Cretaceous sea-surface temperature evolution : constraints from TEX 86 and planktonic foraminiferal oxygen isotopes

• Published in: Earth-Science Reviews
• Main Authors: C. L. O'Brien, S. A. Robinson, R. D. Pancost, J. S. Sinninghe Damsté, S. Schouten, D. J. Lunt, H. Alsenz, A. Bornemann, C. Bottini, S. C. Brassell, A. Farnsworth, A. Forster, B. T. Huber, G. N. Inglis, H. C. Jenkyns, C. Linnert, K. Littler, P. Markwick, A. Mcanena, J. Mutterlose, B. . D. A. Naafs, W. Püttmann, A. Sluijs, N. A. G. M. van Helmond, J. Vellekoop, T. Wagner, N. E. Wrobel
• Other Authors: C.L. O'Brien, S.A. Robinson, R.D. Pancost, J.S. Sinninghe Damsté, D.J. Lunt, S.C. Brassell, B.T. Huber, G.N. Ingli, H.C. Jenkyn, B.D.A. Naaf, A. Sluij, N.A.G.M. van Helmond, N.E. Wrobel
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2017
• Subjects: Cretaceou; Sea-surface temperature; Glycerol dialkyl glycerol tetraether; TEX86; Organic geochemistry; δ18O; Planktonic foraminifera; Geochemical proxie; Palaeoclimate; Greenhouse climate; Settore GEO/01 - Paleontologia e Paleoecologia; Settore GEO/02 - Geologia Stratigrafica e Sedimentologica
• Online Access: http://hdl.handle.net/2434/521617; https://doi.org/10.1016/j.earscirev.2017.07.012

It is well established that greenhouse conditions prevailed during the Cretaceous Period (~ 145–66 Ma). Determining the exact nature of the greenhouse-gas forcing, climatic warming and climate sensitivity remains, however, an active topic of research. Quantitative and qualitative geochemical and palaeontological proxies provide valuable observational constraints on Cretaceous climate. In particular, reconstructions of Cretaceous sea-surface temperatures (SSTs) have been revolutionised firstly by the recognition that clay-rich sequences can host exceptionally preserved planktonic foraminifera allowing for reliable oxygen-isotope analyses and, secondly by the development of the organic palaeothermometer TEX86, based on the distribution of marine archaeal membrane lipids. Here we provide a new compilation and synthesis of available planktonic foraminiferal δ18O (δ18Opl) and TEX86-SST proxy data for almost the entire Cretaceous Period. The compilation uses SSTs recalculated from published raw data, allowing examination of the sensitivity of each proxy to the calculation method (e.g., choice of calibration) and places all data on a common timescale. Overall, the compilation shows many similarities with trends present in individual records of Cretaceous climate change. For example, both SST proxies and benthic foraminiferal δ18O records indicate maximum warmth in the Cenomanian–Turonian interval. Our reconstruction of the evolution of latitudinal temperature gradients (low, <±30°, minus higher, >±48°, palaeolatitudes) reveals temporal changes. In the Valanginian–Aptian, the low-to-higher mid-latitudinal temperature gradient was weak (decreasing from ~ 10–17 °C in the Valanginian, to ~ 3–5 °C in the Aptian, based on TEX86-SSTs). In the Cenomanian–Santonian, reconstructed latitudinal temperature contrasts are also small relative to modern (< 14 °C, based on low-latitude TEX86 and δ18Opl SSTs minus higher latitude δ18Opl SSTs, compared with ~ 20 °C for the modern). In the mid-Campanian to end-Maastrichtian, ...