Biomarker Taphonomy

Summons Lab

Determining how fossils are formed and organic matter persists as lipid biomarkers through geologic time has been a challenge to unravel since diagenesis typically occurs over millions of years while decay begins immediately after senescence. Furthermore, organic matter preservation is highly dependent on depositional setting and the nature of microorganisms partaking in decay. Laboratory experiments running over days can provide some insights, heating can accelerate slower processes, but in order to really understand the process of diagenesis, it is important to catch fossilization in the act.

~11,000 years old - Greens Creek, Ottawa, ON, Canada

~11,000 years old - Greens Creek, Ottawa, ON, Canada

~6,000 years old - Kangerlussuaq, Greenland

~6,000 years old - Kangerlussuaq, Greenland

I this study, we have conducted lipid biomarker analysis of young, Holocene-age concretions from two environments that have produced highly contrasting fossil end-members.

  1. Greens Creek, Ottawa, ON, Canada: a paleo brackish-to-freshwater marine inlet that resulted from the retreat of the Laurentide ice sheet.

  2. Kangerlussuaq, Greenland: a marine environment with recently exposed sediments due to isostatic rebound during the Last Glacial Maximum.

Our objective is to investigate the biological and early diagenetic transformation of organic matter within macrofossils in order to elucidate those processes (e.g., remineralization, sulfurization, etc.) which determine subsequent encapsulation in sedimentary carbonate concretions and the potential range of products that will arise upon late diagenesis.