Antarctic subtropical humid episode at the Paleocene-Eocene boundary: Clay-mineral evidence

Research Article| March 01, 1994 Antarctic subtropical humid episode at the Paleocene-Eocene boundary: Clay-mineral evidence Christian Robert; Christian Robert 1Géologie du Quaternaire, Unité Propre de Recherche 1201, Centre National de la Recherche Scientifique—Luminy, Case 907, 13288 Marseille Cedex 9, France Search for other works by this author on: GSW Google Scholar James P. Kennett James P. Kennett 2Marine Science Institute and Department of Geological Sciences, University of California, Santa Barbara, California 93106 Search for other works by this author on: GSW Google Scholar Author and Article Information Christian Robert 1Géologie du Quaternaire, Unité Propre de Recherche 1201, Centre National de la Recherche Scientifique—Luminy, Case 907, 13288 Marseille Cedex 9, France James P. Kennett 2Marine Science Institute and Department of Geological Sciences, University of California, Santa Barbara, California 93106 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1994) 22 (3): 211–214. https://doi.org/10.1130/0091-7613(1994)0222.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Christian Robert, James P. Kennett; Antarctic subtropical humid episode at the Paleocene-Eocene boundary: Clay-mineral evidence. Geology 1994;; 22 (3): 211–214. doi: https://doi.org/10.1130/0091-7613(1994)0222.3.CO;2 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 Clay-mineral assemblages from East Antarctica have been analyzed at high stratigraphic resolution (20 to 1 ka) throughout the interval from 55.6 to 55.0 Ma, which includes the terminal Paleocene isotopic excursion in Ocean Drilling Program Site 690B on Maud Rise (lat 65°S) in the Weddell Sea region. Changes in the clay associations reflect a major increase in chemical weathering caused by increased temperature and/or rainfall in at least this sector of East Antarctica for a brief (270 ka) interval in the latest Paleocene. This represents the most intense warming known for the Cenozoic. This high-latitude climatic episode is recorded synchronously by stable isotopes and clay minerals. A progression is evident in the clay assemblages during the latest Paleocene that apparently reflects changing relations between temperature and precipitation. This sequence began with the interval of rapid temperature increase that marks the beginning of the oxygen isotopic excursion. A brief increase in kaolinite at the inception of the excursion suggests a temporary increase in year-round precipitation in Antarctica, in response to an increased continent-to-ocean temperature gradient. This kaolinite spike was followed by almost total dominance by smectite for the remainder of the isotopic excursion (∼120 ka), suggesting that warmer Southern Ocean surface temperatures of 18 to 22 °C were associated with seasonal precipitation (alternating wet and dry seasons). Claymineral variations on Antarctica during the isotopic excursion reflect a tight coupling between oceanic and continental climate change. Immediately following the excursion at ∼55.22 Ma, kaolinite percentages increased to values similar to modern subtropical-tropical areas for ∼150 ka, a remarkable event for the Antarctic. Abundant kaolinite suggests perennial rainfall and minimum soil temperatures of 15 °C during at least part of the year. The kaolinite increased during a time of lower Southern Ocean surface-water temperatures, suggesting increased atmospheric heat transport toward the poles. A temporary change in atmospheric circulation is suggested from dominantly zonal to meridional. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.