Strontium, neodymium, and lead isotope variations of authigenic and silicate sediment components from the late Cenozoic Arctic Ocean; implications for sediment provenance and the source of trace metals in seawater

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doi: 10.1016/S0016-7037(97)00215-9
Authors:Winter, Bryce L.; Johnson, Clark M.; Clark, David L.
Author Affiliations:Primary:
University of Wisconsin, Department of Geology and Geophysics, Madison, WI, United States
Volume Title:Geochimica et Cosmochimica Acta
Source:Geochimica et Cosmochimica Acta, 61(19), p.4181-4200. Publisher: Pergamon, Oxford, International. ISSN: 0016-7037
Publication Date:1997
Note:In English. 174 refs.; illus., incl. 4 tables, sketch maps
Summary:Analyses are presented of foraminifera, Fe-Mn micronodules and bulk sediment from the Alpha Ridge, central Arctic Ocean, for calcite, silicate, Rb, Sr, Sm, Nd, Rb-Sr isotopes and Sm-Nd isotopes and Pb isotopes. Samples were taken from 11 cores mainly drilled through an ice island as it drifted over the Alpha Ridge from 1963-1973. Systematic variations in Sr, Nd and Pb isotope compositions of the silicate fractions of sediments deposited over the last 5 m.y. coincide with a change from sea ice to glacial ice sediment transport and changes in provenance, which comprised three end-member sediment source compositions. Between 5 and 1.7 m.y. sediment in the central Arctic Ocean was deposited by sea ice and stemmed from two source regions, one being the East Siberian Shelf. From 1.7 m.y. to the present there was a progressive increase in coarse glacially ice-rafted detritus with most stemming from the N Canada or Queen Elizabeth Island regions. Pb and Nd isotope compositions of bottom Arctic sea-water over the past 5 m.y. coincide with the isotope variations of the silicate fractions, indicating that particulates rafted by sea ice and glacial ice were a major source of REE and Pb to the dissolved reservoir in sea-water in ice-covered oceans. [R.K.H.]
Subjects:Alkaline earth metals; Authigenesis; Biochemistry; Cenozoic; Detritus; Ferromanganese composition; Foraminifera; Geochemistry; Ice rafting; Isotope ratios; Isotopes; Lead; Marine sedimentation; Marine sediments; Metals; Nd-144/Nd-143; Neodymium; Neogene; Nodules; Paleo-oceanography; Pb-206/Pb-204; Pb-207/Pb-204; Pb-208/Pb-204; Planktonic taxa; Pliocene; Provenance; Quaternary; Radioactive isotopes; Rare earths; Sea water; Sediment transport; Sedimentation; Sediments; Siliceous composition; Sr-87/Sr-86; Stable isotopes; Strontium; Tertiary; Trace metals; Upper Cenozoic; Alpha Cordillera; Arctic Ocean; Invertebrata; Micronodules; Protista
Abstract Numbers:98M/1698
Record ID:1998007586
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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