Title Isotopic evidence for glaciation during the Cretaceous supergreenhouse
Author Bornemann, A.; Norris, R.D.; Friedrich, O.; Beckmann, B.; Schouten, S.; Sinninghe Damsté, J.S.; Vogel, J.; Hofmann, P.; Wagner, T.
Author Affil Bornemann, A., Scripps Institution of Oceanography, La Jolla. Other: Universität Köln, Federal Republic of Germany; Royal Netherlands Institute for Sea Research, Netherlands; Newcastle University, United Kingdom
Source Science, 319(5860), p.189-192, . Publisher: American Association for the Advancement of Science, Washington, DC, United States. ISSN: 0036- 8075
Publication Date Jan. 11, 2008
Notes In English. 34 refs. GeoRef Acc. No: 282188
Index Terms climatic change; glacial geology; glaciation; greenhouse effect; ice sheets; isotopes; oxygen; paleoclimatology; Atlantic Ocean--Equatorial Atlantic; Ocean Drilling Program--ODP Site 1259; ancient ice ages; anomalies; Atlantic Ocean; biostratigraphy; clastic rocks; climate change; Cretaceous; Demerara Rise; Equatorial Atlantic; Foraminifera; Invertebrata; isotope ratios; Leg 207; marl; Mesozoic; microfossils; O-18/O- 16; Ocean Drilling Program; ODP Site 1259; paleo-oceanography; paleoenvironment; paleotemperature; Protista; sea-surface temperature; sedimentary rocks; stable isotopes; Turonian; Upper Cretaceous
Abstract The Turonian (93.5 to 89.3 million years ago) was one of the warmest periods of the Phanerozoic eon, with tropical sea surface temperatures over 35°C. High- amplitude sea-level changes and positive delta 18O excursions in marine limestones suggest that glaciation events may have punctuated this episode of extreme warmth. New delta 18O data from the tropical Atlantic show synchronous shifts ~91.2 million years ago for both the surface and deep ocean that are consistent with an approximately 200,000- year period of glaciation, with ice sheets of about half the size of the modern Antarctic ice cap. Even the prevailing supergreenhouse climate was not a barrier 1to the formation of large ice sheets, calling into question the common assumption that the poles were always ice-free during past periods of intense global warming.
URL http://hdl.handle.net/10.1126/science.1148777
Publication Type journal article
Record ID 62002751