Identification of biomarkers of cores from the South China Sea

The principal factor analysis indicates that short chains nC₁₆, nC₁₇.nC₁₈ and nC₁₉ have relatively large positive charge, while long chains nC₂₇ and nC₂₉ have relatively large negative charge.On the third principal factor axis, the carbon with positive charge is almost even carbon, while the carbon with negative charge is almost odd carbon.The parameters of biomarker compounds are divided into 3 groups; (I) nC₃₁l/nC₁₇,nC₂₇/nC₁₇, nC₂₇/T and Pr/Ph recognizing the input of source material; (2) nC₂₇/T, Ph/nC₁₈, CPI and Pr/Ph showing oxidation and reduction of depositional environment; (3) Tm/Ts, Ph/nC₁₈ indicating the maturity of sedimentary organic matter.