CLIMATIC CHANGES IN THE LATE CAMPANIAN--EARLY MAASTRICHTIAN: MICROPALEONTOLOGICAL AND STABLE ISOTOPIC EVIDENCE FROM AN EPICONTINENTAL SEA
2005-07-01

Research Article| July 01, 2005 CLIMATIC CHANGES IN THE LATE CAMPANIAN—EARLY MAASTRICHTIAN: MICROPALEONTOLOGICAL AND STABLE ISOTOPIC EVIDENCE FROM AN EPICONTINENTAL SEA Oliver Friedrich; Oliver Friedrich 1Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany *Present address: Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, 30655 Hannover, Germany. E-mail: oliver. friedrich@bgr.de Search for other works by this author on: GSW Google Scholar Jens O. Herrle; Jens O. Herrle 1Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany2Department of Earth and Ocean Sciences, University of Liverpool, 4 Brownlow Street, Liverpool L69 3GP, United Kingdom Search for other works by this author on: GSW Google Scholar Christoph Hemleben Christoph Hemleben 1Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information Oliver Friedrich *Present address: Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, 30655 Hannover, Germany. E-mail: oliver. friedrich@bgr.de 1Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany Jens O. Herrle 1Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany2Department of Earth and Ocean Sciences, University of Liverpool, 4 Brownlow Street, Liverpool L69 3GP, United Kingdom Christoph Hemleben 1Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany Publisher: Cushman Foundation for Foraminiferal Research Received: 04 Mar 2004 Accepted: 22 Nov 2004 First Online: 03 Mar 2017 Online ISSN: 1943-264X Print ISSN: 0096-1191 © 2005 Journal of Foraminiferal Research Journal of Foraminiferal Research (2005) 35 (3): 228–247. https://doi.org/10.2113/35.3.228 Article history Received: 04 Mar 2004 Accepted: 22 Nov 2004 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Oliver Friedrich, Jens O. Herrle, Christoph Hemleben; CLIMATIC CHANGES IN THE LATE CAMPANIAN—EARLY MAASTRICHTIAN: MICROPALEONTOLOGICAL AND STABLE ISOTOPIC EVIDENCE FROM AN EPICONTINENTAL SEA. Journal of Foraminiferal Research 2005;; 35 (3): 228–247. doi: https://doi.org/10.2113/35.3.228 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyJournal of Foraminiferal Research Search Advanced Search Abstract Benthic foraminiferal and calcareous nannofossil assemblages, as well as stable isotope data from the Campanian/Maastrichtian boundary interval (~71.4 to ~70.7 Ma) of the Kronsmoor section (North German Basin), were investigated in order to characterize changes in surface-water productivity and oxygen content at the seafloor and their link to climatic and paleoceanographic changes. A nutrient index based on calcareous nannofossils is derived for the high-latitude, epicontinental North German Basin, reflecting changes in surface-water productivity. Oxygen isotopes of well-preserved planktic foraminiferal specimens of Heterohelix globulosa reflect warmer surface-water temperatures in the lower part of the studied succession and a cooling of up to 2°C (0.5‰) in the upper part (after 71.1 Ma). For the lower and warmer part of the investigated succession, benthic foraminiferal assemblages and the calcareous nannofossils indicate well-oxygenated bottom waters and low-surface water productivity. In contrast, the upper part of the succession is characterized by cooler conditions, lower oxygen content at the seafloor and increasing surface-water productivity. It is proposed that the cooling phase starting at 71.1 Ma was accompanied by increasing surface-water mixing caused by westerly winds. As a consequence of mixing, nutrients were advected from sub-surface waters into the mixed layer, resulting in increased surface-water productivity and enhanced organic matter flux to the seafloor. We hypothesize that global sea-level fall during the earliest Maastrichtian (~71.3 Ma), indicated by decreasing carbon isotope values, may have led to a weaker water mass exchange through narrower gateways between the Boreal Realm and the open North Atlantic and Tethys oceans. Both the weaker water mass exchange and enhanced surface-water productivity may have led to slightly less ventilated bottom waters of the upper part of the studied section. Our micro-paleontological and stable isotopic approach indicates short-term (<100 kyr) changes in oxygen consumption at the seafloor and surface-water productivity across the homogeneous Boreal White Chalk succession of the North German Basin. 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