14 décembre 2015

Découverte d'une forêt préhistorique

On a découvert les restes fossilisés d'une forêt tropicale... en Norvège! Un beau rappel que notre planète a bien changé au cour des millénaires:

A tropical forest densely packed with 12-foot-tall trees with flared trunks and curved branches of needle leaves — Dr. Seuss would have felt right at home — covered an area near the equator some 380 million years ago. Scientists spotted the fossilized stumps a long way from this location — in Arctic Norway.

Not only did the researchers date the forest as one of Earth’s oldest, but they also suggest it may have contributed to a dramatic drop in atmospheric carbon dioxide levels traced to that time in our planet’s distant past.

During the Devonian period (416 million to 358 million years ago), Earth’s first large trees were emerging. Also around this time, atmospheric carbon dioxide dropped significantly. Scientists look to the earliest forests for evidence that tree growth played a part in scrubbing CO2 from the atmosphere — trees use the greenhouse gas to photosynthesize and form sugary food — contributing to the global cooling event that occurred at the end of the Devonian.

Trouvé ici.

2 commentaires:

Ishang1991 a dit…

I've always been interested in the prehistoric times since you introduced it to your class in 5th grade. I'm not as crazy as you, but I just curiously read some articles. The earth has come a long way...

Prof Solitaire a dit…

Thanks... and not many people are as crazy as me! ;-)