Fig 1.
Map of the studied site of Borneo tropical peatland.
A peat core was collected at the Tinbarap site (N 04°03’01.47” E 114°15’02.45”), which was marked as ☆. A previous study was conducted by Anderson [29] (marked by ) on the vegetation composition of the Borneo peat dome. The map was made using QG is software (version 3.6.2).
Fig 2.
The lithology of Borneo peat core with a total length of 10 m.
The selected intervals for analysis are indicated by black triangles (◄), and charcoals were measured in every 2 cm-interval, indicated by dash lines (˗). The difference between brown and dark brown colours is gradual and not significant.
Table 1.
Measured polycyclic aromatic hydrocarbons (PAHs) identified based on the authentic reference compounds.
Table 2.
List of the measured polycyclic aromatic hydrocarbons (PAHs) identified based on the retention times and mass spectra published by Mita and Shimoyama [35], Marynowski et al.
[36], Mita [37], Romero-Sarmiento et al. [38], and Romero-Sarmiento et al. [39].
Table 3.
The detection limits and reproducibility (standard deviation) of the available PAHs in the standard.
Fig 3.
Total ion chromatogram (TIC) and the mass chromatograms of the molecular ions of the PAHs in sample Hole 8, 361–366 cm.
The numbered spectral peaks are the compounds listed in Tables 1 and 2.
Fig 4.
The relative abundance of pyrogenic compounds averaged in all samples.
Fig 5.
Depth variations in retene (Ret), perylene (Per), cadalene (Cad), and simonellite (Sim) concentrations.
Fig 6.
Depth variations in charcoal abundance with the total concentrations of pyrogenic parent and alkylated PAHs.
Fig 7.
Factor loadings of PC1 and PC2 of PAH compounds.
Fig 8.
Depth plots of factor scores for PC 1 and PC 2.
Fig 9.
Variations of low-molecular-weight and total pyrogenic PAHs (LMW/Total pyrogenic PAHs), high-molecular-weight (HMW), and low-molecular-weight (LMW) PAHs with comparison to the charcoal abundance (5-point moving mean).