| 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 |