Long-term records of erosional change from marine ferromanganese crusts

Journal of Earth system science

R Keith O'Nions1¹  Martin Frank1¹ 

[1] Department of Earth Sciences, University of Oxford, Parks Rd., Oxford OX1 3PR, UK$$

关键词: Ferromanganese crusts;    Atlantic;    Pacific;    Indian Ocean;    Nd and Sr isotopes;    erosion.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Ferromanganese crusts from the Atlantic, Indian and Pacific Oceans record the Nd and Pb isotope compositions of the water masses from which they form as hydrogenous precipitates. The 10Be/9Be-calibrated time series for crusts are compared to estimates based on Co-contents, from which the equatorial Pacific crusts studied are inferred to have recorded ca. 60 Ma of Pacific deep water history.Time series of 𝜀 Nd show that the oceans have maintained a strong provinciality in Nd isotopic composition, determined by terrigenous inputs, over periods of up to 60 Ma. Superimposed on the distinct basin-specific signatures are variations in Nd and Pb isotope time series which have been particularly marked over the last 5 Ma.It is shown that changes in erosional inputs, particularly associated with Himalayan uplift and the northern hemisphere glaciation have influenced Indian and Atlantic Ocean deep water isotopic composi- tions respectively. There is no evidence so far for an imprint of the final closure of the Panama Isthmus on the Pb and Nd isotopic composition in either Atlantic or Pacific deep water masses.

【 授权许可】

Unknown