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From about 470 million years ago, the Middle Ordovician period witnessed a rapid increase in biodiversity. This explosion in numbers of species is almost perfectly contemporaneous with an increased frequency of meteorite impacts.
The relationship between carbon dioxide and climate over millions of years has been a source of controversy. Fossilized liverwort leaves can help illuminate both temperature and atmospheric carbon dioxide levels from 200 to 60 million years ago.
Emerging evidence for threefold higher heat flow across the core–mantle boundary prompts a re-evaluation of the role of thermal plumes in geodynamics and the thermal history of the Earth's core and lower mantle.
