We are presently working on a lake core. Fortunately, for us, the chronology has also worked out well (14C dates as expected, etc.). The core (organic-rich; little obvious marl) has been ashed (550°C for 4 hours).
Details are (approx): 300 cm to 500 cm
In all we have 112 samples. 4-5 g wet wt sample wt; typically gave 0.3-0.5 g ash (mainly about 0.4 g).
What we'd like: geochemical analyses; esp. some of the indicative elements (for soil erosion from the catchment) such as Ca, K, Mg, Ti, Fe, Mn; Maybe someone would have a better idea of indicator elements?
Would appreciate some advice about the digestion of these samples, we plan to do this as an open digestion on a hot plate.
How should we digest this ash for ICP-OES or ICP-MS analysis. What reagents and what quantities and proportions for say an average weight of 0.2 -0.4 g? Could we use NH4F and HNO3 as some suggested in earlier postings. And make up to waht volume?
Harry O' Donnell
Senior Technical Officer
Earth and Ocean Sciences
School of natural Sciences
National University of Ireland, Galway
Tel: +353 91 492269 Fax: +353 91 525005
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