FR UTEXITES FROM STROMATOLITES OF THE GUNFLINT IRON
Bibliographic record
Abstract
The microfossil Frutexites is known from many Palaeozoic and some Proterozoic carbonate sedimentary ocks. We recently found unusually well-preserved xamples in the early Proterozoic Gunflint Iron Formation of Ontario, Canada. These are pre-served in chert, along with other microfossils of the Gunflint microbiota. The Gun-flint examples have previously been described as laminated, columnar-branching micro-stromatolites. We have found narrow tubes (interpreted as trichome moulds) axially placed in many of the microcolumns. By comparison with extant organisms, we inter-pret Frutexites as a thick-sheathed scytonematacean cyanophyte. These are the oldest known fossil scytonemataceans. They apparently grew within mats of other micro-organisms. These probably were photosynthetic organisms, which may have significant implications in the interpretation f some occurrences, uch as in the fore-reef facies of Devonian reefs in Western Australia. INTRODUC~ON The Gunflint microbiota from southern Ontario is famous as the first well-preserved assemblage of Precambrian microfossils to be described (see Awramik and Barghoorn, 1977, for references to earlier work}. Its isotopic age is not well established, but is older than 1685 + 24 Ma, and may be approximately 2000 Ma old (for a discussion see Knoll et al., 1978}. The microfossils are organically preserved in dark grey to black cherts, and in-frequently as iron-oxide replacements or casts in red cherts. The dominant taxa are found in both modes of preservation i the Gunflint Iron Formation
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".