The likely Late Archean-Paleoproterozoic origin for eukaryotes poses a problem for palaeontologists. Molecular clocks predict eukaryotes to have originated as early as 2.5-2.1 Ga yet earliest eukaryotic fossils appear around 1.9-1.7 billion years ago. This fossil record around this time is particularly meagre. With an increase in knowledge of what geochemical and mineralogical signals indicate likely fossiliferous horizons in the shale record, the search for more early eukaryotic organic walled fossils has become more imperative. These fossils will help to contextualise the evolution of eukaryotes in an unfamiliar ancient ocean.
As such, I have targeted two sites of likely preservation of eukaryotic microfossils.
The 1.8 billion year old Rove Formation, Ontario, Canada
The 2.1 to 2.4 billion year old Transvaal Supergroup, South Africa
Stay tuned as I investigate these fossils for signs of early life!
At the same time, I am also investigating microbial life at another key end member of eukaryotic evolution: the origin of metazoans. During this time, microfossils reach peak diversity, and as such can be used to investigate spatial and stratigraphic relationships. One set of rocks in my current interest are the Cango Caves and Gamtoos Groups of South Africa, which likely have an Ediacaran age. This section has not been studied in over 20 years, and therefore opens an existing avenue to go back and re-characterise microfossil diversity in the wake of the first appearances of animals.