Rare earth element deposition in pelagic sediment at the Cenomanian-Turonian boundary, Exmouth Plateau

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doi: 10.1029/94GL03047
Author(s): Dickens, Gerald R.; Owen, Robert M.
Author Affiliation(s): Primary:
University of Michigan, Department of Geological Sciences, Ann Arbor, MI, United States
Volume Title: Geophysical Research Letters
Source: Geophysical Research Letters, 22(3), p.203-206. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276 CODEN: GPRLAJ
Note: In English. 24 refs.; illus., incl. 1 table
Summary: ODP Site 762 (eastern Indian Ocean) includes a section of sediment that spans the Cenomanian-Turonian Boundary (CTB) and was deposited along a continental margin during a period of widespread oceanic O2 deficiency. The rare earth element (REE) content of pre- and post-boundary sediment is similar to that of present-day continental slope material deposited in well-oxygenated seawater, whereas the CTB section is characterized by significantly depleted REE abundances, a bulk Ce anomaly that increases to maximum of 1.0, and a REE pattern that resembles that of present-day fluvial material. We suggest the change in REE patterns reflects release of scavenged REEs upon reductive dissolution of authigenic Fe-Mn oxyhydroxides, such that sediment deposited during the CTB is dominated by the lithogenous REE fraction. These results are consistent with recent models concerning pervasive fractionation of Mn and Fe and redirection of Mn in pelagic CTB waters. Copyright 1995 by the American Geophysical Union.
Year of Publication: 1995
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Authigenic minerals; Cenomanian; Cerium; Continental margin sedimentation; Cretaceous; Deposition; Eh; Exmouth Plateau; Geochemical anomalies; Hydroxides; Indian Ocean; Iron; Iron oxides; Leg 122; Manganese; Manganese oxides; Mesozoic; Metals; Models; ODP Site 762; Ocean Drilling Program; Oxides; Oxygen; Oxyhydroxides; Pelagic sedimentation; Rare earths; Sedimentary rocks; Sedimentation; Solution; Stratigraphic boundary; Turonian; Upper Cretaceous
Coordinates: S195315 S195314 E1121515 E1121514
Record ID: 1995033009
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