Taphonomy in Temporally Unique Settings: An Environmental Traverse in Search of the Earliest Life on Earth

Abstract

There is an apparent preservational paradox in the early rock record. Cellularly preserved and ensheathed microfossils which are remarkably preserved from the late Archaean (c.2700 Ma) onward, have rarely been found in the earlier rock record and when they are their biogenicity is debated. Likewise, the abundance and morphological complexity of stromatolites appears much reduced in the early Archaean and even these lack compelling associations with organic remains of micro- bial mats. This ‘preservational dark age’ may have arisen because microfossils and microbial mats were absent, because conditions for their preservation were rare or, as we suggest here, because scientists have largely been looking in the wrong places. To illustrate the potential of looking far beyond ‘chertified Bahamian lagoons’, we make a traverse across the key potential habitats for early life on Earth and identify some exciting and new taphonomic windows, in the search for Earth’s earliest microfossils, trace fossils and stromatolites. Such habitats include hitherto little explored pillow lavas, hydrothermal vents and beach sandstones. These new windows are already starting to provide surprising insights into the nature of the earliest vital processes.