Updated on June 3, 2003

NCMR work examples

As part of the ORFOIS project we are investigating processes related to the diagenetic conversion of biosiliceous particles to other mineral phases in coastal marine environments. First results from the study of natural diatom particles from Danube deltaic sediments show clear evidence of cation uptake by the siliceous frustule upon burial in the sediments. However these studies have not shown microscopic evidence for substantial conversion of the siliceous frustule to other types of cation-rich mineral phases.
Investigations on these types of processes are also underway for the Mississippi delta and the Ganges-Brachmaputra delta.

Figure 1: Backscatter electron image from diatom frustule separated from the Danube deltaic deposits. Light areas represent enhanced frustule alteration and cation enrichement.

Figure 2: EDS spectrum of elemental composition of the siliceous frustule shows enrichement in Al, K, Ca, Fe and Mg.