Paleocene and Eocene kaolinite distribution in the South Atlantic and Southern Ocean; Antarctic climatic and paleoceanographic implications

Author(s): Robert, Christian; Kennett, James P.
Author Affiliation(s): Primary:
CNRS-Luminy, Géol. Quat., Marseilles, France
Univ. Calif. at Santa Barbara, United States
Volume Title: Marine Geology
Source: Marine Geology, 103(1-3), p.99-110. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 42 refs.; sect., strat. col., sketch maps
Summary: Clay mineral associations of Paleocene and Eocene age have been examined in six drilled sequences from the southern South Atlantic and southern ocean. These sites are located to provide three depth transects across intermediate water masses. Kaolinite was not observed in the latest Cretaceous (Maastrichtian) sediments of Maud Rise. Kaolinite first appears in the clay mineralogical assemblages in the earliest Paleocene (about 65 to 64.5 Ma) at a time of relatively cool intermediate waters and before a warming trend of surface waters. Currents at intermediate water depths transported fine terrigenous sediments from the antarctic continent northwards into the southern ocean. Kaolinitic soils are inferred to have developed strongly in East Antarctica during the latest Paleocene and early Eocene (about 59 to 52 Ma) at a time when the oxygen isotopic data indicate maximum warmth of surface and intermediate waters of the southern ocean. These are interpreted to reflect a Paleocene maximum of antarctic rainfall. This development peaked at 57.3 Ma, close to the Paleocene-Eocene boundary, a time of maximum warmth, based on oxygen isotopic data. Increased illite content (and associated chlorite and random mixed-layer clays) at the end of the middle Eocene (about 41 Ma) suggest local development of poorly weathered soils on Antarctica, favored by a cooling of the southern ocean. Coeval extension of kaolinite into shallower water depths, and similar clay mineral associations in shallower and deeper sites, indicate that the development of cooler conditions led to an increasing influence of antarctic environments upon intermediate water masses at high latitudes. (Auth. mod.)
Year of Publication: 1992
Research Program: ODP Ocean Drilling Program
Key Words: 06 Petrology, Sedimentary; 12 Stratigraphy, Historical Geology and Paleoecology; Antarctic Ocean; Antarctica; Areal studies; Atlantic Ocean; Cenozoic; Clay mineralogy; Clay minerals; Controls; Cores; Eocene; Kaolinite; Leg 113; Leg 114; Marine environment; Marine sediments; Minerals; Ocean Drilling Program; Oceanography; Paleo-oceanography; Paleocene; Paleocirculation; Paleoclimatology; Paleogene; Provenance; Sedimentation; Sediments; Sheet silicates; Silicates; South Atlantic; Southern Ocean; Stratigraphy; Terrigenous materials; Tertiary; Weathering; X-ray diffraction data
Record ID: 1992012388
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from the Antarctic Bibliography, United States

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