Who defined the Cretaceous period in 1822?
Belgian geologist Jean d'Omalius d'Halloy defined the Cretaceous period during 1822. He named it Terrain Crétacé based on extensive chalk beds found in Western Europe.
Questions about Cretaceous
Short answers, pulled from the story.
When did the Cretaceous period begin and end according to modern standards?
The International Commission on Stratigraphy officially dates the start of the Cretaceous to approximately 145 million years ago. The period ended sharply at 66.043 Ma with an iridium-rich layer linked to the Chicxulub impact crater.
What were the climate conditions like during the Mid-Cretaceous Hothouse interval?
Mean annual temperatures at poles exceeded 14 degrees Celsius while tropical sea surface temperatures averaged around 30 degrees Celsius. Deep ocean temperatures reached values as much as 12 to 20 degrees warmer than today's levels.
Which plants first appeared during the late Valanginian era of the Cretaceous?
Monosulcate pollen grains from flowering plants appeared in Israel and Italy approximately 134 million years ago. These fossils represent the earliest widely accepted evidence of angiosperms before they became dominant land plants by the end of the period.
How many major groups of tetrapods disappeared completely during the K, Pg boundary event?
Only three major groups of tetrapods disappeared completely including non-avian dinosaurs plesiosaurs and pterosaurs. Non-avian dinosaurs pterosaurs and large marine reptiles died out due to the catastrophic extinction event that blocked solar energy.