Comment on “Biogenicity of Earthʹs earliest fossils: a resolution of the controversy” by J. William Schopf and Anatoliy B. Kudryavtsev, Gondwana Research 22 (2012), 761–771

The abundant and diverse assemblage of filamentous microbial fossils permineralized in the ~ 3465 Ma Apex chert of northwestern Australia — among the oldest records of life — are arguably the “best studied,” by the most workers using the most advanced techniques, in the history of science. Despite the extensive body of data establishing the biogenicity of the demonstrably cellular carbonaceous Apex fossils, Pinti et al. (2013) and Marshall and Marshall (2013) have raised issues regarding the interpretation of their studies of the Apex chert presented in our recent review article (Schopf and Kudryavtsev, 2012). We agree with the assessment of both of the relevant papers by Pinti et al. (2009, 2013): the observations they report do not apply to the bona fide microscopic fossils of the Apex chert. Similarly, like the minute objects reported by Pinti et al. (2009, 2013), the “quartz and haematite-filled fractures” discussed by Marshall and Marshall (2013) are mineralic pseudofossils that are not relevant to interpretation of the Apex fossil microbes and their suggestion that “multiple populations of carbonaceous material may be a wide-spread issue through out the Precambrian” is without merit.