Isotopic evidence for temperature variation during the early Cretaceous (late Ryazanian-mid-Hauterivian)
- Price, G.D.
- Ruffell, A.H.
- Jones, C.E.
- Kalin, R.M.
- Mutterlose, J.
DOIAbstract
Oxygen and carbon isotopic compositions have been determined from the belemnite genera Acroteuthis and Hibolites sampled from the early Cretaceous (Ryazanian-Hauterivian) interval of the Speeton Clay Formation, Filey Bay, England. The Speeton Clay Formation consists of a series of claystones and calcareous mudrocks deposited in an epicontinental sea. delta(18)O values from belemnites, which met petrographic and chemical criteria for well preserved skeletal carbonate, indicate warm marine palaeotemperatures (c. 12-15 degrees C) for much of the early Valanginian whilst cool temperatures (<9 degrees C) are inferred for the earliest Hauterivian. During the remainder of the Hauterivian, temperatures fluctuated considerably and rose to a maximum ...
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