A four year NERC funded project - £396,429 - Professor Gregory Price (PI) with Dr Stephen Grimes (Coñޓi) Carbonate clumpedñޓisotopic constraints on marine temperatures during the Cretaceous (2012ñޓ2016) NE/J020842/1.
Despite the intensive study of Cretaceous marine temperatures using a variety of techniques, an equatorñޓto-pole temperature profile for the Cretaceous greenhouse world remains poorly constrained.
We aim to address this significant gap in knowledge by undertaking the first quantitative and systematic study of early Cretaceous marine temperatures obtained from fossil molluscs using the novel clumpedñޓisotope palaeothermometer.
This work will build upon the pilot study of Price & Passey (2013) based on data from the Yatria River, Siberia.
In order to construct an equatorial-polar temperature profile, we have selected early Cretaceous sites spanning 15 ñޓ 78 ºN of palaeolatitude [Morocco ñޓ Siberia]. The early Cretaceous (and Valanginian- Hauterivian in particular) has been selected as suitable material of this age is available for each of the study sites and therefore results are directly comparable.
All locations intended for study already have robust biostratigraphic frameworks, to place our findings in an appropriate context, and contain a rich and diverse benthic invertebrate fauna.
From our preliminary analyses (Price & Passey, 2013) we infer sub-arctic Early Cretaceous marine temperatures ranging from 10°C to 20°C. These warm sub-arctic temperatures are warmer than present mean summer water temperatures at 60ñޓ65°N and are therefore consistent with a warmer ñޜgreenhouseñޝ world featuring a shallow (equable) latitudinal temperature gradient.
Our combined temperature and δ18Obelemnite data imply seawater δ18O values that have a remarkably modern character in that they are similar to modern high-latitude seawater but more positive than modelled Cretaceous seawater.
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