Name: Karen Sinclair
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The Late Cretaceous was a greenhouse world
16 April 2019
Well done to our colleague Sam Henson, Graduate Geo-Environmental Consultant, who has co-authored a research article recently published in Paleoceanography and Paleclimatology (AGU). See his introduction on the article below;
The Late Cretaceous (between 100 and 66 Million years ago) was an extremely warm ‘greenhouse world’, showing elevated temperatures and very high atmospheric CO2 levels. However, even in the context of an extreme greenhouse climate, existing climate data from the southern high palaeolatitudes (~55°S), suggests anomalous warmth, with sea‐surface temperatures (SSTs) >30°C for much of the Late Cretaceous.
Over the last 20 years there has been discussion in the scientific community as to whether these high SSTs reflect a genuine temperature signal. Furthermore, if the signal is genuine, was it a local temperature anomaly in the South Atlantic or representative of past global temperatures at 55°S?
To reconstruct past climates, the composition of cell membranes in Archaea (single celled micro-organisms) that live in the surface waters can be related to the temperature of the water that they grow in – this method is known asTEX86. To provide new insights into this southern hemisphere high-latitude warming in the Late Cretaceous, we present new SST records from the Falkland and Kerguelen Plateau (picture; right), using TEX86.