Remarkably preserved prokaryote and eukaryote microfossils within 1 Ga-old lake phosphates of the Torridon Group, NW Scotland

The ∼1000 Ma Torridon Group of northwest Scotland are here shown to contain a rich diversity of organic walled microfossils preserved in exceptional detail within sedimentary phosphate. The phosphatic nodules and bands in which they occur are autochthonous, as are the organic fossils they contain. The associated sedimentology of this phosphate is shown to be consistent with a lacustrine setting. Informal taxonomic treatment of the microfossils allows statistical assessment of the relative abundances of different morphotypes across a range of lacustrine environments. Exceptional preservation of pristine organic-walled eukaryotes and prokaryotes, together with a taphonomic spectrum in both physicochemical and biological degradational conditions allows a picture to be built of the earliest lacustrine ecological communities.

► We identify bedded and nodular sedimentary phosphate throughout lacustrine portions of the 1 Ga-old Torridon Group of NW Scotland.
► A diverse organic microfossil assemblage is found preserved exceptional three dimensional detail within these phosphates.
► The assemblage contains informally classified eukaryotes and prokaryotes, as well as a distinct taphonomic spectrum.
► Such a varied ecological assemblage is rarely found in rocks of this age, and is afforded by the exceptional preservation of the phosphates.
► This work contributes unprecedented detail to the growing picture of a verdantly colonised Precambrian terrestrial environment.