degrees temperature increase and some tropical lethality, but how this led to higher latitude extinctions is hard to see.
While pulses of CAMP eruptions caused CO2 doublings over 10s to 100s of thousands of years, EACH major eruption caused a severe sulfate “volcanic winter” lasting several years plausibly leading to freezing tropical temperatures. And, there were many such coolings as opposed to a few CO2warmings.
Crocodile-line archosaurs and dinosaurs and were relatively resistant to heat induced water stress, but the former lacked insolation, while the latter had it. The lengthy super-greenhouse events allowed some crocodile-line archosaurs to escape to cooler climes, but there was nowhere to go during volcanic winters. I hypothesise that crocodile-line and other herptile extinctions resulted from extreme cold events, for which they had no adaptations. In contrast, dinosaurs and their insulated relatives, as well as burrowing forms withstood the cold spells. This hypothesis is consistent with global post-ETE faunal homogenization, when the higher latitude dinosaurs spread globally taking over the world. This hypothesis predicts that ice crystal impressions should be found in the kinds of facies that typically have reptile footprints in eastern North America deposited simultaneously with specific eruptions that occurred elsewhere in the vast CAMP area. This is a contribution to IGCP 632.
Paraphrasing Robert Frost – ice will suffice.