Structures at Isua are reported as 3.7 Ga stromatolites
Nutman and colleagues described centimetre-scale conical laminated structures in 3,700 million-year-old dolomitic rocks at Isua, exposed by unusually extensive snow-melt, and interpreted them as stromatolites — which would make them by a wide margin the oldest morphological evidence of life. The claim attracted immediate attention precisely because it was morphological: unlike the isotope evidence from the same belt it offered something visible. It also carried an obvious hazard, since the Isua rocks have been metamorphosed and deformed, and deformation can generate structures that mimic layering.
Uncertain — sources disagree, or the dating is contested. Stated here, not resolved.
Subjects
- Isua supracrustal belt, southwest Greenland · site · Greenland
- Stromatolites · ecological phenomenon · Global · not located
Evidence
Partly verified — Core facts are sourced; some optional detail is deliberately absent.
Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures
Supports the reported identification of 3.7 Ga stromatolite-like structures at Isua. This record documents a claim that was subsequently contested; it is cited alongside EV_ALLWOOD_2018 rather than on its own. V55 verification basis: this session had no network access to any source — WebFetch was egress-blocked and the WebSearch budget was exhausted — so the cited work was not retrieved and its pagination was not re-checked. Volume and page range are quoted from standing knowledge and were not re-checked.
Nature · 2016 · Partly verified
Nutman, A. P., Bennett, V. C., Friend, C. R. L., Van Kranendonk, M. J. and Chivas, A. R., Nature, vol. 537 (2016), pp. 535–538
Recorded on Isua supracrustal belt, southwest Greenland
- Carbon-isotope evidence reported from 3.7 Ga Isua sediments
- Structures at Isua are reported as 3.7 Ga stromatolites
- The Isua stromatolite claim is reassessed and rejected
Related
Related because they share a subject in the Atlas — never because the text looks similar.