A Hf‐Nd isotopic correlation in ferromanganese nodules
1998; American Geophysical Union; Volume: 25; Issue: 20 Linguagem: Inglês
10.1029/1998gl900008
ISSN1944-8007
AutoresFrancis Albarède, Antonio Simonetti, Jeffrey D. Vervoort, Janne Blichert‐Toft, Wafa Abouchami,
Tópico(s)Geology and Paleoclimatology Research
ResumoThe 176 Hf/ 177 Hf ratio was measured on 34 ferromanganese nodules, mostly from the Atlantic ocean. The different ocean basins are isotopically distinct with the extreme compositions being less radiogenic in the Atlantic (є Hf ∼ +1) than in the Pacific (є Hf ∼ +9). A good correlation of є Hf and є Nd is observed amongst most samples which supports that Hf isotopic compositions in nodules reflect those of ambient seawater. For a given є Nd , є Hf is more radiogenic in ferromanganese nodules than in rocks from either the mantle or the crust. This correlation makes the coupled Hf‐Nd systems a potential paleoceanographic tool. It is argued that a zircon‐free clayish component of probable eolian origin may account for the radiogenic Hf in nodules.
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