Warm Middle Jurassic-Early Cretaceous high-latitude sea-surface temperatures from the Southern Ocean

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doi: 10.5194/cp-8-215-2012
Author(s): Jenkyns, Hugh C.; Schouten-Huibers, L.; Schouten, Stefan; Sinninghe Damsté, Jaap S.
Author Affiliation(s): Primary:
University of Oxford, Department of Earth Sciences, Oxford, United Kingdom
Other:
Royal Netherlands Institute for Sea Research, Netherlands
Volume Title: Climate of the Past
Source: Climate of the Past, 8(1), p.215-226. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. Includes supplement, http://www.clim-past-discuss.net/7/1339/2011/cpd-7-1339-2011.html; published in Climate of the Past Discussion: 20 April 2011, http://www.clim-past-discuss.net/7/1339/2011/cpd-7-1339-2011.html; accessed in April 2012. 85 refs.; illus., incl. strat. cols., sketch map
Summary: Although a division of the Phanerozoic climatic modes of the Earth into "greenhouse" and "icehouse" phases is widely accepted, whether or not polar ice developed during the relatively warm Jurassic and Cretaceous Periods is still under debate. In particular, there is a range of isotopic and biotic evidence that favours the concept of discrete "cold snaps", marked particularly by migration of certain biota towards lower latitudes. Extension of the use of the palaeotemperature proxy TEX86 back to the Middle Jurassic indicates that relatively warm sea-surface conditions (26-30°C) existed from this interval (∼160 Ma) to the Early Cretaceous (∼115 Ma) in the Southern Ocean, with a general warming trend through the Late Jurassic followed by a general cooling trend through the Early Cretaceous. The lowest sea-surface temperatures are recorded from around the Callovian-Oxfordian boundary, an interval identified in Europe as relatively cool, but do not fall below 25°C. The early Aptian Oceanic Anoxic Event, identified on the basis of published biostratigraphy, total organic carbon and carbon-isotope stratigraphy, records an interval with the lowest, albeit fluctuating Early Cretaceous palaeotemperatures (∼26°C), recalling similar phenomena recorded from Europe and the tropical Pacific Ocean. Extant belemnite δ18O data, assuming an isotopic composition of waters inhabited by these fossils of -1 per mil SMOW, give palaeotemperatures throughout the Upper Jurassic-Lower Cretaceous interval that are consistently lower by ∼14°C than does TEX86 and the molluscs likely record conditions below the thermocline. The long-term, warm climatic conditions indicated by the TEX86 data would only be compatible with the existence of continental ice if appreciable areas of high altitude existed on Antarctica, and/or in other polar regions, during the Mesozoic Era.
Year of Publication: 2012
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Aluminum oxides; Ammonites; Ammonoidea; Antarctica; Aptian; Atlantic Ocean; Belemnitidae; Belemnoidea; Biostratigraphy; Black shale; Callovian; Cephalopoda; Chlorinated hydrocarbons; Clastic rocks; Coleoidea; Cretaceous; DSDP Site 511; Deep Sea Drilling Project; Falkland Plateau; Glacial environment; Global change; Global warming; Halogenated hydrocarbons; IPOD; Invertebrata; Isotope ratios; Isotopes; Jurassic; Leg 113; Leg 71; Lower Cretaceous; Mesozoic; Methylene chloride; Microfossils; Middle Jurassic; Mollusca; Nannofossils; O-18/O-16; ODP Site 693; Ocean Drilling Program; Oceanic anoxic events; Organic compounds; Oxfordian; Oxides; Oxygen; Paleoclimatology; Paleotemperature; Plantae; Sea-surface temperature; Sedimentary rocks; South Atlantic; Southern Ocean; Stable isotopes; Stratigraphic boundary; Total organic carbon; Transantarctic Mountains; Upper Jurassic; Weddell Sea
Coordinates: S510017 S510017 W0465818 W0465818
S704954 S704953 W0143424 W0143425
Record ID: 2013010068
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Copernicus Gesellschaft, Katlenburg-Lindau, Germany