Paleoclimate reconstruction from petrography and biomarker geochemistry from Permian humic coals in Sydney Coal Basin (Australia)

Origin and Maturity of Biomarker Aliphatic Hydrocarbon in Wondama Coal Indonesia

“…Obtained CPI value > 1, which is 7.82 (Table 2) in this study, indicates the sample of immature coal n-alkane has not experienced thermal degradation. This result is also supported by several previous studies which gave CPI values > 1 as an indicator of immature coal [21][22][23][24] and confirmed the terrestrial origin of the organic matter [36].…”

“…In this study, the presence of pristane and phytane compounds in Wondama coal are shown by the Pr/Ph ratio > 3, which is 3.74 as seen in Table 2. The high Pr/Ph ratio values of the samples used indicate that terrigenous organic matter was deposited under relatively oxic conditions [19][20][21][22][23][24]41]. This result is also supported by the Hunt diagram (Pr/n-C17 ratio versus Ph/n-C18) as seen in Figure 4 which shows that the Wondama coal organic compound is produced by terrestrial higher plants which undergo deposition in an oxic environment.…”

“…The m/z 57 fragmentogram is the most stable and specific C4H9 + ion fragment for n-alkane homologs. Identification was carried out by comparing the retention time patterns and mass spectrum data obtained with those previously published (such as: [13,[19][20][21][22][23][24][25]). The distribution of n-alkane biomarkers in Wondama coal samples can be seen in Figure 2 and Table 1.…”

“…Acyclic isoprenoid biomarker groups were identified based on fragmentogram m/z 57. Identification of the structure was done by comparing the retention time and fragmentation of the mass spectrum obtained with the retention time and mass spectrum that had been published by previous researchers (such as: [13,[19][20][21][22][23][24][25]). The acyclic isoprenoid biomarker group in Wondama coal samples consists of two main compounds namely pristane (C19) and phytane (C20).…”

“…CPI = 0,5{[(n-C25 + n-C27 + n-C29 + n-C31 + n-C33)/(n-C24 + n-C26 + n-C28 + n-C30 + n-C32)] + [(n-C25 + n-C27 + n-C29 + n-C31 + n-C33)/(n-C26 + n-C28 + n-C30 + n-C32 + n-C34)]}; Carbon Preference Index; m/z = 57; thermal maturity parameter[33]. b Pr/Ph = pristane/phytane; oxic environmental parameter; m/z = 57[24]. c Pr/n-C17 = pristane/n-heptadecane; m/z = 57[24].d Ph/n-C18 = phytane/n-octadecane; m/z = 57 [24].…”