Long-term records of erosional change from marine ferromanganese crusts |
| |
| Authors: | R Keith O’Nions Martin Frank |
| |
| Institution: | (1) Department of Earth Sciences, University of Oxford, Parks Rd., OX1 3PR Oxford, UK |
| |
| Abstract: | 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. The10Be/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 ɛNd 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 compositions 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. |
| |
| Keywords: | Ferromanganese crusts Atlantic Pacific Indian Ocean Nd and Sr isotopes erosion |
| 本文献已被 SpringerLink 等数据库收录！ |
|
