Middle Miocene climate cooling linked to intensification of eastern equatorial Pacific upwelling

Abstract

Research Article| January 01, 2014 Middle Miocene climate cooling linked to intensification of eastern equatorial Pacific upwelling Ann Holbourn; Ann Holbourn * 1Institute of Geosciences, Christian-Albrechts-University, D-24118 Kiel, Germany *E-mail: [e-mail]. Search for other works by this author on: GSW Google Scholar Wolfgang Kuhnt; Wolfgang Kuhnt 1Institute of Geosciences, Christian-Albrechts-University, D-24118 Kiel, Germany Search for other works by this author on: GSW Google Scholar Mitch Lyle; Mitch Lyle 2Department of Oceanography, Texas A&M University, TAMU 3146, College Station, Texas 77840-3146, USA Search for other works by this author on: GSW Google Scholar Leah Schneider; Leah Schneider 3Integrated Ocean Drilling Program, Department of Geology and Geophysics, Texas A&M University, 1000 Discovery Drive, College Station, Texas 77845, USA Search for other works by this author on: GSW Google Scholar Oscar Romero; Oscar Romero 4Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Avenida de las Palmeras 4, 18100 Armilla-Granada, Spain Search for other works by this author on: GSW Google Scholar Nils Andersen Nils Andersen 5Leibniz Laboratory for Radiometric Dating and Stable Isotope Research, Christian-Albrechts-University, D-24118 Kiel, Germany Search for other works by this author on: GSW Google Scholar Geology (2014) 42 (1): 19–22. https://doi.org/10.1130/G34890.1 Article history received: 02 Jul 2013 rev-recd: 10 Sep 2013 accepted: 10 Sep 2013 first online: 09 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 Ann Holbourn, Wolfgang Kuhnt, Mitch Lyle, Leah Schneider, Oscar Romero, Nils Andersen; Middle Miocene climate cooling linked to intensification of eastern equatorial Pacific upwelling. Geology 2014;; 42 (1): 19–22. doi: https://doi.org/10.1130/G34890.1 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 SocietyGeology Search Advanced Search Abstract During the Middle Miocene, Earth's climate transitioned from a relatively warm phase (Miocene climatic optimum) to a colder mode with reestablishment of permanent ice sheets on Antarctica, thus marking a fundamental step in Cenozoic cooling. Carbon sequestration and atmospheric CO2 drawdown through increased terrestrial and/or marine productivity have been proposed as the main drivers of this fundamental transition. We integrate high-resolution (1–3 k.y.) benthic stable isotope data with X-ray fluorescence scanner–derived biogenic silica and carbonate accumulation estimates in an exceptionally well preserved sedimentary archive, recovered at Integrated Ocean Drilling Program Site U1338, to reconstruct eastern equatorial Pacific productivity variations and to investigate temporal links between high- and low-latitude climate change over the interval 16–13 Ma. Our records show that the climatic optimum (16.8–14.7 Ma) was characterized by high-amplitude climate variations, marked by intense perturbations of the carbon cycle. Episodes of peak warmth at (Southern Hemisphere) insolation maxima coincided with transient shoaling of the carbonate compensation depth and enhanced carbonate dissolution in the deep ocean. A switch to obliquity-paced climate variability after 14.7 Ma concurred with a general improvement in carbonate preservation and the onset of stepwise global cooling, culminating with extensive ice growth over Antarctica ca. 13.8 Ma. We find that two massive increases in opal accumulation ca. 14.0 and ca. 13.8 Ma occurred just before and during the final and most prominent cooling step, supporting the hypothesis that enhanced siliceous productivity in the eastern equatorial Pacific contributed to CO2 drawdown. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.