THE INFLUENCE OF PRETREATMENT ON HUMIC-ACID YIELD AND C-14 AGE OF CAREX PEAT

The object of the study was to assess the effects of a range of pretre atment/extraction schemes on the yields of humic acid and humin obtain ed from peat and the subsequent radiocarbon ages. We analyzed peat fro m Flokadalur in northern Iceland, collecting material from a profile c ontaining seven visible tephra horizons in the upper 3 m, whose form a nd extent indicated little disturbance to the section over the last 40 00 yr. The results of a range of pretreatments demonstrated that time rather than the strength of alkali is the more important factor govern ing the extraction of humic acid. An increase in alkali molarity did n ot correspond to any systematic increase in yield, whereas an increase in time did, implying that the extraction is kinetically controlled. We found no evidence of variability in C-14 age due to pretreatment sc heme or between different geochemical fractions of the peat. Further i mplications from this study are that bog stability and ecological simp licity produce a favorable environment for C-14 dating.