Sea-water temperatures of the early Cretaceous derived from stable isotopes of belemnites and TEX86 of organic-rich sediments
Final Report Abstract
The major findings can be summarized as follows: 1) The Valanginian - Aptian of the Boreal Realm is characterized by significant temperature variations which have been documented by using the palaeo-thermometry of the stable oxygen isotope ratios. The Valanginian and Hauterivian were generally cool, warmest phases have been demonstrated for the early Barremian. The "Aulacoteuthis warm pulse" records the highest T°C throughout the entire Valanginian – Aptian in the Boreal Realm. 2) Both TEX 86 and delta 18 O Bel proxy data indicate very warm water temperatures for the Barremian with, however, a constant off-set of 4°C between both data sets. These findings have been interpreted to indicate a subsurface dwelling of belemnites in water depth of perhaps 100m, explaining the relative “cold” delta 18 O Bel values. 3) Positive delta 13 C excursions, well known from the Tethys, have been documented for the Boreal Realm both for the mid Valanginian and the early Aptian. 4) The Mg incorporation in belemnite rostra suggests a biological control for "Acroteuthis" spp. and "Hibolithes jaculoides", perhaps reflecting different food sources. 5) Modern cephalopds originated 35 my before the Cretaceous/Paleogene extinction in the North Pacific due to faunal isolation.
Publications
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2009. Temperature controlled deposition of early Cretaceous (Barremian - early Aptian) black shales in an epicontinental sea.
Palaeogeography, Palaeoclimatology, Palaeoecology, 273, 330-345.
Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 273. 2009, Issues 3–4, pp. 330–345.
Mutterlose, Jörg; Pauly, Sebastian & Steuber, Thomas
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2010. TEX86 and stable δ18O paleothermometry of early Cretaceous sediments: Implications for belemnite ecology and paleotemperature proxy application. Earth and Planetary Science Letters, Vol. 298. 2010, Issues 3–4, pp. 286–298.
Mutterlose, Jörg; Malkoc, Matthias; Schouten, Stefan; Sinninghe Damsté, Jaap S. & Forster, Astrid
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2010. The early Barremian warm pulse and the late Barremian
cooling: a high-resolution geochemical record of the Boreal Realm.
Palaios, vol. 25. 2010, p. 13–22.
MALKOC, M. & MUTTERLOSE, J.
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2010. Timing of the Early Aptian δ13C excursion in the
Boreal Realm. Newsletters on Stratigraphy, Vol. 43. 2010, Number 3, pp. 251-273.
Malkoč, Matthias; Mutterlose, Jörg & Pauly, Sebastian
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in press. Belemnite extinction and the origin of modern cephalopods 35 m.y. prior to the Cretaceous−Paleogene event. Geology, Vol. 39. 2011, no. 5, pp. 483-486.
Iba, Yasuhiro; Mutterlose, Jörg; Tanabe, Kazushige; Sano, Shin-ichi; Misaki, Akihiro & Terabe, Kazunobu
