Temperate rainforests near the South Pole during peak Cretaceous warmth.
Nature
; 580(7801): 81-86, 2020 04.
Article
in En
| MEDLINE
| ID: mdl-32238944
The mid-Cretaceous period was one of the warmest intervals of the past 140 million years1-5, driven by atmospheric carbon dioxide levels of around 1,000 parts per million by volume6. In the near absence of proximal geological records from south of the Antarctic Circle, it is disputed whether polar ice could exist under such environmental conditions. Here we use a sedimentary sequence recovered from the West Antarctic shelf-the southernmost Cretaceous record reported so far-and show that a temperate lowland rainforest environment existed at a palaeolatitude of about 82° S during the Turonian-Santonian age (92 to 83 million years ago). This record contains an intact 3-metre-long network of in situ fossil roots embedded in a mudstone matrix containing diverse pollen and spores. A climate model simulation shows that the reconstructed temperate climate at this high latitude requires a combination of both atmospheric carbon dioxide concentrations of 1,120-1,680 parts per million by volume and a vegetated land surface without major Antarctic glaciation, highlighting the important cooling effect exerted by ice albedo under high levels of atmospheric carbon dioxide.
Full text:
1
Database:
MEDLINE
Main subject:
Atmosphere
/
Temperature
/
Carbon Dioxide
/
Climate
/
Rainforest
Type of study:
Prognostic_studies
Country/Region as subject:
Oceania
Language:
En
Journal:
Nature
Year:
2020
Type:
Article
Affiliation country:
Germany