Stac Fada is a formation from some impact punctuating our Boring-Billion. Curtin U has redated its zirconia: 990 Mya. Some, the impact had morphed into "reidites" - a word I hadn't seen. Sounds more Norn than Scotch. Anyway - as they put it - the impact reset their internal atomic-clocks.
They haven't found the crater itself. They seem confident it's close-enough the Scottish Highlands, maybe offshore, that it hasn't been buried and/or gobbled by the last 990 My of geology.
The new(er) date would, they say, abut the arrival of eukaryotes to freshwater. Although the article implies these were the ancestors to all eukaryotes - which means, for one, chloroplasts weren't had yet. Maybe chloroplasts are being redated too?
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