Electron Microprobe Facility - Projects

 

4. Climate-related Projects

• Effect of diagenetic overprint on U-Th ages in corals

Old corals, collected from the ocean floor by submersible, provide invaluable information about past climate and sealevel. However, various types of post-growth overprint can potentially distort those ages (which are derived from wet chemistry in the isotope lab). By comparing ages obtained on pristine corals (top image below), to corals infilled with high-Mg calcite and clastic carbonate debris (bottom image below), we can study the magnitude of this effect. These images are part of an ongoing Master's project of Kate Herries, supervised by Ken Rubin.



BSE image of a nearly pristine coral. Minor fine-grained Sr-rich aragonite precipitated on the septa walls.



BSE image of a partly infilled coral. Darker Mg-rich calcite precipitated fills in large fraction of the pores.

• Fe-Mn oxide precipations resulting from submarine discharge of (fresh) groundwaters