Figure 5
Geochemical proxies plots from Valdocarros II in the Jarama Valley. (A) Paq, ratio of macrophytic lipids (n-C23 + n-C25) relative to macrophytic and terrestrial lipids (n-C23 + n-C25 + n-C29 + n-C31) (< 0.4 = no macrophytes; 0.4 to 1 = emergent macrophytes; > 1 = floating macrophytes). (B) Pr/Ph, pristane to phytane (higher values more oxic conditions). (C) C33/C31: Ratio of n-C33 to n-C31, (higher values, more grasses). (D) Palg: Ratios of algal lipids (n-C17 + n-C19) relative to algal and terrestrial plant lipids (n-C17 + n-C19 + n-C29 + n-C31) higher values, more algal input). (E) ACL = ∑(Cn × n)/∑(Cn) Average chain length of individual n-alkane abundances. (F) CPI = [∑odd(C21-33) + ∑odd(C23-35)]/(2∑even C22-34) Carbon preference index, indicative of the abundance of odd over even carbon chain lengths (lower CPIs often indicative of microbial degradation or maturation of the sample). (G) TARFA: Terrigenous to aquatic n-alkanoic acids ratio reflecting the importance of terrigenous and aquatic sources (C24 + C26 + C28)/(C14 + C16 + C18) (higher values, more terrestrial input). (H) API: alcohol preservation index uses only n-hexacosanol and n-nonacosane (higher values more hypoxic conditions).
