Sequential fatty acid analysis of a peat core covering the last two millennia (Tritrivakely lake, Madagascar): diagenesis appraisal and consequences for palaeoenvironmental reconstruction.

Overview & Synopsis

When studying fatty acids (FAs) organic geochemists classically paid attention either to the "free" fraction or to "bound" compounds commonly released by saponication. However, it is now well established that more detailed information can be obtained by a study of the various pools of FAs that can be released successively by different chemical treatments (e.g. [1]). Following previous geochemical and petrographical work [2], we applied such an approach to the analysis of a peat core section to get additional information on the palaeoenvironment of the study area and its changes during the last 2300 yr. Thus, seven samples from the 1m long upper section of a core taken from the centre of the Tritrivakely maar lake (Madagascar), were successively submitted to solvent extraction, acid hydrolysis and saponification to release their "free", H+-labile and OH--labile bound fatty acids, respectively.