Imperial College London
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ProfessorTinavan de Flierdt

Faculty of Engineering, Department of Earth Science & Engineering

Head of the Department of Earth Science and Engineering
 
 
 
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Contact

 

+44 (0)20 7594 1290tina.vandeflierdt

 
 
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Location

 

G.30Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Wilson:2017:10.1016/j.gca.2017.01.052,
author = {Wilson, DJ and van, de Flierdt T and Adkins, JF},
doi = {10.1016/j.gca.2017.01.052},
journal = {Geochimica et Cosmochimica Acta},
pages = {350--374},
title = {Lead isotopes in deep-sea coral skeletons: ground-truthingand a first deglacial Southern Ocean record},
url = {http://dx.doi.org/10.1016/j.gca.2017.01.052},
volume = {204},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Past  changes  in  seawater  lead   (Pb)  isotopes   record the  temporal  evolution  of anthropogenic  pollution,  continental  weathering  inputs,  and  ocean  current  transport.  To advance  our  ability  to  reconstruct  this  signature, we  present  methodological  developments that  allow  us  to  make  precise  and  accurate  Pb  isotope  measurements  on  deep-sea  coral aragonite,  and  apply  our  approach  to  generate  the  first  Pb  isotope  record  for  the  glacial  to deglacial mid-depth Southern Ocean. Our  refined  methodology  includes  a  two-step  anion  exchange  chemistry  procedure and  measurement  using  a 207Pb-204Pb  double  spike  on  a  ThermoFinnigan  Triton  TIMS instrument. By employing a 1012 resistor (in place of a 10 resistor) to measure the low-abundance 204Pb ion beam, we improve the internal precision on 206,207,208Pb/204Pb for a 2 ng load of NIST-SRM-981 Pb from typically ~420 ppm to ~260 ppm (2 s.e.), and the long term external reproducibility from ~960 ppm to ~580 ppm (2 s.d.). Furthermore, for a typical 500 mg coral sample with low Pb concentrations (~6-10 ppb yielding ~3-5 ng Pb for analysis), we obtain  a  comparable  internal  precision  of  ~150-250 ppm  for 206,207,208Pb/204Pb,  indicating  a good  sensitivity  for  tracing  natural  Pb  sources  to the  oceans.  Successful  extraction  of  a seawater signal from deep-sea coral aragonite further relies on careful physical and chemical cleaning  steps,  which  are  necessary  to  remove  anthropogenic  Pb  contaminants  and  obtain results that are consistent with ferromanganese crusts. Applying our approach to a collection of late glacial and deglacial corals  (~12-40 ka BP) from south of Tasmania at ~1.4-1.7 km water depth, we generated the first intermediate water  Pb  isotope  record  from  the  Southern  Ocean.  That  record  reveals  millennial  timescale variability,  controlled  by  binary  mixing  between  two  Pb  sources,  but  no  distinct  glacial-inter
AU  - Wilson,DJ
AU  - van,de Flierdt T
AU  - Adkins,JF
DO  - 10.1016/j.gca.2017.01.052
EP  - 374
PY  - 2017///
SN  - 0016-7037
SP  - 350
TI  - Lead isotopes in deep-sea coral skeletons: ground-truthingand a first deglacial Southern Ocean record
T2  - Geochimica et Cosmochimica Acta
UR  - http://dx.doi.org/10.1016/j.gca.2017.01.052
UR  - http://hdl.handle.net/10044/1/44293
VL  - 204
ER  -
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