REMAINS OF PALEOFLORA IN THE BRECCIAS OF THE ONAPING FORMATION, SUDBURY IMPACT STRUCTURE, ONTARIO, CANADA
Bibliographic record
Abstract
Electron microscopic investigations of four breccia samples of the Onaping Formation, Sudbury impact structure, Canada, have been carried out for the search of possible remains of paleoflora and identification of the nature of organic matter and their composition. Two forms of plant remains were discovered in the breccias. The first form is represented by single plant particles scattered in the matrix of breccias and included in gas vesicles in devitrified glasses. These particles are leaf-shaped, stem-shaped, tubular, and spherical objects, ranging from 5-10 to 200-300 µm in size. It is supposed that algal flora inhabiting the sea basin before the Sudbury impact was the source of this form of plant residues in breccias. The second form of plant remains in breccias is represented by plant detritus in carbon-bearing fragments of mudstones included in the breccia matrix. These fragments, reaching a size to 1000-1200 µm, have irregular shapes and complicated rugged contacts with the host breccia. Plant residues in mudstones are mainly ribbon-like scraps from 3-5 to 200-300 µm long, some while rare particles have a more complex shape. The matrix of the mudstones is a heterogeneous fine-grained clay-like substance with a network of micron-wide open joint fissures. The carbon content in mudstone matrix ranges from 7-10 to 20-25 wt%. Muddy bottom sediments of the pre-impact sea basin are supposed to be a source of mudstone fragments in breccias, while the algal flora inhabited the sea during their sedimentation served as a source of plant detritus in mudstones. Fragments of mudstones and floral residues are an important source of organic carbon in breccias of the Onaping Formation. The discovery of paleofloral remains in the breccias indicates the existence of a previously unknown complex algal flora that inhabited the pre-impact sea before the impact event 1.85 billion years ago at the very end of the Paleoproterozoic. The Sudbury impact structure is comparable in size to the Chicxulub impact structure, the formation of which caused the Cretaceous-Paleogene mass extinction. We assume that the formation of the Sudbury structure had a catastrophic impact on the paleoflora of the late Paleoproterozoic, the remnants of which were preserved in the breccias of the Onaping Formation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.005 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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 source (direct Gemma or distilled Codex), 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".