Proposed physical causes

A. Atmospheric causes

(a) Climate became too hot so they fried

(b) Climate became too cold so they froze

(c) Climate became too wet so they got waterlogged

(d) Climate became too dry so they desiccated

(e) Excessive amounts of oxygen in the atmosphere caused:

(1) changes in atmospheric pressure and/or atmospheric composition that proved fatal; or

(2) global wildfires that burned up the dinosaurs

(f) Low levels of CO2 removed the "breathing stimulus" of endothermic dinosaurs

(g) High levels of CO2 asphyxiated dinosaur embryos

(h) Volcanic emissions (dust, CO2, rare earth elements) poisoned dinosaurs one way or another

B. Oceanic and geomorphic causes

(a) Marine regression produced loss of habitats

(b) Swamp and lake habitats were drained

(c) Stagnant oceans produced untenable conditions on land

(d) Spillover into the world's oceans of Arctic waters that had formerly been restricted to polar regions, and subsequent climatic cooling

(e) The separation of Antarctica and South America, causing cool waters to enter the world's oceans from the south, modifying world climates

(f) Reduced topographical relief and loss of habitats

Based on part upon Benton (1990).

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