Cambrian Explosion: Earth temp high (Introduction)

by David Turell , Friday, May 11, 2018, 14:49 (2177 days ago) @ David Turell

News fossil data shhows the Earth was warm:

https://wattsupwiththat.com/2018/05/10/study-earth-was-warmer-500-million-years-ago-lif...

"Scientists from the UK and France have quantified the temperature of Earth’s oceans over half a billion years ago by combining fossil data and climate models.

"Study suggests early animals diversified in a greenhouse world, with a climate similar to that in which the dinosaurs lived

"Chemical analysis was conducted on tiny fossils shells about 1mm long from blocks of limestone from Shropshire, UK, dated to between 515 – 510 million years old
Findings help to expand our knowledge of early animals and the environment in which they lived

"New research suggests that sea temperatures of around 25C (77F) and a lack of permanent polar ice sheets fuelled an explosion of species diversity that eventually led to the human race.

"Scientists made the discovery while looking for clues in tiny fossil shells in blocks of Shropshire limestone thought to be around 510 million years old.

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"Scientists have long thought that the early Cambrian Period was probably a greenhouse interval in Earth’s climate history, a time when there were no permanent polar ice sheets.
Until now, however, scientists have only had a sense of what the Cambrian climate was like because of the types of rock that were deposited at this time – while it has long been believed that the climate was warm, specific details have largely remained a mystery.

"Data from the tiny fossil shells, and data from new climate model runs, show that high latitude (~65 °S) sea temperatures were in excess of 20 °C. This seems very hot, but it is similar to more recent, better understood, greenhouse climates like that of the Late Cretaceous Period.

***

"Dr Tom Harvey, from the School of Geography, Geology and the Environment, added: “Many marine animals incorporate chemical traces of seawater into their shells as they grow. That chemical signature is often lost over geological time, so it’s remarkable that we can identify it in such ancient fossils.”

"Analyses of the oxygen isotopes of these fossils suggested very warm temperatures for high latitude seas (~65 °S), probably between 20 °C to 25 °C.

"To see if these were feasible sea temperatures, the scientists then ran climate model simulations for the early Cambrian. The climate model simulations also suggest that Earth’s climate was in a ‘typical’ greenhouse state, with temperatures similar to more recent, and better understood, greenhouse intervals in Earth’s climate history, like the late Mesozoic and early Cenozoic eras."

Comment: warm Earth wAs another helpful factor in the Cambrian Explosion.