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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Paleoceanographic changes during the Albian-Cenomanian in the Tethys and North Atlantic and the onset of the Cretaceous chalk

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Giorgioni, Martino [1] ; Weissert, Helmut [1] ; Bernasconi, Stefano M. [1] ; Hochuli, Peter A. [2] ; Keller, Christina E. [1] ; Coccioni, Rodolfo [3] ; Petrizzo, Maria Rose [4] ; Lukeneder, Alexander [5] ; Garcia, Therese I. [1]
Total Authors: 9
[1] ETH, Inst Geol, Dept Earth Sci, CH-8092 Zurich - Switzerland
[2] Univ Zurich, Palaeontol Inst, CH-8006 Zurich - Switzerland
[3] Univ Urbino, Dipartimento Sci Terra Vita & Ambiente, I-61209 Urbino - Italy
[4] Univ Milan, Dipartimento Sci Terra A Desio, I-20133 Milan - Italy
[5] Museum Nat Hist, Dept Geol & Paleontol, Geol Paleontol Dept, A-1010 Vienna - Austria
Total Affiliations: 5
Document type: Journal article
Source: GLOBAL AND PLANETARY CHANGE; v. 126, p. 46-61, MAR 2015.
Web of Science Citations: 22

During the mid-Cretaceous the Earth was characterized by peculiar climatic and oceanographic features, such as very high temperatures, smooth thermal meridional gradient, long-term rising sea level, and formation of oceanic gateways and seaways. At that time widespread deposition of micritic pelagic limestones, generally called chalk, occurred in deep pelagic settings as well as in epeiric seas, both at tropical and at high latitudes. The origin of such extensive chalk deposition in the mid-Cretaceous is a complex and still controversial issue, which involves the interaction of several different factors. In this work we address this topic from the paleoceanographic perspective, by investigating the contribution of major oceanic circulation changes. We characterize several stratigraphic sections from the Tethys and North Atlantic with litho-, bio-, and carbon isotope stratigraphy. Our data show a change between two different oceanic circulation modes happening in the Late Albian. The first is an unstable mode, with oceanographic conditions fluctuating frequently in response to rapid environmental and climatic changes, such as those driven by orbital forcing. The second mode is more stable, with better connection between the different oceanic basins, a more stable thermocline, more persistent current flow, better defined upwelling and downwelling areas, and a more balanced oceanic carbon reservoir. We propose that under the mid-Cretaceous paleogeographic and paleodimatic conditions this change in oceanic circulation mode favored the beginning of chalk sedimentation in deep-water settings. (C) 2015 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 12/15995-5 - Stable isotope geochemistry as main tool to unravel Eocene-Oligocene paleoclimate and paleoceanography
Grantee:Martino Giorgioni
Support type: Scholarships in Brazil - Post-Doctorate