oa Evaluating Grain Size Controls on Lipid Biomarker Distributions in Ancient Marine Sediments

Organic and inorganic geochemical proxies are fundamental to interpreting past climate variability. Organic geochemical analyses uses bulk sediment, whereas inorganic geochemical analyses involves separating sediment into fine (<63 µm) and coarse (>63 µm) grain size fractions. To resolve this, organic geochemical analyses could potentially be performed using grain size fractionated sediment. However, evidence from modern marine sediments suggests that both alkenone and isoprenoidal GDGT distributions vary between different grain sizes and result in temperature deviations of up to 5°C for UK37’ and up to 10°C for TEX86. Here we explore how different terrestrial and marine biomarker compound classes are distributed between different grain size fractions in Cenozoic-aged marine sediments.